C.1.
Material system #1: AlGaAs/ AlGaAs
C.1.1.
Calculation of material compositions and energy band edges.
C.1.2.
Energy level calculations
C.1.3.
Computation of Gain and Laser Characteristics
C.2
Material system #2: InGaAs/InGaAlAs/InP
C.2.1. Calculation of material
compositions and energy band edges.
C.2.2.
Energy level calculations
C.2.3
Computation of Gain and Laser Characteristics
C.3.
Material system #3: InGaAs/InGaAsP/InP_
C.3.1.
Calculation of material compositions and energy band edges.
C.3.2.
Energy level calculations
C.3.3.
Computation of Gain and Laser Characteristics
C.4.
Material system #4: InGaAlAs/InGaAlAs/InP
C.4.1.
Calculation of material compositions and energy band edges.
C.4.2.
Energy level calculations
C.4.3.
Simulations of Gain and Laser properties
C.5.
Material system #5: GaInP/AlzGawIn1-z-wP/Al0.5In0.5P
C.5.1.
Calculation of material compositions and energy band edges.
C.5.2.
Energy level calculations
C.5.3.
Computation of Gain and Laser Characteristics
C.6.
Material system #6: InGaAs/AlGaAs/AlGaAs
C.6.1.
Calculation of material compositions and energy band edges.
C.6.2.
Energy level calculations
C.6.3.
Computation of Gain and Laser Characteristics
C.8.
Material system #8: AlyInxGa1-x-yAs/AlzGa1-zAs/GaAs
C.8.1.
Calculation of material compositions and energy band edges.
C.8.2.
Energy level calculations
C.8.3.
Computation of Gain and Laser Characteristics
C.9.
Material system # 9: InGaAs/AlGaInAs/AlGaInAs
(substrate InP)
C.9.1.
Calculation of material compositions and energy band edges.
C.9.2.
Energy level calculations
C.9.3.
Computation of Gain and Laser Characteristics
C.12.
Material system #12: In(y)Ga(1-y)As(x)N(1-x)/GaAs (dilute N)
C.12.1.
Calculation of material compositions and energy band edges.
C.12.2.
Energy level calculations
C.12.3.
Computation of Gain and Laser Characteristics
C.13.
Material system #13: In(1-x)Ga(x)As(y)P(1-y)/GaAs
C.13.1.
Calculation of material compositions and energy band edges.
In this
appendix, the use of the GAIN program is demonstrated for ten material
systems. Each section below contains an
example of how GAIN is used with one of these material systems.
This is a
simulation of a five-layer laser structure that contains a single quantum well
(QW), two separated confinement heterostructure (SCH) layers, and two cladding
layers as shown in Fig. C.1.1.
Figure
C.1.1. Energy band diagram for the simple quantum well
structure
The first step of the GAIN program is to
calculate the material compositions and energy band edges of the each layer.
The user is asked to enter the photoluminescence wavelength, thickness, and
strain of the QW, SCH, and cladding layers. After these parameters are input,
the GAIN program generates two output files: cbandeg.dat and vbandeg.dat,
containing the material compositions, and the conduction band edges and valence
band edges respectively. The detailed explanation is provided in Chapter 2 of
this manual.
a) The input parameters to the GAIN program in this step islisted in Table.
C.4.1.
Table
C.4.1. Input parameters to the GAIN program in this step.
|
Layer |
l (um) |
Strain |
Thickness (Ǻ) |
|
QW (AlxGa1-xAs) |
0.87 |
------ |
50 |
|
SCH (AlxGa1-xAs) |
0.74 |
------ |
60 |
|
Cladding (AlxGa1-xAs) |
0.58 |
|
100 |
b) The steps in using the GAIN program to
calculate the material compositions and energy band edges are listed in Table
C.1.2
Table C.1.2. steps to run
the GAIN program for necessary parameters.
|
ENTER 1 FOR THE NECESSARY PARAMETERS 2 FOR THE ENERGY VALUES OF CONDUCTION
BAND 3 FOR THE ENERGY VALUES OF HEAVY HOLE
BAND 4 FOR THE ENERGY VALUES OF LIGHT HOLE
BAND 5 FOR THE LASER G-J AND G(LAMBDA) 6 FOR RATE EQUATIONS(TWO SECTION MODEL
INCLUDED) 7 FOR EXIT 1 ENTER 1 FOR AlGaAs/AlGaAs 2 FOR InGaAsP/InGaAsP/InP 3 FOR InGaAs/InGaAsP/InP 4 FOR InGaAlAs/InGaAlAs/InP 5 FOR GaInP/(AlGa)0.5In0.5P/AlInP 6 FOR InGaAs/AlGaAs/AlGaAs 7 FOR
InGaAs/InGaAsP/Ga0.51In0.49P(MATCHED GaAs) 8 FOR AlyInxGa1-x-yAs/AlzGa1-zAs/GaAs 9 FOR InzGa1-zAs/AlyGaxIn1-x-yAs/InP 10 FOR InGaAlAs/InGaAlAs/AlAsxSb1-x(matched
InP) 11 FOR
InzGa1-zAs/AlyGaxIn1-x-yAs/AlAsxSb1-x 12 FOR In(y)Ga(1-y)As(x)N(1-x)/GaAs
(dilute N) 13 FOR In(1-x)Ga(x)As(y)P(1-y)/GaAs 14 FOR EXIT, BACK TO MAIN PAGE! 1 INPUT THE LAYER # FOR GRIN STRUCTURE(STEP) STEP N= 2 INPUT THE WELL WAVELENGTH (um) 0.87 INPUT THE BARRIER WAVELENGTH (um) 0.74 INPUT THE CLADDING WAVELENGTH (um) 0.58 BANDGAP ENERGY OF QUANTUM WELL= 1.42528735632184 eV INPUT CLADDING, BARRIER,QUANTUM WELL WIDTH
(A) 100 60 50 WRITE CONDUCTION BAND PARAMETERS INTO
CBANDEG.DAT WRITE INPUT 1 FOR NEW CALCULATION 2 FOR EXIT INPUT =? 2 ENTER 1 FOR AlGaAs/AlGaAs 2 FOR InGaAsP/InGaAsP/InP 3 FOR InGaAs/InGaAsP/InP 4 FOR InGaAlAs/InGaAlAs/InP 5 FOR GaInP/(AlGa)0.5In0.5P/AlInP 6 FOR InGaAs/AlGaAs/AlGaAs 7 FOR
InGaAs/InGaAsP/Ga0.51In0.49P(MATCHED GaAs) 8 FOR AlyInxGa1-x-yAs/AlzGa1-zAs/GaAs 9 FOR InzGa1-zAs/AlyGaxIn1-x-yAs/InP 10 FOR InGaAlAs/InGaAlAs/AlAsxSb1-x(matched
InP) 11 FOR
InzGa1-zAs/AlyGaxIn1-x-yAs/AlAsxSb1-x 12 FOR In(y)Ga(1-y)As(x)N(1-x)/GaAs
(dilute N) 13 FOR In(1-x)Ga(x)As(y)P(1-y)/GaAs 14 FOR EXIT, BACK TO MAIN PAGE! 14 THIS PROGRAM STOP HERE!, BACK TO MAIN PAGE |
c) The output files, cbandeg.dat and
vbandeg.dat are explained in Table C.1.3.
Table C.1.3. Material
compositions and band offsets:
a) cbandeg.dat for conduction band
|
************************************************************************ QW
strain lattice constant 0.000000E+00
0.565311E-09 material
compositions layer
thickness, Al
conduction band edges
0.10000000E+03 0.56115438E+00 0.0000000 0.4632184 cladding layer
0.60000000E+02
0.20182492E+00
0.0000000 0.1627524 SCH layer
0.50000000E+02
0.10323627E-02
0.0000000 0.0000000 quantum well
0.60000000E+02
0.20182492E+00 0.0000000 0.1627524 SCH layer
0.10000000E+03
0.56115438E+00
0.0000000 0.4632184 cladding layer ************************************************************************ |
b) vbandeg.dat for valence
band
|
****************************************************
******************** QW
strain lattice constant 0.000000E+00
0.565311E-09 material
compositions layer
thickness, Al valence
band edges
0.10000000E+03
0.56115438E+00
0.0000000 -0.2494253 cladding layer
0.60000000E+02
0.20182492E+00
0.0000000 -0.0876359 SCH layer
0.50000000E+02
0.10323627E-02
0.0000000 0.0000000 quantum well 0.60000000E+02 0.20182492E+00 0.0000000 -0.0876359 SCH layer
0.10000000E+03
0.56115438E+00
0.0000000 -0.2494253 cladding layer ************************************************************************ |
After the calculation of the material
compositions and energy band edges, the GAIN program calculates energy levels
in the conduction band and valence bands. The detailed explanations are
discussed in Chapter 3 of this manual.
a) The steps of how to calculate the energy
levels are shown in Table C.1.4.
Table C.4.4. Steps to
calculate the energy levels
i) Steps to calculate the
conduction band energy levels
|
ENTER
1 FOR THE NECESSARY PARAMETERS 2 FOR THE ENERGY VALUES OF
CONDUCTION BAND 3 FOR THE ENERGY VALUES OF HEAVY HOLE
BAND 4 FOR THE ENERGY VALUES OF LIGHT HOLE
BAND 5 FOR THE LASER G-J AND G(LAMBDA) 6 FOR RATE EQUATIONS(TWO SECTION MODEL
INCLUDED) 7 FOR EXIT 2 INPUT THE NUMBER OF QUANTUM WELLS NUM=? 1 INPUT TOTAL LAYERS FOR STRUCTURE--N ODD INPUT N= 5 INPUT THE LOWEST POTENTIAL LAYER(1st
Q-WELL) IC= ? 3 INPUT THE SELECTED CENTER LAYER OF
STRUCTURE ICR= 3 ******************************************************* INPUT I=1 FOR AlGaAs I=2
FOR InGaAsP I=3
FOR In1-xGaxAs/InGaAsP/InP I=4
FOR InGaAlAs/InGaAlAs I=5
FOR GaInP/(AlGa)0.5In0.5P/AlInP I=6
FOR InGaAs/AlGaAs/AlGaAs I=7
FOR InGaAs/InGaAsP/Ga0.51In0.49P(GaAs) I=8
FOR AlyInxGa1-x-yAs/AlzGa1-zAs/GaAs I=9
FOR InzGa1-zAs/AlxGayIn1-x-yAs/InP I=10 FOR
InGaAlAs/InGaAlAs/AlAsxSb1-x(InP) I=11 FOR
InzGa1-zAs/AlxGayIn1-x-yAs/AlAsxSb1-x I=12 FOR
In(y)Ga(1-y)As(x)N(1-x)/GaAs I=13 FOR InGaAs/In(1-y)Ga(x)As(y)P(1-y)/GaAs INPUT I= ? ******************************************************* 1 ENERGY
EIGENVALUE===> 0.639537366786E-01
ERROR= .4682221E-14 ENERGY
EIGENVALUE===> 0.192116584232E+00
ERROR= .4043667E-14 ENERGY
EIGENVALUE===> 0.241763368724E+00
ERROR= .2926458E-14 ENERGY
EIGENVALUE===> 0.310657613785E+00
ERROR= .2317973E-14 ENERGY
EIGENVALUE===> 0.426765405664E+00
ERROR= .1485678E-14 FOR CHECKING THE Schrodinger WAVE FUNCTION
INPUT I==> 1 SKIP INPUT I==> 2 I=? 1 INPUT THE EIGENVALUE EIGEN VALUE= 0.639537366786E-01 INPUT THE NAME OF OUTPUT FILE cb1.txt CONFINEMENT FACTOR OF 1 th LAYER = 0.82988859E-04 CONFINEMENT FACTOR OF 2 th LAYER = 0.95857126E-01 CONFINEMENT FACTOR OF 3 th LAYER = 0.80811977E+00 CONFINEMENT FACTOR OF 4 th LAYER = 0.95857126E-01 CONFINEMENT FACTOR OF 5 th LAYER = 0.82988859E-04 INPUT NEW EIGENVALUE--> 1, BACK TO MAIN
PAGE--> 2 SELECT=? 1 INPUT THE EIGENVALUE EIGEN VALUE= 0.192116584232E+00 INPUT THE NAME OF OUTPUT FILE cb2.txt CONFINEMENT FACTOR OF 1 th LAYER = 0.66304726E-02 CONFINEMENT FACTOR OF 2 th LAYER = 0.39546197E+00 CONFINEMENT FACTOR OF 3 th LAYER = 0.19581511E+00 CONFINEMENT FACTOR OF 4 th LAYER = 0.39546197E+00 CONFINEMENT FACTOR OF 5 th LAYER = 0.66304726E-02 INPUT NEW EIGENVALUE--> 1, BACK TO MAIN
PAGE--> 2 SELECT=? 2 |
ii) Steps to calculate the
heavy hole energy levels
|
ENTER 1 FOR THE NECESSARY PARAMETERS 2 FOR THE ENERGY VALUES OF CONDUCTION
BAND 3 FOR THE ENERGY VALUES OF HEAVY
HOLE BAND 4 FOR THE ENERGY VALUES OF LIGHT HOLE
BAND 5 FOR THE LASER G-J AND G(LAMBDA) 6 FOR RATE EQUATIONS(TWO SECTION MODEL
INCLUDED) 7 FOR EXIT 3 INPUT THE NUMBER OF QUANTUM WELLS NUM=? 1 INPUT TOTAL LAYERS FOR STRUCTURE--N ODD INPUT N= 5 INPUT THE HIGHEST POTENTIAL(1st Q-WELL)
LAYER IC= ? 3 INPUT THE SELECTED CENTER OF THE STRUCTURE
ICR=? 3 ******************************************************* INPUT I=1 FOR AlGaAs I=2
FOR InGaAsP I=3
FOR In(1-x)Ga(x)As/InGaAsP/InP I=4
FOR InGaAlAs/InGaAlAs I=5
FOR GaInP/(AlGa)0.5In0.5P/AlInP I=6
FOR InGaAs/AlGaAs/AlGaAs I=7
FOR InGaAs/InGaAsP/Ga0.51In0.49P(GaAs) I=8
FOR AlyInxGa1-x-yAs/AlzGa1-zAs/GaAs I=9
FOR In(z)Ga(1-z)As/AlxGayIn1-x-yAs/InP I=10 FOR
InGaAlAs/InGaAlAs/AlAsxSb1-x(InP) I=11 FOR
InzGa1-zAs/AlxGayIn1-x-yAs/AlAsxSb1-x I=12 FOR
In(y)Ga(1-y)As(x)N(1-x)/GaAs I=13 FOR InGaAs/In(1-x)Ga(x)As(y)P(1-y)/GaAs INPUT I= ? ******************************************************* 1 ******************************************************* DOES THE STRUCTURE STRAIN OR
STRAIN-COMPENSATED? IF STRAIN ONLY INPUT 1, STRAIN-COMPENSATED
INPUT 2 INPUT SELECT = ? 1 ENERGY EIGENVALUE===>
-0.238975151109E+00 ERROR= .3120685E-14 ENERGY EIGENVALUE===>
-0.197312089899E+00 ERROR= .4405413E-14 ENERGY EIGENVALUE===>
-0.166878855802E+00 ERROR= .2808856E-14 ENERGY EIGENVALUE===>
-0.139814196248E+00 ERROR= .4012646E-14 ENERGY EIGENVALUE===>
-0.111477421547E+00 ERROR= .3853459E-14 ENERGY EIGENVALUE===>
-0.102378800292E+00 ERROR= .1062527E-14 ENERGY EIGENVALUE===>
-0.681164844294E-01 ERROR= .2446502E-14 ENERGY EIGENVALUE===>
-0.188139816633E-01 ERROR= .1912450E-14 FOR CHECKING THE Schrodinger WAVE FUNCTION
INPUT I==> 1 SKIP INPUT I==> 2 I=? 1 INPUT THE EIGENVALUE EIGEN VALUE= -0.188139816633E-01 INPUT THE NAME OF OUTPUT FILE hh1.txt CONFINEMENT FACTOR OF 1 th LAYER = 0.38718131E-06 CONFINEMENT FACTOR OF 2 th LAYER = 0.35292976E-01 CONFINEMENT FACTOR OF 3 th LAYER = 0.92941327E+00 CONFINEMENT FACTOR OF 4 th LAYER = 0.35292976E-01 CONFINEMENT FACTOR OF 5 th LAYER = 0.38718131E-06 INPUT NEW EIGENVALUE--> 1, BACK TO MAIN
PAGE--> 2 SELECT=? 1 INPUT THE EIGENVALUE EIGEN VALUE= -0.681164844294E-01 INPUT THE NAME OF OUTPUT FILE hh2.txt CONFINEMENT FACTOR OF 1 th LAYER = 0.68925350E-04 CONFINEMENT FACTOR OF 2 th LAYER = 0.18086577E+00 CONFINEMENT FACTOR OF 3 th LAYER = 0.63813061E+00 CONFINEMENT FACTOR OF 4 th LAYER = 0.18086577E+00 CONFINEMENT FACTOR OF 5 th LAYER = 0.68925350E-04 INPUT NEW EIGENVALUE--> 1, BACK TO MAIN
PAGE--> 2 SELECT=? 2 |
iii) Steps to calculate the
light hole energy levels
|
ENTER
1 FOR THE NECESSARY PARAMETERS 2 FOR THE ENERGY VALUES OF CONDUCTION
BAND 3 FOR THE ENERGY VALUES OF HEAVY HOLE
BAND 4 FOR THE ENERGY VALUES OF LIGHT
HOLE BAND 5 FOR THE LASER G-J AND G(LAMBDA) 6 FOR RATE EQUATIONS(TWO SECTION MODEL
INCLUDED) 7 FOR EXIT 4 INPUT THE NUMBER OF QUANTUM WELLS NUM=? 1 INPUT TOTAL LAYERS FOR STRUCTURE--N ODD INPUT N= 5 INPUT THE HIGHEST POTENTIAL(1st Q-WELL)
LAYER IC= ? 3 INPUT THE SELECTED CENTER OF THE STRUCTURE
ICR=? 3 ******************************************************* INPUT I=1 FOR AlGaAs I=2
FOR InGaAsP I=3
FOR In(1-x)Ga(x)As/InGaAsP/InP I=4
FOR InGaAlAs/InGaAlAs I=5
FOR GaInP/(AlGa)0.5In0.5P/AlInP I=6
FOR InGaAs/AlGaAs/AlGaAs I=7
FOR InGaAs/InGaAsP/Ga0.51In0.49P(GaAs) I=8
FOR AlyInxGa1-x-yAs/AlzGa1-zAs/GaAs I=9
FOR In(z)Ga(1-z)As/AlxGayIn1-x-yAs/InP I=10 FOR
InGaAlAs/InGaAlAs/AlAsxSb1-x(InP) I=11 FOR InzGa1-zAs/AlxGayIn1-x-yAs/AlAsxSb1-x I=12 FOR
In(y)Ga(1-y)As(x)N(1-x)/GaAs I=13 FOR
InGaAs/In(1-x)Ga(x)As(y)P(1-y)/GaAs INPUT I= ? ******************************************************* 1 ******************************************************* DOES THE STRUCTURE STRAIN OR
STRAIN-COMPENSATED? IF STRAIN ONLY INPUT 1, STRAIN-COMPENSATED
INPUT 2 INPUT SELECT = ? 1 ENERGY EIGENVALUE===>
-0.205954300457E+00 ERROR= .3173697E-14 ENERGY EIGENVALUE===>
-0.149979763519E+00 ERROR= .2832057E-14 ENERGY EIGENVALUE===>
-0.114996860133E+00 ERROR= .2360129E-14 ENERGY EIGENVALUE===>
-0.415229761969E-01 ERROR= .2788797E-14 FOR CHECKING THE Schrodinger WAVE FUNCTION
INPUT I==> 1 SKIP INPUT I==> 2 I=? 1 INPUT THE EIGENVALUE EIGEN VALUE= -0.415229761969E-01 INPUT THE NAME OF OUTPUT FILE lh1.txt CONFINEMENT FACTOR OF 1 th LAYER = 0.38818584E-03 CONFINEMENT FACTOR OF 2 th LAYER = 0.12463156E+00 CONFINEMENT FACTOR OF 3 th LAYER = 0.74996051E+00 CONFINEMENT FACTOR OF 4 th LAYER = 0.12463156E+00 CONFINEMENT FACTOR OF 5 th LAYER = 0.38818584E-03 INPUT NEW EIGENVALUE--> 1, BACK TO MAIN
PAGE--> 2 SELECT=? 1 INPUT THE EIGENVALUE EIGEN VALUE= -0.114996860133E+00 INPUT THE NAME OF OUTPUT FILE lh2.txt CONFINEMENT FACTOR OF 1 th LAYER = 0.13841264E-01 CONFINEMENT FACTOR OF 2 th LAYER = 0.41302518E+00 CONFINEMENT FACTOR OF 3 th LAYER = 0.14626712E+00 CONFINEMENT FACTOR OF 4 th LAYER = 0.41302518E+00 CONFINEMENT FACTOR OF 5 th LAYER = 0.13841264E-01 INPUT NEW EIGENVALUE--> 1, BACK TO MAIN
PAGE--> 2 SELECT=? 2 |
b) The main output file from this part of
GAIN program is energy.dat, containing all the energy levels as shown in Table
C.1.5. After the energy eigen values are calculated, the GAIN program asks the
user whether he would like to check the wave envelope function or not. We
suggest that the user check the wave envelope functions of the first and second
energy levels for conduction and valence bands. The plots of the envelope
functions are shown in Fig. C.1.2, Fig. C.1.3, Fig C.1.4.
Table C.1.5. output file
energy.dat
|
CONDUCTION
BAND ENERGY===> 0.639537366786E-01
ERROR= .4682221E-14
CONDUCTION
BAND ENERGY===> 0.192116584232E+00
ERROR= .4043667E-14
CONDUCTION
BAND ENERGY===> 0.241763368724E+00
ERROR= .2926458E-14
CONDUCTION
BAND ENERGY===> 0.310657613785E+00
ERROR= .2317973E-14 CONDUCTION
BAND ENERGY===> 0.426765405664E+00
ERROR= .1485678E-14
HEAVY HOLE
ENERGY===> -0.238975151109E+00 ERROR= .3120685E-14 HEAVY HOLE
ENERGY===> -0.197312089899E+00 ERROR= .4405413E-14
HEAVY HOLE
ENERGY===> -0.166878855802E+00 ERROR= .2808856E-14 HEAVY HOLE
ENERGY===> -0.139814196248E+00 ERROR= .4012646E-14
HEAVY HOLE
ENERGY===> -0.111477421547E+00 ERROR= .3853459E-14
HEAVY HOLE
ENERGY===> -0.102378800292E+00 ERROR= .1062527E-14
HEAVY HOLE
ENERGY===> -0.681164844294E-01 ERROR= .2446502E-14
HEAVY HOLE
ENERGY===> -0.188139816633E-01 ERROR= .1912450E-14
LIGHT HOLE
ENERGY===> -0.205954300457E+00 ERROR= .3173697E-14
LIGHT HOLE
ENERGY===> -0.149979763519E+00 ERROR= .2832057E-14
LIGHT HOLE
ENERGY===> -0.114996860133E+00 ERROR= .2360129E-14
LIGHT HOLE
ENERGY===> -0.415229761969E-01 ERROR= .2788797E-14
|
|
|
|
|
Fig. C.1.2. Wave envelop
functions for energy levels in conduction band |
Fig. C.1.3. Wave envelop
functions for heavy hole energy levels |

Fig. C.1.4. Wave envelop
functions for light hole energy levels
This is the last step of simulations using
the GAIN program. With the previous calculated material composition, energy
band edges, energy levels, and other parameters like material loss and Auger
coefficient, the GAIN program can simulate the threshold current, threshold
current density, slope efficiency, optical gain and mode gain as functions of
wavelengths and photo energies, and L-I curve. The details are explained in
Chapter 4 of the manual.
In this part of GAIN program, the input file
needs to be constructed with the results of the previous steps and according to
the laser design. In this example, single quantum well structure is used to
simulate a three-QW laser. For the two-quantum-well laser with a ridge length
of 750 µm and ridge width of 3 µm, the input file is shown in Table C.1.6. The
detailed steps of simulations are listed in Table C.1.7. The main output files:
L-I curve, optical gain as a function of the wavelength, and mode gain vs.
current density are plotted in Fig. C.1.5, Fig. C.1.6, and Fig. C.1.7.
a) The input file:
Table C.1.6. Input file for
gain and threshold current calculation
|
cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc c 1.
Input the compositions, width of well, effective index c c and
lasing wavelength. c c Ex:
xx,xz,qy,xy,lx,n,lam c c for
different materials the following are the forms of inputs. c c
c c w --
> well, b -- > barrier cxz and
cxy for cladding. c c c c
a. AlxGa1-xAs : xx (Al w) xz
(Al b) qy (0) xy (0) c c
b. In1-xGaxAsyP1-y : xx (Ga w)
xz (Ga b) qy (As w) xy (As b) c c
c. In1-xGaxAs/InGaAsP : xx (Ga
w) xz (Ga b) qy (0) xy (As b) c c
d. AlxGayIn1-x-yAs/InP : xx (Ga
w) xz (Ga b) qy (Al w) xy (Al b)c c
e.
c c
f. InxGa1-xAs/AlGaAs : xx (In
w) xz (0) qy (0) xy (Al b) c c
g. c c
h. AlyInxGa1-x-yAs/AlGaAs : xx
(Al w) xz (al b) qy (In w) xz (0)c c
i. In1-xGaxAs/AlGaInAs : xx (In
w) xz (0) qy (Al b) xy (Ga b) c c
j. In(y)Ga(1-y)As(x)N(1-x)
:xx(As w),xz(As, b),qy(In w),xy(In b)c c
k. InGaAs/InGaAsP/GaAs: xx (In
w), (0), xz(Ga w) xy (As b) c 2.
Input the energy gap,temperature, barrier band edges(both bands) c Ex:
eg,temp,ec,ev
c cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc 0.10323627E-02 0.20182492E+00 0
0 6.0 3.50
0.82 1.42528735632184 298 0.1627524 0.0876359 cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc c 3.
Input the ist level sub-band energy levels. c c Ex:
ec1,eh1,el1
c c
c c 4.
Input the material loss, reflectivities, number of quantum c c wells
and beta(for spontaneous emission). c c Ex:
alpha,r1,r2,mm,beta. c cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc 0.639537366786E-01
0.188139816633E-01 0.415229761969E-01 1
0.681164844294E-01 1 12.0d0
0.30 0.30 1
5.D-5 cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc c 5.
Input the cavity length, ridge width, internal efficiency c c
Auger, strain(except AlGaAs,put 0) and confinement factor. c c Ex:
cl,cw,etha,ca,es,confine c c
c c 6.
Input the cladding composition and band edges. c c Ex:
cxz,cxy,ecc,evv
c cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc 750.D-4
3D-4 0.96 1.00d-29
0.01 0.009834488 0.56115438E+00 0.0
0.4632184 0.2494253 |
b) The steps for these calculations
mentioned are listed in Table C.1.7
Table
C.1.7. The steps for the gain and threshold current density calculations
|
ENTER
1 FOR THE NECESSARY PARAMETERS 2 FOR THE ENERGY VALUES OF CONDUCTION
BAND 3 FOR THE ENERGY VALUES OF HEAVY HOLE
BAND 4 FOR THE ENERGY VALUES OF LIGHT HOLE
BAND 5 FOR THE LASER G-J AND G(LAMBDA) 6 FOR RATE EQUATIONS(TWO SECTION MODEL
INCLUDED) 7 FOR EXIT 5 THE INPUT FILE NAME= in1_sys1_new.tex SELECT MATERIAL=? 1--AlGaAs 2--InGaAsP 3--In1-zGazAs/InGaAsP/InP 4-- InGaAlAs 5--GaInP/AlzGawIn1-z-wP/Al0.5In0.5P 6-- InxGa1-xAs/AlxGa1-xAs/AlGaAs 7--In1-xGaxAs/InGaAsP/GaxIn1-xP(X=0.51)
MATCHED TO GaAs 8--AlyInxGa1-x-yAs/AlzGa1-zAs/GaAs 9--InzGa1-zAs/AlxGayIn1-x-yAs/InP 10-- InGaAlAs/InGaAlAs/AlAsSb 11--InzGa1-zAs/AlxGayIn1-x-yAs/AlAsSb 12--In(y)Ga(1-y)As(x)N(1-x)/GaAs 13--InGaAs/In(1-x)Ga(x)As(y)P(1-y)/GaAs INPUT SELECTION 1 INPUT MODE = ? FOR TE--> MODE =1, FOR
TM--> MODE =2 INPUT TE OR TM ? 1 IF EL1 BELOW EH1 THEN SELECT 1, OTHERWISE
SELECT 2 SELECTION=? 1
************************************************** CALCULATE THE EFFECTIVE MASS
************************************************** FOR QUASI-FERMI LEVEL SELECT=1, FOR READ EXISTING QUASI-FERMI LEVEL
SELECT=2 SELECT=? 1 J(LEAKAGE)=0.537974D+00 A/cm^2 N=0.239674D+19 1/cm^3 J(LEAKAGE)=0.554846D+00 A/cm^2 N=0.241654D+19 1/cm^3 J(LEAKAGE)=0.572232D+00 A/cm^2 N=0.243634D+19 1/cm^3 J(LEAKAGE)=0.590147D+00 A/cm^2 N=0.245614D+19 1/cm^3 ………. J(LEAKAGE)=0.215349D+04
A/cm^2 N=0.788120D+19 1/cm^3 J(LEAKAGE)=0.221784D+04 A/cm^2 N=0.790100D+19 1/cm^3 J(LEAKAGE)=0.228410D+04 A/cm^2 N=0.792080D+19 1/cm^3 J(LEAKAGE)=0.235231D+04 A/cm^2 N=0.794060D+19 1/cm^3 J(LEAKAGE)=0.242253D+04 A/cm^2 N=0.796040D+19 1/cm^3 J(LEAKAGE)=0.249481D+04 A/cm^2 N=0.798020D+19 1/cm^3 J(LEAKAGE)=0.256922D+04 A/cm^2 N=0.800000D+19 1/cm^3 ************************************************** G(J) PARAMETERS FROM SINGLE WELL Go=0.218113D+02 1/cm Jo=0.303353D+03 A/cm^2 G(N) PARAMETERS FROM SINGLE WELL NGo=0.221783D+04 1/cm XNo=0.136717D+19 1/cm^3 Jtr=0.111597D+03 A/cm^2 NTR=0.502953D+18 1/cm^3 THE OPTIMUM NUMBER OF QUANTUM WELL FOLLOWS
THE ARTICLE BY McIlory et al. IEEE JQE-21 1985. THE OPTIMUM NUMBER OF QUANTUM WELL Nopt
= 2 INPUT Nopt(CAN BE DIFFERENT FROM ABOVE
CALCULATION)=? 2 NUMBER OF QUANTUM WELL(MAY OR MAY NOT BE
Nopt)=? 2
**************************************************
************************************************** 1ST CHECK USE SINGLE WELL TIMES # OF WELLS
**************************************************
************************************************** 2ND CHECK FOLLOWS FORMULA BY McIlory IN
IEEE JOURNAL OF QUANTUM ELECTRONIC QE-21 1985. ************************************************** Gth=
28.0530 1/cm Nth=0.176316D+19 1/cm^3 IY= 85 1ST CHECK Jth= 806.35405951 A/cm^2 2ND CHECK Jth= 631.98567 A/cm^2 1ST CHECK Ith=0.181430D+02 mA NUMBER OF
WELLS= 2 2ND CHECK Ith=0.142197D+02 mA ************************************************** CALCULATE
THE P-I RELATION NDATA= 316 ************************************************** CALCULATE THE SLOPE: mW/mA Y=A+BX CONSTANT A=
-7.3929014 SLOPE B= 0.4074803 ************************************************** INPUT POWER INPUT 0 INPUT 1 FOR THE DYNAMIC CALCULATION. 2 FOR
SKIP INPUT = 2 K-FACTOR= 0.35774 nS MAXIUM FREQ.= 24.8387 GHz
************************************************** INPUT 1 FOR CALCULATE THE GAIN(E) RELATION. INPUT 2 FOR CALCULATE THE LINEWIDTH
ENHENCEMENT FACTOR AND PHOTON ENERGY RELATION INPUT 3 FOR EXIT THE PROGRAM THE INPUT # IS 1 INPUT FERMILEVELS IN C-BAND, V-BAND, AND
CARRIER DENSITY 0.139680787212E+00
-0.953800948086E-02 0.200075187970E+19 CALCULATE THE CONVOLUTION GAIN(E)
COEFFICIENT
************************************************** INPUT THE NAME FOR THE CONVOLUTION OPTICAL
GAIN(LAMBDA) COGLa.txt
************************************************** INPUT THE NAME FOR THE CONVOLUTION MODE
GAIN(LAMBDA) CMGLa.txt INPUT THE NAME FOR THE CONVOLUTION OPTICAL
GAIN(E) COGEa.txt
************************************************** INPUT THE NAME FOR THE CONVOLUTION MODE
GAIN(E) CMGEa.txt ************************************************** INPUT 1 FOR REPEAT THE G(E) CALCULATION INPUT 2 FOR REPEAT THE ALPHA(E) CALCULATION INPUT 3 FOR EXIT 1
************************************************** INPUT 1 FOR CALCULATE THE GAIN(E) RELATION. INPUT 2 FOR CALCULATE THE LINEWIDTH
ENHENCEMENT FACTOR AND PHOTON ENERGY RELATION INPUT 3 FOR EXIT THE PROGRAM THE INPUT # IS 1 INPUT FERMILEVELS IN C-BAND, V-BAND, AND
CARRIER DENSITY 0.160216100041E+00
-0.259237429430E-02 0.251553884712E+19 CALCULATE THE CONVOLUTION GAIN(E)
COEFFICIENT
************************************************** INPUT THE NAME FOR THE CONVOLUTION OPTICAL
GAIN(LAMBDA) COGLb.txt
************************************************** INPUT THE NAME FOR THE CONVOLUTION MODE
GAIN(LAMBDA) CMGLb.txt INPUT THE NAME FOR THE CONVOLUTION OPTICAL
GAIN(E) COGEb.txt
************************************************** INPUT THE NAME FOR THE CONVOLUTION MODE
GAIN(E) CMGEb.txt
************************************************** INPUT 1 FOR REPEAT THE G(E) CALCULATION INPUT 2 FOR REPEAT THE ALPHA(E) CALCULATION INPUT 3 FOR EXIT 3 ENTER
1 FOR THE NECESSARY PARAMETERS 2 FOR THE ENERGY VALUES OF CONDUCTION
BAND 3 FOR THE ENERGY VALUES OF HEAVY HOLE
BAND 4 FOR THE ENERGY VALUES OF LIGHT HOLE
BAND 5 FOR THE LASER G-J AND G(LAMBDA) 6 FOR RATE EQUATIONS(TWO SECTION MODEL
INCLUDED) 7 FOR EXIT 7 |
c) The Output
characteristics of designed laser from step 5 are summarized in Table C.1.7.
Table C.1.7 Characteristics
of the designed laser
|
Optimized number of QWs (Nopt) |
2 |
|
Number of QWs |
2 |
|
Slope efficiency (%) |
40.75 |
|
Jth (A/cm^2) |
806.35
- 1st check, for matching threshold conditions 631.99
– 2nd check, using McIlory method |
|
Ith (mA) |
18.14 - 1st check, for matching
threshold conditions 14.22 - 2nd check, using McIlory
method |
|
Peak l at operating temperature (um) |
0.819 um for carrier density of 2.0E18 /cm3 0.819 um for carrier density of 2.5E18 /cm3 |
|
Peak material gain (1/cm) |
3619.36/cm for carrier density of 2.0E18 /cm3 4386.09 /cm for carrier density of 2.5E18 /cm3 |
|
|
|
|
Fig.
C.1.5. L-I curve of the laser |
Fig.
C.1.6. Optical gain-l curve of the laser |

Fig. C.1.7. Mode gain as a function of
current density (J)
This is a
simulation of a seventeen-layer
laser structure that contains four
quantum wells (QW), two
separated confinement heterostructure (SCH) layers, and two cladding layers as
shown in Fig. C.2.1. This device is a
real one for research purpose. We will see the characteristics of this device.

Figure C.2.2. Energy band diagram for the simple quantum well structure
The first step of the GAIN program is to
calculate the material compositions and energy band edges of the each layer.
The user is asked to enter the photoluminescence wavelength, thickness, and
strain of the QW, SCH, and cladding layers. After these parameters are input,
the GAIN program generates two output files: cbandeg.dat and vbandeg.dat,
containing the material compositions, and the conduction band edges and valence
band edges respectively. The detailed explanation is provided in Chapter 2 of
this manual.
a) The input parameters to the GAIN program in this step are listed in Table. C.2.1.
Table
C.2.1. Input parameters to the GAIN program in this step.
|
Layer |
l (um) |
Strain |
Thickness (Ǻ) |
|
QW (Ga1-xInxAsyP1-y) |
1.525 |
-0.012 |
60 |
|
SCH (Ga1-xInxAsyP1-y) |
1.28 |
|
50 |
|
Cladding (Ga1-xInxAsyP1-y) |
0.98 |
|
100 |
b) The steps in using the GAIN program to
calculate the material compositions and energy band edges are listed in Table
C.2.2
Table C.2.2. steps to run
the GAIN program for necessary parameters.
|
ENTER 1 FOR THE NECESSARY PARAMETERS 2 FOR THE ENERGY VALUES OF CONDUCTION
BAND 3 FOR THE ENERGY VALUES OF HEAVY HOLE
BAND 4 FOR THE ENERGY VALUES OF LIGHT HOLE
BAND 5 FOR THE LASER G-J AND G(LAMBDA) 6 FOR RATE EQUATIONS(TWO SECTION MODEL
INCLUDED) 7 FOR EXIT 1 ENTER 1 FOR AlGaAs/AlGaAs 2 FOR InGaAsP/InGaAsP/InP 3 FOR InGaAs/InGaAsP/InP 4 FOR InGaAlAs/InGaAlAs/InP 5 FOR GaInP/(AlGa)0.5In0.5P/AlInP 6 FOR InGaAs/AlGaAs/AlGaAs 7 FOR
InGaAs/InGaAsP/Ga0.51In0.49P(MATCHED GaAs) 8 FOR AlyInxGa1-x-yAs/AlzGa1-zAs/GaAs 9 FOR InzGa1-zAs/AlyGaxIn1-x-yAs/InP 10 FOR InGaAlAs/InGaAlAs/AlAsxSb1-x(matched
InP) 11 FOR
InzGa1-zAs/AlyGaxIn1-x-yAs/AlAsxSb1-x 12 FOR In(y)Ga(1-y)As(x)N(1-x)/GaAs
(dilute N) 13 FOR In(1-x)Ga(x)As(y)P(1-y)/GaAs 14 FOR EXIT, BACK TO MAIN PAGE! 2 INPUT THE LAYER # FOR GRIN STRUCTURE(STEP) STEP N= 2 INPUT THE WELL WAVELENGTH (um) 1.525 INPUT THE BARRIER WAVELENGTH (um) 1.28 INPUT THE CLADDING WAVELENGTH (um) 98 BANDGAP ENERGY OF QUANTUM WELL= 0.683804000019804 INPUT CLADDING, BARRIER,QUANTUM WELL WIDTH
(A) 100 50 60 In1-xGaxAsyP1-y, in output read Ga first
then AsIN OUTPUT READ Ga FIRST THEN As FOR InGaAsP, only compress strain
(~1.5%) available INPUT EX -0.012 FOR LATTICE MATCHED BARRIER SELECT --> 1 FOR STRAIN COMPENSATED SELECT -- 2 INPUT SELECTION===> ? 1 WRITE
CONDUCTION BAND PARAMETERS INTO CBANDEG.DAT WRITE INPUT 1 FOR NEW CALCULATION, 2 FOR EXIT I= ? 2 ENTER 1 FOR AlGaAs/AlGaAs 2 FOR InGaAsP/InGaAsP/InP 3 FOR InGaAs/InGaAsP/InP 4 FOR InGaAlAs/InGaAlAs/InP 5 FOR GaInP/(AlGa)0.5In0.5P/AlInP 6 FOR InGaAs/AlGaAs/AlGaAs 7 FOR
InGaAs/InGaAsP/Ga0.51In0.49P(MATCHED GaAs) 8 FOR AlyInxGa1-x-yAs/AlzGa1-zAs/GaAs 9 FOR InzGa1-zAs/AlyGaxIn1-x-yAs/InP 10 FOR InGaAlAs/InGaAlAs/AlAsxSb1-x(matched
InP) 11 FOR
InzGa1-zAs/AlyGaxIn1-x-yAs/AlAsxSb1-x 12 FOR In(y)Ga(1-y)As(x)N(1-x)/GaAs
(dilute N) 13 FOR In(1-x)Ga(x)As(y)P(1-y)/GaAs 14 FOR EXIT, BACK TO MAIN PAGE! 14 THIS PROGRAM STOP HERE!, BACK TO MAIN PAGE |
c) The output files, cbandeg.dat and
vbandeg.dat are explained in Table C.2.3.
Table C.2.3. Material compositions and band offsets:
a) cbandeg.dat for conduction band
|
************************************************************************ QW strain
lattice constant -.120000E-01
0.593923E-09 material
compositions layer thickness, Ga Al conduction band edges 0.10000000E+03
0.50731155E-01 0.1116804 0.1763546 cladding layer 0.50000000E+02
0.25335652E+00
0.5501187 0.0606978 SCH layer 0.60000000E+02 0.10405969E+00 0.5965452 0.0481108 quantum well 0.50000000E+02
0.25335652E+00
0.5501187 0.0606978 SCH layer 0.10000000E+03 0.50731155E-01 0.1116804 0.1763546 cladding layer ************************************************************************ |
|
|
b) vbandeg.dat for valence
band
|
****************************************************
******************** QW
strain lattice constant -.120000E-01 0.593923E-09 material
compositions layer
thickness, Ga Al valence band edges 0.10000000E+03 0.50731155E-01 0.1116804 -0.2758368
cladding layer 0.50000000E+02 0.25335652E+00 0.5501187 -0.0949375 SCH layer 0.60000000E+02 0.10405969E+00 0.5965452 -0.0240554 quantum well 0.50000000E+02 0.25335652E+00 0.5501187 -0.0949375 SCH layer 0.10000000E+03
0.50731155E-01
0.1116804 -0.2758368 cladding layer ************************************************************************ |
After the calculation of the material
compositions and energy band edges, the GAIN program calculates energy levels
in the conduction band and valence bands. The detailed explanations are
discussed in Chapter 3 of this manual.
a) The steps of how to calculate the energy
levels are shown in Table C.2.4.
Table C.2.4. Steps to calculate the
energy levels
i) Steps to calculate the
conduction band energy levels
|
ENTER
1 FOR THE NECESSARY PARAMETERS 2 FOR THE ENERGY VALUES OF CONDUCTION BAND 3 FOR THE ENERGY VALUES OF HEAVY HOLE
BAND 4 FOR THE ENERGY VALUES OF LIGHT HOLE
BAND 5 FOR THE LASER G-J AND G(LAMBDA) 6 FOR RATE EQUATIONS(TWO SECTION MODEL
INCLUDED) 7 FOR EXIT 2 INPUT THE NUMBER OF QUANTUM WELLS NUM=? 1 INPUT TOTAL LAYERS FOR STRUCTURE--N ODD INPUT N= 5 INPUT THE LOWEST POTENTIAL LAYER(1st
Q-WELL) IC= ? 3 INPUT THE SELECTED CENTER LAYER OF
STRUCTURE ICR= 3 ******************************************************* INPUT I=1
FOR AlGaAs I=2 FOR InGaAsP I=3
FOR In1-xGaxAs/InGaAsP/InP I=4
FOR InGaAlAs/InGaAlAs I=5
FOR GaInP/(AlGa)0.5In0.5P/AlInP I=6
FOR InGaAs/AlGaAs/AlGaAs I=7
FOR InGaAs/InGaAsP/Ga0.51In0.49P(GaAs) I=8
FOR AlyInxGa1-x-yAs/AlzGa1-zAs/GaAs I=9
FOR InzGa1-zAs/AlxGayIn1-x-yAs/InP I=10 FOR
InGaAlAs/InGaAlAs/AlAsxSb1-x(InP) I=11 FOR
InzGa1-zAs/AlxGayIn1-x-yAs/AlAsxSb1-x I=12 FOR
In(y)Ga(1-y)As(x)N(1-x)/GaAs I=13 FOR InGaAs/In(1-y)Ga(x)As(y)P(1-y)/GaAs INPUT I= ? ******************************************************* 2 ENERGY EIGENVALUE===> 0.670294366291E-01 ERROR= .3576162E-14 ENERGY EIGENVALUE===> 0.101465108959E+00 ERROR= .3081508E-14 ENERGY EIGENVALUE===> 0.155412249439E+00 ERROR= .2750090E-14 FOR CHECKING THE Schrodinger WAVE FUNCTION
INPUT I==> 1 SKIP INPUT I==> 2 I=? 1 INPUT THE EIGENVALUE EIGEN VALUE= 0.670294366291E-01 INPUT THE NAME OF OUTPUT FILE cb1.txt CONFINEMENT
FACTOR OF 1 th LAYER = 0.11124994E-01 CONFINEMENT FACTOR OF 2 th LAYER = 0.18768431E+00 CONFINEMENT FACTOR OF 3 th LAYER = 0.60238139E+00 CONFINEMENT FACTOR OF 4 th LAYER = 0.18768431E+00 CONFINEMENT FACTOR OF 5 th LAYER = 0.11124994E-01 INPUT NEW EIGENVALUE--> 1, BACK TO MAIN
PAGE--> 2 SELECT=? 1 INPUT THE EIGENVALUE EIGEN VALUE= 0.101465108959 INPUT THE NAME OF OUTPUT FILE cb2.txt CONFINEMENT
FACTOR OF 1 th LAYER =
0.46526184E-01 CONFINEMENT FACTOR OF 2 th LAYER = 0.36258718E+00 CONFINEMENT FACTOR OF 3 th LAYER = 0.18177326E+00 CONFINEMENT FACTOR OF 4 th LAYER = 0.36258718E+00 CONFINEMENT FACTOR OF 5 th LAYER = 0.46526184E-01 INPUT NEW EIGENVALUE--> 1, BACK TO MAIN
PAGE--> 2 SELECT=? 2 |
ii) Steps to calculate the
heavy hole energy levels
|
ENTER 1 FOR THE NECESSARY PARAMETERS 2 FOR THE ENERGY VALUES OF CONDUCTION
BAND 3 FOR THE ENERGY VALUES OF HEAVY HOLE BAND 4 FOR THE ENERGY VALUES OF LIGHT HOLE
BAND 5 FOR THE LASER G-J AND G(LAMBDA) 6 FOR RATE EQUATIONS(TWO SECTION MODEL
INCLUDED) 7 FOR EXIT 3 INPUT THE NUMBER OF QUANTUM WELLS NUM=? 1 INPUT TOTAL LAYERS FOR STRUCTURE--N ODD INPUT N= 5 INPUT THE HIGHEST POTENTIAL(1st Q-WELL)
LAYER IC= ? 3 INPUT THE SELECTED CENTER OF THE STRUCTURE
ICR=? 3 ******************************************************* INPUT I=1
FOR AlGaAs I=2
FOR InGaAsP I=3
FOR In(1-x)Ga(x)As/InGaAsP/InP I=4
FOR InGaAlAs/InGaAlAs I=5
FOR GaInP/(AlGa)0.5In0.5P/AlInP I=6
FOR InGaAs/AlGaAs/AlGaAs I=7
FOR InGaAs/InGaAsP/Ga0.51In0.49P(GaAs) I=8
FOR AlyInxGa1-x-yAs/AlzGa1-zAs/GaAs I=9
FOR In(z)Ga(1-z)As/AlxGayIn1-x-yAs/InP I=10 FOR
InGaAlAs/InGaAlAs/AlAsxSb1-x(InP) I=11 FOR InzGa1-zAs/AlxGayIn1-x-yAs/AlAsxSb1-x I=12 FOR
In(y)Ga(1-y)As(x)N(1-x)/GaAs I=13 FOR
InGaAs/In(1-x)Ga(x)As(y)P(1-y)/GaAs INPUT I= ? ******************************************************* 2 ******************************************************* DOES THE STRUCTURE STRAIN OR
STRAIN-COMPENSATED? IF STRAIN ONLY INPUT 1, STRAIN-COMPENSATED
INPUT 2 INPUT SELECT = ? 1 ENERGY EIGENVALUE===>
-0.266289655713E+00 ERROR= .2082626E-14 ENERGY EIGENVALUE===>
-0.220090610686E+00 ERROR= .2912430E-14 ENERGY EIGENVALUE===>
-0.186287733747E+00 ERROR= .4671376E-14 ENERGY EIGENVALUE===>
-0.140850401092E+00 ERROR= .8911599E-14 ENERGY EIGENVALUE===>
-0.122228608502E+00 ERROR= .4338441E-14 ENERGY EIGENVALUE===>
-0.101432618035E+00 ERROR= .1307382E-14 ENERGY EIGENVALUE===>
-0.428488013474E-01 ERROR= .2038714E-14 ENERGY EIGENVALUE===> 0.509274076994E-02 ERROR= .2348418E-14 FOR CHECKING THE Schrodinger WAVE FUNCTION
INPUT I==> 1 SKIP INPUT I==> 2 I=? 1 INPUT THE EIGENVALUE EIGEN VALUE= 0.509274076994E-02 INPUT THE NAME OF OUTPUT FILE hh1.txt CONFINEMENT
FACTOR OF 1 th LAYER =
0.43858757E-06 CONFINEMENT FACTOR OF 2 th LAYER = 0.19049653E-01 CONFINEMENT FACTOR OF 3 th LAYER = 0.96189982E+00 CONFINEMENT FACTOR OF 4 th LAYER = 0.19049653E-01 CONFINEMENT FACTOR OF 5 th LAYER = 0.43858757E-06 SELECT=? 1 INPUT THE EIGENVALUE EIGEN VALUE= -0.428488013474E-01 INPUT THE NAME OF OUTPUT FILE hh2.txt CONFINEMENT
FACTOR OF 1 th LAYER =
0.18387626E-04 CONFINEMENT FACTOR OF 2 th LAYER = 0.90457734E-01 CONFINEMENT FACTOR OF 3 th LAYER = 0.81904776E+00 CONFINEMENT FACTOR OF 4 th LAYER = 0.90457734E-01 CONFINEMENT FACTOR OF 5 th LAYER = 0.18387626E-04 INPUT NEW EIGENVALUE--> 1, BACK TO MAIN
PAGE--> 2 SELECT=? 2 |
iii) Steps to calculate the
light hole energy levels
|
ENTER
1 FOR THE NECESSARY PARAMETERS 2 FOR THE ENERGY VALUES OF CONDUCTION
BAND 3 FOR THE ENERGY VALUES OF HEAVY HOLE
BAND 4 FOR THE ENERGY VALUES OF LIGHT HOLE BAND 5 FOR THE LASER G-J AND G(LAMBDA) 6 FOR RATE EQUATIONS(TWO SECTION MODEL
INCLUDED) 7 FOR EXIT 4 INPUT THE NUMBER OF QUANTUM WELLS NUM=? 1 INPUT TOTAL LAYERS FOR STRUCTURE--N ODD INPUT N= 5 INPUT THE HIGHEST POTENTIAL(1st Q-WELL)
LAYER IC= ? 3 INPUT THE SELECTED CENTER OF THE STRUCTURE
ICR=? 3 ******************************************************* INPUT I=1
FOR AlGaAs I=2 FOR InGaAsP I=3
FOR In(1-x)Ga(x)As/InGaAsP/InP I=4
FOR InGaAlAs/InGaAlAs I=5
FOR GaInP/(AlGa)0.5In0.5P/AlInP I=6
FOR InGaAs/AlGaAs/AlGaAs I=7
FOR InGaAs/InGaAsP/Ga0.51In0.49P(GaAs) I=8
FOR AlyInxGa1-x-yAs/AlzGa1-zAs/GaAs I=9
FOR In(z)Ga(1-z)As/AlxGayIn1-x-yAs/InP I=10 FOR InGaAlAs/InGaAlAs/AlAsxSb1-x(InP) I=11 FOR
InzGa1-zAs/AlxGayIn1-x-yAs/AlAsxSb1-x I=12 FOR
In(y)Ga(1-y)As(x)N(1-x)/GaAs I=13 FOR
InGaAs/In(1-x)Ga(x)As(y)P(1-y)/GaAs INPUT I= ? ******************************************************* 2 ******************************************************* DOES THE STRUCTURE STRAIN OR
STRAIN-COMPENSATED? IF STRAIN ONLY INPUT 1, STRAIN-COMPENSATED
INPUT 2 INPUT SELECT = ? 1 ENERGY EIGENVALUE===>
-0.235564886491E+00 ERROR= .4251760E-14 ENERGY EIGENVALUE===>
-0.159589791816E+00 ERROR= .2633269E-14 ENERGY EIGENVALUE===>
-0.968705335737E-01 ERROR= .1268730E-14 FOR CHECKING THE Schrodinger WAVE FUNCTION
INPUT I==> 1 SKIP INPUT I==> 2 I=? 1 INPUT THE EIGENVALUE EIGEN VALUE= -0.968705335737E-01 INPUT THE NAME OF OUTPUT FILE lh1.txt CONFINEMENT
FACTOR OF 1 th LAYER =
0.83034669E-02 CONFINEMENT FACTOR OF 2 th LAYER = 0.20626333E+00 CONFINEMENT FACTOR OF 3 th LAYER = 0.57086641E+00 CONFINEMENT FACTOR OF 4 th LAYER = 0.20626333E+00 CONFINEMENT FACTOR OF 5 th LAYER = 0.83034669E-02 INPUT NEW EIGENVALUE--> 1, BACK TO MAIN
PAGE--> 2 SELECT=? 1 INPUT THE EIGENVALUE EIGEN VALUE= -0.159589791816E+00 INPUT THE NAME OF OUTPUT FILE lh2.txt CONFINEMENT
FACTOR OF 1 th LAYER =
0.44635531E-01 CONFINEMENT FACTOR OF 2 th LAYER = 0.39731088E+00 CONFINEMENT FACTOR OF 3 th LAYER = 0.11610718E+00 CONFINEMENT FACTOR OF 4 th LAYER = 0.39731088E+00 CONFINEMENT FACTOR OF 5 th LAYER = 0.44635531E-01 INPUT NEW EIGENVALUE--> 1, BACK TO MAIN
PAGE--> 2 SELECT=? 2 |
b) The main output file from this part of
GAIN program is energy.dat, containing all the energy levels as shown in Table
C.2.5. After the energy eigen values are
calculated, the GAIN program asks the user whether he would like to check the
wave envelope function or not. We suggest that the user check the wave envelope
functions of the first and second energy levels for conduction and valence
bands. The plots of the envelope functions are shown in Fig. C.2.2, Fig. C.2.3, Fig C.2.4.
Table C.2.5 Output file energy.dat
|
CONDUCTION
BAND ENERGY===> 0.670294366291E-01
ERROR= .3576162E-14
CONDUCTION
BAND ENERGY===> 0.101465108959E+00
ERROR= .3081508E-14
CONDUCTION
BAND ENERGY===> 0.155412249439E+00
ERROR= .2750090E-14
HEAVY HOLE
ENERGY===> -0.266289655713E+00 ERROR= .2082626E-14
HEAVY HOLE
ENERGY===> -0.220090610686E+00 ERROR= .2912430E-14
HEAVY HOLE
ENERGY===> -0.186287733747E+00 ERROR= .4671376E-14 HEAVY HOLE
ENERGY===> -0.140850401092E+00 ERROR= .8911599E-14
HEAVY HOLE
ENERGY===> -0.122228608502E+00 ERROR= .4338441E-14
HEAVY HOLE
ENERGY===> -0.101432618035E+00 ERROR= .1307382E-14
HEAVY HOLE
ENERGY===> -0.428488013474E-01 ERROR= .2038714E-14
HEAVY HOLE
ENERGY===> 0.509274076994E-02
ERROR= .2348418E-14
LIGHT HOLE
ENERGY===> -0.235564886491E+00 ERROR= .4251760E-14
LIGHT HOLE
ENERGY===> -0.159589791816E+00 ERROR= .2633269E-14
LIGHT HOLE
ENERGY===> -0.968705335737E-01 ERROR= .1268730E-14 |
|
|
|
|
Fig. C.2.2. Wave envelop functions
for energy levels in conduction band |
Fig. C.2.3. Wave envelope functions for heavy hole
energy levels. There is some rounding error with plot |

Fig. C.2.4. Wave envelope functions for light hole
energy levels
This is the last step of simulations using
the GAIN program. With the previous calculated material composition, energy
band edges, energy levels, and other parameters like material loss and Auger
coefficient, the GAIN program can simulate the threshold current, threshold
current density, slope efficiency, optical gain and mode gain as functions of
wavelengths and photon energies, and L-I curve. The details are explained in
Chapter 4 of the manual.
In this part of GAIN program, the input file
needs to be constructed with the results of the previous steps and according to
the laser design. In this example, single quantum well structure is used to
simulate a three-QW laser. For the three-quantum-well laser with a ridge length
of 750 µm and ridge width of 3 µm, the input file is shown in Table C.2.6. The
detailed steps of simulations are listed in Table C.2.7. The main output files:
L-I curve, optical gain as a function of
the wavelength, and mode gain vs. current density are plotted in Fig. C.2.5,
Fig. C.2.6, and Fig. C.2.7.
a) The input file:
Table C.2.6. Input file for
gain and threshold current calculation
|
cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc c 1.
Input the compositions, width of well, effective index c c and
lasing wavelength. c c Ex:
xx,xz,qy,xy,lx,n,lam c c for
different materials the following are the forms of inputs. c c
c c w --
> well, b -- > barrier cxz and
cxy for cladding. c c
c c
a. AlxGa1-xAs : xx (Al w) xz
(Al b) qy (0) xy (0) c c
b. In1-xGaxAsyP1-y : xx (Ga w)
xz (Ga b) qy (As w) xy (As b) c c
c. In1-xGaxAs/InGaAsP : xx (Ga
w) xz (Ga b) qy (0) xy (As b) c c
d. AlxGayIn1-x-yAs/InP : xx (Ga
w) xz (Ga b) qy (Al w) xy (Al b)c c
e.
c c
f. InxGa1-xAs/AlGaAs : xx (In
w) xz (0) qy (0) xy (Al b) c c
g.
c c
h. AlyInxGa1-x-yAs/AlGaAs : xx
(Al w) xz (al b) qy (In w) xz (0)c c
i. In1-xGaxAs/AlGaInAs : xx (In
w) xz (0) qy (Al b) xy (Ga b) c c
j. In(y)Ga(1-y)As(x)N(1-x)
:xx(As w),xz(As, b),qy(In w),xy(In b)c c
k. InGaAs/InGaAsP/GaAs: xx (In
w), (0), xz(Ga w) xy (As b) c 2.
Input the energy gap,temperature, barrier band edges(both bands) c Ex:
eg,temp,ec,ev
c cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc 0.10405969 0.25335652 0.5965452 0.5501187 6.0
3.348741 1.31 0.94656 298 0.0606978 0.0949375 cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc c 3.
Input the ist level sub-band energy levels. c c Ex:
ec1,eh1,el1
c c
c c 4.
Input the material loss, reflectivities, number of quantum c c
wells and beta(for spontaneous emission). c c Ex:
alpha,r1,r2,mm,beta. c cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc 0.0670294366291 -0.509274076994E-02
0.096870533574 0.101465108959
0.0428488013474 0.159589791816 12.0d0
0.30 0.30 1
5.D-5 cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc c 5.
Input the cavity length, ridge width, internal efficiency c c
Auger, strain(except AlGaAs,put 0) and confinement factor. c c Ex:
cl,cw,etha,ca,es,confine c c c c 6.
Input the cladding composition and band edges. c c Ex:
cxz,cxy,ecc,evv
c cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc 750.D-4
3D-4 0.96 1.00d-29
0.000 0.009834488 0.050731155
0.1116804 0.1763546 0.2758368 |
b) The steps for these
calculations mentioned are listed in Table C.2.7
Table C.2.7. The steps for the gain and threshold
current density calculations
|
ENTER
1 FOR THE NECESSARY PARAMETERS 2 FOR THE ENERGY VALUES OF CONDUCTION
BAND 3 FOR THE ENERGY VALUES OF HEAVY HOLE
BAND 4 FOR THE ENERGY VALUES OF LIGHT HOLE
BAND 5 FOR THE LASER G-J AND G(LAMBDA) 6 FOR RATE EQUATIONS(TWO SECTION MODEL
INCLUDED) 7 FOR EXIT 5 THE INPUT FILE NAME= in1.tex SELECT MATERIAL=? 1--AlGaAs 2--InGaAsP 3--In1-zGazAs/InGaAsP/InP 4-- InGaAlAs 5--GaInP/AlzGawIn1-z-wP/Al0.5In0.5P 6-- InxGa1-xAs/AlxGa1-xAs/AlGaAs 7--In1-xGaxAs/InGaAsP/GaxIn1-xP(X=0.51)
MATCHED TO GaAs 8--AlyInxGa1-x-yAs/AlzGa1-zAs/GaAs 9--InzGa1-zAs/AlxGayIn1-x-yAs/InP 10-- InGaAlAs/InGaAlAs/AlAsSb 11--InzGa1-zAs/AlxGayIn1-x-yAs/AlAsSb 12--In(y)Ga(1-y)As(x)N(1-x)/GaAs 13--InGaAs/In(1-x)Ga(x)As(y)P(1-y)/GaAs INPUT SELECTION 2 INPUT MODE = ? FOR TE--> MODE =1, FOR
TM--> MODE =2 INPUT TE OR TM ? 1 IF EL1 BELOW EH1 THEN SELECT 1, OTHERWISE
SELECT 2 SELECTION=? 1
************************************************** CALCULATE THE EFFECTIVE MASS ************************************************** FOR QUASI-FERMI LEVEL SELECT=1, FOR READ EXISTING QUASI-FERMI LEVEL
SELECT=2 SELECT=? 1 J(LEAKAGE)=0.522156D-01 A/cm^2 N=0.328772D+19 1/cm^3 J(LEAKAGE)=0.544163D-01 A/cm^2 N=0.330752D+19 1/cm^3 J(LEAKAGE)=0.567097D-01 A/cm^2 N=0.332732D+19 1/cm^3 J(LEAKAGE)=0.590996D-01 A/cm^2 N=0.334712D+19 1/cm^3 ………. J(LEAKAGE)=0.685423D+04 A/cm^2 N=0.788120D+19 1/cm^3 J(LEAKAGE)=0.689811D+04 A/cm^2 N=0.790100D+19 1/cm^3 J(LEAKAGE)=0.694207D+04 A/cm^2 N=0.792080D+19 1/cm^3 J(LEAKAGE)=0.698612D+04 A/cm^2 N=0.794060D+19 1/cm^3 J(LEAKAGE)=0.703024D+04 A/cm^2 N=0.796040D+19 1/cm^3 J(LEAKAGE)=0.707444D+04 A/cm^2 N=0.798020D+19 1/cm^3 J(LEAKAGE)=0.711872D+04 A/cm^2 N=0.800000D+19 1/cm^3 **************************************************
G(J) PARAMETERS FROM SINGLE WELL G(J)
PARAMETERS FROM SINGLE WELL
Go=0.704410D+01 1/cm
Jo=0.147036D+03 A/cm^2 G(N)
PARAMETERS FROM SINGLE WELL
NGo=0.716265D+03 1/cm
XNo=0.126817D+19 1/cm^3 Jtr=0.540917D+02
A/cm^2 NTR=0.466534D+18 1/cm^3 THE
OPTIMUM NUMBER OF QUANTUM WELL FOLLOWS THE ARTICLE BY
McIlory et al. IEEE JQE-21 1985. THE
OPTIMUM NUMBER OF QUANTUM WELL Nopt = 4 INPUT Nopt(CAN BE DIFFERENT FROM ABOVE
CALCULATION)=? 4 NUMBER OF QUANTUM WELL(MAY OR MAY NOT BE
Nopt)=? 4
**************************************************
************************************************** 1ST CHECK USE SINGLE WELL TIMES # OF WELLS
**************************************************
************************************************** 2ND CHECK FOLLOWS FORMULA BY McIlory IN
IEEE JOURNAL OF QUANTUM ELECTRONIC QE-21 1985.
************************************************** Gth=
28.0530 1/cm Nth=0.629724D+19 1/cm^3 IY= 314 1ST
CHECK Jth= 5406.36686808 A/cm^2 2ND CHECK Jth= 612.65148 A/cm^2 1ST CHECK Ith=0.121643D+03 mA NUMBER OF
WELLS= 4 2ND CHECK Ith=0.137847D+02 mA
************************************************** CALCULATE THE P-I RELATION NDATA=
87
************************************************** CALCULATE THE SLOPE: mW/mA Y=A+BX CONSTANT A= -32.6181898 SLOPE B=
0.2681463
************************************************** INPUT POWER INPUT 0 INPUT 1 FOR THE DYNAMIC CALCULATION. 2 FOR
SKIP INPUT = 2 K-FACTOR= 0.58163 nS MAXIUM FREQ.= 15.2773 GHz
************************************************** INPUT 1 FOR CALCULATE THE GAIN(E) RELATION. INPUT 2 FOR CALCULATE THE LINEWIDTH
ENHENCEMENT FACTOR AND PHOTONN ENERGY RELATION INPUT 3 FOR EXIT THE PROGRAM THE INPUT # IS 1 INPUT FERMILEVELS IN C-BAND, V-BAND, AND
CARRIER DENSITY 0.117426601301 -0.161989946432E-01 0.209974937343E+19 CALCULATE THE CONVOLUTION GAIN(E)
COEFFICIENT
************************************************** INPUT THE NAME FOR THE CONVOLUTION OPTICAL
GAIN(LAMBDA) ol1.txt
************************************************** INPUT THE NAME FOR THE CONVOLUTION MODE
GAIN(LAMBDA) ml1.txt INPUT THE NAME FOR THE CONVOLUTION OPTICAL
GAIN(E) oe1.txt
************************************************** INPUT THE NAME FOR THE CONVOLUTION MODE
GAIN(E) me1.txt
************************************************** INPUT 1 FOR REPEAT THE G(E) CALCULATION INPUT 2 FOR REPEAT THE ALPHA(E) CALCULATION INPUT 3 FOR EXIT 1
************************************************** INPUT 1 FOR CALCULATE THE GAIN(E) RELATION. INPUT 2 FOR CALCULATE THE LINEWIDTH
ENHENCEMENT FACTOR AND PHOTONN ENERGY RELATION INPUT 3 FOR EXIT THE PROGRAM THE INPUT # IS 1 INPUT FERMILEVELS IN C-BAND, V-BAND, AND
CARRIER DENSITY 0.138679340946
-0.441266076305E-02 0.301052631579E+19 CALCULATE THE CONVOLUTION GAIN(E)
COEFFICIENT
************************************************** INPUT THE NAME FOR THE CONVOLUTION OPTICAL
GAIN(LAMBDA) ol2.txt
************************************************** INPUT THE NAME FOR THE CONVOLUTION MODE
GAIN(LAMBDA) ml2.txt INPUT THE NAME FOR THE CONVOLUTION OPTICAL
GAIN(E) oe2.txt ************************************************** INPUT THE NAME FOR THE CONVOLUTION MODE
GAIN(E) me2.txt
************************************************** INPUT 1 FOR REPEAT THE G(E) CALCULATION INPUT 2 FOR REPEAT THE ALPHA(E) CALCULATION INPUT 3 FOR EXIT 3 ENTER
1 FOR THE NECESSARY PARAMETERS 2 FOR THE ENERGY VALUES OF CONDUCTION
BAND 3 FOR THE ENERGY VALUES OF HEAVY HOLE
BAND 4 FOR THE ENERGY VALUES OF LIGHT HOLE
BAND 5 FOR THE LASER G-J AND G(LAMBDA) 6 FOR RATE EQUATIONS(TWO SECTION MODEL
INCLUDED) 7 FOR EXIT 7 |
c) The Output
characteristics of designed laser from step 5 are summarized in Table C.2.7.
Table C.2.7 Characteristics
of the designed laser
|
Optimized number of QWs (Nopt) |
4 |
|
Number of QWs |
4 |
|
Slope efficiency (%) |
26.8 |
|
Jth (A/cm^2) |
5406.4
- 1st check, for matching threshold conditions 612.7
– 2nd check, using McIlory method |
|
Ith (mA) |
121 mA - 1st
check, for matching threshold conditions 13.7 mA - 2nd
check, using McIlory method |
|
Peak l at operating temperature (um) |
1.21 um for carrier density of 2.0E19 /cm3 1.18 um for carrier density of 3.0E19 /cm3 |
|
Peak material gain (1/cm) |
2362 /cm for carrier density of 2.0E19 /cm3 3360 /cm for carrier density of
3.0E19 /cm3 |

Fig.
C.2.5. L-I curve of the laser

Fig.
C.2.6. Optical gain-l curve of the laser

Fig.
C.2.7. Mode gain as a function of current density (J)
This is a
simulation of a five-layer laser structure that contains a single quantum well
(QW), two separated confinement heterostructure (SCH) layers, and two cladding
layers as shown in Fig. C.3.1.

Figure C.3.3. Energy band diagram for the simple quantum well structure
The first step of the GAIN program is to
calculate the material compositions and energy band edges of the each layer.
The user is asked to enter the photoluminescence wavelength, thickness, and
strain of the QW, SCH, and cladding layers. After these parameters are input,
the GAIN program generates two output files: cbandeg.dat and vbandeg.dat,
containing the material compositions, and the conduction band edges and valence
band edges respectively. The detailed explanation is provided in Chapter 2 of
this manual.
a) The input parameters to the GAIN program in this step is listed in Table.
C.3.1.
Table
C.3.1. Input parameters to the GAIN program in this step.
|
Layer |
l (um) |
Strain |
Thickness (Ǻ) |
|
QW (InGaAs) |
1.56 |
0.003507 |
100 |
|
SCH (In1-xGaxAsyP1-y) |
1.21 |
0 |
100 |
|
Cladding (InP) |
0.9185 |
|
1000 |
b) The steps in using the GAIN program to
calculate the material compositions and energy band edges are listed in Table
C.3.2
Table C.3.2. steps to run
the GAIN program for necessary parameters.
|
ENTER 1 FOR THE NECESSARY PARAMETERS 2 FOR THE ENERGY VALUES OF CONDUCTION
BAND 3 FOR THE ENERGY VALUES OF HEAVY HOLE
BAND 4 FOR THE ENERGY VALUES OF LIGHT HOLE
BAND 5 FOR THE LASER G-J AND G(LAMBDA) 6 FOR RATE EQUATIONS(TWO SECTION MODEL
INCLUDED) 7 FOR EXIT 1 ENTER 1 FOR AlGaAs/AlGaAs 2 FOR InGaAsP/InGaAsP/InP 3 FOR InGaAs/InGaAsP/InP 4 FOR InGaAlAs/InGaAlAs/InP 5 FOR GaInP/(AlGa)0.5In0.5P/AlInP 6 FOR InGaAs/AlGaAs/AlGaAs 7 FOR
InGaAs/InGaAsP/Ga0.51In0.49P(MATCHED GaAs) 8 FOR AlyInxGa1-x-yAs/AlzGa1-zAs/GaAs 9 FOR InzGa1-zAs/AlyGaxIn1-x-yAs/InP 10 FOR
InGaAlAs/InGaAlAs/AlAsxSb1-x(matched InP) 11 FOR
InzGa1-zAs/AlyGaxIn1-x-yAs/AlAsxSb1-x 12 FOR In(y)Ga(1-y)As(x)N(1-x)/GaAs
(dilute N) 13 FOR In(1-x)Ga(x)As(y)P(1-y)/GaAs 14 FOR EXIT, BACK TO MAIN PAGE! 3 INPUT THE LAYER # FOR GRIN STRUCTURE(STEP) STEP N= 2 INPUT THE WELL WAVELENGTH (um) 1.56 INPUT THE BARRIER WAVELENGTH (um) 1.21 INPUT THE CLADDING WAVELENGTH (um) 0.9185 BANDGAP ENERGY OF QUANTUM WELL= 0.79487179 INPUT CLADDING, BARRIER,QUANTUM WELL WIDTH
(A) 1000 100 100 FOR BARRIER IS LATTICE MATCHED SELECT
==>1 FOR BARRIER IS STRAIN COMPENSATED SELECT
==> 2 SELECTION IS ===> ? 1 STRAIN FOR In1-xGaxAs=
3.507367375368143E-003 WRITE CONDUCION BAND PARAMETERS INTO
CBANDEG.DAT WRITE INPUT 1 FOR NEW CALCULATION, 2 FOR EXIT I =? 2 ENTER 1 FOR AlGaAs/AlGaAs 2 FOR InGaAsP/InGaAsP/InP 3 FOR InGaAs/InGaAsP/InP 4 FOR InGaAlAs/InGaAlAs/InP 5 FOR GaInP/(AlGa)0.5In0.5P/AlInP 6 FOR InGaAs/AlGaAs/AlGaAs 7 FOR InGaAs/InGaAsP/Ga0.51In0.49P(MATCHED
GaAs) 8 FOR AlyInxGa1-x-yAs/AlzGa1-zAs/GaAs 9 FOR InzGa1-zAs/AlyGaxIn1-x-yAs/InP 10 FOR
InGaAlAs/InGaAlAs/AlAsxSb1-x(matched InP) 11 FOR
InzGa1-zAs/AlyGaxIn1-x-yAs/AlAsxSb1-x 12 FOR In(y)Ga(1-y)As(x)N(1-x)/GaAs
(dilute N) 13 FOR In(1-x)Ga(x)As(y)P(1-y)/GaAs 14 FOR EXIT, BACK TO MAIN PAGE! 14 THIS PROGRAM STOP HERE!, BACK TO MAIN PAGE |
c) The output files, cbandeg.dat and
vbandeg.dat are explained in Table C.3.3.
Table C.3.3. Material
compositions and band offsets:
a) cbandeg.dat for conduction band
|
************************************************************************ QW
strain lattice constant 0.350737E-02 0.584822E-09 material
compositions layer
thickness, Ga As conduction band edges
0.10000000E+04
0.00000000E+00
0.0000000 0.1998462 cladding layer
0.10000000E+03
0.21142234E+00
0.4603684 0.0827718 SCH layer
0.10000000E+03
0.51884522E+00
0.0000000 -0.0190298 quantum well
0.10000000E+03
0.21142234E+00
0.4603684 0.0827718 SCH layer
0.10000000E+04
0.00000000E+00
0.0000000 0.1998462 cladding layer ************************************************************************ |
b) vbandeg.dat for valence
band
|
****************************************************
******************** QW
strain lattice constant 0.350737E-02
0.584822E-09 material
compositions layer
thickness, Ga As valence band edges
0.10000000E+04
0.00000000E+00
0.0000000 -0.3552821 cladding layer
0.10000000E+03 0.21142234E+00 0.4603684 -0.1471498 SCH layer
0.10000000E+03
0.51884522E+00
0.0000000 0.0095149 quantum well
0.10000000E+03
0.21142234E+00
0.4603684 -0.1471498 SCH layer
0.10000000E+04
0.00000000E+00 0.0000000 -0.3552821 cladding layer ************************************************************************ |
After the calculation of the material
compositions and energy band edges, the GAIN program calculates energy levels
in the conduction band and valence bands. The detailed explanations are
discussed in Chapter 3 of this manual.
a) The steps of how to calculate the energy
levels are shown in Table C.3.4.
Table C.3.4. Steps to
calculate the energy levels
i) Steps to calculate the
conduction band energy levels
|
ENTER
1 FOR THE NECESSARY PARAMETERS 2 FOR THE ENERGY VALUES OF CONDUCTION
BAND 3 FOR THE ENERGY VALUES OF HEAVY HOLE
BAND 4 FOR THE ENERGY VALUES OF LIGHT HOLE
BAND 5 FOR THE LASER G-J AND G(LAMBDA) 6 FOR RATE EQUATIONS(TWO SECTION MODEL
INCLUDED) 7 FOR EXIT 2 INPUT THE NUMBER OF QUANTUM WELLS NUM=? 1 INPUT TOTAL LAYERS FOR STRUCTURE--N ODD INPUT N= 5 INPUT THE LOWEST POTENTIAL LAYER(1st
Q-WELL) IC= ? 3 INPUT THE SELECTED CENTER LAYER OF
STRUCTURE ICR= 3 ******************************************************* INPUT I=1
FOR AlGaAs I=2
FOR InGaAsP I=3
FOR In1-xGaxAs/InGaAsP/InP I=4
FOR InGaAlAs/InGaAlAs I=5
FOR GaInP/(AlGa)0.5In0.5P/AlInP I=6
FOR InGaAs/AlGaAs/AlGaAs I=7
FOR InGaAs/InGaAsP/Ga0.51In0.49P(GaAs) I=8
FOR AlyInxGa1-x-yAs/AlzGa1-zAs/GaAs I=9
FOR InzGa1-zAs/AlxGayIn1-x-yAs/InP I=10 FOR InGaAlAs/InGaAlAs/AlAsxSb1-x(InP) I=11 FOR
InzGa1-zAs/AlxGayIn1-x-yAs/AlAsxSb1-x I=12 FOR
In(y)Ga(1-y)As(x)N(1-x)/GaAs I=13 FOR
InGaAs/In(1-y)Ga(x)As(y)P(1-y)/GaAs INPUT I= ? ******************************************************* 3 ENERGY EIGENVALUE===> 0.102677331562E-01 ERROR= .4838213E-14 ENERGY EIGENVALUE===> 0.829312203346E-01 ERROR= .3134953E-14 ENERGY EIGENVALUE===> 0.116110587122E+00 ERROR= .1700480E-14 ENERGY EIGENVALUE===> 0.137409592564E+00 ERROR= .2887171E-14 ENERGY EIGENVALUE===> 0.193078448219E+00 ERROR= .2186428E-14 FOR CHECKING THE Schrodinger WAVE FUNCTION
INPUT I==> 1 SKIP INPUT I==> 2 I=? 1 INPUT THE EIGENVALUE EIGEN VALUE= 0.0102677331562 INPUT THE NAME OF OUTPUT FILE cb1.txt CONFINEMENT FACTOR OF 1 th LAYER = 0.23125143E-04 CONFINEMENT FACTOR OF 2 th LAYER = 0.60295889E-01 CONFINEMENT FACTOR OF 3 th LAYER = 0.87936197E+00 CONFINEMENT FACTOR OF 4 th LAYER = 0.60295889E-01 CONFINEMENT FACTOR OF 5 th LAYER = 0.23125143E-04 INPUT NEW EIGENVALUE--> 1, BACK TO MAIN
PAGE--> 2 SELECT=? 1 INPUT THE EIGENVALUE EIGEN VALUE= 0.0829312203346 INPUT THE NAME OF OUTPUT FILE cb2.txt CONFINEMENT FACTOR OF 1 th LAYER = 0.30920015E-02 CONFINEMENT FACTOR OF 2 th LAYER = 0.29765260E+00 CONFINEMENT FACTOR OF 3 th LAYER = 0.39851080E+00 CONFINEMENT FACTOR OF 4 th LAYER = 0.29765260E+00 CONFINEMENT FACTOR OF 5 th LAYER = 0.30920015E-02 INPUT NEW EIGENVALUE--> 1, BACK TO MAIN
PAGE--> 2 SELECT=? 2 |
ii) Steps to calculate the
heavy hole energy levels
|
ENTER 1 FOR THE NECESSARY PARAMETERS 2 FOR THE ENERGY VALUES OF CONDUCTION
BAND 3 FOR THE ENERGY VALUES OF HEAVY HOLE
BAND 4 FOR THE ENERGY VALUES OF LIGHT HOLE
BAND 5 FOR THE LASER G-J AND G(LAMBDA) 6 FOR RATE EQUATIONS(TWO SECTION MODEL
INCLUDED) 7 FOR EXIT 3 INPUT THE NUMBER OF QUANTUM WELLS NUM=? 1 INPUT TOTAL LAYERS FOR STRUCTURE--N ODD INPUT N= 5 INPUT THE HIGHEST POTENTIAL(1st Q-WELL)
LAYER IC= ? 3 INPUT THE SELECTED CENTER OF THE STRUCTURE
ICR=? 3 ******************************************************* INPUT I=1
FOR AlGaAs I=2
FOR InGaAsP I=3
FOR In(1-x)Ga(x)As/InGaAsP/InP I=4
FOR InGaAlAs/InGaAlAs I=5
FOR GaInP/(AlGa)0.5In0.5P/AlInP I=6
FOR InGaAs/AlGaAs/AlGaAs I=7
FOR InGaAs/InGaAsP/Ga0.51In0.49P(GaAs) I=8
FOR AlyInxGa1-x-yAs/AlzGa1-zAs/GaAs I=9
FOR In(z)Ga(1-z)As/AlxGayIn1-x-yAs/InP I=10 FOR
InGaAlAs/InGaAlAs/AlAsxSb1-x(InP) I=11 FOR
InzGa1-zAs/AlxGayIn1-x-yAs/AlAsxSb1-x I=12 FOR
In(y)Ga(1-y)As(x)N(1-x)/GaAs I=13 FOR
InGaAs/In(1-x)Ga(x)As(y)P(1-y)/GaAs INPUT I= ? ******************************************************* 3 ******************************************************* DOES THE STRUCTURE STRAIN OR
STRAIN-COMPENSATED? IF STRAIN ONLY INPUT 1, STRAIN-COMPENSATED
INPUT 2 INPUT SELECT = ? 1 ENERGY EIGENVALUE===>
-0.345448893969E+00 ERROR= .5479616E-14 ENERGY EIGENVALUE===> -0.313421614966E+00
ERROR= .4977968E-14 ENERGY EIGENVALUE===>
-0.286023116439E+00 ERROR= .3741431E-14 ENERGY EIGENVALUE===>
-0.265617316582E+00 ERROR= .4216452E-14 ENERGY EIGENVALUE===>
-0.234960966106E+00 ERROR= .1892574E-14 ENERGY EIGENVALUE===> -0.220233112417E+00
ERROR= .3492980E-14 ENERGY EIGENVALUE===>
-0.198687987806E+00 ERROR= .2194434E-14 ENERGY EIGENVALUE===>
-0.182167124769E+00 ERROR= .5669799E-14 ENERGY EIGENVALUE===>
-0.173478187551E+00 ERROR= .3761173E-14 ENERGY EIGENVALUE===> -0.156637644140E+00
ERROR= .4590558E-14 ENERGY EIGENVALUE===>
-0.154444131718E+00 ERROR= .2538691E-14 ENERGY EIGENVALUE===>
-0.127480216412E+00 ERROR= .2519639E-14 ENERGY EIGENVALUE===>
-0.758643937665E-01 ERROR= .2498963E-14 ENERGY EIGENVALUE===> -0.356919987894E-01
ERROR= .2709770E-14 ENERGY EIGENVALUE===>
-0.109370594171E-01 ERROR= .2119172E-14 FOR CHECKING THE Schrodinger WAVE FUNCTION
INPUT I==> 1 SKIP INPUT I==> 2 I=? 1 INPUT THE EIGENVALUE EIGEN VALUE= -0.0109370594171 INPUT THE NAME OF OUTPUT FILE hh1.txt CONFINEMENT FACTOR OF 1 th LAYER = 0.18195603E-12 CONFINEMENT FACTOR OF 2 th LAYER = 0.48861990E-02 CONFINEMENT FACTOR OF 3 th LAYER = 0.99022760E+00 CONFINEMENT FACTOR OF 4 th LAYER = 0.48861990E-02 CONFINEMENT FACTOR OF 5
th LAYER = 0.18195603E-12 INPUT NEW EIGENVALUE--> 1, BACK TO MAIN
PAGE--> 2 SELECT=? 1 INPUT THE EIGENVALUE EIGEN VALUE= -0.0356919987894 INPUT THE NAME OF OUTPUT FILE hh2.txt CONFINEMENT FACTOR OF 1 th LAYER = 0.60477885E-11 CONFINEMENT FACTOR OF 2 th LAYER = 0.20535375E-01 CONFINEMENT FACTOR OF 3 th LAYER = 0.95892925E+00 CONFINEMENT FACTOR OF 4 th LAYER = 0.20535375E-01 CONFINEMENT FACTOR OF 5 th LAYER = 0.60477885E-11 INPUT NEW EIGENVALUE--> 1, BACK TO MAIN
PAGE--> 2 SELECT=? 2 |
iii) Steps to calculate the
light hole energy levels
|
ENTER
1 FOR THE NECESSARY PARAMETERS 2 FOR THE ENERGY VALUES OF CONDUCTION
BAND 3 FOR THE ENERGY VALUES OF HEAVY HOLE
BAND 4 FOR THE ENERGY VALUES OF LIGHT HOLE
BAND 5 FOR THE LASER G-J AND G(LAMBDA) 6 FOR RATE EQUATIONS(TWO SECTION MODEL
INCLUDED) 7 FOR EXIT 4 INPUT THE NUMBER OF QUANTUM WELLS NUM=? 1 INPUT TOTAL LAYERS FOR STRUCTURE--N ODD INPUT N= 5 INPUT THE HIGHEST POTENTIAL(1st Q-WELL)
LAYER IC= ? 3 INPUT THE SELECTED CENTER OF THE STRUCTURE
ICR=? 3 ******************************************************* INPUT I=1
FOR AlGaAs I=2
FOR InGaAsP I=3
FOR In(1-x)Ga(x)As/InGaAsP/InP I=4
FOR InGaAlAs/InGaAlAs I=5
FOR GaInP/(AlGa)0.5In0.5P/AlInP I=6
FOR InGaAs/AlGaAs/AlGaAs I=7
FOR InGaAs/InGaAsP/Ga0.51In0.49P(GaAs) I=8
FOR AlyInxGa1-x-yAs/AlzGa1-zAs/GaAs I=9
FOR In(z)Ga(1-z)As/AlxGayIn1-x-yAs/InP I=10 FOR
InGaAlAs/InGaAlAs/AlAsxSb1-x(InP) I=11 FOR
InzGa1-zAs/AlxGayIn1-x-yAs/AlAsxSb1-x I=12 FOR
In(y)Ga(1-y)As(x)N(1-x)/GaAs I=13 FOR
InGaAs/In(1-x)Ga(x)As(y)P(1-y)/GaAs INPUT I= ? ******************************************************* 3 ******************************************************* DOES THE STRUCTURE STRAIN OR
STRAIN-COMPENSATED? IF STRAIN ONLY INPUT 1, STRAIN-COMPENSATED
INPUT 2 INPUT SELECT = ? 1 ENERGY EIGENVALUE===>
-0.324350665429E+00 ERROR= .2529748E-14 ENERGY EIGENVALUE===>
-0.268485842580E+00 ERROR= .4118834E-14 ENERGY EIGENVALUE===>
-0.200300476894E+00 ERROR= .3413517E-14 ENERGY EIGENVALUE===>
-0.181133391050E+00 ERROR= .2018955E-14 ENERGY EIGENVALUE===>
-0.116983827560E+00 ERROR= .3183911E-14 ENERGY EIGENVALUE===>
-0.161551734944E-01 ERROR= .3222829E-14 FOR CHECKING THE Schrodinger WAVE FUNCTION
INPUT I==> 1 SKIP INPUT I==> 2 I=? 1 INPUT THE EIGENVALUE EIGEN VALUE= -0.0161551734944 INPUT THE NAME OF OUTPUT FILE lh1.txt CONFINEMENT FACTOR OF 1 th LAYER = 0.28197495E-05 CONFINEMENT FACTOR OF 2 th LAYER = 0.39958233E-01 CONFINEMENT FACTOR OF 3 th LAYER = 0.92007789E+00 CONFINEMENT FACTOR OF 4 th LAYER = 0.39958233E-01 CONFINEMENT FACTOR OF 5 th LAYER = 0.28197495E-05 INPUT NEW EIGENVALUE--> 1, BACK TO MAIN
PAGE--> 2 SELECT=? 1 INPUT THE EIGENVALUE EIGEN VALUE= -0.116983827560 INPUT THE NAME OF OUTPUT FILE lh2.txt CONFINEMENT FACTOR OF 1 th LAYER = 0.39043702E-03 CONFINEMENT FACTOR OF 2 th LAYER = 0.19969312E+00 CONFINEMENT FACTOR OF 3 th LAYER = 0.59983288E-01 CONFINEMENT FACTOR OF 4 th LAYER = 0.19969312E+00 CONFINEMENT FACTOR OF 5 th LAYER = 0.39043702E-03 INPUT NEW EIGENVALUE--> 1, BACK TO MAIN
PAGE--> 2 SELECT=? 2 |
b) The main output file from this part of
GAIN program is energy.dat, containing all the energy levels as shown in Table
C.3.5. After the energy eigen values are calculated, the GAIN program asks the
user whether he would like to check the wave envelope function or not. We
suggest that the user check the wave envelope functions of the first and second
energy levels for conduction and valence bands. The plots of the envelope
functions are shown in Fig. C.3.2, Fig. C.3.3, Fig C.3.4.
Table C.3.5. output file
energy.dat
|
CONDUCTION
BAND ENERGY===> 0.132273196491E+00
ERROR= .1825400E-14
CONDUCTION
BAND ENERGY===> 0.338026920933E+00
ERROR= .2075989E-14
CONDUCTION
BAND ENERGY===> 0.438393858497E+00
ERROR= .1374688E-14
CONDUCTION
BAND ENERGY===> 0.500546559386E+00
ERROR= .1783885E-14
HEAVY HOLE
ENERGY===> -0.190388140560E+00 ERROR= .3376657E-14
HEAVY HOLE
ENERGY===> -0.178205351549E+00 ERROR= .2794590E-14
HEAVY HOLE
ENERGY===> -0.146868929570E+00 ERROR= .1933278E-14
HEAVY HOLE
ENERGY===> -0.649012884792E-01 ERROR= .1722105E-14
HEAVY HOLE
ENERGY===> -0.584031671619E-02 ERROR= .1782035E-14
LIGHT HOLE
ENERGY===> -0.224692198534E+00 ERROR= .5190988E-14
LIGHT HOLE
ENERGY===> -0.169366776608E+00 ERROR= .3378719E-14 LIGHT HOLE
ENERGY===> -0.978425419323E-01 ERROR= .2045359E-14 |
|
|
|
|
Fig. C.3.2. Wave envelop
functions for energy levels in conduction band |
Fig. C.3.3. Wave envelop
functions for heavy hole energy levels |

Fig. C.3.4. Wave envelop
functions for light hole energy levels
This is the last step of simulations using
the GAIN program. With the previous calculated material composition, energy
band edges, energy levels, and other parameters like material loss and Auger
coefficient, the GAIN program can simulate the threshold current, threshold
current density, slope efficiency, optical gain and mode gain as functions of wavelengths
and photo energies, and L-I curve. The details are explained in Chapter 4 of
the manual.
In this part of GAIN program, the input file
needs to be constructed with the results of the previous steps and according to
the laser design. In this example, a tensile single-quantum-well laser with a
ridge length of 750µm and ridge width of 3 µm, the input file is shown in Table
C.3.6. The detailed steps of simulations are listed in Table C.3.7. The main
output files: L-I curve, optical gain as a function of the wavelength, and mode gain vs. current
density are plotted in Fig. C.3.5, Fig. C.3.6, and Fig. C.3.7.
a) The input file:
Table C.3.6. Input file for
gain and threshold current calculation
|
ccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc c 1.
Input the compositions, width of well, effective index c c and
lasing wavelength. c c Ex:
xx,xz,qy,xy,lx,n,lam c c for
different materials the following are the forms of inputs. c c
c c w --
> well, b -- > barrier cxz and
cxy for cladding. c c
c c
a. AlxGa1-xAs : xx (Al w) xz
(Al b) qy (0) xy (0) c c
b. In1-xGaxAsyP1-y : xx (Ga w)
xz (Ga b) qy (As w) xy (As b) c c
c. In1-xGaxAs/InGaAsP : xx (Ga
w) xz (Ga b) qy (0) xy (As b) c c
d. AlxGayIn1-x-yAs/InP : xx (Ga
w) xz (Ga b) qy (Al w) xy (Al b)c c
e.
c c
f. InxGa1-xAs/AlGaAs : xx (In
w) xz (0) qy (0) xy (Al b) c c
g. c c
h. AlyInxGa1-x-yAs/AlGaAs : xx
(Al w) xz (al b) qy (In w) xz (0)c c
i. In1-xGaxAs/AlGaInAs : xx (In
w) xz (0) qy (Al b) xy (Ga b) c c
c c
c c 2.
Input the energy gap,temperature, barrier band edges(both bands)c c Ex:
eg,temp,ec,ev
c cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc 0.51884522 0.21142234 0.0 0.4603684 10.0 3.32 1.55 0.79487179 298 0.10718016 0.1566647 cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc c 3.
Input the ist level sub-band energy levels. c c Ex:
ec1,eh1,el1
c c
c c 4.
Input the material loss, reflectivities, number of quantum c c
wells and beta(for spontaneous emission). c c Ex:
alpha,r1,r2,mm,beta. c cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc 0.0102677331562 0.0109370594171 0.0161551734944
0.0829312203346 0.0356919987894 0.116983827560 10.0d0 0.3000 0.300 1 5.D-5 cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc c 5.
Input the cavity length, ridge width, internal efficiency c c
Auger, strain(except AlGaAs,put 0) and confinement factor. c c Ex:
cl,cw,etha,ca,es,confine c c
c c 6.
Input the cladding composition and band edges. c c Ex:
cxz,cxy,ecc,evv
c cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc 500.D-4 3D-4 0.97 3.10d-29 0.0 0.018 0.00 0.00
0.218876 0.364797 |
b) The steps for these
calculations mentioned are listed in Table C.3.7
Table
C.3.7. The steps for the gain and threshold current density calculations
|
ENTER
1 FOR THE NECESSARY PARAMETERS 2 FOR THE ENERGY VALUES OF CONDUCTION
BAND 3 FOR THE ENERGY VALUES OF HEAVY HOLE
BAND 4 FOR THE ENERGY VALUES OF LIGHT HOLE
BAND 5 FOR THE LASER G-J AND G(LAMBDA) 6 FOR RATE EQUATIONS(TWO SECTION MODEL
INCLUDED) 7 FOR EXIT 5 THE INPUT FILE NAME= in1.tex SELECT MATERIAL=? 1--AlGaAs 2--InGaAsP 3--In1-zGazAs/InGaAsP/InP 4-- InGaAlAs 5--GaInP/AlzGawIn1-z-wP/Al0.5In0.5P 6-- InxGa1-xAs/AlxGa1-xAs/AlGaAs 7--In1-xGaxAs/InGaAsP/GaxIn1-xP(X=0.51)
MATCHED TO GaAs 8--AlyInxGa1-x-yAs/AlzGa1-zAs/GaAs 9--InzGa1-zAs/AlxGayIn1-x-yAs/InP 10-- InGaAlAs/InGaAlAs/AlAsSb 11--InzGa1-zAs/AlxGayIn1-x-yAs/AlAsSb 12--In(y)Ga(1-y)As(x)N(1-x)/GaAs 13--InGaAs/In(1-x)Ga(x)As(y)P(1-y)/GaAs INPUT SELECTION 3 INPUT MODE = ? FOR TE--> MODE =1, FOR
TM--> MODE =2 INPUT TE OR TM ? 1 IF EL1 BELOW EH1 THEN SELECT 1, OTHERWISE
SELECT 2 SELECTION=? 1
************************************************** CALCULATE THE EFFECTIVE MASS
************************************************** FOR QUASI-FERMI LEVEL SELECT=1, FOR READ EXISTING QUASI-FERMI LEVEL
SELECT=2 SELECT=? 1 J(LEAKAGE)=0.104958D+03 A/cm^2 N=0.328772D+19 1/cm^3 J(LEAKAGE)=0.108158D+03 A/cm^2 N=0.330752D+19 1/cm^3 J(LEAKAGE)=0.111439D+03 A/cm^2 N=0.332732D+19 1/cm^3 J(LEAKAGE)=0.114800D+03 A/cm^2 N=0.334712D+19 1/cm^3 ………. J(LEAKAGE)=0.245553D+05A/cm^2 N=0.788120D+19 1/cm^3 J(LEAKAGE)=0.246733D+05A/cm^2 N=0.790100D+19 1/cm^3 J(LEAKAGE)=0.247912D+05A/cm^2 N=0.792080D+19 1/cm^3 J(LEAKAGE)=0.249092D+05A/cm^2 N=0.794060D+19 1/cm^3 J(LEAKAGE)=0.250272D+05A/cm^2 N=0.796040D+19 1/cm^3 J(LEAKAGE)=0.251453D+05
A/cm^2 N=0.798020D+19 1/cm^3 J(LEAKAGE)=0.252633D+05
A/cm^2 N=0.800000D+19 1/cm^3 **************************************************
G(J)
PARAMETERS FROM SINGLE WELL Go=0.178866D+02 1/cm Jo=0.967184D+02 A/cm^2 G(N) PARAMETERS FROM SINGLE WELL NGo=0.993699D+03 1/cm XNo=0.951378D+18 1/cm^3 Jtr=0.355807D+02 A/cm^2 NTR=0.349993D+18 1/cm^3 THE OPTIMUM NUMBER OF QUANTUM WELL FOLLOWS
THE ARTICLE BY McIlory et al. IEEE JQE-21 1985. THE OPTIMUM NUMBER OF QUANTUM WELL Nopt = |