def modes_n_gain(inc_a_x):
inc_a_y = inc_a_x
# Use all specified parameters to create a waveguide object.
wguide = objects.Struct(
unitcell_x,
inc_a_x,
unitcell_y,
inc_a_y,
inc_shape,
material_bkg=materials.get_material("Vacuum"),
material_a=materials.get_material("SiO2_2016_Smith"),
lc_bkg=1,
lc_refine_1=400.0,
lc_refine_2=50.0)
sim_EM_pump = wguide.calc_EM_modes(num_modes_EM_pump, wl_nm, n_eff=n_eff)
sim_EM_Stokes = mode_calcs.bkwd_Stokes_modes(sim_EM_pump)
k_AC = np.real(sim_EM_pump.Eig_values[EM_ival_pump] -
sim_EM_Stokes.Eig_values[EM_ival_Stokes])
shift_Hz = 4e9
sim_AC = wguide.calc_AC_modes(num_modes_AC,
k_AC,
EM_sim=sim_EM_pump,
shift_Hz=shift_Hz)
set_q_factor = 600.
SBS_gain, SBS_gain_PE, SBS_gain_MB, linewidth_Hz, Q_factors, alpha = integration.gain_and_qs(
sim_EM_pump,
sim_EM_Stokes,
sim_AC,
k_AC,
EM_ival_pump=EM_ival_pump,
EM_ival_Stokes=EM_ival_Stokes,
AC_ival=AC_ival) #, fixed_Q=set_q_factor)
interp_values = plotting.gain_spectra(sim_AC,
SBS_gain,
SBS_gain_PE,
SBS_gain_MB,
linewidth_Hz,
k_AC,
EM_ival_pump,
EM_ival_Stokes,
AC_ival,
freq_min,
freq_max,
num_interp_pts=num_interp_pts,
save_fig=False,
suffix_str='%i' % int(inc_a_x))
# Clear memory
wguide = sim_EM_pump = sim_EM_Stokes = sim_AC = None
SBS_gain = SBS_gain_PE = SBS_gain_MB = linewidth_Hz = Q_factors = alpha = None
return interp_values
num_AC_modes = 20
# The EM pump mode(s) for which to calculate interaction with AC modes.
# Can specify a mode number (zero has lowest propagation constant) or 'All'.
EM_ival_pump = 0
# The EM Stokes mode(s) for which to calculate interaction with AC modes.
EM_ival_Stokes = 0
# The AC mode(s) for which to calculate interaction with EM modes.
AC_ival = 'All'
# Use all specified parameters to create a waveguide object.
wguide = objects.Struct(unitcell_x,
inc_a_x,
unitcell_y,
inc_a_y,
inc_shape,
material_bkg=materials.get_material("Vacuum"),
material_a=materials.get_material("Si_2016_Smith"),
lc_bkg=1,
lc_refine_1=1000.0,
lc_refine_2=400.0)
# Expected effective index of fundamental guided mode.
n_eff = wguide.material_a.n - 0.1
# Calculate Electromagnetic Modes
sim_EM_pump = wguide.calc_EM_modes(num_modes_EM_pump, wl_nm, n_eff=n_eff)
sim_EM_Stokes = mode_calcs.bkwd_Stokes_modes(sim_EM_pump)
k_AC = np.real(sim_EM_pump.Eig_values[0] - sim_EM_Stokes.Eig_values[0])
# The EM Stokes mode(s) for which to calculate interaction with AC modes. Typically 0 for FSBS.
EM_ival_Stokes = EM_ival_pump
# The AC mode(s) for which to calculate interaction with EM modes.
AC_ival = 'All'
# Output files are generated in a folder with the following prefix
prefix_str = 'fsbs-josab-04-450x200nmSi'
# Use all specified parameters to create a waveguide object
wguide = objects.Struct(
unitcell_x,
inc_a_x,
unitcell_y,
inc_a_y,
inc_shape,
material_bkg=materials.get_material("Vacuum"),
material_a=materials.get_material("Si_2021_Poulton"),
lc_bkg=
0.05, # mesh coarseness in background, larger lc_bkg = coarser along horizontal outer edge
lc_refine_1=
20.0, # mesh refinement factor near the interface of waveguide, larger = finer along horizontal interface
lc_refine_2=
30.0, # mesh refinement factor near the origin/centre of waveguide
plt_mesh=
False, # creates png file of geometry and mesh in backend/fortran/msh/
check_mesh=False) # note requires x-windows configuration to work
# Explicitly remind ourselves what data we're using.
print('\nUsing %s material data from' % wguide.material_a.chemical)
print('Author:', wguide.material_a.author)
print('Year:', wguide.material_a.date)
# Number of electromagnetic modes to solve for.
num_modes_EM_pump = 20
num_modes_EM_Stokes = num_modes_EM_pump
# Number of acoustic modes to solve for.
num_modes_AC = 35
# The EM pump mode(s) for which to calculate interaction with AC modes.
# Can specify a mode number (zero has lowest propagation constant) or 'All'.
EM_ival_pump = 0
# The EM Stokes mode(s) for which to calculate interaction with AC modes.
EM_ival_Stokes = 1 # INTERMODE SBS TE0 to TE1
# The AC mode(s) for which to calculate interaction with EM modes.
AC_ival = 'All'
# Si_110 = copy.deepcopy(materials.get_material("Si_2015_Van_Laer")
Si_110 = copy.deepcopy(materials.get_material("Si_2016_Smith")
Si_110.rotate_axis(np.pi/4,'z-axis', save_rotated_tensors=True)
prefix_str = 'fig16-'
# Use specified parameters to create a waveguide object.
wguide = objects.Struct(unitcell_x,inc_a_x,unitcell_y,inc_a_y,inc_shape,
slab_a_x=slab_a_x, slab_a_y=slab_a_y, slab_b_y=slab_b_y,
coat_x=coat_x, coat_y=coat_y, coat2_x=coat2_x, coat2_y=coat2_y,
material_bkg=materials.get_material("Vacuum"),
material_a=Si_110, #plt_mesh=True,
material_b=Si_110, material_c=materials.get_material(["Vacuum"),
material_d=materials.get_material(["Vacuum"), material_e=materials.get_material("Vacuum"),
symmetry_flag=False,
lc_bkg=lc_bkg, lc_refine_1=lc_refine_1, lc_refine_2=lc_refine_2,
lc_refine_3=lc_refine_3, lc_refine_4=lc_refine_4, lc_refine_5=lc_refine_5)
# Number of acoustic modes to solve for.
num_modes_AC = 100
# The EM pump mode(s) for which to calculate interaction with AC modes.
# Can specify a mode number (zero has lowest propagation constant) or 'All'.
EM_ival_pump = 0
# The EM Stokes mode(s) for which to calculate interaction with AC modes.
EM_ival_Stokes = 0
# The AC mode(s) for which to calculate interaction with EM modes.
AC_ival = 'All'
prefix_str = 'lit_10b-'
#reuse_fields=True # use saved data
reuse_fields=False # calculate from scratch
Ge_110 = copy.deepcopy(materials.get_material("Ge_cubic_2014_Wolff"))
print('Initial Ge_100:', Ge_110.full_str())
Ge_110.rotate_axis(np.pi/4., 'y-axis', save_rotated_tensors=True)
print('Rotated Ge_110:', Ge_110.full_str())
# Use specified parameters to create a waveguide object.
# Note use of rough mesh for demonstration purposes.
wguide = objects.Struct(unitcell_x,inc_a_x,unitcell_y,inc_a_y,inc_shape,
material_bkg=materials.get_material("Si3N4_2014_Wolff"),
material_a=Ge_110,
lc_bkg=1, lc_refine_1=50.0, lc_refine_2=50.0)
# Expected effective index of fundamental guided mode.
n_eff = wguide.material_a.n-0.1
num_modes_EM_pump = 20
num_modes_EM_Stokes = num_modes_EM_pump
num_modes_AC = 800
EM_ival_pump = 0
EM_ival_Stokes = 0
AC_ival = 'All'
prefix_str = 'lit_02-'
# Use all specified parameters to create a waveguide object.
wguide = objects.Struct(unitcell_x,
inc_a_x,
unitcell_y,
inc_a_y,
inc_shape,
material_bkg=materials.get_material("Vacuum"),
material_a=materials.get_material("Si_2013_Laude"),
lc_bkg=1,
lc_refine_1=400.0,
lc_refine_2=50.0)
# Expected effective index of fundamental guided mode.
n_eff = 3.4
# Calculate Electromagnetic modes.
sim_EM_pump = wguide.calc_EM_modes(num_modes_EM_pump, wl_nm, n_eff=n_eff)
sim_EM_Stokes = mode_calcs.bkwd_Stokes_modes(sim_EM_pump)
plotting.plot_mode_fields(sim_EM_pump,
xlim_min=0.2,
xlim_max=0.2,
prefix_str = 'lit_09-'
# Use specified parameters to create a waveguide object.
# Note use of rough mesh for demonstration purposes.
wguide = objects.Struct(
unitcell_x,
inc_a_x,
unitcell_y,
inc_a_y,
inc_shape,
slab_a_x=slab_a_x,
slab_a_y=slab_a_y,
coat_x=coat_x,
coat_y=coat_y,
material_bkg=materials.get_material("Vacuum"),
material_a=materials.get_material("As2S3_2017_Morrison"), # waveguide
material_b=materials.get_material("SiO2_2016_Smith"), # slab
material_c=materials.get_material("SiO2_2016_Smith"), # coating
lc_bkg=1,
lc_refine_1=800.0,
lc_refine_2=400.0)
# Expected effective index of fundamental guided mode.
n_eff = wguide.material_a.n - 0.1
# Calculate the Electromagnetic modes of the pump field.
sim_EM_pump = wguide.calc_EM_modes(num_modes_EM_pump, wl_nm, n_eff)
# # np.savez('wguide_data', sim_EM_pump=sim_EM_pump)
# npzfile = np.load('wguide_data.npz')
# sim_EM_pump = npzfile['sim_EM_pump'].tolist()
print('\n\nCommencing NumBAT tutorial 9 - fast mode')
prefix_str = 'ftut_09-'
refine_fac = 1
else:
print('\n\nCommencing NumBAT tutorial 9')
prefix_str = 'tut_09-'
refine_fac = 5
# Use of a more refined mesh to produce field plots.
wguide = objects.Struct(
unitcell_x,
inc_a_x,
unitcell_y,
inc_a_y,
inc_shape,
material_bkg=materials.get_material("Vacuum"),
material_a=materials.get_material("Si_test_anisotropic"),
lc_bkg=1,
lc_refine_1=200.0 * refine_fac,
lc_refine_2=1.0 * refine_fac)
# Expected effective index of fundamental guided mode.
n_eff = wguide.material_a.n - 0.1
# Calculate the Electromagnetic modes of the pump field.
sim_EM_pump = wguide.calc_EM_modes(num_modes_EM_pump, wl_nm, n_eff)
# Display the wavevectors of EM modes.
v_kz = sim_EM_pump.kz_EM_all()
print('\n k_z of EM modes [1/m]:')
for (i, kz) in enumerate(v_kz):
if len(sys.argv) > 1 and sys.argv[
1] == 'fast=1': # choose between faster or more accurate calculation
prefix_str = 'ftut_12-'
refine_fac = 1
else:
prefix_str = 'tut_12-'
refine_fac = 4
# Use of a more refined mesh to produce field plots.
wguide = objects.Struct(unitcell_x,
inc_a_x,
inc_shape=inc_shape,
inc_b_x=inc_b_x,
unitcell_y=unitcell_y,
material_bkg=materials.get_material("Vacuum"),
material_a=materials.get_material("SiO2GeO2_smf28"),
material_b=materials.get_material("SiO2_smf28"),
lc_bkg=.5,
lc_refine_1=1.0 * refine_fac,
lc_refine_2=20 * refine_fac,
plt_mesh=True)
# Expected effective index of fundamental guided mode.
n_eff = wguide.material_a.n - 0.001
new_calcs = True
micron = 1e-6
lam_hi = 1.65
lam_lo = 1.45
# The EM Stokes mode(s) for which to calculate interaction with AC modes.
EM_ival_Stokes = 0
# The AC mode(s) for which to calculate interaction with EM modes.
AC_ival = 'All'
prefix_str = 'lit_10-'
#reuse_fields=True # use saved data
reuse_fields=False # calculate from scratch
# Use specified parameters to create a waveguide object.
# Note use of rough mesh for demonstration purposes.
wguide = objects.Struct(unitcell_x,inc_a_x,unitcell_y,inc_a_y,inc_shape,
#slab_a_x=slab_a_x, slab_a_y=slab_a_y,
#coat_x=coat_x, coat_y=coat_y,
material_bkg=materials.get_material("Si3N4_2014_Wolff"),
material_a=materials.get_material("Ge_cubic_2014_Wolff"), # waveguide
lc_bkg=1, lc_refine_1=50.0, lc_refine_2=50.0)
# Expected effective index of fundamental guided mode.
n_eff = wguide.material_a.n-0.1
# Calculate the Electromagnetic modes of the pump field.
if not reuse_fields:
sim_EM_pump = wguide.calc_EM_modes(num_modes_EM_pump, wl_nm, n_eff)
np.savez('wguide_data', sim_EM_pump=sim_EM_pump)
else:
npzfile = np.load('wguide_data.npz', allow_pickle=True)
sim_EM_pump = npzfile['sim_EM_pump'].tolist()
sim_EM_pump.analyse_symmetries(PointGroup.C2V)
print('\n\nCommencing NumBAT tutorial 7 - fast mode')
else:
prefix_str = 'tut_07-'
refine_fac = 4
print('\n\nCommencing NumBAT tutorial 7')
wguide = objects.Struct(
unitcell_x,
inc_a_x,
unitcell_y,
inc_a_y,
inc_shape,
slab_a_x=slab_a_x,
slab_a_y=slab_a_y,
inc_b_x=inc_b_x,
material_bkg=materials.get_material("Vacuum"), # background
material_a=materials.get_material("As2S3_2017_Morrison"), # slot
material_b=materials.get_material("SiO2_2013_Laude"), # slab
material_c=materials.get_material("Si_2016_Smith"), # walls of slot
lc_bkg=1,
lc_refine_1=200.0 * refine_fac,
lc_refine_2=100.0 * refine_fac,
plt_mesh=True)
# Expected effective index of fundamental guided mode.
n_eff = wguide.material_a.n - 0.1
# Calculate Electromagnetic modes.
sim_EM_pump = wguide.calc_EM_modes(num_modes_EM_pump, wl_nm, n_eff=n_eff)
# np.savez('wguide_data', sim_EM_pump=sim_EM_pump)
# npzfile = np.load('wguide_data.npz', allow_pickle=True)
def ac_mode_freqs(coat_y):
print('Commencing mode calculation for coat_y = %f' % coat_y)
wguide = objects.Struct(
unitcell_x,
inc_a_x,
unitcell_y,
inc_a_y,
inc_shape,
slab_a_x=slab_a_x,
slab_a_y=slab_a_y,
inc_b_x=inc_b_x,
coat_y=coat_y,
material_bkg=materials.get_material("Vacuum"), # background
material_a=materials.get_material("As2S3_2017_Morrison"), # slot
material_b=materials.get_material("SiO2_2013_Laude"), # slab
material_c=materials.get_material("Si_2016_Smith"), # walls of slot
material_d=materials.get_material("SiO2_2013_Laude"), # coating
lc_bkg=1,
lc_refine_1=100.0 * refine_fac,
lc_refine_2=50.0 * refine_fac)
# Expected effective index of fundamental guided mode.
n_eff = wguide.material_a.n - 0.1
# Calculate Electromagnetic modes.
sim_EM_pump = wguide.calc_EM_modes(num_modes_EM_pump, wl_nm, n_eff=n_eff)
sim_EM_Stokes = mode_calcs.bkwd_Stokes_modes(sim_EM_pump)
k_AC = np.real(
sim_EM_pump.kz_EM(EM_ival_pump) - sim_EM_Stokes.kz_EM(EM_ival_Stokes))
shift_Hz = 4e9
# Calculate Acoustic modes.
sim_AC = wguide.calc_AC_modes(num_modes_AC,
k_AC,
EM_sim=sim_EM_pump,
shift_Hz=shift_Hz)
# plotting.plot_mode_fields(sim_AC, xlim_min=0.4, xlim_max=0.4,
# ylim_min=0.7, ylim_max=0.0, EM_AC='AC',
# prefix_str=prefix_str, suffix_str='_%i' %int(coat_y))
set_q_factor = 1000.
SBS_gain, SBS_gain_PE, SBS_gain_MB, linewidth_Hz, Q_factors, alpha = integration.gain_and_qs(
sim_EM_pump,
sim_EM_Stokes,
sim_AC,
k_AC,
EM_ival_pump=EM_ival_pump,
EM_ival_Stokes=EM_ival_Stokes,
AC_ival=AC_ival,
fixed_Q=set_q_factor)
# Construct the SBS gain spectrum, built from Lorentzian peaks of the individual modes.
freq_min = 4 # np.real(sim_AC.nu_AC_all()[0])*1e-9 - 2 # GHz
freq_max = 14 # np.real(sim_AC.nu_AC_all()[-1])*1e-9 + 2 # GHz
plotting.gain_spectra(sim_AC,
SBS_gain,
SBS_gain_PE,
SBS_gain_MB,
linewidth_Hz,
k_AC,
EM_ival_pump,
EM_ival_Stokes,
AC_ival,
freq_min=freq_min,
freq_max=freq_max,
prefix_str=prefix_str,
suffix_str='_%i' % int(coat_y))
# Convert to GHz
mode_freqs = sim_AC.nu_AC_all() * 1.e-9
# Clear memory
wguide = sim_EM_pump = sim_EM_Stokes = sim_AC = None
SBS_gain = SBS_gain_PE = SBS_gain_MB = linewidth_Hz = Q_factors = alpha = None
print('Completed mode calculation for coating coat_y = %f' % coat_y)
# Return the frequencies and simulated k_ac value in a list
return mode_freqs
