Angled: LNOI
Highlighted features: angle etch, mask etch, expand window with lower resolution, overlap integral.
This code example is licensed under the BSD 3-Clause License.
import emodeconnection as emc
import numpy as np
## Set simulation parameters
wavelength = 1550 # [nm] wavelength
dx, dy = 10, 10 # [nm] resolution
w_core = 1000 # [nm] waveguide core width
w_trench = 1000 # [nm] waveguide side trench width
h_core = 500 # [nm] waveguide core height
h_clad = 1000 # [nm] waveguide top and bottom clad
window_width = w_core + w_trench*2 # [nm]
window_height = h_core + h_clad*2 # [nm]
num_modes = 1 # [-] number of modes
boundary = '0S' # boundary condition
## Connect and initialize EMode
em = emc.EMode()
## View material database
em.material_explorer()
## Settings
em.settings(
wavelength = wavelength, x_resolution = dx, y_resolution = dy,
window_width = window_width, window_height = window_height,
num_modes = num_modes, background_material = 'Air',
boundary_condition = boundary,
expansion_resolution = 20, expansion_size = 1500)
## Draw shapes
ln_mgo = emc.MaterialSpec(material = 'LN_MgO', theta = np.pi/2)
em.shape(name = 'BOX', material = 'SiO2', height = h_clad)
em.shape(name = 'core', material = ln_mgo, height = h_core,
etch_depth = h_core*3/4, mask = w_core, sidewall_angle = 15)
## Solve the first mode
em.FDM()
em.confinement(shape_list = 'core')
em.report()
em.label_profile(name = '0') # save the data from the first mode
## Solve the second mode
em.shape(name = 'core', mask = w_core + 100)
em.FDM()
em.confinement(shape_list = 'core')
em.report()
## Calculate the overlap integral
overlap = em.overlap(profile_a = '0', mode_a = 0, mode_b = 0)
print('Power overlap: %0.3f %%' % (overlap*100))
## Plot the field and refractive index profiles
em.plot(window_display = True)
## Get the refractive index of the core
res = em.refractive_index(material = ln_mgo,
wavelength = wavelength, reference = True)
n_LN, ref = res
print('\nRefractive index of LN:', n_LN)
print(ref)
## Close EMode
em.close()
Console output:
EMode3D 0.2.6 - email
Meshing completed in 0.4 sec
Solving modes... completed in 1.6 sec
Wavelength: 1550.0 nm
Mode # n_eff TE % Loss (dB/m) core confinement
-------- -------- ------ ------------- ------------------
TE-0 1.767903 98.8 % 0.000 82.2 %
Meshing completed in 0.3 sec
Solving modes... completed in 1.2 sec
Wavelength: 1550.0 nm
Mode # n_eff TE % Loss (dB/m) core confinement
-------- -------- ------ ------------- ------------------
TE-0 1.789641 99.1 % 0.000 83.4 %
Exited EMode
Power overlap: 99.836 %
Refractive index of LN: [2.13057033 2.20881269 2.20881269]
O. Gayer, Z. Sacks, E. Galun, and A. Arie, "Temperature and wavelength dependent refractive index equations for MgO-doped congruent and stoichiometric LiNbO3," Appl. Phys.B 91, 343 (2008).
Notes: x-cut congruent lithium niobate, 5 % MgO-doped. Temperature is 24.5 C. The n_e is the z-direction and n_o is the x- and y-direction.
Wavelength range: 500 nm to 4000 nm
Figures:
