# LCML - Thermally tunable waveguide | lcml_wg_thermal_1550_2D

#1

This thermally tunable waveguide model is built based on MODE Solutions ans DEVICE simulation results.

## Example Test File

thermally_tuned_waveguide.icp (470.6 KB)

User Guide

lcml_wg_thermal_1550_2D (twg)

LCML: thermally tunable waveguide.

Ports

 Name Type ele_1 Electrical Signal ele_2 Electrical Signal opt_1 Optical Signal opt_2 Optical Signal

CML/Waveguide

 Name Default value Default unit Range wg_length 200 um**std. unit is m [-1e+106, 1e+106]

## Model Development

Parameter extraction
Please refer to the [Thermally Tuned Waveguide] (https://kb.lumerical.com/en/index.html?thermal_thermally_tuned_waveguide.html) page for detailed information on the component level simulations using DEVICE and MODE Solutions. All the files mentioned below can be found in the LCML_resource folder in the download page.

1. Open the project file thermal_tuning_waveguide_2D.ldev in DEVICE and run with the default settings. The temperature distribution profile will be saved to T.mat.

2. Open the project file thermal_tuning_waveguide_2D.lms in MODE Solutions and disable the “temperature” object. Run a frequency sweep and export the mode data to thermal_tuning_waveguide.ldf" for INTERCONNECT.

3. Run the script file thermal_tuning_waveguide_sweep.lsf. This will extract the effective index changes vs. temperature (input power) and save the data in thermally_tuned_wg_neff_power.dat.

INTERCONNECT
The thermally tunable waveguide has an internal circuit that is very similar to that of the [PN phase shifter] (LCML - Phase shifter based on PN junction | lcml_ps_pn_1550), except that the Optical Modulator Measured element now uses the effective index perturbations as a function of the heating power (thermally_tuned_wg_neff_power.dat). The electrical input is voltage, and assuming the resistance is 50 ohm, the voltage is converted to power through an Electrical Multiplier and an Electrical Constant Multiplier (gain = 0.02).

## Test

Download the simulation file thermally_tuned_waveguide.icp` from the top of this page. In this simulation file, the thermally tuned waveguide is measured by an Optical Network Analyzer (ONA). Run the sweep object “sweep_voltage” defined in the file. The following plot is the phase shift in the waveguide under different heating power (represented by driving voltage) at 193.1 THz.

Lumerical Compact Model Library (LCML)
LCML - Ring resonator with thermal tuning | lcml_ring_tunable_1550