Simulation Analysis Of Grating-tunable DFB Laser Based On InN

With the development of communication technology progress, the use of flexible optical sources with high speed and large capacity is necessary to meet the large demand of next generation system. Tunable DFB-LD has become the main source of the optical communication network because of its stable and dynamic single mode output. A 2D steady physical model was established for an InN DFB-LD cavity by using COMSOL software and the simulation analysis of the size parameters of the active layer and grating in the cavity model. Combined with MEMS technology, we presented an electrostatic-actuator structure to output different wavelength of the DFB-LD by changing grating period. Its feasibility was analyzed by using the theory and numerical simulation, so as to provide numerical basis for making the related devices in the future.In this article the grating and active layer of the DFB-LD cavity was InN material. The coupled wave analysis method was used to analyze the DFB-LD and the numerical the single mode output condition was calculated by using the simple method of equivalent waveguide. The structure parameters of the single mode output condition was set up. Then combined with structure parameters, the geometric model was built and different structure parameters were analyzed. The effect on resonant peak was simulated by changing numerical value of T, H and H_t. The FWHM, peak value and wavelength shift were obtained when the structure parameters was changed a little.Finally, we proposed the possible way to make wavelength Tunable DFB-LD in 1290 nm to 1330 nm and 1530 nm to 1565 nm. We designed the actuating voltage comb structure to change indium nitride grating period, and adjust the input voltage for the realization of tunable wavelength. The simulation results show that when choosing an appropriate S value and the input voltage of greater than 152 V, the output wavelength was 1290 nm to 1330 nm and the maximal displacement of grating period was 0.448 um. Furthermore, when the input voltage was greater than 220 V, the output wavelength was 1530 nm to 1565 nm and the maximal displacement of grating period was 1.014 um.