Design of the Single Heterogeneous Quantum Dot Lasers Emitting 4 Wavelengths Using Combination‐Grating Technology

Abstract

AbstractMulti‐wavelength light sources are crucial for high‐bandwidth silicon photonic chips. In this paper, a single heterogeneous quantum dot distributed feedback (DFB) laser emitting 4 wavelengths using the combination‐grating technology is designed. To the best of the knowledge, this is the first heterogeneously integrated quantum dot DFB laser that lases stable multi‐wavelength in a single cavity. When the etching depth, etching width, and total length of gratings are 100 , 550 nm, and 1 000 µm, respectively, 4‐wavelength with 1297.01 , 1303.38 , 1309.74 , and 1316.11 nm are obtained by varying the grating period from 196 to 199 nm with the spacing of 1 nm. Compared to the conventional DFB laser arrays, the DFB laser units are significantly reduced by 3/4 while maintaining the same number of output wavelengths. Additionally, by optimizing the λ/4 phase‐shift position and the duty cycle of gratings, the output power at the front‐end of the 4‐wavelength laser is significantly improved. Specifically, the ratio of the output power from the front‐end and rear‐end of the laser increases from the conventional 1.00 to 2.51. This work provides a competitive candidate for multi‐wavelength, high‐performance, and large‐scale silicon‐based light sources used in data centers, lidar, and component detection.