Enhanced Tuning Performance of In-Series REC-DFB Laser Array

Abstract

In this study, a tunable in-series multi-wavelength distributed feedback laser array (DFB-MLA) based on reconstruction-equivalent-chirp (REC) technique with simple wavelength tuning scheme is presented and experimentally demonstrated. Unlike traditional DFB laser tuned by thermal-electric cooler (TEC), the proposed laser tuned by injection current can realize faster wavelength-tuning and reduce TEC power consumption. By comparing the thermal influence of different structures of heatsink blocks, several optimized block structures are selected for appropriate thermal conductivity and controllable heat dissipation, resulting in a broad and continuous wavelength tuning range. The proposed in-series DFB-MLA on optimized heatsink achieves better tuning performance with a wavelength tuning range of ~2.4 nm per channel from 40 to 120 mA and stable output power of over 20 mW compared to the laser mounted on the standard heatsink block with the tuning range of 1.4 nm per channel. Furthermore, the tunable laser keeps good single-mode stability, with a side mode suppressing ratio (SMSR) of over 40 dB. Thus, this study provides a new perspective for designing a low-cost continuous tunable semiconductor laser with a simple tuning mechanism in the future.