Simultaneous linewidth narrowing for integrated chip of DFB laser array based on self-injection feedback

Abstract

With the rapid development of communication and sensing technology, the requires for optical source with multi-channels and narrow-linewidth raise up. In this paper, a heterogeneously integrated InP-based distributed feedback (DFB) laser array is proposed and demonstrated, which realizes the simultaneous linewidth narrowing of eight wavelengths. By utilizing the photonic wire bonding (PWB) technique, the DFB laser array is integrated with silicon-on-insulator (SOI)-based passive multiplexing devices, i.e., arrayed waveguide grating (AWG). The AWG realizes multi-wavelength combining and routing, and solves the problem of reorientation during wavelengths injection. With the self-injection feedback from circulator, the linewidth of eight wavelengths of DFB laser array is narrowing from MHz to kHz, simultaneously. Eliminating the wavelength dependence on external cavities of conventional method, the proposed scheme enables simultaneous linewidth narrowing of multi-wavelength lasers, which has potential application for coherent optical communications and high-precision detection.