Monolithic Integration of a Multiwavelength Laser Array Associated with SBG Semiconductor Lasers

摘要

There are strong demands of monolithically integrated photonic components for future high capacity optical networks such as those for data center, fifth-generation fronthaul or wavelength-division multiplexing systems. Monolithically integrated multiwavelength laser array (MLA) is a potential photonic component used in the above applications. The monolithically integrated MLA associated with sampled Bragg grating (SBG) semiconductor lasers is proposed and studied here. It is shown in the results that a controllable phase shift can be introduced into the central part of the cavity to tune the lasing wavelength. The effective refractive index along the phase-shift-controlled (PSC) parts was different from those of the side parts with the different currents injected into the PSC parts and the side parts. So the optical path length along the PSC part changed for the lasing wavelength. In other words, an appropriate distributed phase shift along the PSC part could be introduced accordingly. Besides, it is found in the results that the longitudinal photon density distribution of the proposed structure is much flatter than that of the /4 phase-shift structure. Hence, the longitudinal spatial hole burning (SHB) is reduced more effectively. The single longitudinal mode (SLM) stability is better than that of the common /4 phase-shift structure at high injection currents accordingly. A twelve-channel SBG MLA with 50-GHz wavelength spacing was fabricated in the experiment. The channel frequency ranges from 192.70 THz to 192.15 THz. Its operation at designed wavelengths was demonstrated. High side mode suppression ratios (SMSRs) of all channels over 57 dB were observed as well. This paves the way for a compact and cost-efficient light source for large-scale photonic integrated circuit devices.