An 8-channel narrow linewidth multi-wavelength laser hybrid integrated by photonic wire bonding structures for DWDM systems

An 8-channel monolithically integrated narrow linewidth multi-wavelength laser array (NL-MLA) combined with the commercial 8 × 1 planar lightwave circuit (PLC) coupler by the photonic wire bonding (PWB) technique is demonstrated in this paper. A distributed feedback (DFB) laser with the high-reflection and anti-reflection coatings (HR-AR) and the tapered asymmetric corrugation-pitch-modulated (TACPM) grating structure is proposed. The TACPM grating is achieved by the reconstruction equivalent chirp (REC) technique, which is low-cost and of high wavelength accuracy. According to the numerical simulation results, under the unavoidable impact of the facet phase of the HR end, the TACPM DFB laser suppresses the longitudinal spatial hole burning (LSHB) effect significantly, while having better single-mode performance and control of wavelength compared with the conventional HR-AR DFB laser. An 8-channel HR-AR TACPM DFB NL-MLA is fabricated with the 0.8 nm wavelength spacing design. The hybrid integration between the 8-channel NL-MLA and the PLC chip is achieved using the PWB technique. Both good single-mode performance and accurate wavelength interval of 0.8 nm can be obtained when all channels work simultaneously. The laser linewidth is below 273.8 kHz with good uniformity, and the relative intensity noise is under −159.6 dB/Hz for each channel.