High performance DFB laser array combiner enabled by all-dielectric metalens array.

Metalens have the advantages of ultra-thin, low loss, easy integration and flexible phase control mechanism, which have attracted intensive attention in the field of on-chip photonic chips. By designing Si nanocylinder meta-atom on SiO 2 substrate, the structure size is optimized to achieve the optimal light transmittance and phase change covers the range of 2π. In order to achieve the effect of coupling Distributed Feedback Laser (DFB) array into a fiber, it is necessary to accurately arrange the above optimized Si nanocylinder according to a certain phase profile to achieve the effect of off-axis focusing. Here, we designed an off-axis focusing metalens array to efficiently couple the parallel 4-channel DFB laser array into the few-mode fiber (FMF), and the total coupling efficiency reaches 56.48 %. This result provides a new idea for compact, low loss on-chip light sources. • A novel and reliable low loss laser array combining scheme is proposed. • An off-axis focusing metalens array is designed for multi-channel laser combining. • The combiner has the advantages of high integration, low loss, polarization insensitivity, and mode insensitivity. • In the parallel 4-channel laser array, the metalens array exhibits a coupling efficiency of 56.48 %. • The loss of the proposed combiner does not increase with the increase of the laser channels number. [ABSTRACT FROM AUTHOR]