Scalable non-mode selective Hermite–Gaussian mode multiplexer based on multi-plane light conversion

Abstract

Non-mode-selective (NMS) multiplexers (muxes) are highly desirable for coherent power combining to produce a high-power beam with a shaped profile (wavefront synthesis) from discrete, phase-locked emitters. We propose a design for a multi-plane light conversion (MPLC)-based NMS mux, which requires only a few phase masks for coherently combining hundreds of discrete input beams into an output beam consisting of hundreds of Hermite–Gaussian (HG) modes. The combination of HG modes as a base can further construct a beam with arbitrary wavefront. The low number of phase masks is attributed to the identical zero-crossing structure of the Hadamard-coded input arrays and of the output HG modes, enabling the practicality of such devices. An NMS mux supporting 256 HG modes is designed using only seven phase masks, and achieves an insertion loss of − 1.6 dB , mode-dependent loss of 4.7 dB, and average total mode crosstalk of − 4.4 dB . Additionally, this design, featuring equal power for all input beams, enables phase-only control in coherent power combining, resulting in significant simplifications and fast convergence compared with phase-and-amplitude control.

Photonic matrix multiplication lights up photonic accelerator and beyond

“…For example, a scalable nonmode selective Hermite–Gaussian mode multiplexer was proposed, as shown in Fig. 4b , where 256 Hermite–Gaussian modes were designed using only seven phase masks 98 . In Fig.…”

“… a Transverse distance estimation 97 . b Nonmode selective Hermite–Gaussian mode multiplexer 98 . c Mode demultiplexing hybrid 100 .…”