Fiber–Chip–Fiber Mode/Polarization/Wavelength Transmission and Processing with Few‐Mode Fiber, (de)Multiplexing SiO₂ Chip and ROADM Si Chip

AbstractThe emergence of optical communications has opened up new perspectives for high‐capacity data transmission and signal processing, to meet the demand of the increasing data traffic. Despite significant progress in multi‐dimensional multiplexing for capacity scaling in fiber–optic communications or photonic networks‐on‐chip, achieving high‐capacity data transmission and signal processing in an entire fiber–chip–fiber system remains a great challenge. This challenge is attributed to the lack of effective multi‐dimensional coupling between fiber and chip. Here, the 3D (de)multiplexing SiO2 chip inscribed by femtosecond laser direct writing is proposed to achieve the multi‐dimensional coupling between the few‐mode fiber (FMF) transmission link and the silicon processing network. Combined with the 2D silicon chip fabricated by a standard lithography process, a multi‐dimensional fiber–chip–fiber communication system designed to transmit and process the hybrid wavelength‐, mode‐ and polarization‐division multiplexing signals in FMF is constructed. The silicon chip integrates Mach–Zehnder interferometer (MZI) switches and arrayed‐waveguide gratings (AWGs) to serve as a reconfigurable optical add/drop multiplexer (ROADM). As a proof‐of‐concept demonstration, a 96‐channel FMF–chip–FMF communication system with a data transmission capacity of 4.032 Tbit s−1, achieving a bit‐error ratio (BER) of less than 3.8 × 10−3, is successfully implemented.