Low Loss Asymmetric Bragg Grating Mode Couplers on Thin Film Lithium Niobate for Efficient Extraction of Reflected Light

Bragg gratings are important components in integrated photonics, however, efficiently a ccessing t he r eflected wa ves re mains ch allenging. He re, we de monstrate an asymmetric Bragg grating mode coupler in thin-film lithium niobate with 1 dB insertion loss.