On-chip Fourier transform spectrometers by dual-polarized detection

Abstract

Chip-scale Fourier transform spectrometers (FTSs) have recently emerged for inexpensive, high-resolution spectroscopic applications. In particular, spatial-heterodyne FTSs (SH-FTSs) have drawn considerable attention with a simple and stable configuration based on an array of Mach–Zehnder interferometers (MZIs) with linearly increased optical path differences. There is a significant trade-off between spectral performance and the MZI number. In this work, we propose a dual-polarized SH-FTS, detecting both fundamental transverse electric and transverse magnetic modes, on a silicon photonic chip. Our experimental results show that, compared to the conventional single-polarized design, the MZI number of the dual-polarized SH-FTS can be nearly halved for a smaller footprint with little compromise of spectral performance.