Author(s): Tao, JM (Tao, Jinming); Li, XT (Li, Xintong); Li, JY (Li, Jinye); Dai, SX (Dai, Shuangxing); Zhao, YR (Zhao, Yiru); Wei, CC (Wei, Chuangchuang); Liu, JG (Liu, Jianguo)

Source: PHOTONICS Volume: 9 Issue: 10 Article Number: 779 DOI: 10.3390/photonics9100779 Published: OCT 2022

Abstract: We propose a compact, high extinction ratio, and low-loss polarization beam splitter (PBS) on a lithium-niobate-on-insulator (LNOI) platform, based on an asymmetrical directional coupler and using a silicon nitride nanowire assisted waveguide (WG) and a grooved WG. By properly designing Si3N4 nanowires and grooved LN WGs, TE polarization meets the phase matching condition, while significant mismatching exists for TM polarization. Numerical simulations show that the PBS has an ultra-high extinction ratio (ER) of TE0 and TM0 (larger than 40 dB and 50 dB, respectively). The device extinction ratios are larger than 10 dB over 100 nm wavelength ranges. Moreover, the device has an ultra-low insertion loss (IL less than 0.05 dB) at the wavelength of 1550 nm and maintains ILs less than 0.4 dB over 100 nm wavelength ranges.

Accession Number: WOS:000873624800001

eISSN: 2304-6732

Full Text: https://www.mdpi.com/2304-6732/9/10/779