Large Quality Factor Enhancement Based on Cascaded Uniform Lithium Niobate Bichromatic Photonic Crystal Cavities

TL;DR

This paper demonstrates that cascading bichromatic photonic crystal cavities in lithium niobate significantly enhances the quality factor, achieving over 10^5, with practical fabrication methods and potential for high-performance photonic devices.

Contribution

It introduces a cascaded design approach for photonic crystal cavities that substantially increases the quality factor without enlarging device size, validated through simulation and fabrication.

Findings

Quality factor exceeds 10^5 in simulated cascaded cavities

Experimental fabrication of the cascaded cavity with 70° slant holes

Cascading enhances quality factor by an order of magnitude

Abstract

In this paper, by cascading several bichromatic photonic crystals we demonstrate that the quality factor can be much larger compared with that in an isolated cavity without increasing the total size of the device. We take lithium niobate photonic crystal as an example to illustrate that the simulated quality factor of the cascaded cavity can attain 10^5 with a 70{\deg} slant angle, which is an order of magnitude larger than that in isolated cavity. The device can be fabricated easily by current etching technique for lithium niobate. We have fabricated the proposed device experimentally including holes with 70{\deg} slant angle. This work is expected to provide guidance to the design of photonic crystal cavity with high-quality factor.