Generation of optical frequency combs in optically injected integrated gain-switched semiconductor lasers and their applications in Doppler LIDAR

Abstract

This paper introduces an optical frequency comb (OFC) source. It is constructed using a monolithically integrated gain-switched semiconductor laser with the optical injection technique. The theoretical analysis of the working principle of this integrated OFC source based on optical injection is carried out. Fabricated via micro–nano processing technology, the proposed OFC source has been experimentally investigated. The results clearly show that the optical injection method can notably increase the number of comb teeth with a higher carrier-to-noise ratio. The measured phase noise of the beat-frequency signal between comb teeth is less than −102 dBc Hz⁻¹ @ 10 kHz. Moreover, a Doppler velocity-measuring LIDAR system is designed based on this OFC source, and the velocity of a moving target is measured. Compared with single-frequency speed measurement, using multi-comb teeth for speed measurement can significantly reduce the error.