The Design of a Low-Cost Tunable Laser Based on Reconstructed Equivalent Chirp

Abstract

Abstract With the development of optical fiber communication, tunable laser design has become an international research hot spot. In this paper, a new type distributed feedback (DFB) tunable laser is introduced. It uses the Reconstruction-Equivalent-Chirp (REC) technology, combining the stepped chirp sampling structure and superstructure fiber Bragg grating structure. We can obtain continuous tunable multi-channel laser and achieve the purpose of eliminating chirp of the chirp pulse and compressing pulse width at the same time. Through the simulation calculation, it can be known that the output power of each laser’s channel are roughly equal. The laser can realize the tuning between 1530 nm to 1560 nm. And for the initial pulse with the conditions of Tin = 20 ps, the chirp coefficient C = 5 and time-bandwidth product is 2.25, time-bandwidth product will change to 0.458 after REC compression. The compression ratio is about 5:1, which means the pulse frequency chirp can be basically eliminated. The structure only needs to be manufactured by traditional lithography. Its low cost and excellent performance leads to a good applied prospect.