Experimental Demonstration Of A Fast Tunable Laser Based On DFB Semiconductor Laser Array Using Reconstruction-Equivalent-Chirp(REC)Technique

With the advent of big data era,the demand for network bandwidth is increasing rapidly,and the requirement of tunable laser is higher and higher.It is well considered that the optical router will replace the electrical router in the next few years.Among the existing methods of wavelength switching,wavelength tunable laser has shown great potential at an optical router demonstrator.Up to now,there have been several methods mainly used for wavelength tuning in tunable laser,such as lith-ium-niobate Mach-Zehnder-interferometer-based directional coupler switches and semiconductor gate switches based on optical amplifier.However,mode hopping is a huge problem of these method,which cannot meet the needs of optical routers.In this paper,we propose a novel method of wavelength tuning using semiconductor DFB laser array.The DFB semiconductor laser we used is fabricated based on reconstruction-equivalent-chirp(REC)technology,which has the advantages of low cost and accurate wavelength spacing.We also design a high-speed driving circuit to enable the operation of specific laser in the laser array according to our needs.Comparing with the former methods,this approach improves the tuning speed because the switching time is determined by the driving circuit which can reach to nanoseconds and make sure that mode hopping doesn't appear.In the experiment,we realize a wavelength switching time of about 30 ns.