Fast Tubale Wavelength Converter Based On A GCSR Laser

With fast development of the quantity of users and demand of information, digital,wideband,intelligent, integration, personal and global networks have become the main direction of development of modern communications.All-optical network has become the most potential and promising proposal of future communication system. Wavelength converter is always playing an important role in all-optical networks from the date of its birth.It improves the connectivity of high sub networks,provides virtual wavelength routing, which has become a necessary solution to resolve the improvement demand of flexibility of optical switching networks, the lower network congestion and the competition of optical nodes.In this paper, a wavelength converter based on a GCSR laser is demonstrated, which has fast conversion speed and also the ability to suppress hopping-mode wavelengths generated during the tuning process. It mainly contains two parts:a well designed fast digital driver and a GCSR (Grating assisted co-directional Coupler with rear Sampled grating Reflector) laser. The fast digital driver is consisted of four modules: FPGA module, digital to analogy converter module, amplifier module and temperature controller module.The fast digital driver provides four channel of tunable current for the GCSR laser, which respectively direct at the four sections of the GCSR laser-Gain section,coupler section, phase section and reflection section.The controller tunable current drives the tunable wavelength as the output of the GCSR laser.A novel proposal of suppression the hopping-mode wavelength generating during the tuning process of the driver current for the GCSR laser is also introduced in the paper. The results of the experiment show that the wavelength of GCSR laser is successfully converted from 1562.5nm to 1569.1nm with short tunable time of 6ns and coverage of 6.6nm. The hopping-mode wavelength is also successfully suppressed and the suppression ratio can reach 40dB.