2010 seminar topic Multi-wavelength and Broadband Optical Sources for Fiber-Optic Communication

Tunable lasers in the C and L bands of fiber-optic communication have been designed with erbium-doped fiber. Tunability has been achieved without using an intra-cavity filter, merely by changing the intro-cavity parameters in an appropriate manner. Also, mode-locking at GHz frequencies with a very simple economical design is a highlight of this work. The large tuning range possible in this design is further utilized in demonstrating a broadband source by introducing a dispersion shifted fiber as an intra cavity element. The multiple four-wave mixing processes occurring between the longitudinal modes in this fiber result in a spectral broadening throughout the gain spectrum of the EDF. This is a simple and elegant design to realize a tunable broadband source at pump powers less than 200 mW. The mechanism of broadband generation and the utility of the source for applications will be discussed.