Simple approach for wavelength tunable picosecond pulse generation by an external injection seeding scheme

A simple scheme to generate wavelength tunable picosecond pulses by the external injection seeding of a gain-switched Fabry-Perot laser diode (FP-LD) is demonstrated. The key parts of the system consist of a FP-LD, a fiber Bragg grating (FBG), and a 3-dB coupler. The peak wavelength can be tuned from one longitudinal lasing mode to another by changing the Bragg wavelength of the FBG. The wavelength tuning range achieved is about 10 nm and the overall side mode suppression ratio (SMSR) is better than 15 dB.