Generation of wavelength-tunable single-mode picosecond pulses from a self-seeded gain-switched Fabry-Perot laser diode with a high-birefringence fiber loop mirror

We demonstrate a simple self-seeding scheme for generating wavelength-tunab le single-mode picosecond pulses at a fixed repetition rate with a Fabry-Pe rot (FP) laser diode. In this scheme, the FP laser diode is self-seeded fro m a high-birefringence (HiBi) fiber loop mirror that acts as a periodic mul tichannel wavelength filter. By setting the channel spacing of the filter p roperly, stepwise wavelength tuning over a wide range can be achieved by ei ther changing the FP cavity roundtrip phase shift or tuning the fiber loop mirror filter. With this scheme, fast electrical tuning is also possible by incorporating a phase-control section into the FP cavity. Using a HiBi fib er loop mirror with a channel spacing of 1.56 nm and a FP laser diode with a mode spacing of 1.45 nm, we were able to generate picosecond pulses at a repetition rate of approximately 2 GHz, whose wavelength could be tuned ste pwise over ten successive laser cavity modes by either changing the tempera ture of the laser diode or tensioning/pressing a section of the HiBi fiber in the loop mirror. A side-mode suppression ratio over 15 dB over the entir e tuning range was achieved. (C) 2000 American Institute of Physics. [S0003 -6951(00)01625-9].