Generation of electrically wavelength-tunable optical short pulses using a Fabry-Perot laser diode in an external-injection seeding scheme with improved sidemode suppression ratio

Electrically wavelength-tunable optical short pulses are generated from a gainswitched Fabry-Perot (F-P) laser diode with another F-P laser diode used as the external-injection-seeding light source. The injection wavelength is selected by a tunable filter and intensified by the use of an erbium-doped fiber amplifier before being directed to the gain-switched F-P laser diode. The sidemode suppression ratio achieved is better than 25 dB over the wavelength-tuning range of 9 nm. The system is simple and of low cost.