Patent ID: 7027471

Claim:
A fast wavelength-tunable laser system provided in a wavelength division multiplexing (WDM) network comprising: two or more multi-longitudinal-mode Fabry-Perot laser diodes, one of which is an inter-injection type laser diode capable of injecting light to the other diode(s); an optical coupler for coupling lights emitted from said laser diodes by forming a gain resonance cavity with said laser diodes; an optical circulator with reflective/transmissive structure for transmitting light to the other diode(s) and outputting light generated in said gain resonance cavity; a polarization controller for stabilizing the output energy of light by controlling its polarization state; an optical tunable filter for removing undesired wavelength and outputting predetermined wavelength by varying the bias voltage of maximum optical gain in said laser diodes; an Erbium-doped fiber, with a predetermined length based on the maximum gain of light, connected to said optical circulator for outputting light of predetermined wavelength; an Erbium-doped fiber amplifier for amplifying the output of said Erbium-doped fiber and transmitting the amplified light to an optical-to-electrical converter; and an optical-to-electrical converter for receiving and converting said amplified light into electrical signal for the purpose of monitoring and analysis.