MULTIWAVELENGTH PICOSECOND OPTICAL PULSE GENERATION USING AN ACTIVELYMODE-LOCKED MULTICHANNEL GRATING CAVITY LASER

A multichannel grating cavity (MGC) laser is found to be suitable for multiwavelength ultrashort optical pulse generation using active mode- locking techniques. By using different configurations of the MGC laser , dual wavelength picosecond pulses are successfully produced with goo d spectral quality, either simultaneously or with a programmable relat ive delay between the channels. For a channel separation of 2.2 mn, pu lses with a duration of 60 ps and a spectral width of 11.6 GHz have be en obtained. The experimental results are compared with those from a t heoretical analysis of the multiwavelength mode-locking process using a set of modified coupled-cavity rate equations, The minimum achievabl e pulsewidths generated by the actively mode-locked MGC laser are show n to be limited by the resolution bandwidth of grating used, The depen dence of pulsewidth oh RF drive frequency detuning is examined and it is found that the ultrashort pulses can be obtained over a wide range of frequency detuning. The interchannel cross-talk originating from ga in saturation and carrier depletion is also discussed.