Narrow-Linewidth, Electro-Optically Tunable InGaAsP-Ti: LiNbO sub 3 Extended Cavity Laser.

We report an electro-optically tunable, single-frequency extended cavity laser with a linewidth of less than 60 kHz. The laser consists of a 1.5micron InGaAsP gain medium and an electro- optically tunable, narrow-band Ti:LiNbO3 wavelength filter (Delta lambda ~ 12angstroms). The wavelength filter employs a wavelength tunable TE->TM polarization converter, a TE-pass polarizer, and an electro-optic phase shifter. Single-frequency lasing with more than 1 mW output power and better than 20 dB side-mode suppression has been demonstrated. The laser can be broadly tuned over at least 70angstroms via the electro- optically tunable LiNbO sub 3 wavelength filter, and can be continuously fine tuned over more than 1 GHz (0.08angstroms) via the electro-optic phase shifter.