A Ti:LiNbO3 waveguide phase modulator is used as an external frequency stabilizer to reduce the linewidth of an AlGaAs semiconductor laser. A ring interferometer is used as a frequency discriminator, and a wideband servo controller (dc to 30 MHz) is constructed in which feed-forward control of the external phase modulator is combined with feedback control of the injection current. A linewidth of 45 kHz is obtained.
© 1992 Optical Society of America
Original Manuscript: August 16, 1991
Published: January 1, 1992
Hidemi Tsuchida and Takashi Iwasaki, "Frequency stabilization of a semiconductor laser using an external phase modulator," Opt. Lett. 17, 49-51 (1992)