Frequency stabilization of a semiconductor laser using an external phase modulator.
A Ti:LiNbO(3) 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.
Tsuchida
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Iwasaki
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