Small-frequency-difference stabilization of laser diodes using12C2H2 and 13C2H2 absorption lines for transmitter and local oscillator ofoptical heterodyne systems

Small-frequency-difference stabilization of distributed Bragg reflector (DBR) laser diodes has been demonstrated for the first time by using vibrational-rotational absorption of ¹²C₂H ₂ and ¹³C₂H₂ molecules. Frequency stabilization of two DBR laser diodes has been carried out at a wavelength of about 1.536 μm. The frequency difference between the two stabilized lasers was evaluated to be 9 GHz by the beat spectrum measurement. The experimental results suggest that such a pair of frequency-stabilized laser diodes with a small frequency difference could be used as the transmitter and local oscillator of optical heterodyne systems