Frequency Stabilization of 1.5 µm Diode Laser Using Nonlinear Optical Frequency Conversion in Organic Fiber

Second-harmonic generation using 1.5 µm diode lasers in a nonlinear organic fiber with Cerenkov radiation phase matching is demonstrated for the first time. This second harmonic frequency was locked to the center of the rubidium spectral line to stabilize the fundamental frequency of the 1.56 µm diode laser. The resultant frequency fluctuation, which was evaluated by the error signal from the lock-in amplifier, was maintained at less than 0.3 MHz for one hour.