Frequency-locking of 1.5- mu m InGaAsP lasers to an atomic krypton line without dithering the laser frequency

The frequency-locking of a 1.5- mu m distributed-feedback (DFB) laser to an atomic Kr 2p/sub 8/-3d"/sub 1/ transition at 1.5244 mu m that does not dither the laser frequency is discussed. Instead, the frequency-discriminant signal was obtained by dithering the Kr line with a small AC magnetic field using the Zeeman effect. The frequency shift of this Kr line was measured to be 1.25 MHz/G, and is linearly proportional to the applied magnetic field. Since the technique avoids dithering of the laser frequency without adding complexity in the servo-loop, it is well suited for developing master oscillators to be used in optical wavelength-division-multiplexed (WDM) networks.<
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