Faraday effect-based semiconductor laser-frequency stabilization at the Rb absorption line

In order to stabilize the oscillation frequency of a semiconductor laser, we use the external reference-point, in this instance, to determine the degree to which the observed frequency deviates from the reference signal. This is done, by modulating the laser´s injection current. In so doing, however, the oscillation spectrum inevitably broadens. We therefore devised a method that takes full advantage of the Faraday effect to stabilize the oscillation frequency, yet needs no direct modulation