Experimental Implementation of a Fiber Noise Cancellation System for Slow Light Laser Locking
Alexander Bengtsson
An electromagnetic wave propagating through an optical fiber is sensitive to external disturbances, such as mechanical vibrations and temperature and pressure fluctuations, which add phase noise onto the wave. For high-precision frequency-based applications this phase noise has to be removed. By partially reflecting light from the remote end of the fiber back through the fiber, and comparing it to light that has not passed through the fiber, their beat note can be phase locked to a stable reference, using an acousto-optic modulator for phase noise compensation. This effectively cancels the phase noise at the remote end of the fiber. In this project, two such fiber noise cancellation systems have been successfully assembled. The fiber noise cancellation systems will be used for laser locking to a slow light crystal cavity. Using spectral hole burning, a very low group velocity can be obtained in rare-earth-ion-doped crystals. By depositing mirrors on such a crystal, it could act as a reference cavity with a very long effective length, but without the increased difficulty of isolating the cavity from mechanical vibrations associated with a physically long cavity. By locking a laser to a slow light crystal cavity, an improved stability could potentially be achieved. A possible setup for slow light crystal cavity laser locking experiments, where the fiber noise cancellation systems have been integrated, is also presented in this thesis.
•Jan 1, 2017•0 citations