Abstract

The injection of a monochromatic signal into a laser is a well-known technique for locking the laser phase to that of the injection. Some years ago another type of injection, called rocking [1,2], was introduced to render the laser phase-locking bistable. Rocking consists of the modulation of the amplitude injection so that its sign changes periodically, or even randomly [3], in time. Here we present an alternative to rocking that leads to the same type of behaviour, namely the appearance of bistable phase locking and, in the case of large Fresnel number lasers, to stable (phase bistable) cavity solitons and extended patterns. The new type of injection we present here is monochromatic, unlike usual rocking, but it is spatially modulated across the transverse plane of the cavity, so that its sign varies periodically, or even randomly, in space. Advantages of the proposed injection technique with respect to usual rocking are evident, as in usual rocking the time modulation scale can interact with relevant time scales of the laser, limiting its performance [4], a feature that is absent in the present proposal. As well, the intrinsic polychromaticity of rocking requires that the cavity line-width be larger than the injection bandwidth a limitation that, again, does not affect the technique put forward here.

© 2009 IEEE