All-optical flip-flop based on coupled laser diodes

An all-optical set-reset flip-flop is presented that is based on two couple d lasers with separate cavities and lasing at different wavelengths. The la sers are coupled so that lasing in one of the lasers quenches lasing in the other laser. The flip-flop state is determined by the laser that is curren tly lasing, A rate-equation based model for the flip-flop is developed and used to obtain steady-state characteristics. Important properties of the sy stem, such as the minimum coupling between lasers and the optical power req uired for switching, are derived from the model. These properties are prima rily dependent on the laser mirror reflectivity, the inter-laser coupling, and the power emitted from one of the component lasers, affording the desig ner great control over the flip-flop properties. The flip-flop is experimen tally demonstrated with two lasers constructed from identical semiconductor optical amplifiiers (SOAs) and fiber Bragg gratings of different wavelengt hs. Good agreement between the theory and experiment is obtained. Furthermo re, switching over a aide range of input wavelengths is shown; however, inc reased switching power is required for wavelengths far from the SOA gain pe ak.