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Sonobuoy fields, consisting of many distributed emitter and receiver sonar sensors on buoys, are used to seek and track underwater targets in a defined search area. The authors seek a scheduling protocol, selecting both the emitter and its waveform in each time interval that optimises tracking performance. This study describes a stationary scheduling algorithm for sonobuoy fields called the continuous probability states algorithm. The algorithm replaces a full partially observed Markov decision process by a computationally feasible Markov decision process by focusing on probability of target detection. This approach is shown to result in high‐quality tracks for multiple targets in a realistic simulation of a sonobuoy field.

We have investigated a series of ridge waveguide lasers with deeply etched slots in the ridges. The slots do not penetrate the active region, but are deep enough to strongly perturb the longitudinal modes. By the addition of slots, a transition between perturbed-mode and coupled-cavity behavior is crossed. With a group of four or more slots, the below-threshold amplified spontaneous emission spectrum from each end of the laser has different periods and the facet-facet oscillations are suppressed indicating that the different sections have become quasi-independent. A model using a distributed emitter in the cavity reproduces this behavior. Above threshold, the single contact coupled cavity lasers are single mode with greater than 30-dB sidemode suppression ratio over a wide range of currents [ABSTRACT FROM PUBLISHER]