Blue-Green Laser for Undersea Communication

In response to the SPAWAR solicitation for a blue/green laser for underwater communications Aculight propose the development of a hybrid laser system comprising a low-power semiconductor seed source generating the desired pulse duration and repetition frequency, followed by a multistage Yb-doped fiber amplifier to generate the peak and average power required for efficient harmonic conversion. The achievable peak powers and near perfect beam quality allows high conversion efficiency with either KTP or non-critically phase matched LBO, one of the most rugged and robust harmonic conversion materials. Our proposed fiber laser solution will deliver > 10 W of average 532nm power at 100kHz-10MHz rep-rates in a small (~ 0.1 ft3), air or conduction-cooled package. Aculight will develop electronics control circuitry capable of varying the pulse format to address the variable data rate requirements. State of the art optical fibers and specifically engineered fiber components will be integrated into a high gain amplifier in which nonlinearities are mitigated at a level consistent with the specification. A frequency doubling module incorporating a collimator and nonlinear crystal will be integrated with the laser system. In an option task Aculight propose an upgrade to the system to address higher energy or higher data rate requirements.