Mutual Injection Fiber Laser Array

The OSD is seeking new approaches to coherent beam combination of fiber lasers for high-brightness fiber laser arrays, considering the brightness of the array (which is the output intensity divided by the beam far-field divergence angle, and determines how much intensity can be placed on a target in the far field) as more important than pure power. To address this need, Physical Optics Corporation (POC) proposes to develop a new Mutual Injection Fiber Laser Array (MIFLA). This proposed device is based on an application of POC's mutual injection locking and volume Bragg grating technologies to fiber lasers to increase the brightness of the array. The MIFLA will make fiber laser arrays scalable to 100 kW levels, without the loss in brightness inherent in incoherent beam combination (spectral combination, spatial combination, etc.), keeping the brightness at ~3,000 GW/cm^2-sr. In Phase I POC will demonstrate the feasibility of MIFLA by locking the wavelengths of several independent lasers with an external Bragg grating and phase-locking the outputs together by mutual injection locking. In Phase II POC plans to fabricate an engineering prototype of a fully phase locked fiber laser array using the aforementioned POC technologies.