Scalable and compact blue diode laser arrays enabled by photonic lanterns and volume gratings

In this STTR, Hololase Photonics LLC intends to collaborate with the College of Optics and Photonics (CREOL) at the University of Central Florida (UCF) and proposes to develop a novel scalable platform for achieving high-brightness and high-power laser emission centered around 450 nm by utilizing coherently combined blue diode laser arrays enabled by photonic lanterns and volume gratings. The approach will use antireflection (AR) coated Āsingle diodes or diode arrays coupled into a photonic lantern fibers with the common output of the lantern interfaced with a volume Bragg grating (VBG) which will provide the passive coherent locking feedback to all the laser sources. The main components of this innovative system, the photonic lantern and the VBG, are robust and compatible with high-power laser sources operating in the blue spectral region. The system also has the benefits of being very compact and operating in passive coherent combining regime. This eliminates the need for any active feedback, computer control, and all associated optics needed when active coherent combining is implemented.ĀThe main advantages that makeĀthis approach very valuable are: First, the laser diodes or bars before being locked will be in working in amplified spontaneous emission mode. Therefore they will need very minimal feedback in order to start lasing. Second, the commonĀfeedback by the VBG and the random splitting provided from the photonic lantern will force all the diodes to lase coherently. The feedback needed will be only on the order of 15% a therefore the VBG will be with thickness on the order of 1mm. This means that any heating issues will be minimal even ot power levels ot hundreds of Watts. In addition, the system is easily scalable by the use of photonic lantern fiber with more inputs. As a whole, the envisioned passive CBC blue diode system is a new path for achieving high-brightness and high-power coherent sources operating around 450nm, that could find applications related to DE or machining of different materials. Furthermore, the same approach could be applied to other diode sources and this proposal could be the development phase of a more broad and general system for passive coherent combining of laser diode sources. We are confident that the teams from HoloLase Photonics and CREOL have solid experience in the direction of fiber lanterns, diffractive optics and coherent beam combining in order to make this Phase I and the following Phase II successful.