SBIR-STTR Award

The Phase I effort aims to demonstrate a new approach to coilable crystalline fiber lasers that builds on Onyx Optics’ experience of manufacturing adhesive-free composite waveguide structures to produce bendable double-core laser ribbons. Onyx Optics proposes to focus on the manufacturing and characterization aspects of the technology because it appears essential to develop a reproducible process and characterize optical, and mechanical properties of coilable waveguides with the objective of presenting an alternative to glass fiber lasers for power scaling to 100 kW and 1000kW output. The lasing demonstration of single and multimode flexible ribbons at ARL is a critical element of Phase I. In effect, the Phase I should lay the groundwork for demonstrating the competitiveness with optical fibers and bulk crystal lasers for Directed Energy Weapons. There are many critical parameters for establishing crystalline ribbon fiber lasers. Accuracy of fabrication is a prerequisite. The design of the ribbon for performance as a laser is an important consideration. The difference in refractive index between the core and inner cladding, the transmitted wavefront as well as the passive loss due to scattering and background absorption have to be determined. The mechanical properties of the ribbon will be predicted and experimentally confirmed.

Keywords:
Coilable Crystalline Fiber Ribbon Laser; Eye-Safe Ribbon Laser; Er:Yag, Tm:Yag Core Ribbon; Single Or Multimode Crystal Fiber; Broadband Or Single Frequency Er:Yag Crystal Fib

Yb:YAG crystalline fiber lasers can have a 9 times higher power limit (16.9 kW vs 1.89 kW) for narrowband lasers than a Yb-silica fiber laser due to the higher thermal conductivity (10.7 vs 1.38 W/m C) and the reduced SBS (stimulated Brillouin scattering) gain coefficient (10**(-15) to 10**(-12) vs 10**(-11) m/W). Thus, there are many efforts underway to develop crystalline fibers using laser media such as YAG. One of the difficulties of the technique appears to consist of attaining optical quality and accurate diameter control on fiber drawing or consolidation of the green ceramic fibers.

Keywords:
Afb(R), Adhesive-Free Bond, True Crystalline Fibers, Double-Clad Crystal Fibers, Low Loss Crystal Fiber, Double Clad Planar Waveguides