SITIS Topic Details |
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| Proposals Accepted: | |
| Program: | SBIR |
| Topic Number: | AF103-015 (AirForce) |
| Title: | KW Fiber Pump Combiner with Polarization Maintaining Feed Through | Research & Technical Areas: | Sensors, Weapons |
| The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), which controls the export and import of defense-related material and services. Offerors must disclose any proposed use of foreign nationals, their country of origin, and what tasks each would accomplish in the statement of work in accordance with section 3.5.b.(7) of the solicitation. | Objective: | Develop innovative, bi-directional fiber laser/amplifier pump coupler/combiners for use in high power fiber laser weapon systems, extending the efficiency, reliability and power handling beyond 1kW.
| Description: | High energy lasers (HELs) are required for a number of military applications including long range sensing, target designation and illumination and missile defense. Electric lasers are considered the laser of choice in the long term since the energy supply is rechargeable and clean. The preferred type of electric laser is the semiconductor diode-pumped fiber laser, which integrates well with other sensors and electro-optic elements in an aerospace environment. This topic seeks proposals for demonstration of concepts and hardware which would enable high-brightness, high-power scaling of fiber lasers/amplifiers. Cladding pumped (double clad) fiber lasers can utilize a range of laser diode pump sources which are themselves rapidly advancing to higher levels of power and brightness. Pump combiners are used to transport the pump light between the high-brightness laser diode pump sources and the double clad gain fiber in an all-fiber amplifier. Pump combiners are essential for development of all-fiber architecture to maximize ruggedness and reliability. The ideal pump combiner minimizes the loss in brightness between multiple pump diodes and the gain fiber. It also has minimal loss for signal and polarization preservation both for efficiency and power handling capability. Coherently combinable fiber laser systems inherently require a narrow line width, polarized output master oscillator power amplifier (MOPA) configuration. Couplers are needed that are compatible with double clad fibers (DCF), polarization-maintaining (PM), large mode area (LMA) fibers. These fibers are typically low numerical aperture and may not be strictly single mode, making them sensitive to external stresses and deformations both contributing to bend loss and conversion to higher order mode guiding. In addition, couplers for photonic band gap or photonic crystal fibers (PCF) are needed for power handling and reliability. Coupler designs are targeted for lasing of Ytterbium (Yb) ~1064nm and Thulium(Tm) ~2000nm. Optical efficiency of the pump combiner and scalability of the number of fibers, total power, bi-directionality and polarization preservation will be used as metrics for all phases.
| PHASE I: KW power combiner designs and packaging for pump coupling to DCF Yb and Tm are sought. Criteria for the design include brightness preservation, bi-directional power handling capability, polarization preservation and robust packaging. Designs compatible with LMA and PCF gain fibers are sought.
| PHASE II: Based on Phase I designs and models: build, test, and demonstrate multi-kW capable bi-directional prototype hardware and conduct in-depth characterization of hardware to show a maturity of technology toward potential commercial and military applications. Delivery of packaged devices for Air Force Research Laboratory (AFRL/RDLA) evaluation is required.
| PHASE III | DUAL USE COMMERCIALIZATION: Military Application: Air Force directed energy applications include illuminators, infrared countermeasures and secure communications.
Commercial Application: Communications, medical, printing and materials processing (welding, marking, cutting).
| References: | 1. F. Gonthier, "All-Fiber Pump Coupling Techniques for Double-Clad Fiber Amplifiers," Lasers and Electro-Optics Europe, 2005. CLEO/Europe. 2005 Conference, pp. 716-716. 2. F. Gonthier et al, "High-Power All-Fiber Components: The Missing Link for High-Power Fiber Lasers," Proc. SPIE 5335 (2004). 3. C. Headley et al, "Tapered Fiber Bundles for Combining Laser Pumps," Proc. SPIE 5709, pp. 263-272, (2005). 4. A. Wetter et al, "Tapered Fused-Bundle Splitter Capable of 1 kW CW Operation," Proc. SPIE 6453, 64530I (2007). 5. M. Nielsen et al, "High Power PCF-Based Pump Combiners," Proc. SPIE 6453, 64532C (2007). |
| Keywords: | Fiber Laser, Pump Combiner, Double Clad Fiber |
Questions and Answers: |
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