Invention:
Researchers at the University of Arizona College of Optical Sciences have developed a means of increasing power output in single mode fiber lasers by significantly increasing the mode area available for doping, thus providing higher power in shorter fiber lasers. Instead of the conventional refractive index relationship between the cladding (outer) region and the core (inner) region of the fiber, a material of lower refractive index is used in the core region. This approach significantly lowers control and fabrication tolerances, thus lowering the total cost of production. Using a novel geometry of "holey fibers", also called "photonic crystal fibers" (PCF), the invention is a low-cost approach to the design and manufacture of waveguides for optical switching, high-speed data transmission, laser surgery, and welding applications.
Background:
The field of high-power fiber lasers hits limitations with conventional single-mode step-index fibers because the high ion doping concentrations needed for high power require a long length of fiber, making it difficult to maintain a single mode. Shorter lengths of fiber can remain single mode, but can only achieve powers in the milliwatt range because the short length cannot support sufficient ion doping concentrations to achieve higher power. Part of the problem is due to the small mode area of single-mode step-index fibers.
Applications:
- Compact high-power fiber lasers and amplifiers
- Optical sensors
- Pump sources
- Passive single mode fibers with core sizes >600 µm2
Advantages:
- Continuous high-power single mode operation with narrow linewidth
- Compact
- Lower manufacturing costs- Fabrication tolerances eased
- Compatible with existing technologies
- Passive and active fibers with large mode diameters
- Reduces optical non-linear effects and instability
Status: U.S. Patent No. 8,731,356 was issued on 20 May, 2014
