Abstract: A narrow-linewidth high-power single-frequency laser is realized by pumping a laser cavity with a pair of polarized single-mode pump lasers that are driven below their respective “micro-kink” regions and combined with a polarized beam combiner. The pump lasers emit at the same wavelength and include a length of polarization-maintaining (PM) fiber to maintain the polarization of the respective pumps. The laser cavity is selected from microchip, fiber and waveguide devices and is provided with optical feedback. This laser is capable of producing a stable high-power single-mode signal with a very narrow linewidth, e.g. less than 10 kHz and preferably less than 3 kHz.

Abstract: A compact low-cost continuous single-mode fiber laser delivers output powers in excess of 50 mW over the C-band (1530 nm-1565 nm). The phosphate glass fiber supports the high doping concentrations of erbium and ytterbium (Er:Yb) without self-pulsation that are required to provide sufficient gain per centimeter needed to achieve high power in the ultra short cavity lengths necessary to support single-mode lasers. The use of fiber drawing technology provides a lower cost solution than either combined solution doping/MCVD fiber fabrication or waveguide fabrication. The ability to multi-mode clad pump the fiber further reduces cost, which is critical to the successful deployment of fiber lasers in the burgeoning metro markets.