Abstract: The present invention provides an active fiber package for use in a fiber laser, amplifier, or ASE source comprising: a plate-shape base comprising a groove having a configuration of at least two spirals for receiving and fixedly holding an active fiber therein, said at least two spirals are coplanar enabling visibility of said active fiber, the outer loop of one spiral transitioning smoothly to the outer loop of another spiral, and the inner loop of each one of said spirals transitioning smoothly into a relatively short straight section; wherein a portion of said straight section of one of said spirals spliced to a coupling fiber, and wherein multiple inner loops of each one of said spirals in proximity to said straight section having a relatively low radius of curvature for enabling tight coiling of said active fiber, thus, for reducing thermal modal instability (TMI) and increasing lasing power.

Abstract: The present invention provides an active fiber package for use in a fiber laser, amplifier, or ASE source comprising: a plate-shape base comprising a groove having a configuration of at least two spirals for receiving and fixedly holding an active fiber therein, said at least two spirals are coplanar enabling visibility of said active fiber, the outer loop of one spiral transitioning smoothly to the outer loop of another spiral, and the inner loop of each one of said spirals transitioning smoothly into a relatively short straight section; wherein a portion of said straight section of one of said spirals spliced to a coupling fiber, and wherein multiple inner loops of each one of said spirals in proximity to said straight section having a relatively low radius of curvature for enabling tight coiling of said active fiber, thus, for reducing thermal modal instability (TMI) and increasing lasing power.

Abstract: Fiber lasers and methods are provided, in which the modal instability threshold is raised to provide more laser power. Fiber lasers comprise an active optical fiber having at least one absorption peak wavelength (?peak) and capable of supporting more than a fundamental mode during operation, and a plurality of pump diodes connected to deliver radiation emitted thereby into the optical fiber. At least one of the pump diodes is a wavelength-locked (WL) diode and at least one of the pump diodes is configured to deliver radiation at at least ???(not necessarily the same diode(s)). The pump diodes may comprise any of WL diode(s) at ???peak, WL diode(s) at ?=?peak and non-WL diode(s). Pumping radiation off the fiber's absorption peak increases the modal instability threshold, most likely by reducing the temperature gradient in the active fiber at the fiber pump entrance point and along the fiber.

Abstract: Fiber lasers and methods are provided, in which the modal instability threshold is raised to provide more laser power. Fiber lasers comprise an active optical fiber having at least one absorption peak wavelength (?peak) and capable of supporting more than a fundamental mode during operation, and a plurality of pump diodes connected to deliver radiation emitted thereby into the optical fiber. At least one of the pump diodes is a wavelength-locked (WL) diode and at least one of the pump diodes is configured to deliver radiation at at least ???(not necessarily the same diode(s)). The pump diodes may comprise any of WL diode(s) at ???peak, WL diode(s) at ?=?peak and non-WL diode(s). Pumping radiation off the fiber's absorption peak increases the modal instability threshold, most likely by reducing the temperature gradient in the active fiber at the fiber pump entrance point and along the fiber.