Abstract: A fiber amplifier for amplifying an optical signal, comprising a pump energy source capable of emitting energy at a pump wavelength: optical apparatus for transmitting the optical signal, the optical apparatus having a plurality of discrete portions, each discrete portion comprising a length of optical fiber and first and second components disposed at first and second respective locations and configured to substantially prevent energy having an intermediate wavelength in the discrete portion from entering other discrete portions of the optical apparatus; and a plurality of waveguides, each waveguide coupled to the pump energy source and to one of the plurality of discrete portions, each waveguide for providing energy at the pump wavelength from the pump energy source to its corresponding discrete portion, thereby increasing an intensity of light at the discrete portion's intermediate wavelength.

Abstract: Optical fibers (e.g., fiber lasers and fiber amplifiers), and systems containing such optical fibers are disclosed.

Abstract: An all-optical modulator for modulating the output power of a high-power optical pump source is disclosed. More particularly, with the optical modulator of the invention, the output power of a CW fiber laser is modulated by a low-power laser, such as a diode laser. The modulator comprises two optical couplers which are preferably wavelength-selective and interconnected by a nonlinear single mode optical fiber with a high Raman gain. A laser system comprising a high-power pump laser, a fast signal laser with a suitable modulation depth and the optical modulator of the invention can advantageously employed in materials processing and graphics arts printing applications.