Patent ID: 9595802
Date: 2017-03-14
CPC Classifications: G02B,H01S

Claim:
1. An optical amplifier for amplifying light from a near-diffraction-limited input, the optical amplifier comprising: a length of multi-mode optical fiber comprising a gain medium and having an output, the length of multi-mode optical fiber configured to propagate a fundamental mode; a length of single mode optical fiber configured to propagate a single mode; a splice between the length of multi-mode optical fiber and the length of single-mode optical fiber, wherein the splice is operably arranged to match the single mode of the length of single mode fiber to the fundamental mode of the length of multimode fiber; a pump source operably arranged to inject pump light into said length of multi-mode optical fiber to excite said gain medium; and an input providing a nearly diffraction limited input beam optically coupled to said length of multi-mode fiber, said input comprising a laser source, said input comprising said length of single-mode optical fiber configured to propagate the single mode, said length of multi-mode fiber providing at said output an output beam amplified by said gain medium that is substantially in the fundamental mode, wherein said input beam comprises a wavelength and a spectrum of said amplified output beam comprises said wavelength, and wherein the length of single mode fiber is operably arranged to excite the fundamental mode of the length of multimode fiber with an efficiency of at least 90%.