Systems and Techniques for Suppressing Backward Lasing in High-Power Cascaded Raman Fiber Lasers

Abstract

In a light amplification system and technique, a pump source provides pump power at a source wavelength. The pump power is launched as an input into a cascaded Raman resonator. A wavelength-dependent loss element is connected such that it precedes the cascaded Raman resonator. The wavelength-dependent loss element is configured to transmit light power at the source wavelength with low loss, and to provide high loss at the first Stokes shift. The wavelength-dependent loss element prevents buildup of light power between the pump source and the cascaded Raman resonator, thereby preventing backward propagation of light power back into the pump source.

Description

CROSS REFERENCE TO RELATED APPLICATION[0001]The present application claims the priority benefit of United States Provisional Patent Application Ser. No. 61 / 177,058, filed on May 11, 2009, which is owned by the assignee of the present application, and which is incorporated herein by reference in its entirety.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates generally to optical fiber devices and methods, and in particular to improved systems and techniques for suppressing backward lasing in high-power cascaded Raman fiber lasers.[0004]2. Background Art[0005]Stimulated Raman scattering in optical fibers is a useful effect that can be used to provide nonlinear gain at wavelength regions where rare-earth doped fibers do not operate. A cladding-pumped, Yb-doped fiber can serve as a brightness converter to convert high-power multi-mode diodes at 915 nm or 975 nm to single-mode radiation in the region of 1.0 to 1.2 micrometers. This can then be u...

AI Technical Summary

Benefits of technology

The present invention provides a light amplification system and technique that suppresses backward lasing. This is achieved by using a wavelength-dependent loss element that prevents buildup of light power between the pump source and the cascaded Raman resonator, thereby preventing backward propagation of light power back into the pump source. Additionally, the invention also discusses scaling to higher powers through the use of an amplifier fiber with a larger modefield diameter and a wavelength-dependent loss element with a broader bandwidth.

Problems solved by technology

Ultimately, it can cause pulsing of the laser which can lead to component failure.

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