Abstract: The disclosure is directed toward an optical transmission system comprising a primary path disposed between a first end and a second end. The primary path is configured to transmit optical signals between the first end and the second end. A secondary path is disposed between the first end and the second end. The secondary path is configured to transmit optical signals between the first end and the second end, e.g., in the event of a break in the primary path. A first variable ratio coupler is coupled to the primary path and the secondary path between the first end and the second end. The first variable ratio coupler is configured to adjust a coupling ratio between the primary path and the secondary path.

Abstract: A method of operating a stretched-pulse Raman fiber laser includes producing laser radiation gain in a laser cavity using predominantly Raman amplification. Such a stretched-pulse Raman fiber laser has a laser cavity that includes a Negative Group Velocity Dispersion Fiber connected in series with a Positive Group Velocity Dispersion Fiber, a polarization controller and an isolator. In some examples, the Negative Group Velocity Dispersion Fiber is a Dispersion Compensating Fiber. In other examples, the Negative Group Velocity Dispersion Fiber is replaced by a Raman Specialty Fiber.

Abstract: A multiplexing/demultiplexing optical device comprises a beam distribution element to receive an input optical signal comprising one or more wavelengths and to distribute the optical signal into a plurality of beams. The optical device also comprises a variable path length element to receive the distributed optical signal from the first optical element, where the variable path length element comprises a plurality path sections, where a length of at least one of the path sections is variable. The optical device further comprises a beam interaction element to receive the plurality of beams from the variable path length element, wherein the plurality of beams are combined and allowed to interfere, and are thereby demultiplexed. A controller operatively coupled to the variable path length element can be provided to programmatically vary the length of one or more of the path sections.

Abstract: A multiplexing/demultiplexing optical device comprises a beam distribution element to receive an input optical signal comprising one or more wavelengths and to distribute the optical signal into a plurality of beams. The optical device also comprises a variable path length element to receive the distributed optical signal from the first optical element, where the variable path length element comprises a plurality path sections, where a length of at least one of the path sections is variable. The optical device further comprises a beam interaction element to receive the plurality of beams from the variable path length element, wherein the plurality of beams are combined and allowed to interfere, and are thereby demultiplexed. A controller operatively coupled to the variable path length element can be provided to programmatically vary the length of one or more of the path sections.