Fiber optical amplifier, has multimode dual core fiber with transversal mode selection element on it or in it near one end that suppresses higher modes than fundamental mode

摘要

The amplifier has a laser source of narrowband signal radiation at one or more wavelengths at a first end of an amplifier fiber (12). Amplified signal radiation can be coupled out of the second fiber end. The multimode dual core fiber has a pump core and a laser core that is end pumped or laterally pumped. The fiber has a transversal mode selection element (27) on it or in it near one end that suppresses higher modes than the fundamental mode.