Optical fiber coupler for coupling signal beams into a non-circularly shaped optical beam

摘要

An optical fiber coupler configured to couple signal beams into a non-circularly shaped output optical beam or device is provided. The coupler includes an adiabatically tapered optical device. The tapered optical device has a core taper ratio equal to the ratio between a second core diameter and a first core diameter and a mode taper ratio equal to the ratio between a second mode field diameter and a first mode field diameter. The mode taper ratio is greater than the core taper ratio. A spacing between adjacent cores at the output end is less than a spacing between adjacent cores at the input end by approximately the core taper ratio, thereby increasing brightness of a combined output optical signal relative to the combined brightness of the plurality of input optical fibers by approximately a factor equal to the ratio of the mode taper ratio to the core taper ratio.