Patent attributes
A first optical device has an optical fiber mount with an optical fiber disposed thereon, and an optical demultiplexer for demultiplexing a portion of an optical signal beam transmitted through the optical fiber, as a demultiplexed optical signal beam, and guiding the demultiplexed optical signal beam out of the optical fiber. The optical fiber has a first tapered surface for emitting the demultiplexed optical signal beam therethrough. The first tapered surface is inclined at an angle θ1 of at least 1° to an optical axis of the optical fiber. The distance (h) between the optical axis of the optical fiber and the first tapered surface is progressively greater along the direction in which the optical signal beam travels through the optical fiber.