Narrow-beam aluminum-mirrored fiber optical-taps with controllable tapped power

A fiber optical-tap has been fabricated and tested. Two separate fiber tips were polished with an angle of 45°, and one of the tips was coated with aluminum inside a vacuum deposition unit. Then, the coated and uncoated polished tips were spliced together using a fusion splicer to form a fiber optical-tap. The power of the tapped light is controllable by controlling the thickness of the aluminum coating during vacuum deposition. As the aluminum coating thickness increases, the amount of tapped light increases and consequently the power transmitted after the fiber optical-tap decreases. For the same aluminum coating thickness, the tapped beam power from a single-mode fiber tap is higher than that from a multimode fiber tap. In addition to the feasibility of tapping a narrow light beam and controlling its power, the fabricated optical tap has a short length, which means that it can be integrated easily in optical signal-processing circuits. The mechanical strength of the tap has been tested in the laboratory and found to be capable of supporting between 75 and 180 g before breaking