Single-mode fiber-optical power divider: encapsulated etching technique

Abstract

A straightforward and dependable method to fabricate a low-loss single-mode fiber-to-fiber coupler is reported, in which two twisted single-mode fibers are etched by an HF:NH4F solution in an elongated container with four ports, two ports for fiber passage and the other two ports for etchant filling and draining. Coupling efficiency was controllable anywhere between zero and unity simply by manipulating a threaded cap attached on top of the container. Throughput losses of 2 dB were routinely achieved.