Optical Coupling Technique Based on Fiber Side-Polishing Without Service Interruption

We propose an optical coupler insertion technique based on fiber side-polishing that does not interrupt service. We clarify that fiber side-polishing with an insertion loss of 0.64 dB or less is possible by polishing while monitoring the loss and halting the polishing when the loss reaches the target value. Experiments on fabricated couplers confirm coupling efficiencies of up to 95% when another side-polished fiber is set close to the polished in-service fiber.