Inspection Technique for Cleaved Optical Fiber Ends Based on Fabry–Perot Interferometer

We propose an inspection technique for cleaved optical fiber ends based on the Fabry-Perot interferometer. An inspected fiber end is determined as uneven or flat depending on whether both the measured return losses from the fiber end at two wavelengths are around 14.7 dB. We also developed a system that uses this technique for inspecting cleaved fiber ends. We discuss several requirements for the fiber stage where two optical fiber ends are set to create a Fabry-Perot interferometer. We fabricated a prototype of a fiber stage for outside usage based on these requirements. Several samples with incorrectly cleaved fiber ends were fabricated by intentionally misadjusting the bend radius during fiber cleaving. The images of the inspected flat and uneven fiber ends obtained experimentally with our proposed inspection system with the fabricated fiber stage were in good agreement with those obtained using a scanning electron microscope (SEM).