Methods and apparatus for making optical fiber couplers

摘要

A cladding portion (15) of an optical fiber (16) is laser machined by focusing a laser beam (13) that is of an appropriate wavelength to ablate the cladding. When the laser beam completely penetrates through the cladding (15) to impinge on the optical fiber core (18) light is transmitted to the two ends of the fiber. A photodetector (31) is placed in close proximity to one of the ends of the optical fiber (16) with the photodetector output being connected to a laser control device (23). When the light detected by the detector exceeds a threshold, it generates a signal that stops the laser. Even if the cladding is of an unpredicted thickness, the laser beam is not terminated until there has been complete penetration through the cladding, and after complete ablation the laser beam is promptly terminated so as to avoid subsequent damage to the optical fiber.