Easy and safe coated optical fiber direct connection without handling bare optical fiber

•We propose a coated optical fiber connection without handling bare optical fiber.•The keys techniques are a cleaving and removing coated optical fiber.•As the cleaving technique, we employed a stretching method.•With the removal technique, we incorporated a circular cone coating removal part.

We propose a novel field installable splicing technique for the direct connection of 250 μm diameter coated optical fiber that does not require bare optical fiber to be handled. Our proposed technique can realize a low insertion loss over a wide field installation temperature range of −10–40 °C. The keys to coated optical fiber direct connection are a cleaving technique and a technique for removing coated optical fiber. As the cleaving technique, we employed a method where the fiber is stretched and then a blade is pushed perpendicularly against the stretched fiber. As a result we confirmed that fiber endfaces cleaved at −10–40 °C were all mirror endfaces. With the removal technique, the coating is removed inside the connecting component by incorporating a circular cone shaped coating removal part. A mechanical splice based on these techniques successfully achieved a low insertion loss of less than 0.11 dB and a return loss of more than 50 dB at −10, 20, and 40 °C. In addition, the temperature cycle characteristics were stable over a wide temperature range of −40–75 °C.