The relation between connection loss and fiber diameter is investigated for a ferrule-type single mode multi-fiber connector. The theory for the connector loss statistics is derived taking the centering effect in a ferrule-type connector into account. Five-fiber connectors for single mode fibers are manufactured. Their connection losses are measured and compared to the theory.

This letter proposes a novel type of 12 optical switch with a plastic-molded ferrule wherein an alignment mechanism is formed. Discussing the errors in ferrule fabrication, the insertion loss of the switch has been evaluated. The constructed switch for multimode fibers has shown an insertion loss of 0.7 dB and a switching time of 4 msec.

This letter describes design and performance of small-size push-on type connectors. Considering bending and tensile stress applied to the push-on type coupling, the minimum dimensions of the coupling have been clarified. The constructed connectors for multimode fibers showed average insertion losses of 0.1-0.2 dB.

A discharge fusion splicing technique for fluoride optical fibers has been investigated. Discharge heating conditions were experimentally examined by making a fiber offset from the electrode axis. An average splice loss of 0.14 dB was achieved for 50µm-core fibers.

A demountable optical connector for a single-mode fiber-ribbon has been developed, using a multi-V-groove molding method. The connecting loss due to the errors in ferrule fabrication has been analyzed in detail. The fabricated 5-fiber connector exhibited an average connecting loss of 0.5 dB.

A bit-error-free optical signal switching method from one to another fiber has been proposed for high-bit-rate optical transmission lines. The intensity modulated signal powers of 1.8 Gbit/s, which had been divided by an acousto-optic deflector and propagated through the 2 fibers, were recombined without bit-errors. Optical signals were switched successfully between 25 km long fibers without degradation of bit-error-rate performance.

A novel optical signal splitting method using a holographic transmission grating is proposed for optical communication use. An input beam from a SM-fiber is variably split into two output SM-fibers. Its applicability to the bit-error-free switching of a 1.8 Gbit/s signal is successfully demonstrated.

Single-mode 1 N switch for 10-fiber ribbon has been developed. The switch has a movable 10-fiber connector plug and linear arrangement of 10-fiber plugs to be mated. The plugs are precisely aligned by inserting alignment pins. The tested 1 50 switch exhibits an average insertion loss of 0.5 dB for single-mode potical fibers with 10µm core. The minimum and the maximum switching times are 17 msec for port 1 to 2 and 80 msec for port 1 to 50, respectively. Insertion loss change after over 1000 times switching is less than 0.1 dB.