We have developed a 7-core-fiber connector. To maintain both the ferrule floating mechanism and precise alignment around the ferrule axis, we employed Oldham's coupling mechanism inside an MU-type connector plug housing and realized an average attenuation of 0.13dB and an average return loss of 48.2dB.

Optical connectors for printed circuit board interfaces are required for the implementation of reliable high-density multi-fiber connection. We developed a 16-fiber fiber physical contact (FPC) connector with an MU connector coupling mechanism and a compact shutter to meet this requirement. In the FPC connector, two arrays of fibers are aligned in micro-holes without ferrules. A micro-hole array is a key component as regards the optical characteristics of the FPC connector. We developed a 16-ch micro-hole array composed of injection molded zirconia ceramics. The 16-fiber FPC connectors with a zirconia ceramic micro-hole array had an insertion loss of less than 0.3 dB with an average value of 0.07 dB and a return loss of over 45 dB. The optical characteristics remained stable in environmental and mechanical tests.

Optical connectors for printed circuit board interfaces are required for the implementation of high-density multi-fiber connection. We have developed a fiber physical contact (FPC) connector to meet this requirement. The FPC connector has to ensure reliability when bare fibers are used. Moreover, the FPC connector must employ an established coupling mechanism and provide higher density connection. To meet these requirements, we developed a 16-fiber FPC connector that utilizes the MU connector coupling mechanism and a shutter. We connect the 16 fibers in the housing of the duplex MU connector. We developed compact shutters that open only when they come into contact with each other. Moreover, the developed FPC connector enables us to clamp the fibers to a plug without adhesive. This structure can greatly boost the production yield. We confirmed that the developed FPC connector has an easy connection operation and good optical performance, and we verified that the shutters open properly.

We developed a new MU-type fixed optical attenuator for 4.5 mm pitch packaging. We succeeded in miniaturizing the attenuator by adopting a design employing an MUJ plug. This fixed optical attenuator achieved a tensile strength of greater than 70 N, which is the same as that of a conventional fixed optical attenuator, and also exhibited good environmental and mechanical durability. The new fixed optical attenuator can be used in existing communication devices in which 4.5 mm pitch MU adaptors are already installed.

Various optical fiber connectors have been developed during the 20 years since optical fiber communications systems were first put into practical use. As the domain of optical fiber communication systems expanded from trunk lines to subscriber lines and customer premises the main focus changed from performance improvement to miniaturization and cost reduction. This paper describes the technical background, recent trends in standard optical connectors, and recent issues related to photonic connection technologies.

This paper presents a design approach for developing MU-type single-mode miniature optical connectors featuring 1. 25 mm diameter zirconia ferrules. They are smaller and have a higher packaging density than conventional optical connectors. The ferrule pitch is 1/2, the plug volume 2/5 and the cross-sectional area 2/5 that of the SC connector. The aim of our approach is to reduce the ferrule size and to realize durable connectors. With 10/125 SM fibers, these MU connectors produced an average insertion loss of 0. 07 dB and an average return loss of 49. 4 dB, and there was no degradation during or after mechanical and environmental tests.