Ryo Nagase

SC-type single-mode optical fiber connectors

SC-type single-mode optical fiber connectors specifically developed for subscriber loop networks are discussed. The properties and design of precision zirconia ceramic ferrules which have been found to be ideal for high-performance, low-cost single-mode optical fiber connectors are described. A design approach featuring a plastic-molded rectangular connector housing using a push-pull coupling mechanism which has also been found to be suitable for durable, compact, and low-cost connectors is presented. SC connectors used with 10/125 single-mode fibers exhibit insertion loss of 0.06 dB and return loss of 38.6 dB, with no degradation during and after mechanical and environmental tests. To realize higher packaging density, duplex-ferrule connectors, quadruple-ferrule connectors and optical attenuators have also been developed on the basis of the SC connector design. >

Miniature optical connector with small zirconia ferrule

The problems and design targets related to miniaturizing an optical connector are described, and the results of optical characteristic measurements after a trial fabrication are presented. Miniaturized optical connectors using 1.25-mm-diameter ferrules have been developed. They are smaller and have a higher packaging density than conventional optical connectors. Ferrule pitch is 1/2, plug volume is 2/5, and cross-sectional area is 2/5 that of the SC connector. Excellent optical performance, an average insertion loss of 0.04 dB, and an average return loss of 50.1 dB have been achieved.<<ETX>>

Highly stable physical-contact optical fiber connectors with spherical convex ends

Highly stable physical-contact optical fiber connectors achieved by optimizing ferrule end structures are described. Ceramic ferrule material, the curvature radius of the ferrule endfaces, and the convex vertex eccentricity from the ferrule central axis were studied. On the basis of these studies, single-mode and multimode fiber connectors with stable low-insertion loss and high-return-loss characteristics were fabricated. >

Compact and self-retentive multi-ferrule optical backpanel connector

A compact optical backpanel connector called a compact and self-retentive multi-ferrule optical backpanel connector or an MU optical backpanel connector has been developed Eight plugs/jacks can be installed within the MU backpanel connector which is 42 mm high and 13 mm wide. A novel self-retentive mechanism, 1.25-mm diameter ferrules and advanced PC (APC) technology are used to realize a high performance connector with a low insertion loss of 0.1 dB and a high return loss of 50.3 dB. >

Silica-based 8/spl times/8 optical matrix switch module with hybrid integrated driving circuits and its system application

A compact, low-crosstalk 8/spl times/8 optical matrix switch module has been developed. A thermooptic switch chip and driving circuits with TTL interfaces are integrated on a 100-mm/sup 2/ ceramic substrate. It achieved a low insertion loss of 10.0 dB, a low crosstalk level of -25.9 dB, and had excellent stability in practical operation. A photonic intermodule connector for electronic switching systems in the near future is also demonstrated through the use of these optical switch modules. >

Connection mechanism of physical-contact optical fiber connectors with spherical convex polished ends

We present an experimental and analytical investigation of the connection mechanism of physical-contact optical-fiber connectors with spherical convex polished ends and confirm that reducing the curvature radius of the spherical convex ferrule end face is effective for establishing a stable connection with slight axial compressive force on the ferrules.

Silica-based 8/spl times/8 optical matrix switch integrating new switching units with large fabrication tolerance

An 8/spl times/8 optical matrix switch consisting of asymmetric Mach-Zehnder (MZ) interferometer switching units with a waveguide intersection was fabricated using silica-based planar lightwave circuits (PLCs) on a silicon substrate. This switching unit can realize a high extinction ratio and a wide operation wavelength range even if the coupling ratios of the directional couplers (DCs) consisting the switching unit, deviate greatly from the ideal value of 50%. A matrix switch with a DC-coupling ratio of 30% was fabricated to test the validity of the proposed geometry. The average insertion loss was 7.3 dB in the transverse electric (TE) mode and 7.5 dB in the transverse magnetic (TM) mode. The average extinction ratio was 31.2 dB in the TE mode and 31.3 dB in the TM mode. The wavelength range with an extinction ratio greater than 20 dB was over 100 nm.

Fiber fuse generation in single-mode fiber-optic connectors

The evolution of the fiber fuse phenomenon in a single-mode fiber-optic connector was studied theoretically. A narrow air gap of the order of 1 /spl mu/m was assumed to be formed between the fiber end-faces in the connector as a result of the adhesion of dust to both the ferrule and the fiber end-faces. It was assumed that there was a thin water layer in the gap because condensable water molecules in the air could easily be trapped by the SiOH groups on the silica-glass surface. The water layer exhibited a large absorption coefficient of about 850 cm/sup -1/ at 1.48 /spl mu/m. The temperature distributions near the air gap were numerically calculated by using the explicit finite-difference method. When a high-power laser operating at 1.48 /spl mu/m was input into the connector, the temperature along the fiber-core center increased abruptly at the thin water layer. The air gap was heated above 4/spl times/10/sup 5/ K when the optical power was 2 W and the gap was 1 /spl mu/m. The heat in the air gap gradually diffused into the neighboring optical fiber over time. The temperature of the heated fiber reached over 1/spl times/10/sup 4/ K, which is high enough to initiate the fiber fuse phenomenon.

Advanced physical contact technology for optical connectors

An advanced low-reflection PC (physical contact) optical connector with an average return loss of 46 dB has been realized while maintaining a reliability as high as that of conventional PC optical connectors. The high return loss and reliability of the APC have been achieved by suppressing damaged layer generation and by reducing fiber withdrawal from the ferrule endface. Slight variations in the damaged layer significantly affect the return loss and distribution of the APC connector, because the refractive index of the layer is very close to that of silica fiber core.<<ETX>>

Fiber fuse terminator

We developed a fiber fuse terminator to ensure the safe operation of high power optical network systems. The performance of this fiber fuse terminator was satisfactory as regards an optical input of 2 W.