Nippon Telegraph and Telephone Corporation

Hirobumi Kimura

Masao Kawachi

Akira Nagayama

Kunihiko Sasakura

Mitsuhiro Makihara

Tsuneo Kanai

Shigefumi Hosokawa

Shigeru Umemura

Syuichirou Inagaki

In an optical MDF (main distributing frame) for interconnecting external subscriber optical lines (122) with office optical lines (131) through jumpering operation, a matrix waveguide (128, 129, 130) having a plurality of crosspoints coupled with external lines and office lines is used. The matrix waveguide has a groove (235 in FIG. 4A) at each crosspoint so that said crosspoint is switched ON or OFF depending upon whether said groove is filled with matching oil or not, so that one of the external lines is connected to the selected office line. Said matching oil has the same refractive index as that of waveguides. Each crosspoint groove is coupled with a respective oil pool (236), which supplies matching oil which has essentially the same refractive index as that of a waveguide to said groove. Switching at a crosspoint is carried out in a manner that a light signal in a waveguide goes straight through the crosspoint when a groove is filled with matching oil, and the light signal changes its direction at the crosspoint through total internal reflection when the groove is empty. A jumpering operation to connect or disconnect a crosspoint is carried out by a robot (133), which fills or pulls out matching oil in the oil pool at the designated coordinates. Each external line is branched by using an optical directional coupler (237) for test purposes, and one of the branch lines subject to test is selected by using a similar 1.times.N type matrix waveguide. (FIG. 4A)

Automated optical main distributing frame system

Growing community of inventors

Saitama, Japan

Hirobumi Kimura