PURPOSE:To obtain a low-loss coupler by covering a single-mode optical fiber with a core glass part, the 1st clad glass part, and further the 2nd clad glass part with a lower refractive index. CONSTITUTION:Two single-mode optical fibers 1-1a and 2-2a are composed of the 1st clad glass part 21b and the 2nd clad glass part 21c surrounding a center core glass part 21a. Light incident on the core glass part 21a at a fiber end 1 spreads gradually to the whole 1st clad glass part 21b because the core diameter 2A decreases in a taper shape, and then propagates in the single-mode waveguide consists of the 1st clad glass part 21b as the core part and the 2nd clad glass part 21c as the clad part; the ratio of the core diameter decreases much more at a heat-sealed and drawn part than at the fiber end, so the low-loss fiber type directional coupler is constituted without any etching process.

Fiber type directional coupler

An optical network architecture can include a first pair of tapered mixing rods and a second pair of tapered mixing rods. The optical network architecture can also include a first plurality of plastic optical fibers communicatively coupled from the first pair of tapered mixing rods to a first plurality of line replaceable units and a second plurality of plastic optical fibers communicatively coupled from the second pair of tapered mixing rods to a second plurality of line replaceable units. The optical network architecture can also include at least one plastic optical fiber communicatively coupled from the first pair of tapered mixing rods to the second pair of tapered mixing rods.

Plastic optical fiber bus network

PURPOSE:To roll a rolling material into a plate having a large step difference without causing turbulence in its flatness by controlling the advancing and returning rollings of the material, in rolling a rolling material by leaving a part of the material by a prescribed length and rolling the other part into a thinner one through several passes of reversing rollings. CONSTITUTION:A steel plate 1 rolled into the sheet thickness t1 is rolled into the sheet thickness t1' by upper and lower work rolls 2, 3 having a roll gap S1 between them, and when the top of plate 1 is detected by a steel plate detector 4, the rotation of mill is stopped to leave a thick-plate part having thickness t1 by a length l1. Successively a return rolling is performed by reversing the mill to obtain a thin-plate part having sheet thickness t1''. Further, the 2nd pass rolling is performed to obtain a thin plate-thickness t2' part by regulating the roll gap to S2(S1>S2), and the mill is reversed when the detector 4 detects the top of plate 1 to obtain a thin plate-thickness t2 part. In this way, a plate with different thicknesses is obtained, which consists of a part having a prescribed length l1 and a sheet thickness t1 and a remaining part having a sheet thickness t2.

Rolling method for providing step difference to thick plate

PURPOSE:To facilitate assembling operation and realize mass-production by coupling one single-port optical fiber cable, light guide part, intervenient cable bundle, and plural multiple-port side optical fiber cables together so that end surfaces are brought into contact with one another. CONSTITUTION:A holder7 has a bundle-side sleeve insertion hole 7e into which a bundle-side sleeve 11 is inserted and a light guide part 6 which has one end surface facing the hole 7 and projects light received from one end surface from the other end surface. A multiple-port receptacle 16 which has plural separation- side sleeve insertion holes 16c into which respective separation-side sleeves 13 are inserted and holds plugs 15 fitted to plural multiple-port side optical fiber cables 14 opposite to the separation-side sleeve insertion holes 16c, and a single- port receptacle 3, holder 7, intervenient cable bundle 8, and multiple-port side optical receptacle 16 are stored in order in cases 17 and 18 so that light is transferred between one single-port side optical fiber cable 1 and plural multiple- port side fiber cables 11.

Optical brancher and coupler

PURPOSE:To easily realize a bilateral transmission system with simple constitution using optical fibers between a central office and many terminals by successively arranging a light emitting part, a light mixing part, collimating lens, a filter, a condensing lens, and an optical fiber flux. CONSTITUTION:The light projected from a light emitting element 1, which emitts light with the wavelength of lambda1, is mixed by a light mixing means 2, collimated by a lens 3, transmitted through a filter 6, condensed by a lens 5 and then made incident to a fiber flux. The light with the wavelength of lambda2 transmitted through plural optical fibers 4 is collimated by the 2nd lens 5, reflected by the filter, condensed by a lens 8, and made incident to a photodetecror 7. For the light mixing means 2, a prescribed glass rod of which periphery is covered with a medium of low refractive index is used. A bilateral transmission system through optical fibers between a central office and many terminals can be realized by using the light branching and dividing circuit.

Light branching and dividing circuit

PURPOSE:To make possible branching of light from one optical fiber to a plurality of optical fibers by connectin one optical fiber and a fiber bundle containin containing a plurality of ootical fibers by way of an optical fiber whose outside diameter gradually changes.

Optical fiber branching inserter

PURPOSE: To reduce the insertion loss while controlling the degree of coupling by removing the clad between optical fibers and disposing clads of different refractive indices. COPYRIGHT: (C)1979,JPO&Japio

Minoru Maeda

Papers

Optical fiber branching inserter

Optical fiber directivity coupler