Ring-shaped line concentration-distribution system using optical mixing-branching filter

Abstract

Abstract PURPOSE:To improve reliability as well as efficiency of the use of optical fiber by composing a line concentrator-distributor of only passive components and by making duplex communication possible by using only one optical fiber line for each subscriber. CONSTITUTION:Subscribers send signals of difference wavelength to an exchange and receive signals of wavelength different from those from the exchange. A line concentrator-distributor, equipped with dielectric multi-layer film filter 9, discriminates waveform. Since light beams of wavelengths (lambdaa) and (lambda'aa') are passed through and light beams of (lambdab) and (lambdac) are reflected, three beams of different wave lengths from optical fiber 81 are reflected, collimated by lens 71 and then made to strike filter 9; as a result, a beam of (lambdaa) is coupled with fiber 83 by way of lens 73, and beams of (lambdab) and (lambdac) are reflected and focused by lens 74 before being coupled with fiber 84. Incident light from other optical fiber is selectively passed through or reflexted to extract and send back light of specific wavelength transmitted through basic transmission lines 81 and 84.

Inventors

• 👤 Kiyoshi Nosu
• 👤 Hideki Ishio

Bibliographic Details