Showing papers on "Wavelength-division multiplexing published in 1978"

Viabilities of the Wavelength-Division-Multiplexing Transmission System Over an Optical Fiber Cable

Abstract: This paper describes the feasibility and the applicability of the Wavelength-Division-Multiplexing (WDM) system with two types of preliminary WDM transmission experiments. Through this study, it has become clear that WDM technologies play a major role in optical fiber systems and have the possibilities of realizing the various optical fiber transmission systems.

Fiber optics duplex module

Abstract: A duplex module for simultaneous bidirectional transmit-receive communication with the end of an optical fiber or fiber bundle. The end face of an optical fiber in optical coupling registry with one end of a common bidirectional transmit-receive optical path is tilted to divert any transmit signal back-reflected from such end out of such path. The other end of the transmit-receive path is affiliated with signal receiver and transmitter means via a beam splitter.

Optical demultiplexer using coupling between nonidentical waveguides.

Abstract: A demultiplexer using wavelength dependent coupling between nonidentical waveguides is proposed and demonstrated for single-mode fiber transmission systems. The demultiplexer, consisting of rf-sputtered glass thin film layers, demultiplexes 4880-A, 5145-A, and 6328-A light waves with larger than 14-dB crosstalk attenuations and with less than 5.2-dB insertion losses.

Fiber optic communication - A technology coming of age

Abstract: In a little over ten years, lightwave communication using optical fibers has progressed from a laboratory proposal to a near commercial reality. Losses in optical fiber waveguides have been reduced from hundreds of dB/Km in the early seventies to less than 1 dB/km at some wavelengths today. Bandwidths of multimode fibers can now exceed 1 GHz in km lengths. Strengths in kilometer length fibers have been increased to hundreds of KPSI (more than steel). Cables containing hundreds of fibers, multiple fiber splices, and single fiber connectors have been developed. Lasers which had lifetimes measured in minutes or hours in the early seventies now have extrapolated lifetimes of over a million hours. New material systems which can use the lower loss longer wavelength regions of the optical spectrum are evolving. Meanwhile, prototype systems carrying voice, data, and video services have been placed in service for commercial telephone and military applications. We can anticipate the widespread use of optical fibers on a routine basis beginning in the early eighties. Along with this will come reduced costs for existing services and the introduction of new services made more economical by this new transmission medium.

Optical Fiber Transmission System Demonstration Over 32 km with Repeaters Data Rate Transparent Up to 2.3 Mbits/s

Abstract: An initial optical fiber transmission system under development for Army long haul tactical communications is described and evaluated. The system interfaces with the 2.304 Mbit/s data input and output of an Army inventory multiplexer and its orderwire. The system includes transmitter and receiver end terminals, three data rate transparent repeaters, 8 km of graded index optical fiber, plus three optical attenuators and various optical connectors for simulating transmission up to 32 km. Long repeater spacing is achieved using low loss fiber, semiconductor lasers stabilized using optical feedback, and avalanche photodiodes. The system met all of the specified requirements and shows that optical fiber transmission systems have excellent prospects of meeting full military specifications. The versatility of data rate transparent repeaters is achievable even for transmission up to the 64 km distance desired for Army long haul tactical communications.