Optical local area network using a common optical carrier with separate user angle modulation

Abstract

Abstract The present invention relates to a multiple-user communication system wherein one carrier source is shared by a cascade of users of the system. More particularly, the present communication system uses a single carrier propagating along the system's transmissin medium onto which each user directly impresses the associated data or communication signal destined for another user preferably using either subcarrier angle modulation (phase or frequency) or TDM techniques for intensity or angle modulation. In the present system using subcarrier angle modulation, each user can either transmit or receive at a fixedly assigned or selectively assigned subcarrier channel, which is different from the subcarrier channel assigned to each of the other users. Where TDM techniques are used, the communication signal from a user can be directly impressed on the single carrier using intensity or phase modulation. With such communication system, amplifiers can be liberally used along the bus with no inter-modulation distortion since the amplifiers see a constant envelope signal. The use of ampmlifiers solves the problem of excessive signal loss incurred when multiple users tap into or out of, for example, an optical fiber bus.

Inventors

• 👤 Paul S. Henry

Bibliographic Details