POLARIZATION AND TIME DIVISION LIGHT MULTIPLEX COMMUNCIATION SYSTEM

• US 3,584,221 A
• Filed: 12/26/1968
• Issued: 06/08/1971
• Est. Priority Date: 12/29/1967
• Status: Expired due to Term

• Current Assignee: Furukawa Motoaki
• Original Assignee: Furukawa Motoaki
• Inventors: FURUKAWA MOTOAKI
• Application Number:
  US04/787,031
• Time in Patent Office: 894 Days
• US Class Current: 398/65
• CPC Class Codes: H04B 10/1121 One-way transmission

Abstract

A multiplexed light pulse communication system is described wherein light pulses of different phase and polarization orientations are combined and then subjected to selective polarization variations in response to pulse code modulated signals. The polarization varied light pulses are then amplitude modulated by passing them through a birefringent prism. A receiver for the detection of the thus transmitted amplitude modulated light pulse signals is described to recover the pulse code modulated signals.

Claims

1. A multiplex light communication system comprising:

a transmitter including means for producing a plurality of pairs of light beams of mutually perpendicular planes of polarization, each beam including a light pulse train of a predetermined repetition rate;

a corresponding plurality of first birefringent prisms for respectively synthesizing each of said pairs of light beams into a single light beam;

means for subjecting each of said synthesized light beams to selected rotation of their respective planes of polarization in response to pulse-code-modulated signals applied to said light beam rotation subjecting means, a second birefringent prism in optical communication with said light beam rotation subjecting means for converting said polarization-plane rotated light beams into two amplitudemodulated light pulse trains along differently oriented paths, and a receiver in the optical communication path of said transmitter and positioned to respond to one of said modulated light pulse trains and having a third birefringent prism for dividing the received light beam into two light beams having mutually perpendicular planes of polarization; and

means for demodulating said divided light beams to reproduce said pulsecode-modulated signals.

2. The communication system of claim 1, in which said modulation signals each comprise first and second signals occurring in respective synchronism with said light pulse trains, said beam rotation subjecting means including means for rotating the polarization plane of said light beam by one sense for a given value of said first signal and for a different sense for said given value of said second signal.