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Phase-modulated fiber optic telecommunications system

Imported: 23 Feb '17 | Published: 22 Oct '02

Peter Snawerdt

USPTO - Utility Patents

Abstract

A fiber optic data transmission system has a transmitter having a laser emitting a continuous wave light, a phase modulator phase modulating the continuous wave light so as to create an optical signal bearing information in phase-modulated form, and a telecommunications optical fiber connected to at least one receiver, the phase-modulator being connected to the telecommunications fiber so that the phase-modulated information optical signal is transmitted over the telecommunications fiber without recombining with the continuous wave light.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred continuous-wave laser embodiment of the present invention is described below by reference to the following drawings, in which:

FIG. 1 shows a schematic of the system of the present invention;

FIG. 2 shows details of the circuit of the controller of FIG. 1;

FIG. 3 shows in a larger view the interferometer FIG. 1;

FIG. 4 shows details of an electronic data stream and the respective phase-modulated optical signals of the present invention, in representative binary form; and

FIG. 5 shows details of other electronic data streams and phase-modulated optical signals of the present invention, in representative binary form.

Claims

1. A fiber optic data transmission system comprising:

2. The system as recited in claim 1 wherein the laser has a wavelength that does not vary by more than 2 nm.

3. The system as recited in claim 2 wherein the wavelength does not vary by more than 1 nm.

4. The system as recited in claim 1 wherein the phase-modulator phase modulates all of the continuous wave light.

5. The system as recited in claim 1 further comprising a tap detection monitor monitoring an amplitude of the phase-modulated information optical signal.

6. The system as recited in claim 1 wherein an amplitude of the phase-modulated optical signal is constant.

7. A method for sending data in phase-modulated form over a telecommunications optical fiber comprising the steps of:

8. The method as recited in claim 7 further comprising monitoring the optical fiber for a reduction in an amplitude of the phase-modulated signal.

9. The method as recited in claim 7 wherein the laser has a wavelength that does not vary by more than 2 nm.

10. The method as recited in claim 9 wherein the wavelength does not vary by more than 1 nm.

11. The method as recited in claim 9 wherein all of the continuous wave light from the laser is phase-modulated by a single phase-modulator.

12. A method for sending data in phase-modulated form over a telecommunications optical fiber comprising the steps of:

13. The method as recited in claim 12 wherein the monitoring occurs at a receiver for the phase-modulated optical data.

14. The method as recited in claim 12 wherein the feedback time delay is a function of a bit rate of the electronic input data.

15. The method as recited in claim 12 wherein the feedback time delay equals the interferometric delay.

16. The method as recited in claim 12 further comprising passing the electronic input data and the feedback through an exclusive-or gate.

17. The method as recited in claim 7 wherein the feedback time delay is a function of a bit rate of the electronic input data.

18. The method as recited in claim 7 further comprising passing the electronic input data and the feedback through an exclusive-or gate.

19. A fiber optic data transmission system comprising:

20. The system as recited in claim 19 wherein the receiver includes the energy level detector.