Optical fiber reflective signal modulation system

• US 4,956,877 A
• Filed: 06/10/1987
• Issued: 09/11/1990
• Est. Priority Date: 06/10/1987
• Status: Expired due to Fees

• Current Assignee: CHERNE, LLOYD AND JOAN
• Original Assignee: Cherne Medical, Inc.
• Inventors: Kroll, Mark W., Pommrehn, Mark R.
• Primary Examiner(s): Orsino, Joseph A.
• Assistant Examiner(s): Van Beek, L.
• Application Number:
  US07/060,740
• Time in Patent Office: 1,189 Days
• Field of Search: 455/605, 455/603, 455/606, 455/607, 340/870.28, 340/870.29, 340/505, 340/825.54, 370/3
• US Class Current: 398/170
• CPC Class Codes: H04B 10/2587 using a single light source for multiple stations

Abstract

The device of the present invention provides a signal modulation system. The system has a first station communicatively connected to an optical fiber. The first station has a transmitter to produce an unmodulated light carrier signal through the optical fiber and a receiver to convert a modulated light signal received from the optical fiber to a demodulated electrical signal for output. The system also has a second station communicatively connected to the optical fiber. The second station has an amplifier and power source which receive input carrier modulating signals, a modulation circuit, and an electro-optical reflector constructed and arranged to modulate reflection of the carrier signal emitted from the transmitter to the receiver via the optical fiber.

Claims

1. A signal modulation system comprising:

a. an optical fiber;

b. a first station communicatively connected to said optical fiber and having means to transmit an unmodulated light carrier signal through said optical fiber, and first means to convert a modulated light carrier signal from said optical fiber to a demodulated electrical signal for output, said first station further having means to separate said unmodulated light carrier signal and said modulated light carrier signal; and

c. a second station communicatively connected to said optical fiber and having at least one terminal to receive an electrical input signal, an amplifier connected to said at least one terminal, a power source connected to said amplifier, a digital modulator connected to said amplifier and converting said input signal to a modulating signal, an optical shutter constructed and arranged to modulate and reflect said unmodulated light carrier signal emitted from said optical fiber back to said optical fiber, said optical shutter being responsive to said modulating signal, and means to direct both said unmodulated light carrier signal emitted from said optical fiber to said optical shutter, and said modulated light carrier signal reflected to said optical fiber.

2. The system of claim 1, wherein said power source comprises a beam splitter constructed and arranged to partially transmit said carrier signal to and from said optical shutter and one or more photovoltaic batteries constructed and arranged to receive carrier signal light energy reflected by said beam splitter.

3. The system of claim 1, wherein said power source comprises a battery.

4. The system of claim 1, wherein said means to separate comprises a partially reflecting mirror constructed and arranged to transmit said unmodulated carrier signal from said means to transmit to said optical fiber and to reflect said modulated carrier signal to said first means to convert.

5. The system of claim 1, wherein said power source comprises a beam splitter constructed and arranged to partially reflect said carrier signal to and from said optical shutter and one or more photovoltaic batteries constructed and arranged to receive carrier signal light energy transmitted through said beam splitter.

6. The system of claim 5, wherein said beam splitter is a partially reflecting mirror.

7. The system of claim 5, wherein said power source additionally comprises a DC to DC converter connected to said photovoltaic batteries.

8. The system of claim 5, wherein said photovoltaic batteries are comprised of at least two diodes.

9. The system of claim 1, wherein said power source comprises a plurality of photovoltaic batteries and wherein a plurality of second optical fibers are arranged to receive said unmodulated light carrier signal from said means to transmit, and to provide optical energy to each of said plurality of photovoltaic batteries.

10. The system of claim 1, wherein said power source comprises one or more transparent photovoltaic batteries disposed in-line with and between said optical shutter and said optical fiber, and wherein said power source additionally comprises a DC to DC converter connected to said photovoltaic batteries.

11. The system of claim 1, wherein said power source comprises one or more photovoltaic batteries disposed posterior to said optical shutter and capacitor means connected to said photovoltaic batteries, and wherein said optical shutter is normally open, and wherein said power source additionally comprises a DC to DC converter connected to said photovoltaic batteries.

12. The system of claim 1, wherein said power source comprises one or more photovoltaic batteries and wherein a second optical fiber is arranged to receive said unmodulated light carrier signal from said means to transmit, and to provide optical energy to said one or more photovoltaic batteries.

13. The system of claim 1, wherein said first means to convert comprises a photodetector, an output circuit connected to said photodetector, a frequency to voltage converter connected to said output circuit and at least one terminal connected to said frequency to voltage converter.

14. The system of claim 1, wherein said digital modulator comprises a voltage to frequency converter connected to said means to receive and a voltage amplifier connected to said voltage to frequency converter.

15. The system of claim 1, wherein said means to transmit comprises a laser diode and a power supply connected to said laser diode.

16. An optical fiber reflective signal modulation system for input of an electrical signal at a location electrically removed from a location at which both an unmodulated optical carrier signal is generated and a demodulated, digital electrical signal having the same characteristics of the input signal is outputted, comprising:

a. an optical fiber transmitting both an unmodulated and a modulated carrier signal;

b. a main station communicatively connected to said optical fiber having an unmodulated optical transmitter transmitting said unmodulated carrier signal through said optical fiber, said transmitter having a light source and a power supply connected to said light source, said main station further having a receiver converting said modulated carrier signal emitted from said optical fiber to a modulated electrical signal, said receiver having a light detector and an output circuit connected to said light detector, said main station further having a demodulator connected to said output circuit for outputting said demodulated electrical signal, and means to separate said unmodulated carrier signal and said modulated carrier signal; and

c. a remote station having a high speed, reflective shutter communicatively connected to said optical fiber at its end opposite said main station, said remote station further having means to receive the electrical input signal, a power source connected to said means to receive, a bit serial digital modulator communicatively connected to said means to receive and to said reflective shutter, said modulator receiving the input signal and controlling said reflective shutter, and collimating means constructed and arranged to focus the unmodulated carrier signal emitted from said optical fiber and to focus said modulated carrier signal reflected from said reflective shutter, said power source comprising a beam splitter constructed and arranged to separate said unmodulated light carrier signal into a power signal and a data signal, and one or more photovoltaic batteries constructed and arranged to receive said power signal, said data signal being reflected by said reflective shutter to said optical fiber to provide said modulated light carrier signal.

17. The system of claim 16, wherein the input is a bioelectric signal carrier modulating signal.

18. The system of claim 26, wherein said power source comprises a plurality of photovoltaic batteries and wherein a plurality of second optical fibers are arranged to receive said unmodulated light carrier signal from said optical transmitter, and to provide optical energy to each of said plurality of photovoltaic batteries.

19. The system of claim 16, wherein said light source comprises a laser diode.

20. The system of claim 16, wherein said light detector comprises a photodiode.

21. The system of claim 16, wherein said demodulator comprises frequency to voltage converter.

22. The system of claim 16, wherein said optical fiber is a high power, plastic optical fiber.

23. The system of claim 16, wherein said reflective shutter comprises a fast, uniaxial birefringent liquid crystal.

24. The system of claim 16, wherein said reflective shutter comprises a Kerr cell.

25. The system of claim 16, wherein said reflective shutter comprises a Pockel cell.

26. The system of claim 16, wherein said modulator comprises a voltage to frequency converter connected to said amplifier and a voltage amplifier connected to said voltage to frequency converter and to said reflective shutter.

27. The system of claim 16, wherein said power source additionally comprises a DC to DC converter connected to said photovoltaic batteries.

28. The system of claim 16, wherein said beam splitter comprises a partially reflecting mirror constructed and arranged to reflect said data signal to and from said reflective shutter, and to transmit said power signal to said one or more photovoltaic batteries.

29. The system of claim 16, wherein said beam splitter comprises a partially reflecting mirror constructed and arranged to transmit said data signal to and from said reflective shutter, and to reflect said power signal to said one or more photovoltaic batteries.

30. The system of claim 16, wherein said means to receive comprises at least one terminal and an amplifier.

31. A signal modulation system comprising:

a. an optical fiber;

b. a first station communicatively connected to said optical fiber and having means to transmit an unmodulated light carrier signal through said optical fiber, first means to convert a modulated light carrier signal from said optical fiber to a demodulated electrical signal for output and means to separate said unmodulated light carrier signal and said modulated light carrier signal; and

c. a second station communicatively connected to said optical fiber and having means to receive an input signal, second means to convert said input signal to a modulating signal, an electro-optical reflection means constructed and arranged to modulate reflection of said unmodulated light carrier signal emitted from said optical fiber back to said optical fiber, said electro-optical reflection means being responsive to said modulating signal, and means to direct said unmodulated light carrier signal emitted from said optical fiber and said modulated light carrier signal reflected to said optical fiber, said second station further comprising a power source connected to said means to receive and having one or more photovoltaic batteries disposed posterior to said electro-optical reflection means, capacitor means and a DC to DC converter connected to said photovoltaic battery, and wherein said electro-optical reflection means is normally open.