Bidirectional optical modulator having lightwave signal conservation

• US 5,528,707 A
• Filed: 09/30/1994
• Issued: 06/18/1996
• Est. Priority Date: 09/30/1994
• Status: Expired due to Term

• Current Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Original Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Inventors: Bendett, Mark P., Sullivan, Charles T.
• Primary Examiner(s): Lee, John D.
• Application Number:
  US08/315,511
• Time in Patent Office: 627 Days
• Field of Search: 385/1-10, 385/12, 385/13, 385/15, 385/16, 359/237-240, 359/245, 359/249, 359/254, 359/298, 359/315, 359/320
• US Class Current: 385/2
• CPC Class Codes: G02B 6/12004 Combinations of two or more optical elements
• CPC Class Codes: G02B 6/42 Coupling light guides with opto-electronic elements
• CPC Class Codes: G02F 1/025 in an optical waveguide structure G02F1/017, G02F1/2257 take precedence
• CPC Class Codes: G02F 1/0327 Operation of the cell; Circuit arrangements G02F1/05 takes precedence

Abstract

A modulating optical element having ports wherein either port can output or receive light signals. An electrooptic effect is applied to the optical element to allow the light signals to pass or not pass through the optical element. Due to the electrooptic effect in preventing signals from passing through the optic element, light signals radiate out of the optical element and are absorbed by the substrate of the optical element assembly. Rather than being lost, the energy from the light signal is converted to current which may be used for other purposes in the modulator system, such as bias stabilization.

Claims

1. A bidirectional optical modulating element having energy recapture of deflected light, comprising:

modulating means for conveying, modulating and deflecting light;

first waveguide means, connected to said modulating means, for conveying light to or from said modulating means;

second waveguide means, connected to said modulating means, for conveying light to or from said modulating means;

absorbing means, connected to said modulating means, for absorbing light deflected by said modulating means; and

detection means, connected to said absorbing means, for recapturing and converting the absorbed light to an electrical current.

2. The bidirectional optical modulating element of claim 1 further comprising voltage source means, connected to said modulating means, for applying a voltage to said modulating means for modulating and deflecting light in accordance with a magnitude of the voltage.

3. The bidirectional optical modulating element of claim 2 further comprising controlling means, connected to said voltage source means, for sending a signal to said voltage source means to indicate a state of modulating and deflecting light.

4. The bidirectional optical modulating element of claim 3 further comprising a processing element, connected to said controlling means, for receiving from and/or transmitting information to said controlling means.

5. The bidirectional optical modulating element of claim 4 wherein said detection means is connected to said controlling means.

6. A plurality of bidirectional optical modulating elements wherein:

each bidirectional optical modulating element comprises;

a modulator for modulating light;

a first port, connected to said modulator, for conveying light to said modulator;

a second port, connected to said modulator for conveying light from said modulator;

an absorbing device, connected to said modulator, for absorbing light from said modulator and converting the absorbed light into electrical power;

a light source, connected to said first port, for providing light;

a voltage source, connected to said modulator, for providing a voltage to said modulator to implement a degree of modulation of light in accordance with the voltage;

a control logic device, connected to said absorbing device and to said voltage source, for monitoring the electrical power from said absorbing device and for controlling a magnitude of the voltage provided by said voltage source to said modulator; and

a processing element, connected to said control logic device, for processing information received from or sent to said control logic device; and

said plurality of bidirectional optical modulating elements are interconnected with one another; and

said plurality of bidirectional optical modulating elements are connected to a master controller, said master controller designating when each bidirectional optical modulating element can transmit information or receive information.

7. The plurality of bidirectional optical modulating elements of claim 6 further comprising a star coupler for effecting an interconnection among said plurality of bidirectional optical modulating elements.

8. A bidirectional optical modulator comprising:

a first waveguide, having first and second ends, for conveying light;

at least one electrode proximate to said waveguide;

an electrical signal source, connected to said at least one electrode, for providing an electrical signal to said at least one electrode, effecting an electrooptic effect deflecting light in said first waveguide, resulting in modulating of the light conveyed in said first waveguide;

second waveguide connected to the first end of said first waveguide, for conveying light to and from said first waveguide;

a third waveguide, connected to the second end of said first waveguide, for conveying light to and from said first waveguide;

a light absorber, proximate to said first, second and third waveguides, for absorbing light deflected from said first, second or third waveguide; and

a first detector, proximate to said light absorber, in conjunction with said light absorber for converting the light deflected from said first, second or third waveguide, into electrical power.

9. The bidirectional optical modulator of claim 8 wherein the light deflected from said first, second or third waveguide, that is absorbed by said light absorber, results in electron-hole pairs which are collected by said first detector to output electrical power.

10. The bidirectional optical modulator of claim 9 wherein:

said light absorber is a substrate;

said first waveguide comprises;

a lower clad formed on said substrate;

a core formed on said lower clad;

an upper clad formed on said core;

a ground electrode, connected to said electrical signal source, formed on said lower clad; and

a signal electrode, connected to said electrical signal source, formed on said upper clad;

said second waveguide comprises;

a lower clad formed on said substrate;

a core formed on said lower clad; and

an upper clad formed on said core;

said third waveguide comprises;

a lower clad formed on said substrate;

a core formed on said lower clad; and

an upper clad formed on said core; and

said first detector comprising;

a first electrode formed on said substrate; and

a second electrode formed on said substrate.

11. The bidirectional optical modulator of claim 10 wherein:

said substrate comprises gallium arsenide;

said lower clad of said first, second and third waveguides, comprises aluminum gallium arsenide;

said core of said first, second and third waveguides, comprises aluminum gallium arsenide; and

said upper clad of said first, second and third waveguides, comprises aluminum gallium arsenide.

12. The bidirectional optical modulator of claim 11 wherein:

said ground and signal electrodes of said first waveguide, each comprise a material containing gold and titanium; and

said first and second electrodes of said first detector, each comprise material containing gold and titanium.

13. The bidirectional optical modulator of claim 8 further comprising:

a second detector, proximate to said light absorber; and

an electrical power storage device connected to said first detector.

14. The bidirectional modulator of claim 13 further comprising:

a control logic device connected to said electrical signal source, and to said first and second detectors;

a master controller connected to said control logic device; and

an information processor connected to said control logic device.

15. The bidirectional modulator of claim 14 further comprising:

a first optical fiber connected to said second waveguide;

a second optical fiber connected to said third waveguide; and

a light source connected to said first optical fiber.

16. The bidirectional optical modulator of claim 15 wherein:

said first detector outputs leveling and monitoring control information to said control logic device;

said second detector outputs data received information to said control logic device;

said master controller outputs control information to said control logic device; and

said information processor receives, processes and transmits useful information from and to said control logic device.

17. A bidirectional optical modulator comprising:

a substrate;

a first waveguide, having first and second ends, formed on said substrate;

a first electrode formed on said first waveguide;

a first detector having a second electrode formed on said substrate; and

wherein;

said first waveguide is for conveying a significant amount of light from the first end to the second end of said first waveguide;

first said electrode is for applying an electrooptic effect to the light in said first waveguide upon application of a sufficient voltage on said first electrode, the electrooptic effect deflecting the light into said substrate, to be absorbed by said substrate, resulting in an insignificant amount of light exiting from the second end of said first waveguide, and an application of an insufficient voltage on said first electrode resulting in a significant amount of light exiting from the second end of said first waveguide; and

the second electrode of said first detector collects current from said substrate caused by light absorbed in said substrate.

18. The bidirectional optical modulator of claim 17 wherein:

said substrate comprises gallium arsenide;

said first waveguide comprises aluminum gallium arsenide; and

the light absorbed in said substrate causes electron-hole pairs which are collected by the second electrode of said first detector to result in an electrical current at the second electrode of said first detector.

19. The bidirectional optical modulator of claim 18 further comprising an electrical power storage device, connected to said first detector, for storing the electrical current at the electrode of said first detector.

20. The bidirectional optical modulator of claim 19 further comprising:

a voltage source connected to said electrode formed on said first waveguide;

a second waveguide connected to the first end of said first waveguide;

a third waveguide connected to the second end of said first waveguide; and

a second detector having an electrode formed on said substrate.

21. The bidirectional optical modulator of claim 20 further comprising:

a light source connected to said second waveguide; and

a control logic device connected to said voltage source, and to said first and second detectors.

22. The bidirectional optical modulator of claim 21 wherein an output of said electrical power storage device is connected to said voltage source and to said control logic device.

23. The bidirectional optical modulator of claim 22 further comprising:

a master controller connected to said control logic device; and

an information processing element connected to said control logic device.

24. A bidirectional optical modulating element having energy recapture of deflected light, comprising:

modulating means for conveying, modulating and deflecting light;

absorbing means, connected to said modulating means, for absorbing light deflected by said modulating means; and

detection means, connected to said absorbing means, for recapturing and converting the absorbed light to an electrical current.

25. The bidirectional optical modulating element of claim 24 further comprising a storage means, connected to said detection means, for storing the electrical current.