Electro-optical device

• US 5,404,373 A
• Filed: 11/08/1991
• Issued: 04/04/1995
• Est. Priority Date: 11/08/1991
• Status: Expired due to Term

• Current Assignee: Science & Technology Corporation
• Original Assignee: The University of New Mexico
• Inventors: Cheng, Julian
• Primary Examiner(s): Davie, James W.
• Application Number:
  US07/789,172
• Time in Patent Office: 1,243 Days
• Field of Search: 372/50, 372/8, 372/92
• US Class Current: 372/50.124
• CPC Class Codes: G06E 1/04 for performing computations using exclusively denominational number representation, e.g. using binary, ternary, decimal representation
• CPC Class Codes: H01L 31/153 formed in, or on, a common substrate
• CPC Class Codes: H01S 5/0261 Non-optical elements, e.g. laser driver components, heaters H01S5/0265 takes precedence
• CPC Class Codes: H01S 5/0262 Photo-diodes, e.g. transceiver devices, bidirectional devices H01S5/0265 takes precedence
• CPC Class Codes: H01S 5/042 Electrical excitation ; Circuits therefor monolithically integrated laser drive components H01S5/0261
• CPC Class Codes: H01S 5/18308 having a special structure for lateral current or light confinement
• CPC Class Codes: H01S 5/2063 obtained by particle bombardment
• CPC Class Codes: H03K 19/14 using opto-electronic devices, i.e. light-emitting and photoelectric devices electrically- or optically-coupled optical logic elements G02F3/00
• CPC Class Codes: H03K 19/21 EXCLUSIVE-OR circuits, i.e. giving output if input signal exists at only one input; COINCIDENCE circuits, i.e. giving output only if all input signals are identical

Abstract

An electro-optical device includes a vertical cavity surface emitting laser a heterojunction light emitting device and heterojunction phototransistor on a semiconductor substrate. Layers of the heterojunction phototransistor and the heterojunction light-emitting device are electrically and optically coupled so there is regenerative optical and electrical feedback between them. Layers of the heterojunction light-emitting devices are proton implanted to control the feedback. Plural such devices are electrically and optically coupled together to perform logic functions, such as EXCLUSIVE OR, in response to optical signals.

Claims

1. An electro-optical device comprising a semiconductor substrate,

a vertical cavity surface emitting laser having multiple stacked layers on the substrate,

a heterojunction phototransister having plural stacked layers at a position on the substrate that is optically isolated from the layers of said laser so said laser and said phototransistor are optically isolated from each other,

said laser add phototransistor being electrically connected and arranged so that optical energy incident on said phototransistor causes current to be coupled from said phototransistor to said laser to energize said laser into a lasing condition,

a heterojunction light emitting device including plural stacked layers on said heterojunction phototransistor, said layers of said heterojunction light emitting device and said layers of said heterojunction phototransistor being arranged so there are optical and electrical feedback paths between them.

2. The electro-optical device of claim 1 wherein said substrate includes a plurality of said vertical cavity surface emitting lasers, a plurality of said heterojunction light emitting devices, and a plurality of said heterojunction phototransistors, each laser being electrically connected to at least one of said heterojunction phototransistors, said light emitting devices and phototransistors being optically and electrically connected to each other to form photothyristors, said photothyristors and lasers being electrically connected so each laser is activated to a lasing condition in response to optical energy being incident on a phototransistor connected to said laser, said photothyristors and lasers being optically and electrically coupled together for performing binary operations on binary optical signals coupled to said phototransistors.

3. The electro-optical device of claim 1 wherein said substrate includes a plurality of said vertical cavity surface emitting lasers, a plurality of said heterojunction light emitting devices, and a plurality of said heterojunction phototransistors, each laser being electrically connected to at least one heterojunction phototransistor, said light emitting devices and phototransistors being optically and electrically connected to each other to form photothyristors, said photothyristors and lasers being electrically connected so each laser is activated to a lasing condition in response to optical energy being incident on a phototransistor connected to said laser, said photothyristors and lasers being optically coupled together for performing binary operations on binary optical signals coupled to said phototransistors.

4. The electro-optical device of claim 1 wherein said substrate includes a plurality of said vertical cavity surface emitting lasers, a plurality of said heterojunction light emitting devices, and a plurality of said heterojunction phototransistors, each laser being electrically connected to a heterojunction phototransistor, said light emitting devices and phototransistors being optically and electrically connected to each other to form photothyristors, said photothyristors and lasers being electrically connected so each laser is activated to a lasing condition in response to optical energy being incident on said phototransistor connected to said laser, said photothyristors and lasers being electrically coupled together for performing binary operations on binary optical signals coupled to said phototransistors.

5. An electro-optical device comprising a semiconductor substrate,

a vertical cavity surface emitting laser having multiple stacked layers on the substrate,

a heterojunction phototransistor having plural stacked layers at a position on the substrate that is optically isolated from the layers of said laser so said laser and said phototransistor are optically isolated from each other,

said laser and phototransistor being electrically connected and arranged so that optical energy incident on said phototransistor causes current to be coupled from said phototransistor to said laser to energize said laser into a lasing condition,

a heterojunction light emitting device including plural stacked layers on said heterojunction phototransistor, said layers of said heterojunction light emitting device and said layers of said heterojunction phototransistor being arranged and biased so (1) there are regenerative optical and electrical feedback paths between them and (2) said heterojunction light emitting device and said heterojunction transistor have a negative resistance characteristic so they are activated from an OFF condition to an 0N condition in response to optical energy incident on them from an external source having an intensity exceeding a first determined level and are activated from an ON condition to an OFF condition in response to said incident optical energy having an intensity dropping below a second determined level, where said second level is substantially less than said first level.

6. The electro-optical device of claim 5 wherein layers of said heterojunction light emitting device are implanted with protons to control feedback between said light emitting device and said phototransistor.

7. An electro-optical device comprising a semiconductor substrate,

a vertical cavity surface emitting laser having multiple stacked layers on the substrate,

a heterojunction phototransistor having plural stacked layers at a position on the substrate that is optically isolated from the layers of said laser so said laser and said phototransistor are optically isolated from each other,

said laser and phototransistor being electrically connected and arranged so that optical energy incident on said phototransistor causes current to be coupled from said phototransistor to said laser to energize said laser into a lasing condition,

said substrate including a plurality of said vertical cavity surface emitting lasers and a plurality of said heterojunction phototransistors, each laser being electrically connected to a heterojunction phototransistor so each laser is activated to a lasing condition in response to optical energy being incident on said phototransistor connected to said laser, said phototransistors and lasers being coupled together for performing binary operations on binary optical signals coupled to said phototransistors.

8. An electro-optical device comprising a semiconductor substrate,

a vertical cavity surface emitting laser having multiple stacked layers on the substrate,

a heterojunction phototransistor having plural stacked layers at a position on the substrate that is optically isolated from the layers of said laser so said laser and said phototransistor are optically isolated from each other,

said laser and phototransistor being electrically connected and arranged so that optical energy incident on said phototransistor causes current to be coupled from said phototransistor to said laser to energize said laser into a lasing condition,

said substrate including a plurality of said vertical cavity surface emitting lasers and a plurality of said heterojunction phototransistors, each laser being electrically connected to a heterojunction phototransistor so each laser is activated to a lasing condition in response to optical energy being incident on said phototransistor connected to said laser, said phototransistors and lasers being optically and electrically coupled together for performing binary operations on binary optical signals coupled to said phototransistors.

9. An electro-optical device comprising a semiconductor substrate,

a vertical cavity, surface emitting laser having multiple stacked layers on the substrate,

a heterojunction phototransistor having plural stacked layers at a position on the substrate that is optically isolated from the layers of said laser so said laser and said phototransistor are optically isolated from each other,

said laser and phototransistor being electrically connected and arranged so that optical energy incident on said phototransistor causes current to be coupled from said phototransistor to said laser to energize said laser into a lasing condition,

said substrate including a plurality of said vertical cavity surface emitting lasers and a plurality of said heterojunction phototransistors, each laser being electrically connected to a heterojunction phototransistor so each laser is activated to a lasing condition in response to optical energy being incident on said phototransistor connected to said laser, said phototransistors and lasers being electrically coupled together for performing binary operations on binary optical signals coupled to said phototransistors.

10. An electro-optical device comprising a semiconductor substrate,

a vertical cavity surface emitting laser having multiple stacked layers on the substrate,

a heterojunction phototransistor having plural stacked layers at a position on the substrate that is optically isolated from the layers of said laser so said laser and said phototransistor are optically isolated from each other,

said laser and phototransistor being electrically connected and arranged so that optical energy incident on said phototransistor causes current to be coupled from said phototransistor to said laser to energize said laser into a lasing condition, said device being used for processing first and second optical binary signals, said device including first and second of said heterojunction phototransistors respectively responsive to said first and second optical binary signals, said vertical cavity surface emitting laser being included in vertical cavity surface emitting laser means electrically connected to said phototransistors so that said optical energy from said first and second signals incident on said phototransistors causes said laser means to emit optical energy in accordance with binary operations.

11. The electro-optical device of claim 10 wherein said first and second phototransistors have paths connected in series with each other and said laser means so that a voltage connected to said phototransistors and laser means energizes said laser means only in response to said first and second optical binary signals being respectively incident on said first and second phototransistors to provide the AND binary operation.

12. The electro-optical device of claim 10 wherein said first and second phototransistors have paths connected in parallel with each other and said laser means so that a voltage connected to said phototransistors and laser means energizes said laser means in response to either of said first and second optical binary signals being respectively incident on said first and second phototransistors to provide the OR binary operation.

13. The electro-optical device of claim 10 wherein said first and second phototransistors have paths connected in parallel with each other and said laser means so that a voltage connected to said phototransistors and laser means energizes said laser means only in response to said first and second optical binary signals not being respectively incident on said first and second phototransistors to provide the NOR binary operation.

14. The electro-optical device of claim 10 wherein said first and second phototransistors have paths connected in series with each other and a node between them, said laser means being connected in shunt with said node so that a voltage connected to said phototransistors and laser means energizes said laser means only in response to said first and second optical binary signals respectively incident on said first and second phototransistors having differing values to provide the EXCLUSIVE OR binary operation.

15. The electro-optical device of claim 10 wherein said first and second phototransistors have paths connected in series with each other and in shunt with said laser means so that a voltage connected to said phototransistors and laser means energizes said laser means except in response to said first and second optical binary signals being respectively incident on said first and second phototransistors to provide the NAND binary operation.

16. The electro-optical device of claim 10 wherein said device is configured as an EXCLUSIVE OR gate including the first and second phototransistors, the first and second phototransistors being connected to each other so that a node connected to the phototransistors is at first and second different voltages in response to the optical signals respectively having the same and differing values, and the laser means being connected to said node so that optical energy emitted by said laser means has first and second states in response to the first and second voltages being at the node, respectively.

17. An electro-optical device comprising a semiconductor substrate,

a vertical cavity surface emitting laser having multiple stacked layers on the substrate,

a heterojunction phototransistor having plural stacked layers at a position on the substrate that is optically isolated from the layers of said laser so said laser and said phototransistor are optically isolated from each other,

said laser and phototransistor being electrically connected and arranged so that optical energy incident on said phototransistor causes current to be coupled from said phototransistor to said laser to energize said laser into a lasing condition, said multiple stacked layers forming said laser and said plural stacked layers forming said phototransistor being located at different positions from each other relative to a common surface of said substrate on which they are mounted to provide said optical isolation of said laser and said phototransistor.

18. An electro-optical device comprising:

a non-metallic substrate;

a vertical-cavity surface-emitting laser disposed over only a first area of said substrate, the laser including a metal biasing layer;

an isolation layer structure vertically disposed over only a second area of said substrate, said first and second areas being non-overlapping;

a vertically-arranged photodetector having plural stacked semiconductor layers disposed on said isolation layer structure in non-overlapping relation with said first area so said photodetector and laser are optically isolated from each other, said photodetector having an area for receiving a controlling optical beam for selectively turning on said photodetector, an upper semiconductor layer of the photodetector having a biasing electrode thereon,

metal layer means extending from a lower semiconductor layer of the photodetector to the metal biasing layer so that when optical energy is incident on the receiving area of the photodetector a current path subsists from the biasing electrode through the photodetector and the metal layer means to the metal biasing layer to enable activation of the laser.

19. The electro-optical device of claim 18 wherein the laser and photodetector are constructed so the laser can emit optical energy having the same wavelength as optical energy to which the photodetector is responsive.

20. The electro-optical device of claim 18 wherein a space is provided between layers forming (i) the laser and layers overlaid by the isolation layer structure and (ii) the photodetector layers, the metal layer means extending along walls of the space.

21. The electro-optical device of claim 20 wherein the walls of the space are-overlaid by an electric insulating layer, in turn overlaid by the metal layer means.

22. The electro-optical device of claim 21 wherein the photodetector comprises a phototransistor.

23. The electro-optical device of claim 21 wherein the photodetector comprises a photothyristor.

24. The electro-optical device of claim 18 wherein the laser is arranged to emit optical energy away from the substrate and the area of the photodetector is arranged to be responsive to optical energy propagating toward the substrate.

25. An electro-optical device comprising:

a non-metallic substrate;

a vertical-cavity surface-emitting laser carried by said substrate, the laser including a metal biasing layer;

a vertically-arranged photodetector carried by said substrate and having plural stacked layers;

an optical isolation layer structure carried by said substrate arranged to optically decouple said laser and photodetector from each other;

the photodetector having an area for receiving a controlling optical beam for selectively turning on said photodetector, a semiconductor layer of the photodetector proximate a first end of the photodetector having a biasing electrode thereon; and

metal layer means extending from a semiconductor layer of the photodetector proximate a second end of the photodetector to the metal biasing layer via a path proximate the isolation layer structure so that when optical energy is incident on the receiving area of the photodetector a current path subsists from the biasing electrode through the photodetector and the metal layer means to the metal biasing layer to enable activation of the laser.