Common aperture holographic optical element devices for a free space optical transceiver

• US 6,597,476 B1
• Filed: 05/09/2001
• Issued: 07/22/2003
• Est. Priority Date: 05/09/2001
• Status: Expired due to Fees

• Current Assignee: Pertex Telecommunication LLC (Intellectual Ventures LLC)
• Original Assignee: Terabeam Corporation (Proxim Wireless Corporation)
• Inventors: Okorogu, Albert O.
• Primary Examiner(s): Robinson, Mark A.
• Assistant Examiner(s): AMARI, ALESSANDRO V
• Application Number:
  US09/852,825
• Time in Patent Office: 804 Days
• Field of Search: 359/15, 359/1, 359/130, 359/159, 359/152, 359/153, 250/216, 250/237.R, 250/236.G, 356/457, 369/103, 369/112.1, 369/275.1
• US Class Current: 359/15
• CPC Class Codes: G02B 5/32 Holograms used as optical elements

Abstract

A free space optical transceiver includes a first holographic optical element (HOE) device having a first recorded interference pattern to diffract a received light signal into a plurality of orders. A second HOE device has a second recorded interference pattern and is positioned relative to the first HOE device to reflect the orders of the diffracted light signal towards corresponding optical components. Use of the reflected orders in this manner in conjunction with the optical components provides the transceiver with multiple functionalities, such as communication, tracking, and alignment. Also, the first and second HOE devices have their interference patterns recorded on an emulsion material that is shaped to provide a common aperture through which to pass a transmitted light signal, thereby adding to the overall compactness of the transceiver.

Claims

1. An apparatus, comprising:

a first holographic optical element (HOE) device to diffract a received light signal into a plurality of orders, the first HOE device having an aperture therein; and

a second HOE device to direct the orders of the diffracted light signal to corresponding optical components, the second HOE device having an aperture therein.

2. The apparatus of claim 1 wherein the second HOE device comprises a reflective HOE device to separate and reflect the orders of the diffracted light signal.

3. The apparatus of claim 1, further comprising a transmitter to transmit another light signal through the apertures of the first and second HOE devices.

4. The apparatus of claim 3, further comprising a beam splitter to direct a first portion of the light signal transmitted from the transmitter through the apertures of the first and second HOE devices, and to direct a second portion of that light signal to an optical circuit.

5. A system, comprising:

a first holographic optical element (HOE) device to diffract a received light signal into a plurality of orders, the first HOE device being shaped to provide a first aperture;

a second HOE device to reflect the orders of the diffracted light signal to corresponding optical components, the second HOE device being shaped to provide a second aperture; and

a transmitter to transmit another light signal through the first and second apertures.

6. The system of claim 5 wherein the second HOE device includes:

an emulsion material disposed between first and second elements; and

an interference pattern recorded on the emulsion material, the recorded interference pattern being capable to reflect with separation the orders of the diffracted light signal received from the first HOE device.

7. The system of claim 5, further comprising a beam splitter positioned adjacent to the second aperture of the second HOE device, the beam splitter capable to direct a first portion of the transmitted light signal towards the first aperture of the first HOE device, the beam splitter capable to direct a second portion of the transmitted light signal to an optical circuit.

9. The method of claim 5, further comprising transmitting another light signal through the apertures of the first and second HOE devices in addition to receiving the received light signal.

11. The method of claim 9, further comprising:

splitting the transmitted light signal into a plurality of portions;

directing one of the portions of the transmitted light signal through the common aperture; and

directing at least another one of the portions of the transmitted light signal towards a corresponding optical circuit.

8. A method, comprising:

diffracting a received light signal into a plurality of orders using a first HOE device having an aperture therein;

separating the plurality of orders and directing at least some of the plurality of orders towards corresponding optical components using a second HOE device having an aperture therein; and

using the optical components to obtain, from the at least some of the plurality of orders, information related to the received light signal.

10. The system claim 8 wherein separating the plurality of orders and directing at least some of the plurality of orders towards corresponding optical components includes using a reflective holographic optical element to separate and direct the orders.

12. An apparatus, comprising:

a first holographic optical element (HOE) device having a first recorded interference pattern to diffract a received light signal into a plurality of orders;

a second HOE device having a second recorded interference pattern and positioned relative to the first HOE device to reflect the orders of the diffracted light signal towards corresponding optical components, the first and second HOE devices having their interference patterns recorded on emulsion materials that are shaped to provide a common aperture through which to pass a transmitted light signal; and

a beam splitter to split the transmitted light signal into a first portion and into a second portion, the beam splitter positioned to direct the first portion of the transmitted light signal through the common apertures of the first and second HOE devices, the beam splitter positioned to direct the second portion of the transmitted light signal to an optical circuit.

13. The apparatus of claim 12 wherein one of the optical components comprises a communication detector to receive one of the orders of the diffracted light signal reflected from the second HOE device.

14. The apparatus of claim 12 wherein one of the optical components comprises a tracking detector to receive one of the orders of the diffracted light signal reflected from the second HOE device.

15. The apparatus of claim 12, further comprising a transmitter positioned adjacent to the second HOE device to transmit the transmitted light signal through the aperture shaped in the emulsion material of the second HOE device.

16. The apparatus of claim 12 wherein the second recorded interference pattern of the second HOE device comprises a grating that is recorded to provide separation between the orders of the diffracted light signal reflected therefrom.

17. The apparatus of claim 12 wherein the optical circuit comprises a phase error correction circuit or a scintillation sensor circuit.

18. The apparatus of claim 12 wherein the beam splitter is positioned within the aperture of the second HOE device.

19. The apparatus of claim 14, further comprising a mirror positioned between the second HOE device and the tracking detector to direct that order from the second HOE device to the tracking detector.

20. An apparatus, comprising:

a first holographic optical element (HOE) having an optical aperture therein and a first recorded interference pattern to diffract a received light signal into a plurality of orders; and

a second HOE having an optical aperture therein and a second recorded interference pattern, the second HOE being positioned relative to the first HOE device to reflect the orders of the diffracted light signal towards corresponding optical components and to provide a common aperture through which to pass a transmitted light signal.

21. The apparatus of claim 20 wherein one of the optical components comprises a communication detector to receive one of the orders of the diffracted light signal reflected from the second HOE device.

22. The apparatus of claim 20 wherein one of the optical components comprises a tracking detector to receive one of the orders of the diffracted light signal reflected from the second HOE device.

23. The apparatus of claim 20, further comprising a transmitter positioned adjacent to the second HOE device to transmit the transmitted light signal through the aperture shaped in the emulsion material of the second HOE device.

24. The apparatus of claim 20 wherein the second recorded interference pattern of the second HOE device comprises a grating that is recorded to provide separation between the orders of the diffracted light signal reflected therefrom.

25. The apparatus of claim 20, further comprising a beam splitter to split the transmitted light signal into a first portion and into a second portion, the beam splitter positioned to direct the first portion of the transmitted light signal through the apertures of the first and second HOE devices, the beam splitter positioned to direct the second portion of the transmitted light signal to an optical circuit.

26. The apparatus of claim 22, further comprising a mirror positioned between the second HOE device and the tracking detector to direct that order from the second HOE device to the tracking detector.

27. The apparatus of claim 25 wherein the optical circuit comprises a phase error correction circuit or a scintillation sensor circuit.

28. The apparatus of claim 25 wherein the beam splitter is positioned within the aperture of the second HOE device.