Multi-channel optical transceiver

• US 6,490,067 B2
• Filed: 05/16/2001
• Issued: 12/03/2002
• Est. Priority Date: 05/16/2000
• Status: Expired due to Term

• Current Assignee: CommWorks Solutions, LLC (IP Investments Group LLC)
• Original Assignee: Airfiber, Inc.
• Inventors: Bloom, Scott H., Alwan, Jim, Chan, Victor J.
• Primary Examiner(s): Pascal, Leslie
• Assistant Examiner(s): Phan, Hanh
• Application Number:
  US09/860,078
• Publication Number:
  US 20010043379A1
• Time in Patent Office: 566 Days
• Field of Search: 359/113, 359/114, 359/152, 359/153, 359/127, 359/133, 359/172, 359/159, 359/110, 385/88, 385/89, 385/92, 385/93
• US Class Current: 398/128
• CPC Class Codes: H04B 10/1125 using a single common optical path
• CPC Class Codes: H04B 10/2587 using a single light source for multiple stations

Abstract

An optical transceiver such as used, for example, in a wireless optical network (WON), includes multiple laser sources including a first laser source configured to transmit a first 5 output channel beam having a first optical characteristic and at least a second laser source configured to transmit a second output channel beam having a second optical characteristic; multiple detectors including a first detector configured to detect a first input channel beam having the first optical characteristic and at least a second detector configured to detect a second input channel beam having the second optical characteristic; and multiple apertures including a first aperture through which the first output channel beam and the second input channel beam pass and a second aperture through which the second output channel beam and the first input channel beam pass.

Claims

1. An optical transceiver configured for communicating high data rates via free space lasers while maintaining a safe exposure level to an observer'"'"'s eye, the optical transceiver comprising:

a plurality of laser sources including a first laser source configured to transmit a first output channel beam having a first optical characteristic and at least a second laser source configured to transmit a second output channel beam having a second optical characteristic;

a plurality of detectors including a first detector configured to detect a first input channel beam having the first optical characteristic and at least a second detector configured to detect a second input channel beam of the second optical characteristic; and

a plurality of apertures including a first aperture through which the first output channel beam and the second input channel beam pass and a second aperture through which the second output channel beam and the first input channel beam pass, wherein the first aperture and the second aperture are physically separated to limit a maximum observable power density to a predetermined value.

2. The system of claim 1, wherein the first output channel beam and the second output channel beam overlap in a region, such that the maximum observable power density in the region does not exceed the predetermined value.

3. The system of claim 2, wherein the physical separation between the first aperture and the second aperture is about 25 millimeters or greater.

4. The system of claim 2, wherein the first aperture has a first diameter and the second aperture has a second diameter, both diameters being selected such that the maximum observable power density in the region does not exceed the predetermined value.

5. The system of claim 4, wherein the first diameter is different from the second diameter.

6. The system of claim 4, wherein the first diameter is the same as the second diameter.

7. The system of claim 6, wherein the first diameter and the second diameter are about 75 millimeters.

8. The system of claim 4, wherein the predetermined value provides a safe exposure level to an observer'"'"'s eye.

9. The system of claim 8, wherein the safe exposure level satisfies a class 1 AEL level.

10. The system of claim 8, wherein the safe exposure level satisfies a class 1M AEL level.

11. An optical transceiver configured for communicating high data rates via free space lasers while maintaining a safe exposure level to an observer'"'"'s eye, the optical transceiver comprising:

a plurality of dichoric mirrors, each dichoric mirror configured to pass a beam of a first wavelength and reflect a beam of a second wavelength;

a plurality of laser sources including a first laser source arranged to transmit a first output channel beam of the first wavelength through a first dichoric mirror and a second laser source arranged to transmit a second output channel beam of the second wavelength that is reflected by a second dichoric mirror;

a plurality of photodetectors including a first detector configured to detect a first input channel beam of the second wavelength reflected by the first dichoric mirror and a second detector configured to detect a second input channel beam of the first wavelength passed by the second dichoric mirror; and

a plurality of lenses including a first lens arranged to focus the first output channel beam and the first input channel beam and a second lens arranged to focus the second output channel beam and the second input channel beam, wherein the first lens and the second lens are physically separated to reduce a laser exposure level for an observer'"'"'s eye to a predetermined level.

12. The system of claim 11, wherein the first output channel beam and the second output channel beam overlap such that the laser exposure level in the region does not exceed the predetermined value.

13. The system of claim 12, wherein the physical separation between the first lens and the second lens is about 25 millimeters or greater.

14. The system of claim 12, wherein the first lens has a first diameter and the second lens has a second diameter, wherein the first diameter and the second diameter are selected such that the laser exposure level does not exceed the predetermined value.

15. The system of claim 14, wherein the first diameter is different from the second diameter.

16. The system of claim 14, wherein the first diameter is the same as the second diameter.

17. The system of claim 16, wherein the first diameter and the second diameter are about 75 millimeters.

18. The system of claim 14, wherein the predetermined value provides a safe exposure level to an observer'"'"'s eye.

19. The system of claim 18, wherein the safe exposure level satisfies a class 1 AEL level.

20. The system of claim 18, wherein the safe exposure level satisfies a class 1M AEL level.

21. A method for controlling laser power, from an optical transceiver configured for communicating high data rates via free space lasers using a plurality of beams, while maintaining a safe exposure level to an observer'"'"'s eye, the method comprising:

transmitting at a first data rate using a first beam through a first aperture at a first power level that does not exceed a predetermined value;

transmitting at a second data rate using a second beam through a second aperture at a second power level that does not exceed the predetermined value, wherein the first aperture and the second aperture are physically separated a distance S so that in a region where the first beam and the second beam overlap a combined observable laser power does not exceed the predetermined value;

increasing the first data rate and the first power level while not exceeding the predetermined value;

if increasing the first power level will exceed the predetermined value, allocating a portion of the first data rate to the second beam; and

transmitting the portion using the second beam through the second aperture at a third power level that does not exceed the predetermined value.

22. The method of claim 21, wherein the first beam and the second beam transmit using different wavelengths.

23. The method of claim 22, wherein the distance S is about 25 millimeters or greater.

24. The method of claim 21, further comprising selecting a diameter D1 for the first aperture and a diameter D2 for the second aperture, both selected so that the combined observable laser power does not exceed the predetermined value.

25. The method of claim 24, wherein the diameter D1 is different than the diameter D2.

26. The method of claim 24, wherein the diameter D1 is the same as the diameter D2.

27. The method of claim 26, wherein the diameter D1 and the diameter D2 are about 75 millimeters.

28. The method of claim 24, wherein the predetermined value provides a safe exposure level to an observer'"'"'s eye.

29. The method of claim 28, wherein the safe exposure level satisfies a class 1 AEL level.

30. The method of claim 28, wherein the safe exposure level satisfies a class 1M AEL level.

31. An optical transceiver configured for communicating high data rates via free space lasers while maintaining a safe exposure level to an observer'"'"'s eye, the optical transceiver comprising:

a first laser source configured for communicating information via a first beam using up to a maximum power level;

a second laser source configured for communicating information via a second beam using up to the maximum power level, wherein the first beam and the second beam interfere in a region where a maximum observable power level does not exceed the maximum power level;

a first lens coupled to the first laser source and located in the path of the first beam, the first lens having a diameter D1; and

a second lens coupled to the second laser source at a distance S from the first lens and located in the path of the second beam, the second lens having a diameter D2, wherein the distance S and the diameters D1 and D2 are selected to ensure that the maximum observable power level does not exceed the maximum power level.

32. The optical transceiver of claim 31, wherein the first beam transmits using a first wavelength and the second beam transmits using a second wavelength.

33. The optical transceiver of claim 32, further comprising:

a first detector configured to detect a first input beam which passes through the first aperture using the first wavelength; and

a second detector configured to detect a second input beam which passes through the second aperture using the second wavelength.

34. The optical transceiver of claim 33, wherein the distance S is about 25 millimeters or greater.

35. The optical transceiver of claim 33, wherein the diameter D1 is different from the diameter D2.

36. The optical transceiver of claim 33, wherein the diameter D1 is the same as the diameter D2.

37. The optical transceiver of claim 36, wherein the diameters D1 and D2 are about 75 millimeters.

38. The optical transceiver of claim 33, wherein the maximum power level provides a safe exposure level to an observer'"'"'s eye.

39. The optical transceiver of claim 38, wherein the safe exposure level satisfies a class 1 AEL level.

40. The optical transceiver of claim 38, wherein the safe exposure level satisfies a class 1M AEL level.

41. A method for use in a system having a plurality of optical transceivers, each transceiver configured to transmit data via a plurality of laser beams and receive data via a plurality of laser beams, both while maintaining a safe exposure level to an observer'"'"'s eye, the method comprising:

transmitting a first communication beam from a first transceiver through a first aperture to a second transceiver at a first power level which maintains a safe exposure level to an observer'"'"'s eye;

transmitting a second communication beam from the first transceiver through a second aperture to the second transceiver at a second power level, wherein the second aperture is located at a distance S from the first aperture to maintain the safe exposure level to an observer'"'"'s eye; and

if the first power level will be exceeded when transmitting a data from the first transceiver to the second transceiver via the first communication beam, allocating a first portion of the data for its transmission via the second communication beam to maintain the safe exposure level to an observer'"'"'s eye.

42. The method of claim 41, further comprising selecting a diameter D1 for the first aperture and a diameter D2 for the second aperture, both to maintain the safe exposure level to an observer'"'"'s eye.

43. The method of claim 42, wherein the first communication beam and the second communication beam overlap such that the laser exposure level in the region does not exceed the safe exposure level to an observer'"'"'s eye.

44. The method of claim 43, wherein the safe exposure level to an observer'"'"'s eye satisfies a class 1 AEL level.

45. The method of claim 43, wherein the safe exposure level to an observer'"'"'s eye satisfies a class 1M AEL level.

46. A method for use in a system having a plurality of optical transceivers, each transceiver configured to transmit data via a plurality of laser beams and receive data via a plurality of laser beams, both while maintaining a safe exposure level to an observer'"'"'s eye, the method comprising:

transmitting a first communication beam from a first transceiver, through a first aperture with a diameter D1, to a second transceiver at a first power level which maintains a safe exposure level to an observer'"'"'s eye;

transmitting a second communication beam from the first transceiver, through a second aperture with a diameter D2, to the second transceiver at a second power level, wherein the second aperture is located at a distance S from the first aperture to maintain the safe exposure level to an observer'"'"'s eye; and

allocating data between the first communication beam and the second communication beam to maintain the safe exposure level to an observer'"'"'s eye.

47. The method of claim 46, wherein the observer'"'"'s eye is exposed to the first communication beam or the second communication beam.

48. The method of claim 47, wherein the observer'"'"'s eye is located in a region where the first communication beam and the second communication beam overlap.

49. The method of claim 48, further comprising selecting D1 and D2 to limit a size of the region.