Integrated optical channel

• US 6,775,068 B2
• Filed: 11/06/2002
• Issued: 08/10/2004
• Est. Priority Date: 11/06/2002
• Status: Active Grant

• Current Assignee: Bigbangwidth, Inc.
• Original Assignee: Bigbandwidth
• Inventors: McLaughlin, Dean Edward, Lomas, Stuart John
• Primary Examiner(s): MACK, RICKY LEVERN
• Application Number:
  US10/289,475
• Publication Number:
  US 20040085651A1
• Time in Patent Office: 643 Days
• Field of Search: 385/18, 385/33, 385/15, 385/16, 385/17, 359/619, 359/290, 359/291
• US Class Current: 359/619
• CPC Class Codes: G02B 6/266 the optical element being an attenuator
• CPC Class Codes: G02B 6/2937 In line lens-filtering-lens devices, i.e. elements arranged along a line and mountable in a cylindrical package for compactness, e.g. 3- port device with GRIN lenses sandwiching a single filter operating at normal incidence in a tubular package
• CPC Class Codes: G02B 6/29395 configurable, e.g. tunable or reconfigurable switching G02B6/35
• CPC Class Codes: G02B 6/32 having lens focusing means positioned between opposed fibre ends with lens being an integral part of the single fibre end G02B6/262
• CPC Class Codes: G02B 6/3514 the reflective optical element moving along a line so as to translate into and out of the beam path, i.e. across the beam path
• CPC Class Codes: G02B 6/3546 NxM switch, i.e. a regular array of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/3582 Housing means or package or arranging details of the switching elements, e.g. for thermal isolation

Abstract

An apparatus and method that provides for improved optical communication between at least one source and at least one destination, with reduced loss of power and superior retention of the quality of a signal when compared with the prior art. The apparatus has a body having at least one integrated optical channel along which a light signal is transmitted via an N-fold plurality of lenses. A light signal transmitted along the integrated optical channel is repeatedly refocused along the optical axis and is then highly focused at the second end. Optionally, the light signal can be switched, attenuated, filtered, tapped or monitored by positioning appropriate optical devices between the lenses.

Claims

1. An apparatus for transmitting an optical signal between a source and a destination, the apparatus having:

a body providing;

at least one first optical channel which is adapted for positioning in a space between a first end and a second end, such that in order for an optical signal beam to pass between the first end and the second end the optical signal beam must pass through the first optical channel;

the first optical channel having a first optical axis extending in a straight line between the first end and the second end;

the first end being in optical communication with one of the source and the destination;

the second end being in optical communication with the other of the source and the destination;

the optical channel having an N fold first plurality of lenses comprising a first lens, a second lens and an N−

2 fold plurality of third lenses,

the first lens being situated toward the first end of the first optical channel and spaced from the first distal end of the one of the source and the destination, the second lens being situated toward the second end of the first optical channel and spaced from the second distal end of the other of the source and the destination, and the third lenses being situated between the first lens and the second lens;

the lenses being axially situated at intervals along the first optical axis, so that the optical signal beam emitted from the first distal end of the source is repeatedly refocused along the first optical axis toward the destination, and is focused at the second distal end of the destination;

thereby providing for optical communication between the source and the destination along the first optical channel.

2. The apparatus as defined in claim 1, wherein the first optical channel can be operated in one of:

a unidirectional manner, in which the source must be at the first end and the destination must be at the second end of the first optical channel;

a reversible unidirectional manner, in which the source is at one of the first end and the second end and the destination is at the other of the first end and the second end of the first optical channel; and

a bi-directional manner in which there is a device that serves as a source and a destination at both of the first end and the second end of the first optical channel.

3. The apparatus as defined in claim 1, wherein the number of lenses, N, is an integer number at least 2.

4. The apparatus as defined in claim 3, wherein the number of lenses, N, is an integer number in the range from 2 to about 9.

5. The apparatus as defined in claim 1, wherein the lenses are selected from light focusing elements including but not limited to ball lenses, thin lenses, GRIN lenses, and composite lenses.

6. The apparatus as defined in claim 1, wherein:

the lenses have closely similar focal lengths and each lens is spaced from a neighbouring lens along the first optical axis by a first length that is closely similar for each pair of neighbouring lenses,

the first lens is spaced from the first distal end of the source by a second length that is approximately one-half of the first length, and the second lens is spaced from the second distal end also by the second length.

7. The apparatus as defined in claim 6, wherein the lenses are spaced from neighbouring lenses by a length that is not greater than four times the focal length of each of the lenses.

8. The apparatus as defined in claim 1, wherein:

the lenses have closely similar focal lengths and lenses are spaced from neighbouring lenses by a regular pattern of spacings along the first optical axis so that successive lens are spaced from preceding lenses by a regular pattern of long spacings and short spacings, and

the first lens is spaced from the first distal end of the source by a length that is not larger than twice the focal length of said first lens and the second lens is spaced from the destination by a length that is not larger than twice the focal length of said second lens.

9. The apparatus as defined in claim 1, wherein:

the lenses comprise at least two sets of lenses, each lens in a set of lenses having substantially the same focal length, the first set of lenses including the first lens and the second lens, the N−

2 fold plurality of third lenses including at least one second set of lenses,

each lens in the second set of lenses having a focal length longer than the focal length of each lens in the first set of lenses,

the lenses being spaced from each other in a regular pattern along the first optical axis,

the first lens being spaced from the first distal end of the source by a second length that is not greater than twice the focal length of the first lens, and the second lens being spaced from the second distal end by a similar second length, and

the spacing between neighbouring lenses each of which is a member of the second set of lenses being greater than a spacing between a lens from the first set of lenses and a neighbouring lens that is from the second set of lenses,

so that a light signal emitted from the first distal end of the source is continuously refocused by the succession of lenses and is focused at the second distal end of the destination;

thereby providing for optical communication between the source and the destination along the first optical channel.

10. The apparatus as defined in claim 1, wherein the source is a first distal end of a first optical fiber situated at and in optical communication with the first end of the first optical channel, and the destination is a second distal end of a second optical fiber situated at and in optical communication with the second end of the first optical channel.

11. The apparatus as defined in claim 6, wherein the lenses are ball lenses and the second length is about 5% less than one-half of the first length, so as to effect an improvement in the quality of the light signal transmitted along the first optical channel by reducing the impact of spherical aberration arising from the shape of the ball lenses.

12. The apparatus as defined in claim 11, wherein:

each of the lenses is situated axially along the first optical axis with a radial displacement that has a value no more than 1 percent of the diameter of each lens, and

each of the lenses is situated axially along the first optical axis with an axial displacement that has a value no more than 10 percent of the diameter of the lens, so as to optimize performance of the first optical channel for transmission of the optical signal.

13. The apparatus as defined in claim 1, wherein the apparatus is a microengineered apparatus for optical communications, manufactured by a process comprising a combination of micromachining and/or etching the shape of the movable portions and the base from a monolithic wafer.

14. The apparatus as defined in claim 13, wherein the monolithic wafer is a silicon crystal.

15. The apparatus as defined in claim 14, wherein the monolithic wafer comprises a first layer that is silicon, a second layer that is silica, and a third layer that is silicon.

16. The apparatus as defined in claim 1, wherein at least one optical device is situated between at least one of pairs of neighbouring lenses, to allow said optical device to perform one of processing and intercepting the light beam that is transmitted along the first optical channel, so as to perform a function that is selected from functions including monitoring, tapping, switching, filtering, and attenuating an optical signal emitted from the source.

17. An apparatus for transmitting an optical signal from a source to a destination, the apparatus having:

a body providing;

at least one first optical channel which is adapted for positioning in a space between a first end and a second end, such that in order for an optical signal beam to pass between the first end and the second end the optical signal beam must pass through the first optical channel;

the first end being in optical communication with one of the source and the destination;

the second end being in optical communication with the other of the source and the destination;

the optical channel having an N fold first plurality of lenses comprising a first lens, a second lens and an N−

2 fold plurality of third lenses, where N is an integer at least 2,

the first lens being situated toward the first end of the first optical channel and spaced from the first distal end of the one of the source and the destination, the second lens being situated toward the second end of the first optical channel and spaced from the second distal end of the other of the source and the destination, and the third lenses being situated between the first lens and the second lens;

the lenses being axially situated at intervals along a straight line defining a first optical axis extending between the first end and the second end, so that the optical signal beam emitted from the first distal end of the source is repeatedly refocused along the first optical axis toward the destination, and is focused at the second distal end of the destination,

the lenses being selected from light focusing elements including ball lenses, thin lenses, GRIN lenses, and composite lenses,

the lenses having closely similar focal lengths, and each lens is spaced from a neighbouring lens along the first optical axis by a first length that is closely similar for each pair of neighbouring lenses,

the first lens is spaced from the first distal end of the source by a second length that is approximately one-half of the first length, and the second lens is spaced from the second distal end also by the second length,

the lenses being spaced from neighbouring lenses by a length that is not greater than four times the focal length of each of the lenses;

thereby providing for optical communication between the source and the destination along the first optical channel,

the apparatus being adapted so that the first optical channel operates in one of;

a unidirectional manner, in which the source must be at the first end and the destination must be at the second end of the first optical channel;

a reversible unidirectional manner, in which the source is selectively at one of the first end and the second end and the destination is at the other of the first end and the second end of the first optical channel; and

a bi-directional manner in which there is a source and a destination at both of the first end and the second end of the first optical channel.

18. The apparatus as defined in claim 17, wherein:

the lenses are ball lenses;

the second length is about 5% less than one-half of the first length, so as to effect an improvement in the quality of the light signal transmitted along the first optical channel by reducing the impact of spherical aberration arising from the shape of the ball lenses;

each of the lenses is situated axially along the first optical axis with a radial displacement that has a value no more than 1 percent of the diameter of each lens; and

each of the lenses is situated axially along the first optical axis with an axial displacement that has a value no more than 10 percent of the diameter of the lens, so as to optimize performance of the first optical channel for transmission of the optical signal.

19. The apparatus as defined in claim 17, wherein at least one optical device is situated between at least one of pairs of neighbouring lenses, to allow said optical device to perform one of processing and intercepting the light beam that is transmitted along the first optical channel, so as to perform a function that is selected from functions including monitoring, tapping, switching, filtering, and attenuating an optical signal emitted from the source.

20. An apparatus for transmitting an optical signal from a source to a destination, the apparatus having:

a body providing;

at least one first optical channel which is adapted for positioning in a space between a first end and a second end, such that in order for an optical signal beam to pass between the first end and the second end the optical signal beam must pass through the first optical channel;

the first end being in optical communication with one of the source and the destination;

the second end being in optical communication with the other of the source and the destination;

the optical channel having an N fold first plurality of lenses comprising a first lens, a second lens and an N−

2 fold plurality of third lenses, where N is an integer at least 2,

the first lens being situated toward the first end of the first optical channel and spaced from the first distal end of the one of the source and the destination, the second lens being situated toward the second end of the first optical channel and spaced from the second distal end of the other of the source and the destination, and the third lenses being situated between the first lens and the second lens;

the lenses being axially situated at intervals along a straight line defining a first optical axis extending between the first end and the second end, so that the optical signal beam emitted from the first distal end of the source is repeatedly refocused along the first optical axis toward the destination, and is focused at the second distal end of the destination,

the lenses being selected from light focusing elements including ball lenses, thin lenses, GRIN lenses, and composite lenses,

the lenses having closely similar focal lengths and lenses are spaced from neighbouring lenses by a regular pattern of spacings along the first optical axis so that successive lens are spaced from preceding lenses by a regular pattern of long spacings and short spacings, and

the first lens being spaced from the first distal end of the source by a second length that is not larger than twice the focal length of each lens and the second lens being spaced from the destination also by said second length;

thereby providing for optical communication between the source and the destination along the first optical channel,

the apparatus being adapted so that the first optical channel operates in one of;

a unidirectional manner, in which the source must be at the first end and the destination must be at the second end of the first optical channel;

a reversible unidirectional manner, in which the source is selectively at one of the first end and the second end and the destination is at the other of the first end and the second end of the first optical channel; and

a bi-directional manner in which there is a source and a destination at both of the first end and the second end of the first optical channel.

21. The apparatus as defined in claim 20, wherein:

the lenses are ball lenses;

the second length is about 5% less than one-half of the first length, so as to effect an improvement in the quality of the light signal transmitted along the first optical channel by reducing the impact of spherical aberration arising from the shape of the ball lenses;

each of the lenses is situated axially along the first optical axis with a radial displacement that has a value no more than 1 percent of the diameter of each lens; and

each of the lenses is situated axially along the first optical axis with an axial displacement that has a value no more than 10 percent of the diameter of the lens,

so as to optimize performance of the first optical channel for transmission of the optical signal.

22. The apparatus as defined in claim 20, wherein at least one optical device is situated between at least one of pairs of neighbouring lenses, to allow said optical device to perform one of processing and intercepting the light beam that is transmitted along the first optical channel, so as to perform a function that is selected from functions including monitoring, tapping, switching, filtering, and attenuating an optical signal emitted from the source.

23. An apparatus for transmitting an optical signal from a source to a destination, the apparatus having:

a body providing;

at least one first optical channel which is adapted for positioning in a space between a first end and a second end, such that in order for an optical signal beam to pass between the first end and the second end the optical signal beam must pass through the first optical channel;

the first end being in optical communication with one of the source and the destination;

the second end being in optical communication with the other of the source and the destination;

the optical channel having an N fold first plurality of lenses comprising a first lens, a second lens and an N−

2 fold plurality of third lenses, where N is an integer at least 2,

the first lens being situated toward the first end of the first optical channel and spaced from the first distal end of the one of the source and the destination, the second lens being situated toward the second end of the first optical channel and spaced from the second distal end of the other of the source and the destination, and the third lenses being situated between the first lens and the second lens;

the lenses being axially situated at intervals along a straight line defining a first optical axis extending between the first end and the second end, so that the optical signal beam emitted from the first distal end of the source is repeatedly refocused along the first optical axis toward the destination, and is focused at the second distal end of the destination,

the lenses being selected from light focusing elements including ball lenses, thin lenses, GRIN lenses, and composite lenses,

the lenses comprising at least two sets of lenses, each lens in a set of lenses having substantially the same focal length, the first set of lenses including the first lens and the second lens, the N−

2 fold plurality of third lenses including at least a second set of lenses, each lens in the second set of lenses having a focal length longer than the focal length of each lens in the first set of lenses,

the lenses being spaced from each other in a regular pattern along the first optical axis,

the first lens being spaced from the first distal end of the source by a second length that is not greater than twice the focal length of the first lens, and the second lens being spaced from the second distal end by a similar second length, and

the spacing between neighbouring lenses each of which is a member of the second set of lenses being greater than a spacing between a lens from the first set of lenses and a neighbouring lens that is from the second set of lenses,

so that a light signal emitted from the first distal end of the source is continuously refocused by the succession of lenses and is focused at the second distal end of the destination;

thereby providing for optical communication between the source and the destination along the first optical channel,

the apparatus being adapted so that the first optical channel operates in one of;

a unidirectional manner, in which the source must be at the first end and the destination must be at the second end of the first optical channel;

a reversible unidirectional manner, in which the source is selectively at one of the first end and the second end and the destination is at the other of the first end and the second end of the first optical channel; and

a bi-directional manner in which there is a source and a destination at both of the first end and the second end of the first optical channel.

24. The apparatus as defined in claim 23, wherein:

the lenses are ball lenses;

the second length is about 5% less than one-half of the first length, so as to effect an improvement in the quality of the light signal transmitted along the first optical channel by reducing the impact of spherical aberration arising from the shape of the ball lenses;

each of the lenses is situated axially along the first optical axis with a radial displacement that has a value no more than 1 percent of the diameter of each lens; and

each of the lenses is situated axially along the first optical axis with an axial displacement that has a value no more than 10 percent of the diameter of the lens,

so as to optimize performance of the first optical channel for transmission of the optical signal.

25. The apparatus as defined in claim 23, wherein at least one optical device is situated between at least one of pairs of neighbouring lenses, to allow said optical device to perform one of processing and intercepting the light beam that is transmitted along the first optical channel, so as to perform a function that is selected from functions including monitoring, tapping, switching, filtering, and attenuating an optical signal emitted from the source.

26. A method for transmitting an optical signal from a source to a destination, comprising:

providing an apparatus having;

a body providing;

at least one first optical channel which is adapted for positioning in a space between a first end and a second end, such that in order for an optical signal beam to pass between the first end and the second end the optical signal beam must pass through the first optical channel;

a source having a first distal end of a first optical fiber situated at the first end of the first optical channel, the source being in optical communication with the first end, and

a destination having a second distal end of a second optical fiber situated at the second end of the first optical channel, the destination being in optical communication with the second end; and

the first optical channel having an N fold first plurality of lenses comprising a first lens, a second lens and an N−

2 fold plurality of third lenses,

the first lens being situated toward the first end of the first optical channel and spaced from the first distal end of the source, the second lens being situated toward the second end of the first optical channel and spaced from the second distal end of the destination, and the third lenses being spaced at intervals between the first lens and the second lens;

the lenses being selected from light focusing elements including ball lenses, thin lenses, GRIN lenses, and composite lenses,

the lenses being axially situated at intervals along a straight line defining a first optical axis extending between the first end of the first optical fiber and the second end of the second optical fiber, so that the optical signal beam emitted from the first end of the first optical fiber is regularly and repeatedly re-focused along the first optical axis, and, when the first optical channel is operated in the reverse direction, an optical signal beam emitted from a source at the second end similarly is repeatedly re-focused in the opposite direction along the first optical axis,

so that a light signal emitted from the first distal end of the source is continuously refocused by the succession of lenses and is focused at the second distal end of the destination;

a first lens being situated toward the source and spaced by a second length from the first distal end of the first optical fiber, a second lens being situated toward the destination and spaced by the second length from the second distal end of the second optical fiber, the second length being approximately one-half of the first length;

emitting a light signal from the first distal end of the first optical fiber that is continuously refocused by the succession of lenses and is focused at the second distal end of the second optical fiber,

thereby providing for transmission of said light signal from the source to the second communication channel;

the apparatus being adapted so that the first optical channel operates in one of;

a unidirectional manner, in which the source must be at the first end and the destination must be at the second end of the first optical channel;

a reversible unidirectional manner, in which the source is selectively at one of the first end and the second end and the destination is at the other of the first end and the second end of the first optical channel; and

a bi-directional manner in which there is a source and a destination at both of the first end and the second end of the first optical channel.

27. The method as defined in claim 26, wherein the number of lenses, N, is an integer number at least 2.

28. The method as defined in claim 26, wherein the number of lenses, N, is an integer number in the range from 2 to about 9.

29. The method as defined in claim 26, wherein:

the lenses have closely similar focal lengths and each lens is spaced from a neighbouring lens along the first optical axis by a first length that is closely similar for each pair of neighbouring lenses, and

the first lens is spaced from the first distal end of the source by a second length that is approximately one-half of the first length, and the second lens is spaced from the second distal end also by the second length.

30. The method as defined in claim 29, wherein the lenses are spaced from neighbouring lenses by a length that is not greater than four times the focal length of each of the lenses.

31. The method as defined in claim 26, wherein:

the lenses have closely similar focal lengths and lenses are spaced from neighbouring lenses by a regular pattern of spacings along the first optical axis so that successive lens are spaced from preceding lenses by a regular pattern of long spacings and short spacings, and

the first lens is spaced from the first distal end of the source by a second length that is not larger than twice the focal length of each lens and the second lens is spaced from the destination also by said second length.

32. The method as defined in claim 26, wherein:

the lenses comprise sets of lenses, each lens in a set of lenses having substantially the same focal length, the first set of lenses including the first lens and the second lens, the N−

2 fold plurality of third lenses including the second set of lenses,

each lens in the second set of lenses having a focal length longer than the focal length of the lenses in the first set of lenses,

the lenses being spaced from each other in a regular pattern along the first optical axis,

the first lens being spaced from the first distal end of the source by a second length that is not greater than twice the focal length of the first lens, and the second lens being spaced from the second distal end by a second length that is not greater than the twice the focal length of the second lens, and

the spacing between neighbouring lenses each of which is a member of the second set of lenses being greater than a spacing between a lens from the first set of lenses and a neighbouring lens that is from the second set of lenses,

so that a light signal emitted from the first distal end of the source is continuously refocused by the succession of lenses and is focused at the second distal end of the destination;

thereby providing for optical communication between the source and the destination along the first optical channel.

33. The method as defined in claim 26, wherein the source is a first distal end of a first optical fiber situated at the first end of the first optical channel, and the destination is a second distal end of a second optical fiber situated at the second end of the first optical channel.

34. The method as defined in claim 26, wherein the lenses are ball lenses and the second length is about 5% less than one-half of the first length, so as to effect an improvement in the quality of the light signal transmitted along the first optical channel by reducing the impact of spherical aberration arising from the shape of the ball lenses.

35. The method as defined in claim 34, wherein each of the lenses is situated axially along the first optical axis with a radial displacement that has a value no greater than 1 percent of the diameter of the lens, so as to obtain optimum performance of the first optical channel for transmission of the optical signal.

36. The method as defined in claim 34, wherein each of the lenses is situated axially along the first optical axis with an axial displacement that has a value no greater than 10 percent of the diameter of the lens, so as to obtain optimum performance of the first optical channel for transmission of the optical signal.

37. The method as defined in claim 26, wherein the apparatus is a microengineered apparatus for optical communications, manufactured by a process comprising a combination of micromachining and/or etching the shape of the movable portions and the base from a monolithic wafer.

38. The method as defined in claim 37, wherein the monolithic wafer is a silicon crystal.

39. The method as defined in claim 37, wherein the monolithic wafer comprises a first layer that is silicon, a second layer that is silica, and a third layer that is silicon.

40. The method as defined in claim 26, wherein at least one optical device is situated between at least one of pairs of neighbouring lenses, to allow said optical device to perform one of processing and intercepting the light beam that is transmitted along the first optical channel, so as to perform a function that is selected from functions including monitoring, tapping, switching, filtering, and attenuating an optical signal emitted from the source.