Optical gate array device

• US 20080101747A1
• Filed: 12/07/2007
• Published: 05/01/2008
• Est. Priority Date: 08/23/2006
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Nakagawa, Goji
• Granted Patent: US 7,548,669 B2
• Time in Patent Office: Days
• US Class Current: 385/17
• CPC Class Codes: G02B 6/4201 Packages, e.g. shape, construction, internal or external details
• CPC Class Codes: G02B 6/4206 Optical features G02B6/4207, G02B6/421 take precedence
• CPC Class Codes: G02B 6/4249 comprising arrays of active devices and fibres
• CPC Class Codes: G02B 6/4271 with thermo electric cooling
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 2011/0013 using gating amplifiers
• CPC Class Codes: H04Q 2011/0016 using wavelength multiplexing or demultiplexing
• CPC Class Codes: H04Q 2011/0026 using free space propagation (e.g. lenses, mirrors)

Abstract

An optical gate array device which permits the use of an optical gate array with a pitch smaller than the diameter of optical fibers. The optical gate array has an array of optical gates, and an optical fiber array has an array of optical fibers. A lens is arranged between the optical gate array and the optical fiber array, for collectively achieving optical coupling between all of the optical gates of the optical gate array and all of the optical fibers of the optical fiber array.

Claims

1. An optical gate array device for controlling optical signals, comprising:

an optical gate array having an array of optical gates;

an optical fiber array having an array of optical fibers; and

a lens arranged between the optical gate array and the optical fiber array, for collectively achieving optical coupling between all of the optical gates of the optical gate array and all of the optical fibers of the optical fiber array.

2. The optical gate array device according to claim 1, wherein an end face of the optical gate array, a principal plane of the lens and an end face of the optical fiber array are arranged in parallel to one another.

3. The optical gate array device according to claim 1, wherein the lens has an image magnification so determined as to be equal to the ratio of a beam spot size of the optical fibers to a beam spot size of the optical gates, and the ratio of a pitch of the optical fiber array to a pitch of the optical gate array is set so as to be equal to the image magnification.

4. The optical gate array device according to claim 3, wherein, provided that the image magnification, which is so determined as to be equal to the ratio of the beam spot size of the optical fibers to that of the optical gates, is equal to b/a, the optical gate array is positioned at a distance “

a”

from the lens, the optical fiber array is positioned at a distance “

b”

from the lens, and the lens has a focal distance “

f”

satisfying (1/a)+(1/b)=(1/f).

5. The optical gate array device according to claim 3, wherein the lens includes a first lens and a second lens, and

provided that the first and second lenses have focal distances f1 and f2, respectively, the optical gate array and the first lens constitute a confocal system with the optical gate array positioned at the focal distance “

f1”

from the first lens, the second lens and the optical fiber array constitute a confocal system with the optical fiber array positioned at the focal distance “

f2”

from the second lens, and the image magnification, which is so determined as to be equal to the ratio of the beam spot size of the optical fibers to that of the optical gates, is equal to f2/f1.

6. The optical gate array device according to claim 5, wherein the first and second lenses are positioned such that centers thereof are not aligned with each other but separate from each other.

7. The optical gate array device according to claim 1, further comprising an optical isolator arranged between the optical gate array and the optical fiber array and having an aperture large enough to admit all light beams emerging from the optical gate array.

8. The optical gate array device according to claim 1, wherein the lens comprises a cut lens which is cut in a manner such that the lens is elongate in an arraying direction of the optical gate array and the optical fiber array and has an aperture in a perpendicular direction large enough to admit light radiated from the optical gate array.

9. The optical gate array device according to claim 1, wherein the lens has a center aligned with a center of the optical gate array in an arraying direction thereof so that light beams emerging from the optical gates may pass through one half of the lens.

10. An optical gate array module for controlling transmission of optical signals, comprising:

an optical gate unit including an optical gate array constituted by an array of N optical gates, a single optical gate, and an N;

1 coupler for coupling the optical gate array and the signal optical gate with each other, the optical gate unit having N ports on one end face thereof and a single port on the other end face thereof;

an optical fiber array located on one side of the optical gate unit close to the N ports and including an array of N optical fibers;

an N-port-side lens arranged between the optical gate unit and the optical fiber array, for collectively achieving optical coupling between all of the N optical gates of the optical gate array and all of the N optical fibers of the optical fiber array;

a single optical fiber located on the other side of the optical gate unit close to the single port; and

a single port-side lens arranged between the optical gate unit and the single optical fiber, for optically coupling the single optical gate and the single optical fiber with each other.

11. The optical gate array module according to claim 10, wherein the N-port-side lens includes a first lens and a second lens, and

provided that the first and second lenses have focal distances f1 and f2, respectively, the optical gate unit and the first lens constitute a confocal system with the optical gate unit positioned at the focal distance f1 from the first lens, the second lens and the optical fiber array constitute a confocal system with the optical fiber array positioned at the focal distance f2 from the second lens, and an image magnification of the first and second lenses, which is so determined as to be equal to the ratio of a beam spot size of all the N optical fibers of the optical fiber array to that of all the N optical gates of the optical gate array, is equal to f2/f1.

12. The optical gate array module according to claim 10, wherein the single port-side lens includes a third lens arranged close to the optical gate unit and a fourth lens arranged close to the single optical fiber, and

the optical gate array module further comprises an optical isolator arranged between the third and fourth lenses, for shutting off reflected light.

13. The optical gate array module according to claim 10, further comprising an optical gate carrier carrying the optical gate unit thereon and connecting optical gate-driving terminals, which are module terminals, to the optical gates of the optical gate unit,

wherein the optical gate carrier has an N-port-side end face parallel with the N-port-side end face of the optical gate unit, and has a single port-side end face inclined at an angle corresponding to an emergence angle of light from the optical gate unit.

14. The optical gate array module according to claim 10, further comprising optical gate-driving terminals and ground terminals as module terminals, wherein the optical gate-driving terminals and the ground terminals are alternately arranged.

15. An optical switch system for controlling m×

n switching of optical signals, comprising;

m optical splitters each having one input and n outputs, for splitting light into n beams;

n optical gate array modules each having m inputs and one output,

each of the optical gate array modules including

an optical gate unit including an optical gate array constituted by an array of m optical gates connected to respective output lines of the m optical splitters, a single optical gate, and an m;

1 coupler for coupling the optical gate array and the signal optical gate with each other, the optical gate unit having m input ports on an input-side end face thereof and a single output port on an output-side end face thereof,

an optical fiber array located on one side of the optical gate unit close to the inputs ports and including an array of m optical fibers,

an input port-side lens arranged between the optical gate unit and the optical fiber array, for collectively achieving optical coupling between all of the m optical gates of the optical gate array and all of the m optical fibers of the optical fiber array,

a single optical fiber located on the other side of the optical gate unit close to the output port, and

an output port-side lens arranged between the optical gate unit and the single optical fiber, for optically coupling the single optical gate and the single optical fiber with each other; and

a switch controller for controlling driving of the optical gate units.

16. The optical switch system according to claim 15, wherein the input port-side lens of each of the optical gate array modules includes a first lens and a second lens, and

provided that the first and second lenses have focal distances f1 and f2, respectively, the optical gate unit and the first lens constitute a confocal system with the optical gate unit positioned at the focal distance f1 from the first lens, the second lens and the optical fiber array constitute a confocal system with the optical fiber array positioned at the focal distance f2 from the second lens, and an image magnification of the first and second lenses, which is so determined as to be equal to the ratio of a beam spot size of all the m optical fibers of the optical fiber array to that of all the m optical gates of the optical gate array, is equal to f2/f1.

17. The optical switch system according to claim 15, wherein the output port-side lens of each of the optical gate array modules includes a third lens arranged close to the optical gate unit and a fourth lens arranged close to the single optical fiber, and

each of the optical gate array modules further includes an optical isolator arranged between the third and fourth lenses, for shutting off reflected light.

18. The optical switch system according to claim 15, wherein each of the optical gate array modules further includes an optical gate carrier carrying the optical gate unit thereon and connecting optical gate-driving terminals, which are module terminals, to the optical gates of the optical gate unit, and

the optical gate carrier has an input-side end face parallel with the input-side end face of the optical gate unit, and has an output-side end face inclined at an angle corresponding to an emergence angle of light from the optical gate unit.

19. The optical switch system according to claim 15, wherein each of the optical gate array modules further includes optical gate-driving terminals and ground terminals as module terminals, and the optical gate-driving terminals and the ground terminals are alternately arranged.