Optical switch

• US 7,206,476 B2
• Filed: 05/06/2005
• Issued: 04/17/2007
• Est. Priority Date: 03/02/2001
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Oikawa, Yoichi, Kuroyanagi, Satoshi
• Primary Examiner(s): Wood; Kevin S.
• Application Number:
  US11/123,095
• Publication Number:
  US 20050196098A1
• Time in Patent Office: 711 Days
• Field of Search: 385 18- 24
• US Class Current: 385/18
• CPC Class Codes: G02B 2006/12145 Switch
• CPC Class Codes: G02B 6/122 Basic optical elements, e.g. light-guiding paths
• CPC Class Codes: G02B 6/3512 the optical element being reflective, e.g. mirror
• 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 6/3518 the reflective optical element being an intrinsic part of a MEMS device, i.e. fabricated together with the MEMS device MEMS devices in general B81B; manufacture of MEM devices in general B81C; micromechanical devices controlling the direction of light G02B26/0833
• CPC Class Codes: G02B 6/3538 based on displacement or deformation of a liquid controlling the intensity of light by displacement or deformation of a fluid in general G02B26/004; fluid-filled lens of variable focal length G02B3/14
• CPC Class Codes: G02B 6/3546 NxM switch, i.e. a regular array of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/356 in an optical cross-connect device, e.g. routing and switching aspects of interconnecting different paths propagating different wavelengths to (re)configure the various input and output links switching polarized beams G02B6/3594; power equalizers G02B6/356 and G02B6/3594; path selecting means H04Q11/0001
• CPC Class Codes: G02B 6/3582 Housing means or package or arranging details of the switching elements, e.g. for thermal isolation
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 2011/0024 using space switching
• CPC Class Codes: H04Q 2011/003 using switches based on microelectro-mechanical systems [MEMS]

Abstract

An optical switch having a plurality of switch cells. The optical switch has n inputs (n is a natural number) and m outputs (m is a natural number). The optical switch has a unit size defined as the distance between any two adjacent ones of the switch cells. The optical switch comprises a substrate having a switch size of K×L (K is an integer satisfying n≦K, and L is an integer satisfying m≦L), first and second mirrors parallel to each other and perpendicular to a principal surface of the substrate, and an optical unit providing a plurality of input optical paths for the n inputs and a plurality of output optical paths for the m outputs. The plurality of input optical paths are inclined relative to the first and second mirrors, and the plurality of output optical paths are inclined relative to the first and second mirrors. Each switch cell comprises a switch mirror provided movably relative to the substrate. With this configuration, the path dependence of loss is substantially eliminated.

Claims

1. An optical switch having a plurality of switch cells, wherein:

said optical switch has n inputs (n is a natural number) and m outputs (m is a natural number);

said optical switch has a unit size defined as the distance between any two adjacent ones of said switch cells;

said optical switch comprises;

a substrate having a switch size of K×

L (K is an integer satisfying n≦

K, and L is an integer satisfying m≦

L), where K and L represent a number of rows and a number of columns, respectively, of said optical switch;

first and second mirrors parallel to each other and perpendicular to a principal surface of said substrate; and

an optical unit providing a plurality of input optical paths for said n inputs and a plurality of output optical paths for said m outputs, said plurality of input optical paths being inclined relative to said first and second mirrors, said plurality of output optical paths being inclined relative to said first and second mirrors; and

each of said switch cells comprises a switch mirror provided movably relative to said substrate, wherein

each switch cell switches between a first condition where said switch mirror is parallel to said principal surface of said substrate and a second condition where said switch mirror is perpendicular to said principal surface of said substrate, and

said plurality of switch cells, said first and second mirrors, and said optical unit are arranged so that path lengths from said inputs to said outputs are equal.

2. An optical switch having a plurality of switch cells, wherein:

said optical switch has n inputs (n is a natural number) and m outputs (m is a natural number);

said optical switch has a unit size defined as the distance between any two adjacent ones of said switch cells;

said optical switch comprises;

a substrate having a switch size of K×

L (K is an integer satisfying n≦

K, and L is an integer satisfying m≦

L), where K and L represent a number of rows and a number of columns, respectively, of said optical switch;

first and second mirrors parallel to each other and perpendicular to a principal surface of said substrate; and

an optical unit providing a plurality of input optical paths for said n inputs and a plurality of output optical paths for said m outputs, said plurality of input optical paths being inclined relative to said first and second mirrors, said plurality of output optical paths being inclined relative to said first and second mirrors; and

each of said switch cells comprises a switch mirror provided movably relative to said substrate, wherein;

said plurality of switch cells comprise n×

m switch cells;

said n×

m switch cells being provided at n×

m lattice positions on said principal surface; and

said plurality of switch cells, said first and second mirrors, and said optical unit are arranged so that path lengths from said inputs to said outputs are equal.

3. An optical switch having a plurality of switch cells, wherein:

said optical switch has n inputs (n is a natural number) and m outputs (m is a natural number);

said optical switch has a unit size defined as the distance between any two adjacent ones of said switch cells;

said optical switch comprises;

a substrate having a switch size of K×

L (K is an integer satisfying n≦

K, and L is an integer satisfying m≦

L), where K and L represent a number of rows and a number of columns, respectively, of said optical switch;

first and second mirrors parallel to each other and perpendicular to a principal surface of said substrate; and

an optical unit providing a plurality of input optical paths for said n inputs and a plurality of output optical paths for said m outputs, said plurality of input optical paths being inclined relative to said first and second mirrors, said plurality of output optical paths being inclined relative to said first and second mirrors;

each of said switch cells comprises a switch mirror provided movably relative to said substrate, wherein n=m=K=L; and

said plurality of switch cells, said first and second mirrors, and said optical unit are arranged so that path lengths from said inputs to said outputs are equal.

4. An optical switch having a plurality of switch cells, wherein:

said optical switch has n inputs (n is a natural number) and m outputs (m is a natural number);

said optical switch has a unit size defined as the distance between any two adjacent ones of said switch cells;

said optical switch comprises;

a substrate having a switch size of K×

L (K is an integer satisfying n≦

K, and L is an integer satisfying m≦

L), where K and L represent a number of rows and a number of columns, respectively, of said optical switch;

first and second mirrors parallel to each other and perpendicular to a principal surface of said substrate; and

an optical unit providing a plurality of input optical paths for said n inputs and a plurality of output optical paths for said m outputs, said plurality of input optical paths being inclined relative to said first and second mirrors, said plurality of output optical paths being inclined relative to said first and second mirrors;

each of said switch cells comprises a switch mirror provided movably relative to said substrate, wherein said plurality of input optical paths comprise odd-numbered channels and even-numbered channels crossing each other, and said plurality of output optical paths comprise odd-numbered channels and even-numbered channels crossing each other; and

said plurality of switch cells, said first and second mirrors, and said optical unit are arranged so that path lengths from said inputs to said outputs are equal.

5. An optical switch having a plurality of switch cells, wherein:

said optical switch has n inputs (n is a natural number) and m outputs (m is a natural number);

said optical switch has a unit size defined as the distance between any two adjacent ones of said switch cells;

said optical switch comprises;

a substrate having a switch size of K×

L (K is an integer satisfying n≦

K, and L is an integer satisfying m≦

L), where K and L represent a number of rows and a number of columns, respectively, of said optical switch;

first and second mirrors parallel to each other and perpendicular to a principal surface of said substrate; and

an optical unit providing a plurality of input optical paths for said n inputs and a plurality of output optical paths for said m outputs, said plurality of input optical paths being inclined relative to said first and second mirrors, said plurality of output optical paths being inclined relative to said first and second mirrors;

each of said switch cells comprises a switch mirror provided movably relative to said substrate, wherein said plurality of input optical paths are parallel to each other, and said plurality of output optical paths are parallel to each other; and

said plurality of switch cells, said first and second mirrors, and said optical unit are arranged so that path lengths from said inputs to said outputs are equal.

6. An optical switch according to claim 5, wherein n ones of said switch cells connected to said n inputs are alternately inverted in logic, and m ones of said switch cells connected to said m outputs are alternately inverted in logic.

7. An optical switch according to claim 5, wherein said plurality of switch cells comprise n first switch cells connected to said n inputs and at least (n²−

1) second switch cells provided relatively near to said m outputs.

8. An optical switch according to claim 7, wherein:

each of said first switch cells switches the corresponding input optical path into between a first optical path including reflection on said first mirror and a second optical path not including reflection on said first mirror; and

each of said second switch cells is located so as to correspond to each of said first and second optical paths, and determines a final optical path reaching each output.

9. An optical switch according to claim 7, wherein:

the positions of said first switch cells are expressed in the form of (row, column) as (i,

     1);

i=1 to n; and

the positions of said second switch cells are expressed in the form of (row, column) as;

(n/2+i, 2(n−

1)−

n/2+1−

i);

i=0 to (n−

1)

(n/2+i, 2(n−

1)−

n/2+2−

i);

i=0 to (n−

1)

(n/2+i+1, 2(n−

1)−

n/2+1−

i);

i=0 to (n−

1)

(n−

1+i, 2(n−

1)−

i);

i=0 to (n−

1)

(n+i, 2(n−

1)−

i);

i=0 to (n−

1).

10. An optical switch according to claim 7, wherein K=L=2(n−

1).

11. An optical switch according to claim 7, wherein K=L=2n−

1.

12. An optical switch according to claim 11, wherein said at least (n²−

1) second switch cells become substantial when the number of said second switch cells are equal to or greater than n², whereby said second mirror becomes unnecessary.

13. An optical switch according to claim 7, wherein K=L=2n.

14. An optical switch according to claim 13, wherein said at least (n²−

1) second switch cells become substantial when the number of said second switch cells is equal to or greater than n², whereby said second mirror becomes unnecessary.

15. An optical switch according to claim 7, wherein said optical switch further comprises a plurality of lenses provided between said first switch cells and said second switch cells.

16. An optical switch according to claim 15, wherein each of said plurality of lenses comprises a rod lens.

17. An optical switch according to claim 15, wherein said plurality of lenses comprise 2n lenses.

18. An optical switch according to claim 15, wherein:

n is less than 6;

said principal surface of said substrate has an excess space; and

said plurality of lenses are provided in said excess space.

19. An optical switch according to claim 15, wherein:

n is greater than 5; and

said plurality of lenses are provided on said principal surface of said substrate.

20. An optical switch having a plurality of switch cells, wherein:

said optical switch has n inputs (n is a natural number) and m outputs (m is a natural number);

said optical switch has a unit size defined as the distance between any two adjacent ones of said switch cells;

said optical switch comprises;

a substrate having a switch size of K×

L (K is an integer satisfying n≦

K, and L is an integer satisfying m≦

L);

first and second mirrors parallel to each other and perpendicular to a principal surface of said substrate; and

an optical unit providing a plurality of input optical paths for said n inputs and a plurality of output optical paths for said m outputs, said plurality of input optical paths being inclined relative to said first and second mirrors, said plurality of output optical paths being inclined relative to said first and second mirrors; and

each of said switch cells comprises a switch mirror provided movably relative to said substrate, wherein;

n=m=K, L=n+1, and n is an even number;

K and L represent a number of rows and a number of columns, respectively, of said optical switch;

said optical switch further comprises n lenses provided in the (n/2+1)-th column; and

said plurality of switch cells, said first and second mirrors, and said optical unit are arranged so that path lengths from said inputs to said outputs are equal.

21. An optical switch according to claim 20, wherein each of said n lenses comprises a spherical lens.

22. An optical switch having a plurality of switch cells, wherein:

said optical switch has n inputs (n is a natural number) and m outputs (m is a natural number);

said optical switch has a unit size defined as the distance between any two adjacent ones of said switch cells;

said optical switch comprises;

a substrate having a switch size of K×

L (K is an integer satisfying n≦

K, and L is an integer satisfying m≦

L);

first and second mirrors parallel to each other and perpendicular to a principal surface of said substrate; and

an optical unit providing a plurality of input optical paths for said n inputs and a plurality of output optical paths for said m outputs, said plurality of input optical paths being inclined relative to said first and second mirrors, said plurality of output optical paths being inclined relative to said first and second mirrors; and

each of said switch cells comprises a switch mirror provided movably relative to said substrate, wherein;

n=m=K, L=n+1, and n is an odd number;

K and L represent a number of rows and a number of columns, respectively, of said optical switch;

said optical switch further comprises n lenses provided in the [(n+1)/2+1]-th column; and

said plurality of switch cells, said first and second mirrors, and said optical unit are arranged so that path lengths from said inputs to said outputs are equal.

23. An optical switch according to claim 22, wherein each of said n lenses comprises a spherical lens.

24. An optical switch having a plurality of switch cells, wherein:

said optical switch has n inputs (n is a natural number) and m outputs (m is a natural number);

said optical switch has a unit size defined as the distance between any two adjacent ones of said switch cells;

said optical switch comprises;

a substrate having a switch size of K×

L (K is an integer satisfying n≦

K, and L is an integer satisfying m≦

L);

first and second mirrors parallel to each other and perpendicular to a principal surface of said substrate; and

an optical unit providing a plurality of input optical paths for said n inputs and a plurality of output optical paths for said m outputs, said plurality of input optical paths being inclined relative to said first and second mirrors, said plurality of output optical paths being inclined relative to said first and second mirrors; and

each of said switch cells comprises a switch mirror provided movably relative to said substrate, wherein;

n=m=K, and L=n+1;

K and L represent a number of rows and a number of columns, respectively, of said optical switch;

said optical switch further comprises n lenses provided in an arbitrary one of said columns; and

said plurality of switch cells, said first and second mirrors, and said optical unit are arranged so that path lengths from said inputs to said outputs are equal.

25. An optical switch having a plurality of switch cells, wherein:

said optical switch has n inputs (n is a natural number) and m outputs (m is a natural number);

said optical switch has a unit size defined as the distance between any two adjacent ones of said switch cells;

said optical switch comprises;

a substrate having a switch size of K×

L (K is an integer satisfying n≦

K, and L is an integer satisfying m≦

L), where K and L represent a number of rows and a number of columns, respectively, of said optical switch;

first and second mirrors parallel to each other and perpendicular to a principal surface of said substrate; and

an optical unit providing a plurality of input optical paths for said n inputs and a plurality of output optical paths for said m outputs, said plurality of input optical paths being inclined relative to said first and second mirrors, said plurality of output optical paths being inclined relative to said first and second mirrors; and

each of said switch cells comprises a switch mirror provided movably relative to said substrate, wherein;

n=m, K=n+1, and L=n+2;

said optical switch further comprises 2n lenses provided substantially along a diagonal line of said principal surface; and

said plurality of switch cells, said first and second mirrors, and said optical unit are arranged so that path lengths from said inputs to said outputs are equal.

26. An optical switch according to claim 25, wherein each of said 2n lenses comprises a rod lens.

27. An optical switch having a plurality of switch cells, wherein:

said optical switch has n inputs (n is a natural number) and m outputs (m is a natural number);

said optical switch has a unit size defined as the distance between any two adjacent ones of said switch cells;

said optical switch comprises;

a substrate having a switch size of K×

L (K is an integer satisfying n≦

K, and L is an integer satisfying m≦

L), where K and L represent a number of rows and a number of columns, respectively, of said optical switch;

first and second mirrors parallel to each other and perpendicular to a principal surface of said substrate; and

an optical unit providing a plurality of input optical paths for said n inputs and a plurality of output optical paths for said m outputs, said plurality of input optical paths being inclined relative to said first and second mirrors, said plurality of output optical paths being inclined relative to said first and second mirrors; and

each of said switch cells comprises a switch mirror provided movably relative to said substrate, wherein;

K=L=n+1=m+1;

said plurality of switch cells are provided at (n+1)×

(n+1) lattice positions on said principal surface of said substrate; and

said plurality of switch cells, said first and second mirrors, and said optical unit are arranged so that path lengths from said inputs to said outputs are equal.

28. An optical switch according to claim 27, wherein:

said plurality of switch cells comprise first switch cells and second switch cells;

said switch mirror in each of said first switch cells is oriented in a first direction; and

said switch mirror in each of said second switch cells is oriented in a second direction opposite to said first direction.

29. An optical switch according to claim 28, wherein said optical switch further comprises a plurality of lenses provided between said first switch cells and said second switch cells.

30. An optical switch according to claim 29, wherein each of said lenses is a rod lens.

31. An optical switch having a plurality of switch cells, wherein:

said optical switch has n inputs (n is a natural number) and m outputs (m is a natural number);

said optical switch has a unit size defined as the distance between any two adjacent ones of said switch cells;

said optical switch comprises;

a substrate having a switch size of K×

L (K is an integer satisfying n≦

K, and L is an integer satisfying m≦

L), where K and L represent a number of rows and a number of columns, respectively, of said optical switch;

first and second mirrors parallel to each other and perpendicular to a principal surface of said substrate; and

an optical unit providing a plurality of input optical paths for said n inputs and a plurality of output optical paths for said m outputs, said plurality of input optical paths being inclined relative to said first and second mirrors, said plurality of output optical paths being inclined relative to said first and second mirrors; and

each of said switch cells comprises a switch mirror provided movably relative to said substrate, wherein

said optical switch further comprises a lens provided on said substrate, and

said plurality of switch cells, said first and second mirrors, and said optical unit are arranged so that oath lengths from said inputs to said outputs are equal.

32. An optical switch having a plurality of switch cells, wherein:

said optical switch has n inputs (n is a natural number) and m outputs (m is a natural number);

said optical switch has a unit size defined as the distance between any two adjacent ones of said switch cells;

said optical switch comprises;

a substrate having a switch size of K×

L (K is an integer satisfying n≦

K, and L is an integer satisfying m≦

L), where K and L represent a number of rows and a number of columns, respectively, of said optical switch;

first and second mirrors parallel to each other and perpendicular to a principal surface of said substrate; and

an optical unit providing a plurality of input optical paths for said n inputs and a plurality of output optical paths for said m outputs, said plurality of input optical paths being inclined relative to said first and second mirrors, said plurality of output optical paths being inclined relative to said first and second mirrors;

each of said switch cells comprises a switch mirror provided movably relative to said substrate, wherein n=m; and

said plurality of switch cells, said first and second mirrors, and said optical unit are arranged so that path lengths from said inputs to said outputs are equal.