Optical switch with mobile components and method for making same

• US 20030138191A1
• Filed: 10/01/2002
• Published: 07/24/2003
• Est. Priority Date: 04/17/2000
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Original Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Inventors: Pouteau, Patrick, Margail, Jacques
• Granted Patent: US 6,833,080 B2
• Time in Patent Office: Days
• US Class Current: 385/16
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• 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 6/3546 NxM switch, i.e. a regular array of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/357 Electrostatic force electrostatic forces controlling reflecting elements in general G02B26/0841
• CPC Class Codes: G02B 6/358 Latching of the moving element, i.e. maintaining or holding the moving element in place once operation has been performed; includes a mechanically bistable system
• CPC Class Codes: G02B 6/3584 constructional details of an associated actuator having a MEMS construction, i.e. constructed using semiconductor technology such as etching MEMS per se B81B, B81C

Abstract

Optical switch comprising optical means (120) and driving means (114, 115, 124) on a substrate (100), cooperating with optical means to make them pivot between a rest position and at least one active position. According to the invention, the switch comprises first mobile stop means (122), rigidly fixed to the optical means (120, 130) so that they can pivot with the optical means, and second fixed stop means (128) arranged in a plane approximately parallel to the main face (110) of the substrate and cooperating with the first stop means, to fix the said active position of the optical means.

Application to make an optical cross connect.

Claims

1. Optical switch comprising optical means (120, 130) on a substrate (100, 200) capable of interacting with switching light, and driving means (114, 115, 124) cooperating with the optical means to make them pivot between a first “

rest”

position and at least one second “

active”

position, first mobile stop means (122) rigidly fixed to the optical means (120, 130) so that they can be pivoted with the optical means, and second fixed stop means (128) formed in a plane approximately parallel to the main face (110) of the substrate and cooperating with the first stop means to fix the said active position of the optical means, this switch being characterized in that it is integrated, the first stop means (122) and the optical means (120, 130) are connected to the substrate (100, 200) by a torsion beam (126) extending along a pivot axis forming a single assembly with the torsion beam (126), the angular spacing between the first stop means (122) and the optical means (120) being approximately a right angle, and that in the rest position, the optical means (120) extend approximately parallel to the main face (110) of the substrate (100).

2. Switch according to claim 1, in which the driving means comprise at least one electrode (124) said to be mobile, fixed to the optical means (120) so that it can pivot with the optical means, and at least one electrode (114) said to be fixed, that is rigidly attached to the substrate, associated with a corresponding mobile electrode to exert electrostatic pivoting forces between each mobile electrode and the corresponding fixed electrode.

3. Switch according to claim 2, in which the first stop means (112) form at least one mobile electrode.

4. Switch according to claim 2, in which the first stop means carry at least one mobile electrode (124).

5. Switch according to claim 1, in which the optical means (120, 130) comprise at least one of several means among a mirror, a separating strip, a lens, a plate of an absorbent material, and a plate of reflecting material.

6. Switch according to claim 1, in which the optical means have a first part (120) with a first optical property upright on the substrate in a first active position and a second part (130) with a second optical property, different from or the same as the first optical property, upright on the substrate in a second active position.

7. Optical cross connecting device (10) comprising several optical switches (20) according to claim 1, arranged in lines and rows of optical switches, an optical input channel being associated with each line or each row of switches and an optical output channel being associated with each row or line of the switch.

8. Cross connecting device according to claim 7, comprising several optical fibres (12, 16) coupled to the lines and rows of optical switches, respectively.

9. Cross connecting device according to claim 1, characterised in that the substrate is divided into two parts attached by plane contact faces, one of the parts carrying the second stop means (128) and the other carrying parts supporting the assembly consisting of the torsion beam (126), the first stop means (122) and the optical means (120, 130).

10. Process for manufacturing an optical switch comprising optical means (120, 130) capable of interacting with switching light and driving means (114, 115, 124) cooperating with the optical means to make them pivot between a first “

rest”

position and at least a second “

active”

position, on a substrate (100, 200), the first mobile stop means (122) rigidly fixed to the optical means (120, 130) so that they can pivot with the optical means, and second stop means (128), fixed and arranged in a plane approximately parallel to the main face (110) of the substrate, and cooperating with the first stop means to fix the said active position of the optical means, comprising the following steps in sequence;

a) the formation of at least one fixed electrode on a main face (110) of a first substrate (100), and definition of optical means (120) on a second substrate (200), parallel to a main face (210) of the second substrate,

b) assembly of the first and second substrates, by putting the said main faces (110, 210) facing each other,

c) etching of the second substrate (200) by a free rear face opposite the main face, to form at least one mobile stop (122) in the substrate, rigidly fixed to the optical means (120), and to release the optical means.

11. Process according to claim 10, in which a second substrate made from a non-insulating material is used such that the stop (122) forms an electrode.

12. Process according to claim 10, also comprising the formation of an electrode (124) on the stop.

13. Process according to claim 10, in which step a) also comprises etching of at least one cavity (112) in the first substrate (100), to contain the optical means.

14. Process according to claim 10, in which the step a) also comprises the definition of at least one fixed stop (128) in the first substrate, cooperating with the mobile stop (122) formed in the second substrate, to fix a position of the optical means in the active position and/or the rest position.

15. Process according to claim 10, in which a second substrate (200) is used with a surface layer (201) separated from a solid part (203) by a buried layer (202) and in which a plate forming the optical means (120) and torsion bars (126) connecting the plate to a fixed part of the surface layer are defined by etching in the surface layer.

16. Process according to claim 15, in which a layer of an optical material (121) is deposited on the surface layer in a region in which the said plate is defined.

17. Process according to claim 15, in which step c) includes etching of the second substrate with a stop on the buried layer (202).

18. Process according to claim 15, in which the second substrate (200) is of the SOI (Silicon On Insulator) type.

19. Process according to claim 10, in which at least one groove (102) is etched to enable movement of the optical means in the first substrate (100).