# US 5,345,521 A · Architecture for optical switch

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- Number: US 5,345,521 A
- Document ID: US5345521A
- Status: Granted
- Kind: A
- Application number: 08/090,862
- Filed: 1993-07-12
- Granted: 1994-09-06
- Earliest claimed: 1993-07-12
- Assignees: Texas Instrument Incorporated
- Inventors: T. Gus McDonald; R. Mark Boysel
- Web page: https://patentgrep.com/patent/US5345521A

## CPC

- G02B 6/3564: {Mechanical details of the actuation mechanism associated with the moving element or mounting mechanism details}
- G02B 26/0841: {the reflecting element being moved or deformed by electrostatic means}
- G02B 6/3512: {the optical element being reflective, e.g. mirror}
- G02B 6/3556: {NxM switch, i.e. regular arrays of switches elements of matrix type constellation}
- 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}
- G02B 6/3582: {Housing means or package or arranging details of the switching elements, e.g. for thermal isolation}
- 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)}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

An optical switching device with switch elements (224) similar to digital micromirror devices (DMD). The switching element (224) resides in a trench (216) between two elevated areas on the substrate (214a, 214b). Sending and receiving fibers (218a, 218b) face each other across the trench (216) with the switch element (224) between them. When the switch is ON, light travels through lenses (220a, 220b) in the trench (216) from one fiber (218b) to the other (218a). When the switch is flipped OFF, the element (224) is activated and blocks the light from the sending fiber (218b) by reflecting or absorbing the light from the sending fiber (218b). The switch is activated and possibly deactivated by addressing electrodes (226a, 226b) under the element (224), which deflects through an air gap towards the activated electrode (226b). For better deflection angles the posts can be arranged closer to one end of the element than the other. An alternate hinge architecture is also provided.

## Claims

### Claim 1

An optical switching device, comprising:
a. a substrate;
b. at least one switching element, each said element comprising:
i. at least one addressing electrode on said substrate;
ii. at least one support post adjacent said at least one addressing electrode, wherein each said support post has a hinge;
iii. at least one landing electrode, said landing electrodes arranged adjacent said at least one addressing electrode on the opposite side of said addressing electrode from said at least one support post;
iv. a movable member suspended from said hinge attached to said at least one support post, such that when said addressing electrode is activate, said movable member moves towards said addressing electrode and a portion of said movable member comes into contact with said landing electrode;
c. elevated areas on said substrate on either side of said switching element;
d. at least one sending fiber and at least one receiving fiber, wherein each said sending fibers are arrange collinear and opposite each said receiving fiber on said elevated areas on opposite sides of such switching elements, wherein when said switching element is activated, the non-deflecting side of said switching element blocks transmission of light from said sending fiber to said receiving fiber.

### Claim 2 (depends on 1)

The device of claim 1 wherein said at least one addressing electrode further comprises two addressing electrodes, arranged on the substrate underneath opposite sides of said movable member.

### Claim 3 (depends on 1)

The device of claim 1 wherein said at least one landing electrode further comprises two landing electrodes arranged on the substrate underneath opposite sides of movable member.

### Claim 4 (depends on 2)

The device of claim 2 where said at least one landing electrode further comprises two landing electrodes arranged on the substrate underneath opposite sides of movable member, and said landing electrodes are farther from the center of said movable surface that said addressing electrodes.

### Claim 5 (depends on 1)

The device of claim 1 wherein said at least one support posts further comprises two support posts arranged at the midpoint on opposite sides of said movable member.

### Claim 6 (depends on 1)

The device of claim 1 wherein said at least one support posts further comprises two support posts arranged directly across from each other closer to one end of the movable member than the other.

### Claim 7 (depends on 6)

The device of claim 6 wherein said hinge attached to each said support post is a Y hinge.

### Claim 8 (depends on 6)

The device of claim 6 wherein said hinge attached to each said support post comprises multiple parallel hinges.