Mars optical modulators

• US 7,180,652 B2
• Filed: 02/18/2005
• Issued: 02/20/2007
• Est. Priority Date: 04/24/2001
• Status: Expired due to Term

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Agere Systems Incorporated (Broadcom, Inc.), Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Goossen, Keith Wayne, Greywall, Dennis S., Walker, James Albert, Bishop, David John
• Primary Examiner(s): Lester; Evelyn A.
• Application Number:
  US11/060,870
• Publication Number:
  US 20050225835A1
• Time in Patent Office: 732 Days
• Field of Search: 359290-292, 359/295, 359/298, 359/350, 359/847, 359/224
• US Class Current: 359/291
• CPC Class Codes: G02B 26/0825 the reflecting element being a flexible sheet or membrane, e.g. for varying the focus flexible mirrors for cosmetic use A45D42/24

Abstract

The specification describes an improved Moving Anti-Reflection Switch (MARS) device structure that largely eliminates charge build up on the movable membrane, and reduces stresses that cause curling of the membrane. The improved device uses a movable membrane made of single crystal silicon.

Claims

1. An electrooptic device comprising:

a. an electrically conductive substrate having a surface S₁,

b. a movable membrane having a top surface and a bottom surface s₂, the movable membrane comprising a single crystal silicon layer with a thickness in the range 1000–

5000 Angstroms,

c. a laser for directing light onto the movable membrane, the light having a wavelength λ

,

d. a support for positioning the movable membrane at a first position spaced from said substrate by an air gap d₁ between surface s₁ and s₂, and

e. bias means for applying an electrical bias across the air gap to move the movable membrane from the first position to a second position spaced from said substrate by an air gap d₂ between surface s₁ and s₂, where d₂–

d₁ is in the approximate range 1500 to 5000 angstroms and where the change from the first to the second position causes a change in the amount of light from said laser that is reflected from the movable membrane.

2. The device of claim 1 wherein the conductive substrate is a semiconductor.

3. The device of claim 2 wherein the conductive substrate is silicon.

4. The device of claim 1 wherein the laser has a wavelength λ

in the range 1500–

1600 nm.

5. A method for switching light comprising:

a. directing a beam of laser light with a wavelength λ

on a substrate,

the substrate supporting a movable membrane spaced from said substrate, the movable membrane consisting of single crystal silicon with a thickness in the range 1000–

5000 Angstroms and having,

a support for positioning said membrane at a first position spaced from said substrate by an air gap mλ

/4, where m is an even number, and a second position d₁ spaced from said substrate by an air gap nλ

/4 and n is an odd number, and

b. applying an electrical bias across said air gap to move said membrane from said first position to said second position d₂ where d₂–

d₁ is in the approximate range 1500 to 5000 angstroms and where the change from the first to the second position changes the light that is reflected from the movable membrane from anti-reflecting to reflecting.

6. The method of claim 5 wherein said substrate is silicon.

7. The method of claim 5 wherein λ

is approximately 1.55 μ

m.