Micromechanical modulator

Claim 2

A modulator for modulating an optical signal comprising: a conductive substrate; a conductive membrane comprising at least a first layer of material, the first layer having a refractive index which is approximately equal to the square root of the refractive index of the substrate, and a thickness approximately equal to one-quarter of a wavelength of the optical signal, as measured within the first layer, the membrane further having an optically transparent portion; a flexible support for positioning the membrane in a first position wherein the membrane is oriented in spaced and superposed relation to the substrate, defining an air gap which is approximately equal to an integer multiple of one-quarter of a wavelength of the optical signal, as measured in air; and a means for supplying bias; where, under the action of bias, the membrane moves to a second position, changing the air gap by approximately one-quarter of a wavelength of the optical signal, as measured in air, where the change from the first to the second position causes a change in the amount of the optical signal that is reflected from the membrane.

Claim 3

The modulator of claim 1 where, under the action of bias, the flexible support flexes and the membrane moves toward the substrate.

Claim 4

The modulator of claim 2 where the substrate is a semiconductor.

Claim 5

The modulator of claim 2 where the substrate is silicon.

Claim 6

The modulator of claim 2 where the first layer of material is selected from the group consisting of silicon nitride and silicon oxide.

Claim 7

The modulator of claim 2 where the membrane comprises a second layer of material having a refractive index approximately equal to the refractive index of the substrate.

Claim 8

The modulator of claim 6 where the second layer of material has a thickness approximately equal to one-quarter of a wavelength of the optical signal, as measured within the second layer.

Claim 9

The modulator of claim 6 where the second layer of material is the same material as the substrate.

Claim 10

The modulator of claim 6 where the second layer of material is polysilicon.

Claim 11

The modulator of claim 2 where the integer multiple is one so that the air gap in the first position is approximately equal to one-quarter of a wavelength of the optical signal, as measured in air.

Claim 12

The modulator of claim 2 where at least a portion of the membrane is coated with a conductive material which is selected from the group consisting of aluminum, gold, platinum, tungsten and conducting silicon.

Claim 13

The modulator of claim 6 where the second layer of material is conductive.

Claim 14

The modulator of claim 12 where the flexible support comprises a plurality of flexible support arms.

Claim 15

The modulator of claim 13 where at least a portion of the flexible support arms are conductive.

Claim 16

A modulator of claim 1 further comprising a support for an optical fiber.

Claim 17

A modulator for modulating an optical signal comprising: a conductive substrate; an optical fiber having a first end in optical communication with an optically transparent portion of a conductive membrane; the conductive membrane having a first and a second surface and comprising an optically active layer having a refractive index which is approximately equal to the square root of the product of the refractive indices of the conductive substrate and the optical fiber, and a thickness approximately equal to one-quarter of a wavelength of the optical signal, as measured within the optically active layer; and a means for supplying bias, wherein the first end of the optical fiber is in superposed relation to the first surface of the conductive membrane and is spaced from the first surface by approximately an integer multiple of one-quarter of a wavelength of the optical signal, as measured in air, and where the conductive substrate is oriented in superposed relation to the second surface of the conductive membrane and is spaced from the second surface by approximately an integer multiple of one-quarter of a wavelength of the optical signal, as measured in air, where the space between the second surface of the conductive membrane and the conductive substrate defines a first position of the conductive membrane, and where under the action of bias, the conductive membrane moves to a second position, changing the space between the second surface and the conductive substrate by approximately one-quarter of a wavelength of the optical signal, as measured in air, the change from the first to the second position causing a change in the amount of the optical signal that is reflected from the membrane.

Claim 18

A modulator for modulating an optical signal comprising: a conductive substrate; an optical fiber having a first end in optical communication with an optically transparent portion of a conductive membrane; the conductive membrane having a first and a second surface and comprising an optically active layer having a refractive index which is approximately equal to the square root of the product of the refractive indices of the conductive substrate and the optical fiber, and a thickness approximately equal to one-quarter of a wavelength of the optical signal, as measured within the optically active layer; and a means for supplying bias, wherein the first end of the optical fiber is in superposed relation to the first surface of the conductive membrane and is spaced from the first surface by approximately an integer multiple of one-quarter of a wavelength of the optical signal, as measured in air, and where the conductive substrate is oriented in superposed relation to the second surface of the conductive membrane and is spaced from the second surface by approximately an integer multiple of one-quarter of a wavelength of the optical signal, as measured in air, where the space between the second surface of the conductive membrane and the conductive substrate defines a first position of the conductive membrane, and where under the action of bias, the conductive membrane moves to a second position, changing the space between the second surface and the conductive substrate by approximately one-quarter of a wavelength of the optical signal, as measured in air, the change from the first to the second position causing a change in the amount of the optical signal that is reflected from the membrane.

Claim 21

The device of claim 17 where the substrate is formed of a conductive material.

Claim 22

The device of claim 17 where the substrate is a semiconductor.

Claim 23

The device of claim 17 where the substrate is silicon.

Claim 24

The device of claim 17 where the first layer of material has a thickness approximately equal to one-quarter of a wavelength of the optical signal, as measured within the first layer.

Claim 25

The device of claim 17 where the first layer of material is silicon nitride.

Claim 26

The device of claim 17 where the membrane comprises a second layer of material having a refractive index approximately equal to the refractive index of the substrate.

Claim 27

The device of claim 23 where the second layer of material has a thickness approximately equal to one-quarter of a wavelength of the optical signal, as measured within the second layer.

Claim 28

The device of claim 23 where the second layer of material is the same material as the substrate.

Claim 29

The device of claim 23 where the second layer of material is polysilicon.

Claim 30

The device of claim 18 where in the first position, the air gap is approximately equal to an integer multiple of one-quarter of a wavelength of the optical signal, as measured in air.

Claim 31

The device of claim 27 wherein the integer multiple equals one so that the air gap is approximately equal to one-quarter of a wavelength of the optical signal, as measured in air.

Claim 32

The device of claim 27 where at least a portion of the membrane is conductive.

Claim 33

The device of claim 29 where the conductive portion of the membrane comprises a layer of conductive material.

Claim 34

The device of claim 30 where the conductive material is selected from the group consisting of aluminum, gold, platinum, tungsten and conducting silicon.

Claim 35

The device of claim 23 where the second layer of material is conductive.

Claim 36

The device of claim 29 further comprising a means for supplying bias.

Claim 37

The device of claim 33 where, under the action of bias, the membrane moves to a second position, changing the air gap by approximately one-quarter of a wavelength of the optical signal, as measured in air.

Claim 38

The device of claim 34 where, in the second position, the air gap is approximately one-quarter of a wavelength of the optical signal, as measured in air, less than the air gap in the first position.

Claim 39

The device of claim 17 where the flexible support is flexible support arms.

Claim 40

The device of claim 17 where at least a portion of the flexible support is conductive.

Claim 41

The device of claim 36 where there are four flexible support arms.

Claim 42

The device of claim 17 further comprising a support for an optical fiber.

Claim 45

The device of claim 40 where the space between the optical fiber and the membrane is approximately equal to one-quarter of a wavelength of the optical signal, as measured in air.

Claim 48

The method of claim 42 wherein the step of providing a conductive membrane further comprises providing a conductive, flexible support to support the membrane over the substrate.

Claim 49

The method of claim 42 wherein the step of providing a membrane further comprises orienting the membrane and substrate so that the space between them is approximately equal to an integer multiple of one-quarter of a wavelength of the optical signal, as measured in air.

Claim 50

The method of claim 42 where the step of applying a bias to move the membrane from the first position to the second position further comprises decreasing the size of the space between the membrane and the substrate by one-quarter of a wavelength of the optical signal, as measured in air.

Claim 53

The method of claim 46 where the step of applying a bias to move the membrane from the first position to the second position further comprises decreasing the size of the air gap by one-quarter of a wavelength of the optical signal, as measured in air.

Claim 56

The method of claim 48 where the step of providing a conductive substrate further comprises appropriately doping a semiconductor.

Claim 57

The method of claim 48 where the step of forming a membrane further comprises selecting the first layer of material from the group consisting of silicon nitride and silicon oxide.

Claim 58

The method of claim 48 where the step of forming a membrane further comprises spacing the membrane from the substrate so that the air gap is approximately equal to an integer multiple of one-quarter of a wavelength of the optical signal, as measured in air.

Claim 61

The method of claim 52 where the step of forming a membrane further comprises spacing the membrane from the substrate so that the air gap is approximately equal to an integer multiple of one-quarter of a wavelength of the optical signal, as measured in air.

Claim 62

The method of claim 52 where the step of forming a membrane further comprises forming the first layer of material comprising the membrane so that it has a thickness approximately equal to one-quarter of a wavelength of the optical signal, as measured within the first layer of material.

Claim 63

The method of claim 52 where the step of attaching the optical fiber to the support further comprises orienting the optical fiber so that it is in optical communication with the membrane.