Micromechanical modulator and methods for fabricating the same
First Claim
1. A modulator for modulating an optical signal comprising:
- a conductive substrate;
a conductive membrane comprising at least a first layer of material having a thickness approximately equal to one-third of a wavelength of the optical signal, as measured within the first layer, and a second layer of material having a thickness approximately equal to one-tenth of a wavelength of the optical signal, as measured within the second layer;
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;
a substrate layer of material overlaying the conductive substrate and having a thickness approximately equal to one-seventh of the wavelength of the optical signal; 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.
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Accused Products
Abstract
A method and apparatus for modulating an optical signal using a micromechanical modulator are disclosed. The modulator comprises a membrane, which includes a first and a second layer, a substrate layer, and a substrate, spaced from the membrane to form an air gap. The layers of the membrane are characterized in that there is a relationship between the refractive indices of the layers and the refractive index of the substrate. The membrane is suspended in a first position over the substrate by a flexible support arrangement. Bias is applied to the membrane and the substrate to create an electrostatic force to move the membrane towards the substrate to a second position. The reflectivity of the device to an optical signal changes as the membrane moves from the first position to the second position, thereby modulating the signal. In a preferred embodiment, the thickness of the first and second layers of the membrane are approximately equal to one-third and one-tenth, respectively, of a wavelength of the optical signal, as measured within the first and second layers, respectively. The thickness of the substrate layer is approximately equal to one-seventh of the wavelength of the optical signal, as measured within the substrate layer.
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Citations
63 Claims
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1. A modulator for modulating an optical signal comprising:
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a conductive substrate;
a conductive membrane comprising at least a first layer of material having a thickness approximately equal to one-third of a wavelength of the optical signal, as measured within the first layer, and a second layer of material having a thickness approximately equal to one-tenth of a wavelength of the optical signal, as measured within the second layer;
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;
a substrate layer of material overlaying the conductive substrate and having a thickness approximately equal to one-seventh of the wavelength of the optical signal; 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A modulator for modulating an optical signal comprising:
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a conductive substrate;
a substrate layer overlaying the conductive substrate having a thickness approximately equal to one-seventh of the wavelength of the optical signal, as measured within the substrate layer;
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, where the second surface is closest to the conductive substrate, 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-third of a wavelength of the optical signal, as measured within the optically active layer, the conductive membrane further comprising another layer positioned adjacent the second surface and having a refractive index which is approximately equal to the refractive index of the conductive substrate, and a thickness approximately equal to one-tenth of the wavelength of the optical signal, as measured within the 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.
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25. A device which, under the action of an applied bias, has a variable reflectivity to an incident optical signal received by the device, comprising:
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a substrate;
a membrane comprising a first and a second 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 the second layer having a refractive index approximately equal to the refractive index of the substrate, the membrane further having an optically transparent portion;
a substrate layer having a refractive index which is approximately equal to the square root of the refractive index of the substrate; and
a flexible support for positioning the membrane in a first position wherein the membrane is oriented in spaced and superposed relation to the substrate to form an air gap. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49)
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50. A device which, under the action of an applied bias, has a variable reflectivity to an incident optical signal received by the device, comprising:
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a substrate coated with a conductive material to a thickness of one-seventh of a wavelength of the optical signal, as measured within the conductive material; and
an optical fiber having a first end in optical communication with an optically transparent portion of a membrane;
the membrane having a first and a second surface and comprising a first layer having a thickness of one-third of the wavelength of the optical signal, as measured within the first layer, and a second layer having a thickness of one-tenth of the wavelength of the optical signal, as measured within the second layer;
wherein the first end of the optical fiber is in superposed and spaced relation to the first surface of the membrane, and where the substrate is oriented in superposed and spaced relation to the second surface of the membrane so that the membrane is positioned between the first end of the optical fiber and the substrate. - View Dependent Claims (51, 52)
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53. A method for modulating an optical signal comprising:
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providing a conductive substrate;
providing a conductive membrane in spaced and superposed relation to the substrate where the membrane comprises a first layer of material having a thickness of one-third of a wavelength of the optical signal, as measured within the first layer, and a second layer of material having a thickness of one-tenth of the wavelength of the optical signal, as measured within the second layer, the membrane further having a first and second position;
providing a substrate layer on a surface of the conductive substrate closest to the conductive membrane, the substrate layer comprises a material having a thickness of one-seventh of the wavelength of the optical signal, as measured within the conductive material;
exposing the membrane to an optical signal; and
applying a bias to move the membrane from the first position to the second position causing the reflectivity of the membrane to change. - View Dependent Claims (54, 55, 56)
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57. A method for making a modulator for modulating an optical signal comprising:
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providing a conductive substrate;
providing a substrate layer of material on the conductive substrate having a thickness of one-tenth of a wavelength of the optical signal, as measured within the substrate layer; and
forming a conductive membrane on the substrate so that an air gap is defined between the membrane and a portion of the substrate, where the membrane comprises a first layer of material having a thickness of one-third of the wavelength of the optical signal, as measured within the first layer, and a second layer of material having a thickness of one-tenth of the wavelength of the optical signal, as measured within the second layer. - View Dependent Claims (58, 59, 60)
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61. A method for making a modulator for modulating an optical signal comprising:
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providing a conductive substrate;
providing a substrate layer of material on the conductive substrate having a thickness of one-tenth of a wavelength of the optical signal, as measured within the substrate layer;
forming a conductive membrane on the substrate so that an air gap is defined between the membrane and a portion of the substrate, where the membrane comprises a first layer of material having a thickness approximately equal to one-third of the wavelength of the optical signal, as measured within the first layer of material, and a refractive index which is approximately equal to the square root of the product of the refractive indices of the substrate and the optical fiber, and a second layer of material having a thickness approximately equal to one-tenth of the wavelength of the optical signal, as measured within the second layer of material;
forming a support to support an optical fiber so that the optical fiber is spaced from the first layer of the membrane by approximately an integer multiple of one-quarter of a wavelength of the optical signal, as measured in air; and
attaching the optical fiber to the support. - View Dependent Claims (62, 63)
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Specification