Polarizing apparatus and method utilizing an optical fiber

Claim 1

An apparatus, comprising: a single mode optical fiber having an input end portion for receiving light and an output end portion for outputting said light, said fiber having a core and a cladding, the refractive index of said core higher than the refractive index of said cladding, the cladding having a cladding surface intermediate said input and output end portions which is sufficiently close to the core to expose the evanescent field of said light at a selected location along the length of said fiber; and a plurality of liquid crystal molecules in communication with said evanescent field at said selected location to form an interaction region, said liquid crystal molecules having at least two states of orientation, a first of said states providing a first refractive index for light propagating in said fiber in a first polarization, and a second refractive index for light propagating in said fiber in a second polarization, orthogonal to said first polarization, a second of said states providing a third refractive index for light propagating in said fiber in said first polarization and a fourth refractive index for light propagating in said fiber in said second polarization, at least one of said first and second refractive indices being less than the refractive index of the core so that light propagating in said polarization corresponding to said at least one of said first and second refractive indices is well-guided by said optical fiber when said liquid crystal molecules have said first state of orientation, and at least one of said third and fourth refractive indices being less than the refractive index of the core so that light propagating in said polarization corresponding to said at least one of said third and fourth refractive indices is well-guided by said optical fiber when said liquid crystal molecules have said second state of orientation.

Claim 2

An apparatus, comprising: a single mode optical fiber having an input end portion for receiving light and an output end portion for outputting said light, said fiber having a core and a cladding, the refractive index of said core higher than the refractive index of said cladding, the cladding having a cladding surface intermediate said input and output end portions which is sufficiently close to the core to expose the evanescent field of said light at a selected location along the length of said fiber; and a plurality of liquid crystal molecules in communication with said evanescent field at said selected location to form an interaction region, said liquid crystal molecules having at least two states of orientation, a first of said states providing a first refractive index for light propagating in said fiber in a first polarization, and a second refractive index for light propagating in said fiber in a second polarization, orthogonal to said first polarization, a second of said states providing a third refractive index for light propagating in said fiber in said first polarization and a fourth refractive index for light propagating in said fiber in said second polarization, at least one of said first and second refractive indices being less than the refractive index of the core so that light propagating in said polarization corresponding to said at least one of said first and second refractive indices is well-guided by said optical fiber when said liquid crystal molecules have said first state of orientation, and at least one of said third and fourth refractive indices being less than the refractive index of the core so that light propagating in said polarization corresponding to said at least one of said third and fourth refractive indices is well-guided by said optical fiber when said liquid crystal molecules have said second state of orientation.

Claim 16

A method of polarizing light utilizing an optical fiber having a cladding surface in close proximity to the core of the optical fiber to expose the evanescent field of light propagating through the optical fiber, said method comprising: positioning a plurality of elongate liquid crystal molecules proximate to said cladding surface to cause light of one polarization to preferentially escape from said fiber at said cladding surface while causing light of an orthogonal polarization to be preferentially guided by said fiber at said cladding surface; and driving said liquid crystal molecules to change the orientation of said molecules proximate to said cladding surface to cause light of said orthogonal polarization to preferentially escape from said fiber at said cladding surface while causing light of said one polarization to be preferentially guided by said fiber at said cladding surface.

Claim 17

A method of polarizing light utilizing an optical fiber having a cladding surface in close proximity to the core of the optical fiber to expose the evanescent field of light propagating through the optical fiber, said method comprising: positioning a plurality of elongate liquid crystal molecules proximate to said cladding surface to cause light of one polarization to preferentially escape from said fiber at said cladding surface while causing light of an orthogonal polarization to be preferentially guided by said fiber at said cladding surface; and driving said liquid crystal molecules to change the orientation of said molecules proximate to said cladding surface to cause light of said orthogonal polarization to preferentially escape from said fiber at said cladding surface while causing light of said one polarization to be preferentially guided by said fiber at said cladding surface.

Claim 18

A method of transforming the polarization of light utilizing an optical fiber having a cladding surface in close proximity to the core of the optical fiber to expose the evanescent field of light propagating in the optical fiber, said method comprising: positioning a plurality of elongate liquid crystal molecules proximate to said cladding surface with substantially all of said molecules proximate to said cladding surface oriented with respect to said cladding surface to cause said fiber to exhibit birefringence at said cladding surface, said plurality of liquid crystal molecules having refractive indices lower than that of the fiber core for both of two orthogonal polarizations to prevent light of either polarization from escaping from the fiber at the cladding surface; and selectively reorienting substantially all of said plurality of liquid crystal molecules proximate to said cladding surface with respect to said cladding surface to produce a selected amount of said birefringence at said cladding surface to transform the polarization of light propagating through said fiber while maintaining said refractive indices of said plurality of liquid crystal molecules for both of said polarizations below the refractive index of the core.

Claim 19

A method of transforming the polarization of light utilizing an optical fiber having a cladding surface in close proximity to the core of the optical fiber to expose the evanescent field of light propagating in the optical fiber, said method comprising: positioning a plurality of elongate liquid crystal molecules proximate to said cladding surface with substantially all of said molecules proximate to said cladding surface oriented with respect to said cladding surface to cause said fiber to exhibit birefringence at said cladding surface, said plurality of liquid crystal molecules having refractive indices lower than that of the fiber core for both of two orthogonal polarizations to prevent light of either polarization from escaping from the fiber at the cladding surface; and selectively reorienting substantially all of said plurality of liquid crystal molecules proximate to said cladding surface with respect to said cladding surface to produce a selected amount of said birefringence at said cladding surface to transform the polarization of light propagating through said fiber while maintaining said refractive indices of said plurality of liquid crystal molecules for both of said polarizations below the refractive index of the core.

Claim 23

A method of manufacturing an optical polarizing device utilizing an optical fiber having a core and a cladding, said core having a core refractive index and said cladding having a cladding refractive index, said optical fiber having a cladding surface in close proximity to the core of the optical fiber to expose the evanescent field of light propagating through the optical fiber, said method comprising: placing a plurality of liquid crystal molecules on the cladding surface for exposure to the evanescent field; orienting the liquid crystal molecules relative to the fiber core and selecting the material structure of the liquid crystal molecules such that said liquid crystal molecules exhibit a first refractive index for a first polarization of said light which is above the refractive index of the core and exhibit a second refractive index for a second orthogonal polarization which is below the refractive index of the core so that light having said first polarization is not well-guided by said optical fiber at said cladding surface and so that light having said second polarization is well-guided by said optical fiber at said cladding surface; and mounting electrodes to drive said liquid crystal molecules to change their orientation such that the second refractive index is raised above the refractive index of the core and the first refractive index is lowered below the refractive index of the core so that light having said first polarization is well-guided by said optical fiber at said cladding surface and so that light having said second polarization is not well-guided at said cladding surface.

Claim 24

A method of manufacturing an optical polarizing device utilizing an optical fiber having a core and a cladding, said core having a core refractive index and said cladding having a cladding refractive index, said optical fiber having a cladding surface in close proximity to the core of the optical fiber to expose the evanescent field of light propagating through the optical fiber, said method comprising: placing a plurality of liquid crystal molecules on the cladding surface for exposure to the evanescent field; orienting the liquid crystal molecules relative to the fiber core and selecting the material structure of the liquid crystal molecules such that said liquid crystal molecules exhibit a first refractive index for a first polarization of said light which is above the refractive index of the core and exhibit a second refractive index for a second orthogonal polarization which is below the refractive index of the core so that light having said first polarization is not well-guided by said optical fiber at said cladding surface and so that light having said second polarization is well-guided by said optical fiber at said cladding surface; and mounting electrodes to drive said liquid crystal molecules to change their orientation such that the second refractive index is raised above the refractive index of the core and the first refractive index is lowered below the refractive index of the core so that light having said first polarization is well-guided by said optical fiber at said cladding surface and so that light having said second polarization is not well-guided at said cladding surface.

Claim 25

A method of manufacturing a device for transforming the polarization of light, said device utilizing an optical fiber having a cladding surface in close proximity to the core of the optical fiber to expose the evanescent field of light propagating through the optical fiber, said method comprising: placing a plurality of elongate liquid crystal molecules on the cladding surface for exposure to the evanescent field; orienting substantially all of the liquid crystal molecules relative to the fiber core and selecting the material structure of said liquid crystal molecules such that said liquid crystal molecules exhibit first and second refractive indices for first and second orthogonal polarization which are below the refractive index of the core; and mounting electrodes proximate to said cladding surface to drive said liquid crystal molecules to change the orientation of substantially all of said liquid crystal molecules proximate to said cladding surface such that the refractive index for one of said first and second polarizations change relative to the refractive index of the other of said first and second polarizations while maintaining the refractive indices for both polarizations below the refractive index of the core.

Claim 26

A method of manufacturing a device for transforming the polarization of light, said device utilizing an optical fiber having a cladding surface in close proximity to the core of the optical fiber to expose the evanescent field of light propagating through the optical fiber, said method comprising: placing a plurality of elongate liquid crystal molecules on the cladding surface for exposure to the evanescent field; orienting substantially all of the liquid crystal molecules relative to the fiber core and selecting the material structure of said liquid crystal molecules such that said liquid crystal molecules exhibit first and second refractive indices for first and second orthogonal polarization which are below the refractive index of the core; and mounting electrodes proximate to said cladding surface to drive said liquid crystal molecules to change the orientation of substantially all of said liquid crystal molecules proximate to said cladding surface such that the refractive index for one of said first and second polarizations change relative to the refractive index of the other of said first and second polarizations while maintaining the refractive indices for both polarizations below the refractive index of the core.