Optical transmission system including strain-biased electrooptic ceramic devices

Claim 2

An optical retardation device which comprises: a. a polycrystalline electrooptic plate which is in a condition of strain bias in the plane of the plate, by virtue of a stress applied to the plate, thereby defining an axis of tension (or compression) in the plate; and b. means for producing an electric field in at least a portion of the plate in a direction in the plane of the plate which is oriented at an oblique angle with respect to said axis, whereby birefringence is induced in at least said portion of the plate with respect to a beam of optical radiation propagating through this portion of the plate.

Claim 3

The device recited in claim 1 in which the plate is essentially a fine grain ferroelectric ceramic material.

Claim 4

The device recited in claim 2 in which the material is essentially lead zirconate-lead titanate doped with an impurity.

Claim 5

The device recited in claim 3 in which the material is lanthanum doped lead zirconate-lead titanate, and in which the size of the grains in the material is approximately 2 microns or less.

Claim 6

The device recited in claim 1 in which said means include a pair of electrodes geometrically arranged to produce the electric field in response to voltages applied across said electrodes.

Claim 7

An optical light gate which comprises: a. the device recited in claim 1; and b. an optical polarizer and an optical analyzer located on opposite sides of the plate.

Claim 8

The device recited in claim 1 which further includes means for producing the strain bias in the plate.

Claim 9

An optical retardation device in accordance with claim 2 in which the oblique angle is approximately 45* .

Claim 10

An optical system which comprises: a. first optical retardation device including a first electrooptic plate which is in a condition of strain bias in the plane of the plate, thereby defining a first axis of tension (or compression) in the plate and means for producing an electric field in at least a portion of the plate at an angle between 10* and 80* with respect to said first axis, whereby birefringence is induced in at least said portion of the first plate with respect to a beam of optical radiation propagating through this portion of the first plate; and b. a second optical retardation device including a second electrooptic plate which is in a condition of strain bias in the plane of the plate, thereby defining a second axis of tension (or compression) in the plate, the second axis oriented at an angle with respect to the first axis, and means for producing an electric field in at least a portion of the second plate in a direction which is oriented at an angle between 10* and 80* with respect to said second axis, whereby birefringence is induced in at least said portion of the second plate with respect to the beam of optical radiation propagating through this portion of the second plate after propagating through the first plate.

Claim 11

An optical system which comprises: a. first optical retardation device including a first electrooptic plate which is in a condition of strain bias in the plane of the plate, thereby defining a first axis of tension (or compression) in the plate and means for producing an electric field in at least a portion of the plate at an angle between 10* and 80* with respect to said first axis, whereby birefringence is induced in at least said portion of the first plate with respect to a beam of optical radiation propagating through this portion of the first plate; and b. a second optical retardation device including a second electrooptic plate which is in a condition of strain bias in the plane of the plate, thereby defining a second axis of tension (or compression) in the plate, the second axis oriented at an angle with respect to the first axis, and means for producing an electric field in at least a portion of the second plate in a direction which is oriented at an angle between 10* and 80* with respect to said second axis, whereby birefringence is induced in at least said portion of the second plate with respect to the beam of optical radiation propagating through this portion of the second plate after propagating through the first plate.

Claim 12

An optical system in accordance with claim 9 in which the first axis is oriented substantially at right angles with respect to the second axis.

Claim 13

An optical retardation system which comprises first and second polycrystalline electrooptic plates, the first plate being under an applied tension and the second plate being under an applied compression, the axis of tension in the first plate being parallel to the axis of compression in the seCond plate, and means for producing an electric field in the first plate and in the second plate, the electric field in the first plate being oriented at an angle between 10* and 80* with respect to the axis of tension, and the electric field in the second plate being oriented at an angle between 10* and 80* with respect to the axis of compression, whereby birefringence is induced in the first and second plates with respect to a beam of optical radiation propagating through the plates.

Claim 14

An optical retardation system which comprises first and second polycrystalline electrooptic plates, the first plate being under an applied tension and the second plate being under an applied compression, the axis of tension in the first plate being parallel to the axis of compression in the seCond plate, and means for producing an electric field in the first plate and in the second plate, the electric field in the first plate being oriented at an angle between 10* and 80* with respect to the axis of tension, and the electric field in the second plate being oriented at an angle between 10* and 80* with respect to the axis of compression, whereby birefringence is induced in the first and second plates with respect to a beam of optical radiation propagating through the plates.

Claim 15

The system recited in claim 11 which is provided with an optically reflecting layer located and oriented in space such that the beam of optical radiation can simultaneously pass through both plates and be reflected by said reflecting layer back through both plates.

Claim 16

The device recited in claim 11 in which the first and second plates are bonded to opposite sides of a transparent elastic member, said member being under a bending moment which produces the tension and the compression in the first and second plates, respectively.