Reentrant traveling-wave single sideband optical modulator

Claim 2

A reentrant electro-optic modulator for modulating a laser signal with a microwave signal to generate signals in a single frequency sideband, said modulator comprising: an outer housing extending along and coaxial with a propagation axis; a microwave electrode means including a plurality of electrode elements symmetrically configured within said housing along said propagation axis; an optically active element extending along said propagation axis within said electrode means for guiding the laser signal through the modulator; and a passive dielectric material positioned within housing activities formed adjacent said electrode elements: the modulator being characterized by an interface between said electrode elements and said optical element such that said optical element dimension substantially exceeds said electrode element dimension.

Claim 3

The modulator of claim 1 wherein said optical element comprises a gallium phosphide (GaP) crystal.

Claim 4

The modulator of claim 1 wherein said passive dielectric material comprises a material with a dielectric constant of 12.

Claim 5

The modulator of claim 3 wherein said optical element and said electrode element dimensions at said interface are 0.048" and 0.024", respectively.

Claim 6

The modulator of claim 1 wherein said elements each extend radially outward from said interface.

Claim 7

A transition structure for coupling microwave signals with a reentrant modulator having a plurality of symmetric electrode metal portions, said structure comprising, a plurality of metal fin electrodes each adapted to receive at a first end thereof a corresponding one of the modulator electrode metal portions; and each of said metal fin electrodes having a tapered Portion opposing said first end to provide an impedance match to an adjacent microwave signal carrying element.

Claim 8

A transition structure for coupling microwave signals with a reentrant modulator having a plurality of symmetric electrode metal portions, said structure comprising, a plurality of metal fin electrodes each adapted to receive at a first end thereof a corresponding one of the modulator electrode metal portions; and each of said metal fin electrodes having a tapered Portion opposing said first end to provide an impedance match to an adjacent microwave signal carrying element.

Claim 9

The structure of claim 6 wherein said tapered portion comprises a linear taper.

Claim 10

The structure of claim 6 wherein said adjacent microwave signal carrying element is a square rectangular waveguide.

Claim 11

The structure of claim 6 wherein said metal fin electrode tapered portions are configured so that a central optical element of the reentrant modulator protrudes from said electrode first ends.

Claim 12

The structure of claim 6 wherein said metal fin electrode tapered portions are configured so that a central optical element of the reentrant modulator is recessed from said electrode first ends.

Claim 13

An optical frequency shifting circuit for providing carrier suppressed single sideband modulation at microwave frequencies of an optical signal, said circuit comprising: a microwave signal source means providing spatially orthogonal and time quadrature microwave signals, for launching circularly polarized orthogonal mode microwave signals; a first transition structure adapted to receive said microwave signals, including four fin electrodes each adapted to receive at a first end thereof a corresponding modulator electrode metal portion; each of said fin electrodes having a tapered portion opposing said first end to provide an impedance match to said microwave signal source means; a reentrant modulator receiving said first transition structure having first and second end portion, including an outer housing extending along and coaxial with a propagation axis; a microwave electrode means including four electrode elements symmetrically configured within said housing along said propagation axis; an optically active element extending along said propagation axis within said electrode means for guiding the laser signal through the modulator; a dielectric surrogate material positioned within housing cavities formed adjacent said elements; the modulator being characterized by an interface between said elements and said optical element such that said optical element dimension substantially exceeds said elements dimension; a second transition structure adapted to receive the modulator second end portion including a plurality of fin electrodes each adapted to receive at a first end thereof a corresponding one of the modulator electrode portions; each of said fin electrodes having a tapered portion opposing said first end to provide an impedance match to an adjacent microwave signal carrying element; and a matched load configured with said second transition structure for terminating said microwave signals without reflection.

Claim 14

An optical frequency shifting circuit for providing carrier suppressed single sideband modulation at microwave frequencies of an optical signal, said circuit comprising: a microwave signal source means providing spatially orthogonal and time quadrature microwave signals, for launching circularly polarized orthogonal mode microwave signals; a first transition structure adapted to receive said microwave signals, including four fin electrodes each adapted to receive at a first end thereof a corresponding modulator electrode metal portion; each of said fin electrodes having a tapered portion opposing said first end to provide an impedance match to said microwave signal source means; a reentrant modulator receiving said first transition structure having first and second end portion, including an outer housing extending along and coaxial with a propagation axis; a microwave electrode means including four electrode elements symmetrically configured within said housing along said propagation axis; an optically active element extending along said propagation axis within said electrode means for guiding the laser signal through the modulator; a dielectric surrogate material positioned within housing cavities formed adjacent said elements; the modulator being characterized by an interface between said elements and said optical element such that said optical element dimension substantially exceeds said elements dimension; a second transition structure adapted to receive the modulator second end portion including a plurality of fin electrodes each adapted to receive at a first end thereof a corresponding one of the modulator electrode portions; each of said fin electrodes having a tapered portion opposing said first end to provide an impedance match to an adjacent microwave signal carrying element; and a matched load configured with said second transition structure for terminating said microwave signals without reflection.

Claim 15

The modulator of claim 11 wherein said optical element comprises a gallium phosphide (GaP) crystal.

Claim 16

The modulator of claim 11 wherein said dielectric surrogate material comprises a material with a dielectric constant of 12.

Claim 17

The modulator of claim 13 wherein said optical element and said electrode elements at said interface are 0.029" and 0.024", respectively.

Claim 18

The modulator of claim 11 wherein said elements each extend radially outward from said interface.

Claim 19

The modulator of claim 11 wherein said optical element comprises gallium arsenide.

Claim 20

The modulator of claim 11 wherein said optical element comprises cadmium telluride.

Claim 21

The modulator of claim 1 wherein said electrode means is integral with said housing.