Phase modulated optical carrier data link for a focal plane array

Claim 2

Apparatus for coupling an output signal of a radiation detector to a signal measurement apparatus comprising: means for providing an optical carrier signal having a frequency component and a phase component associated therewith; means, coupled to an output of the carrier providing means and to an output signal of a radiation detector, for varying the phase component of the carrier signal as a function of a magnitude of the radiation detector output signal; means, coupled to an output of the phase varying means, for conveying the carrier signal, including the phase component, therefrom; and means, coupled to said conveying means and responsive to the phase component of the carrier signal, for generating an output signal having a characteristic which is a function of the magnitude of the radiation detector output signal.

Claim 3

Apparatus as set forth in claim 1 wherein the means for varying the phase component of the carrier signal is an electro-optic device.

Claim 4

Apparatus as set forth in claim 2 wherein the conveying means includes at least one fiber optic cable.

Claim 5

Apparatus as set forth in claim 3 wherein the carrier providing means comprises a sinusoidal source of radiation.

Claim 6

Apparatus as set forth in claim 2 wherein the means for varying the phase component of the carrier signal includes at least one optical waveguide means.

Claim 7

Apparatus as set forth in claim 5 wherein the means for varying the phase component of the carrier signal further includes at least one interferometer means.

Claim 8

An optical link for coupling one or more output signals from an array of radiation detectors to one or more signal receiving and processing devices, comprising: a carrier signal generated by a source of optical radiation having at least one characteristic frequency component and a phase component associated therewith; first means for coupling the carrier signal from the source; phase modulating means having at least one first input coupled to an output signal from an array of radiation detectors and a second input coupled to the carrier coupling means for receiving the carrier signal therefrom, the phase modulating means being responsive to the array output signal for modulating the phase component of the carrier signal in accordance therewith; second means for coupling the phase modulated carrier signal from the phase modulating means; and means, coupled to the phase modulated carrier coupling means, for demodulating the carrier signal, the demodulating means having an output signal which is expressive of a characteristic of the output signal from the array of radiation detectors.

Claim 9

An optical link for coupling one or more output signals from an array of radiation detectors to one or more signal receiving and processing devices, comprising: a carrier signal generated by a source of optical radiation having at least one characteristic frequency component and a phase component associated therewith; first means for coupling the carrier signal from the source; phase modulating means having at least one first input coupled to an output signal from an array of radiation detectors and a second input coupled to the carrier coupling means for receiving the carrier signal therefrom, the phase modulating means being responsive to the array output signal for modulating the phase component of the carrier signal in accordance therewith; second means for coupling the phase modulated carrier signal from the phase modulating means; and means, coupled to the phase modulated carrier coupling means, for demodulating the carrier signal, the demodulating means having an output signal which is expressive of a characteristic of the output signal from the array of radiation detectors.

Claim 10

An optical link as set forth in claim 7 wherein the first and the second means for coupling each comprise at least one fiber optic cable.

Claim 11

An optical link as set forth in claim 8 wherein the phase modulating means comprises an electro-optic waveguide structure.

Claim 12

An optical link as set forth in claim 9 wherein the electro-optic waveguide structure comprises a 50--50 Y-junction device having a fiber optic cable coupled to each arm of the Y-junction for redundantly outputting two substantially identical phase modulated carrier signals.

Claim 13

An optical link as set forth in claim 9 wherein the electro-optic waveguide structure comprises at least one interferometer structure.

Claim 14

An optical link as set forth in claim 11 wherein the interferometer structure is a Mach Zehnder type of interferometer structure.

Claim 15

An optical link as set forth in claim 9 wherein the phase modulating means is comprised of lithium niobate.

Claim 16

An optical link as set forth in claim 8 wherein the source of optical radiation comprises a super-luminescent diode, wherein the first and the second coupling means are a single mode, polarization preserving type of optical fiber, and wherein the demodulating means comprises at least one detector comprised of Group III-V material.

Claim 17

An optical link as set forth in claim 8 wherein the source of optical radiation comprises a light emitting diode, wherein the first and the second coupling means are a germanium doped single mode type of optical fiber, and wherein the demodulating means comprises at least one detector comprised of Group II-VI material.

Claim 18

An optical link as set forth in claim 8 wherein the source of optical radiation generates a plurality of different wavelengths of radiation, wherein the second coupling means comprises a plurality of output optical fibers individual ones of which couple one of the wavelengths from the phase modulating means, and wherein the phase modulating means comprises a wavelength selective radiation directing means for directing radiation of different wavelengths into an associated one of the plurality of output optical fibers.

Claim 19

An optical link as set forth in claim 16 wherein the radiation directing means comprises a prism means disposed to selectively reflect the different wavelengths into the associated one of the plurality of output optical fibers.

Claim 20

An optical link as set forth in claim 7 and further comprising a voltage to frequency converting means coupled between the array output signal and the phase modulation means for converting a voltage signal output of the array to a frequency signal output, the phase modulating means phase modulating the carrier signal in response to the frequency signal output.

Claim 21

An optical link as set forth in claim 8 wherein the demodulating means includes a synthetic heterodyne demodulator for demodulating the phase component of the carrier signal.

Claim 22

An optical link as set forth in claim 8 wherein the demodulating means includes a homodyne demodulator for demodulating the phase component of the carrier signal.

Claim 23

A phase modulator for modulating a phase component of a substantially sinusoidal optical carrier signal in accordance with an input signal generated by a radiation detecting array, comprising a substrate comprised of electro-optic material; and at least one interferometer fabricated on the substrate, the interferometer comprising: an optical waveguide having a substantially linear input portion having an exterior end and an interior end, the input portion for coupling an optical carrier signal into the interferometer, a substantially linear output portion having an interior end and an exterior end, the input and output portions being substantially colinear one with the other, and a substantially hexagonal portion interposed between the interior ends of the input and output portions, the hexagonal portion having one corner coupled to the interior end of the linear input portion and an oppositely opposed corner coupled to the interior end of the linear output portion; at least one signal ground electrode disposed within a perimeter of the hexagonal portion; and at least one pair of signal electrodes individual ones of which are disposed on opposite sides of the hexagonal structure such that the signal ground electrode is disposed between the pair of signal electrodes, each of the signal electrodes being coupled in common to at least one output signal generated by a radiation detector.

Claim 24

A phase modulator for modulating a phase component of a substantially sinusoidal optical carrier signal in accordance with an input signal generated by a radiation detecting array, comprising a substrate comprised of electro-optic material; and at least one interferometer fabricated on the substrate, the interferometer comprising: an optical waveguide having a substantially linear input portion having an exterior end and an interior end, the input portion for coupling an optical carrier signal into the interferometer, a substantially linear output portion having an interior end and an exterior end, the input and output portions being substantially colinear one with the other, and a substantially hexagonal portion interposed between the interior ends of the input and output portions, the hexagonal portion having one corner coupled to the interior end of the linear input portion and an oppositely opposed corner coupled to the interior end of the linear output portion; at least one signal ground electrode disposed within a perimeter of the hexagonal portion; and at least one pair of signal electrodes individual ones of which are disposed on opposite sides of the hexagonal structure such that the signal ground electrode is disposed between the pair of signal electrodes, each of the signal electrodes being coupled in common to at least one output signal generated by a radiation detector.

Claim 25

A phase modulator as set forth in claim 21 and further comprising: a second signal ground electrode disposed within the perimeter of the hexagonal portion; and a second pair of signal electrodes individual ones of which are disposed on opposite sides of the hexagonal portion such that the second signal ground electrode is disposed between the second pair of signal electrodes, each of the second pair of signal electrodes being coupled in common to a frequency signal having a frequency which is a function of the optical carrier frequency.

Claim 26

A phase modulator as set forth in claim 22 wherein the substrate is comprised of lithium niobate.

Claim 27

A phase modulator as set forth in claim 23 wherein the signal ground electrodes and signal electrodes are comprised of titanium.

Claim 28

A phase modulator as set forth in claim 22 wherein the interferometer is a Mach Zehnder type of interferometer.

Claim 31

A method as set forth in claim 26 wherein the step of varying the phase component of the carrier signal is accomplished with an electro-optic device.

Claim 32

A method as set forth in claim 27 wherein the step of transmitting is accomplished with at least one fiber optic cable.

Claim 33

A method as set forth in claim 27 wherein the step of varying the phase component of the carrier signal further includes a step of applying the carrier signal to at least one interferometer means.

Claim 34

A method as set forth in claim 29 wherein the step of varying the phase component is accomplished by operating the interferometer means in push-pull.

Claim 37

A method as set forth in claim 31 wherein the step of phase modulating is accomplished with an electro-optic waveguide structure having a 50--50 Y-junction device including a fiber optic cable coupled to each arm of the Y-junction.

Claim 38

A method as set forth in claim 31 wherein the step of demodulating is accomplished by a homodyne demodulator.

Claim 39

A method as set forth in claim 31 wherein the step of phase modulating is accomplished with a Mach Zehnder type of interferometer.

Claim 40

A method as set forth in claim 31 wherein the step of generating generates a plurality of different wavelengths of radiation, and wherein the step of phase modulating includes a step of directing radiation of different wavelengths into an associated one of a plurality of output optical fibers.

Claim 41

A method as set forth in claim 31 wherein the step of phase modulating includes a first step of converting the radiation detector output signal to a frequency signal.

Claim 42

A method as set forth in claim 31 wherein the step of demodulating is accomplished by a synthetic heterodyne demodulator.