Optical encoder devices and systems
Devices, systems and methods for encoding information using optical components are described. An example photonic filtered sampler includes a spectral shaper configured to receive an optical pulse train, a dispersive element positioned to receive an output of the spectral shaper and to expand spectral contents thereof in time, and a modulator configured to receive an output of the dispersive element and a radio frequency (RF) signal, and to produce a modulated output optical signal in accordance with the RF signal. In this configuration, one or more characteristics of the modulated output optical signal is determined based on a spectral shape provided by the spectral shaper and dispersive properties of the dispersive element.
1. A photonic filtered sampler, comprising:
a spectral shaper configured to receive an optical pulse train, the spectral shaper including a first diffraction grating configured to separate optical frequencies in space, a spatial light modulator configured to alter insertion loss of each optical frequency individually, and a second diffraction grating to combine the optical frequencies back together;
a dispersive element positioned to receive an output of the spectral shaper and to expand spectral contents thereof in time; and
a modulator configured to receive an output of the dispersive element and a radio frequency (RF) signal, and to produce a modulated output optical signal in accordance with the RF signal, wherein one or more characteristics of the modulated output optical signal is determined based on a spectral shape provided by the spectral shaper and dispersive properties of the dispersive element.
2. The photonic filtered sampler of claim 1 , wherein the one or more characteristics includes a shift in a center frequency and a spectral width of the modulated output optical signal.
3. The photonic filtered sampler of claim 1 , including a delay line interferometer, wherein the one or more characteristics is determined at least in-part based on an amount of delay provided by the delay line interferometer.
4. The photonic filtered sampler of claim 3 , wherein the delay line interferometer includes:
an optical splitter configured to receive the optical pulse train and to produce two versions of the optical pulse train,
an optical delay component configured to receive a first version of the optical pulse train and impart a time delay thereto to produce a delayed optical pulse train, and
an optical coupler configured to receive the delayed optical pulse train and a second version of the optical pulse train, and to produce an output that is provided to the dispersive element.
5. The photonic filtered sampler of claim 1 , wherein the dispersive element has fixed dispersive properties.
6. The photonic filtered sampler of claim 4 , wherein the optical delay component is configured to impart a fixed delay value to the first version of the optical pulse train.
7. The photonic filtered sampler of claim 4 , wherein one or both of the optical delay component or the dispersive element is tunable.
8. The photonic filtered sampler of claim 7 , wherein the optical delay component comprises one or more of the following components to effect tunability:
a mechanical free space stage,
one or more switches operable to select a particular delay value using an array of fixed time delay elements, or
a phase shifter configured to tune a fringe phase of an optical signal in the delay line interferometer relative to an envelope of thereof.
9. The photonic filtered sampler of claim 7 , wherein the dispersive element comprises one or more of the following components to effect tunability:
a heater, or
one or more switches operable to use an array of fixed dispersion elements to select different dispersion values.
10. A photonic filtered sampler, comprising:
a spectral shaper configured to receive an optical pulse train;
a dispersive element positioned to receive an output of the spectral shaper and to expand spectral contents thereof in time; and
a modulator configured to receive an output of the dispersive element and a radio frequency (RF) signal, and to produce a modulated output optical signal in accordance with the RF signal, wherein one or more characteristics of the modulated output optical signal is determined based on a spectral shape provided by the spectral shaper and dispersive properties of the dispersive element, and wherein the photonic filtered sampler is configured as part of a filtered photonic encoder comprising:
an optical multiplexer configured to receive the modulated output optical signal from the modulator and an optical probe signal,
a non-linear optical medium positioned to receive an output of the optical multiplexer, and
an optical demultiplexer configured to receive an output of the non-linear optical medium and to produce a phase-modulated probe signal.
11. The photonic filtered sampler of claim 10 , wherein the filtered photonic encoder further comprises an optical compressive element positioned between the modulator and the optical multiplexer to reduce a width of optical pulses that are output from the modulator before reaching the optical multiplexer.
12. The photonic filtered sampler of claim 10 , wherein the photonic filtered encoder comprises an optical source configured to produce the optical probe signal.
13. The photonic filtered sampler of claim 1 , wherein the modulator is an electro-optic intensity modulator.
14. The photonic filtered sampler of claim 10 , wherein the spectral shaper includes an optical filter including a thin-film or Bragg grating.
15. The photonic filtered sampler of claim 1 , wherein the first diffraction grating is the same as the second diffraction grating.
16. A photonic filtered sampler, comprising:
a delay line interferometer configured to receive an optical pulse train;
a dispersive element positioned to receive an output of the delay line interferometer and to expand spectral contents thereof in time; and
a modulator configured to receive an output of the dispersive element and a radio frequency (RF) signal, and to produce a modulated output optical signal in accordance with the RF signal, wherein one or more characteristics of the modulated output optical signal is determined based on an amount of delay provided by the delay line interferometer, and wherein the photonic filtered sampler is configured as part of a filtered photonic encoder comprising:
an optical multiplexer configured to receive the modulated output optical signal from the modulator and an optical probe signal,
a non-linear optical medium positioned to receive an output of the optical multiplexer, and
an optical demultiplexer configured to receive an output of the non-linear optical medium and to produce a phase-modulated probe signal.
17. The photonic filtered sampler of claim 16 , wherein the delay line interferometer includes:
an optical splitter configured to receive the optical pulse train and to produce two versions of the optical pulse train,
an optical delay component configured to receive a first version of the optical pulse train and impart a time delay thereto to produce a delayed optical pulse train, and
an optical coupler configured to receive the delayed optical pulse train and a second version of the optical pulse train, and to produce an output that is provided to the dispersive element.
18. The photonic filtered sampler of claim 16 , wherein the filtered photonic encoder further comprises an optical compressive element positioned between the modulator and the optical multiplexer to reduce a width of optical pulses that are output from the modulator before reaching the optical multiplexer.
19. The photonic filtered sampler of claim 16 , wherein the one or more characteristics includes a shift in a center frequency and a spectral width of the modulated output optical signal.
20. The photonic filtered sampler of claim 16 , wherein the dispersive element has fixed dispersive properties.
21. The photonic filtered sampler of claim 17 , wherein the optical delay component is configured to impart a fixed delay value to the first version of the optical pulse train.
22. The photonic filtered sampler of claim 17 , wherein one or both of the optical delay component or the dispersive element is tunable.
23. The photonic filtered sampler of claim 17 , wherein the optical delay component comprises one or more of the following components to effect tunability:
a mechanical free space stage,
one or more switches operable to select a particular delay value using an array of fixed time delay elements, or
a phase shifter configured to tune a fringe phase of an optical signal in the delay line interferometer relative to an envelope of thereof.
24. The photonic filtered sampler of claim 16 , wherein the dispersive element comprises one or more of the following components to effect tunability:
a heater, or
one or more switches operable to use an array of fixed dispersion elements to select different dispersion values.