Optically synthesized tracking signal source and network analyzer using same
First Claim
1. An optically synthesized tracking signal source comprising:
- a first square-law photodetector configured to provide a first output signal having a frequency equal to a frequency difference between optical signals of a first pair of optical signals;
a second square-law photodetector configured to provide a second output signal having a frequency equal to a frequency difference between optical signals of a second pair of optical signals, the second optical signal pair being a frequency-shifted version of the first pair of optical signals; and
an optical wavemeter configured to determine one or both of the frequency difference between optical signals of the first pair of optical signals, and the frequency difference between optical signals of the second pair of optical signals,wherein the first and second output signals are tracking signals having a frequency offset determined by a relative frequency shift between the first and second pairs of optical signals.
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Accused Products
Abstract
Optical synthesis of frequency-tracking signals employs square-law based frequency conversion of pairs of optical signals having a predetermined, relative frequency shift to provide output signals. An optically synthesized tracking signal source includes a square-law photodetector configured to provide a first output signal having a frequency equal to a frequency difference between a first optical signal pair. Another square-law photodetector is configured to provide a second output signal having a frequency equal to a frequency difference between a second optical signal pair that is a frequency-shifted version of the first pair. The signal source further includes an optical wavemeter configured to determine one or both of the first pair frequency difference and the second pair frequency difference. The first and second output signals are tracking signals having a frequency offset determined by a relative frequency shift between the first and second pairs of optical signals.
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Citations
20 Claims
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1. An optically synthesized tracking signal source comprising:
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a first square-law photodetector configured to provide a first output signal having a frequency equal to a frequency difference between optical signals of a first pair of optical signals; a second square-law photodetector configured to provide a second output signal having a frequency equal to a frequency difference between optical signals of a second pair of optical signals, the second optical signal pair being a frequency-shifted version of the first pair of optical signals; and an optical wavemeter configured to determine one or both of the frequency difference between optical signals of the first pair of optical signals, and the frequency difference between optical signals of the second pair of optical signals, wherein the first and second output signals are tracking signals having a frequency offset determined by a relative frequency shift between the first and second pairs of optical signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A network analyzer having an optically synthesized tracking signal source, the network analyzer comprising:
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a radio frequency (RF) source comprising a square-law photodetector configured to generate an RF test signal from a first pair of optical signals, an optical signal of the first pair being tunable; a local oscillator (LO) source comprising another square-law photodetector configured to generate an LO signal from a second pair of optical signals derived from the first pair, the second pair comprising an optical signal having a predetermined frequency shift relative to a corresponding optical signal the first pair; and an optical wavemeter configured to determine a frequency difference between optical signals of a respective pair of one or both of the first pair and the second pair, wherein the RF test signal and the LO signal are configured to track one another with a frequency difference corresponding to the predetermined frequency shift. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A method of optically synthesizing a pair of tracking signals, the method comprising:
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generating a first output signal using a square-law photodetector, the first output signal having a frequency equal to a frequency difference between optical signals of a first pair of optical signals; generating a second output signal using another square-law photodetector, the second output signal having a frequency equal to a frequency difference between optical signals of a second pair of optical signals, the second optical signal pair being a frequency-shifted version of the first pair of optical signals; and determining one or both of the frequency difference between the optical signals of the first pair, and the frequency difference between the optical signals of the second pair using an optical wavemeter, wherein the first and second output signals track one another over a tunable frequency range of an optical signal of the first optical signal pair. - View Dependent Claims (19, 20)
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Specification