Coherent Optical Frequency Comb Receiver for Wideband Signal Processing
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Solution Overview
Problem
Conventional DFT processors face energy efficiency challenges due to high energy costs of multiplier operations and bandwidth limitations in wideband signal processing, particularly in ultrawideband (UWB) communications and real-time pattern recognition, where high-speed analog-to-digital converters (ADCs) induce noise and dissipate excessive power.
Innovation Solution
A photonics-assisted receiver architecture using mutually coherent frequency combs for spectral decomposition, allowing for real-time detection of wideband signals without the need for high-rate electronic front-ends or narrow-band optical filtering, enabling sub-Nyquist receiver bandwidth and reducing the requirement for physical channelization filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional DFT processors use high-rate electronic front-ends for wideband signal processing, then signal processing capability is improved, but power consumption increases due to high energy costs of multiplier operations and ADC dissipation
Solution Approach 1:
The patent replaces electronic DFT processing with an optical processing system. The optical system uses frequency combs and optical spectrum analysis to perform spectral decomposition and signal processing functions that would otherwise require high-speed electronic multipliers and ADCs, thereby reducing power consumption while maintaining processing capability.
Solution Approach 2:
The patent changes the operating domain from electronic to optical by using frequency combs with specific tooth spacings that match the signal bandwidth. This parameter change allows the system to process wideband signals using optical frequency division rather than electronic time-domain processing, reducing the energy cost of operations.
2Productivity
If conventional DFT processors use high-rate ADCs for wideband signal conversion, then bandwidth coverage is improved, but measurement precision deteriorates due to noise introduction
Solution Approach 1:
The patent substitutes electronic ADC conversion with optical spectrum analysis. The optical system directly measures the spectral content of wideband signals using frequency combs and optical spectrum analyzers, avoiding the noise introduction inherent in high-rate electronic ADC conversion while maintaining full bandwidth coverage.
3Measurement precision
If conventional DFT processors use narrow-band optical filtering for spectral decomposition, then frequency resolution is improved, but device complexity increases due to requirement for physical channelization filters
Solution Approach 1:
The patent extracts the spectral decomposition function from physical filter banks and implements it through optical frequency comb generation and optical spectrum analysis. This approach obtains frequency resolution without requiring complex assemblies of narrow-band filters, reducing device complexity while maintaining resolution capability.
Solution Approach 2:
The patent uses frequency combs to create multiple optical copies of the input signal at different frequency offsets. These spectral copies are then analyzed to obtain frequency-domain information, providing an alternative to physical filter banks for spectral decomposition.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables efficient, real-time processing of wideband signals with reduced power consumption and increased spectral resolution, overcoming the limitations of conventional DFT technologies in UWB communications and pattern recognition applications.
Implementation Method 1
the coherent beating between an optical signal and an optical tone generated by a local oscillator
Implementation Method 2
subsequent balanced detection of the optical hybrid outputs produces electrical signals
Data Source
AI summary
A receiver architecture for physically-assisted computing of transforms, such as discrete Fourier transforms (DFT) and discrete Hilbert transforms (DHT), employs mutually-coherent optical frequency combs for detection of the coherent beating between an optical signal and a reference optical tone generated by a local oscillator (LO). A signal replication mixer generates a plurality of signal optical tones having a frequency pitch with an input signal mapped thereon. A reference mixer (local oscillator) generates a plurality of reference optical tones having an offset frequency pitch relative to the signal tones. A receiver backplane detects coherent beating between the signal optical tones and the reference optical tones. The input signal may be in the optical domain or in the radio-frequency domain.