Photonic Monopulse Comparator Angle of Arrival
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Solution Overview
Problem
Monopulse radar systems face challenges with electronic or fiber optic components regarding performance, loss, and size limitations in determining the angle of arrival of electromagnetic signals.
Innovation Solution
A photonic monopulse comparator using an array of squinted monopulse elements with integrated photonics, including a laser source, optical phase modulators, hybrid couplers, and balanced photodiodes to modulate and detect optical signals, enabling the calculation of angle of arrival in the optical domain with high speed and ultrawide bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electronic or fiber optic components are used in monopulse radar systems, then the system can determine angle of arrival, but the components suffer from performance degradation, signal loss, and size limitations
Solution Approach 1:
The patent replaces electronic components and fiber optic components with a photonic system. The monopulse comparator is implemented using optical elements including a light source, optical modulators, optical waveguides, and photodetectors. This substitution eliminates the performance degradation, loss, and size limitations associated with electronic and fiber optic components while maintaining the angle of arrival determination capability.
2Measurement precision
If electronic components are used for signal processing, then angle of arrival can be calculated, but the system experiences high power consumption and susceptibility to RF interference
Solution Approach 1:
The patent substitutes electronic signal processing with photonic signal processing. The system uses optical modulators to encode the RF signals from monopulse elements onto optical carriers, transmits them through optical waveguides, and detects them with photodetectors. The angle of arrival calculation is performed by comparing the optical signals in the photonic domain, eliminating RF interference and reducing power consumption compared to electronic processing.
3Speed
If fiber optic components are used to transmit signals, then signal transmission is achieved, but the components exhibit signal loss and size constraints
Solution Approach 1:
The patent replaces fiber optic components with integrated photonic circuit elements. The system uses on-chip optical waveguides, modulators, and photodetectors that are monolithically integrated or closely coupled. This integration eliminates the connection losses and size constraints associated with discrete fiber optic components while maintaining high-speed signal transmission capability.
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
The solution provides improved amplitude and phase balance across a broad bandwidth, high linearity, and reduced size, minimizing electronic calculations and power consumption while immune to RF interference.
Implementation Method 1
cascading optical phase modulators, each optical phase modulator connected to a monopulse element and capable of modulating the optical signal according to the RF signal received therefrom
Implementation Method 2
array of balanced photodiode pairs, each pair of photodiodes capable of detecting a hybrid output signal and generating an RF output signal corresponding to the output signal
Data Source
AI summary
An integrated photonics monopulse comparator includes an array of squinted monopulse elements, each monopulse element producing an RF signal in response to a received inbound signal and each RF signal having a squinted RF voltage. The comparator includes a laser source for producing a wavelength division multiplexed (WDM) optical signal comprising multiple components having discrete wavelengths. The component signals may be multiplexed and demultiplexed and routed through cascading optical phase modulators, each phase modulator connected to a monopulse element and capable of modulating a component signal according to the voltages of the RF signals produced by the corresponding monopulse element. The resulting modulated component optical signals undergo coherent photodetection by arrays of paired photodiodes, each pair receiving component signals of like wavelength. The output signals of each array are proportional in voltage to sums and differences from which arrival angles of the inbound signal may be calculated.