Multi-Repetition-Rate Pulsed Light Source for High-Frequency Signal Measurement
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Solution Overview
Problem
Current systems for measuring high-frequency electromagnetic signals with unknown frequency ranges or broadband signals face challenges in accurately determining the down-conversion ratio and selecting appropriate devices for measurement, especially when multiple optical pulse trains with different repetition rates are involved.
Innovation Solution
A system utilizing a multi-repetition-rate pulsed light source with a single laser cavity, generating multiple optical pulse trains with different repetition rates, which mix with the signal to be measured to produce multiple frequency combs, allowing for real-time repetition rate measurement and data acquisition to determine the signal's time-frequency characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional down-conversion method is used to measure high-frequency electromagnetic signals, then measurement capability is achieved, but device complexity increases and adaptability decreases for signals with unknown frequency range or broadband signals
Solution Approach 1:
The patent employs a single pulsed laser source that simultaneously generates multiple optical pulse trains with different repetition rates through modal dispersion, polarization mode dispersion, birefringence, chromatic dispersion, or non-linear effects. This multi-functional light source can measure electromagnetic signals across a wide frequency range without requiring different down-conversion devices, thereby improving adaptability while reducing device complexity
Solution Approach 2:
The system changes the repetition rate parameter of the optical pulse trains to cover different frequency ranges. By adjusting the repetition rates (e.g., f1, f2, f3 with different values), the same measurement system can adapt to electromagnetic signals with unknown or varying frequency ranges, eliminating the need for fixed down-conversion device selection
2Measurement precision
If only one optical pulse signal is used to obtain one down-converted signal, then measurement simplicity is maintained, but the value of m (comb line order) cannot be determined uniquely
Solution Approach 1:
The patent segments the single optical pulse train into multiple pulse trains with different repetition rates (at least three: f1, f2, f3). Each pulse train generates a separate down-converted beat signal, providing multiple independent measurements. This segmentation allows the system to uniquely determine the comb line order m by comparing results from multiple repetition rates, thereby achieving precise frequency measurement without losing information about the signal's position in the frequency spectrum
3Device complexity
If multiple optical pulse trains with different repetition rates are generated using a single laser cavity, then system integration is improved and structure is simplified, but the complexity of determining which comb line mixes with the signal increases
Solution Approach 1:
The patent implements a feedback mechanism where the system measures the repetition rates of the generated optical pulse trains and uses this information to calculate and determine the relative position of the electromagnetic signal with respect to the frequency comb lines. The data processing unit receives beat signal frequencies and repetition rate information, then uniquely determines the signal frequency by solving the system of equations formed by multiple measurements, thereby resolving the difficulty of identifying the correct comb line order
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
Enables accurate measurement of frequency, amplitude, phase, and variations of high-frequency electromagnetic signals, offering a simpler structure and better integration compared to traditional methods, while allowing for unique determination of the signal's relative position to the frequency comb lines.
Implementation Method 1
A single pulsed laser can simultaneously output more than three optical pulse trains with different repetition rates in the same laser cavity by utilizing differences in modal dispersion
Implementation Method 2
A single pulsed laser can simultaneously output more than three optical pulse trains with different repetition rates in the same laser cavity by utilizing differences in modal dispersion, polarization mode dispersion
Implementation Method 3
A single pulsed laser can simultaneously output more than three optical pulse trains with different repetition rates in the same laser cavity by utilizing differences in modal dispersion, polarization mode dispersion, birefringence
Implementation Method 4
A single pulsed laser can simultaneously output more than three optical pulse trains with different repetition rates in the same laser cavity by utilizing differences in modal dispersion, polarization mode dispersion, birefringence, chromatic dispersion
Implementation Method 5
A single pulsed laser can simultaneously output more than three optical pulse trains with different repetition rates in the same laser cavity by utilizing differences in modal dispersion, polarization mode dispersion, birefringence, chromatic dispersion, non-linear effect
Implementation Method 6
A single pulsed laser can simultaneously output more than three optical pulse trains with different repetition rates in the same laser cavity by utilizing differences in modal dispersion, polarization mode dispersion, birefringence, chromatic dispersion, non-linear effect or mode-locking mechanism
Implementation Method 7
The multi-repetition-rate pulse trains generated by the multi-repetition-rate pulsed light source and the signal to be measured are mixed in the frequency mixer, and three or more mixed signals are respectively generated
Implementation Method 8
The optical mixer and a photodetector, or a photoconductive antenna. The frequency mixed signals are generated by mixing the signal to be measured with the comb line of each multi-repetition-rate optical pulse train respectively
Data Source
AI summary
This invention disclosed a system and method for characteristics measurement of electromagnetic signals. The measurement system comprises a multi-repetition-rate pulsed light source, a frequency mixer for electrical signal and optical signal, and a data acquisition and processing device. The measurement system accurately determines the characteristic information of the signal to be measured, such as frequency, phase, intensity, and their variations, by measuring the low frequency mixed signal generated by the multi-repetition-rate pulsed light source and the signal to be measured in the frequency mixer. This system has the advantages of simple structure, high measurement accuracy, low cost and large measurable frequency range. The system can be applied to the measurement of various electromagnetic signals, covering the spectral range from microwave, millimeter wave, to terahertz and even light wave.