Terahertz Dual-Comb Stabilization Without Femtosecond Laser
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Solution Overview
Problem
Existing terahertz dual-comb spectrum systems face challenges in locking the carrier offset frequency without introducing a femtosecond laser, which increases system complexity and limits miniaturization.
Innovation Solution
A terahertz dual-comb spectrum stabilization system that uses a multi-chain frequency multiplication chain and a Schottky diode harmonic mixer to down-convert terahertz optical frequency combs to the microwave band, allowing for carrier offset frequency locking through electrical phase-locked loops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a femtosecond laser is introduced to lock the carrier offset frequency, then the carrier offset frequency can be locked, but the system size and complexity increase
Solution Approach 1:
The patent extracts and removes the femtosecond laser component from the system. Instead of using a femtosecond laser to generate the seed signal, the invention uses a directly modulated laser combined with a frequency multiplication chain to achieve carrier offset frequency locking, thereby eliminating the complex femtosecond laser subsystem while maintaining the locking function
Solution Approach 2:
The patent changes the operating parameters of the laser system by using direct modulation of the laser current to generate frequency chirp, followed by frequency multiplication through a nonlinear optical process. This parameter change approach replaces the need for femtosecond pulse generation while achieving the same carrier offset frequency locking effect
2Reliability
If a femtosecond laser is introduced to lock the carrier offset frequency, then the carrier offset frequency can be locked, but the integration and miniaturization are limited
Solution Approach 1:
By removing the femtosecond laser component, the patent significantly reduces the system volume. The replacement architecture using directly modulated lasers and frequency multiplication chains occupies much less space, enabling better integration and miniaturization while maintaining carrier offset frequency locking capability
3Measurement precision
If traditional spectrometers with mechanical scanning structures are used, then spectral measurement can be performed, but real-time detection is difficult
Solution Approach 1:
The patent replaces the mechanical scanning structure of traditional spectrometers with an all-optical frequency comb-based spectral measurement system. By using two frequency combs with slightly different repetition rates and performing heterodyne detection, the system achieves real-time spectral measurement without any moving mechanical parts, thereby simultaneously maintaining measurement precision and enabling real-time detection
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 solution enhances the stability of the dual-comb frequency, enabling a stable terahertz dual-comb spectrum system without the need for a femtosecond laser, thus improving integration and miniaturization possibilities.
Implementation Method 1
Terahertz dual-comb spectrum refers to the multi-heterodyne spectrum formed by two terahertz quantum cascade laser optical frequency combs with slightly different repetition frequency
Implementation Method 2
the multi-chain frequency multiplication chain is used for performing frequency multiplication processing on a radio frequency signal, then a local oscillator frequency in terahertz frequency range is generated by means of frequency multiplication by the frequency mixer
Implementation Method 3
a first phase-locking device, used for locking the phase of the comb tooth extracted by the first signal extraction device
Data Source
AI summary
The invention relates to a terahertz dual-comb spectrum stabilization system, including an optical loop for coupling a first optical frequency comb signal (OFCS) to a second OFCS; and a frequency mixer for performing frequency mixing on the coupled first OFCS and second OFCS to generate a dual-comb signal. A local oscillator signal end of the frequency mixer is connected to a multi-chain frequency multiplication chain, the multi-chain frequency multiplication chain is used for performing frequency multiplication processing on a radio frequency signal, a local oscillator frequency in terahertz frequency range is generated the local oscillator frequency in terahertz frequency range is respectively mixed with the first OFCS and the second OFCS in the frequency mixer, and two down-converted OFCSs are generated in microwave frequency range. One line of comb teeth of the two down-converted OFCSs are respectively locked to obtain a stable multi-heterodyne dual-comb spectrum.