Atomic Resonator Using Acoustic Frequency Divider for Stable CPT Locking
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Solution Overview
Problem
Existing atomic resonators face challenges in miniaturization, low power consumption, and achieving stable frequency stabilization due to low S/N ratio and phase noise characteristics, particularly when using PLL or injection-locked circuits with low Q value inductors.
Innovation Solution
The use of an acoustic resonator with a high Q value as a passive element in an injection-locked frequency divider circuit replaces traditional inductors, enabling stable modulation signals and frequency division without digital discriminators, enhancing phase noise characteristics and frequency stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a PLL circuit or injection-locked circuit with a low Q value inductor is used for frequency division, then the device can be miniaturized and power consumption can be reduced, but the phase noise characteristics deteriorate and frequency stabilization becomes unstable
Solution Approach 1:
The patent changes the Q value parameter of the resonator from low (in traditional inductors) to high (in acoustic resonators). By using an acoustic resonator with high Q value instead of a traditional inductor, the system achieves both miniaturization and stable frequency stabilization, resolving the contradiction between device size and frequency stability.
2Reliability
If a digital discriminator with lock-in amplifier is used to generate error signal, then frequency stabilization can be achieved, but device complexity increases and miniaturization is hindered
Solution Approach 1:
The patent extracts and eliminates the complex digital discriminator with lock-in amplifier from the system. By using direct feedback of atomic resonance signal to the laser drive current, the system achieves frequency stabilization without requiring the complex digital discrimination circuitry, thus reducing device complexity while maintaining stabilization capability.
Solution Approach 2:
The system uses self-service by directly feeding back the atomic resonance signal to control the laser frequency without external complex processing equipment. The atomic resonance signal itself serves as the reference for frequency stabilization, eliminating the need for separate digital discriminators and lock-in amplifiers.
3Volume of moving object
If the S/N ratio of CPT resonance signal is low, then miniaturization can be achieved, but frequency measurement precision deteriorates
Solution Approach 1:
The patent replaces the traditional electronic inductor-based oscillation auxiliary circuit with an acoustic resonator-based circuit. The acoustic resonator's high Q value provides better signal filtering and noise rejection, improving the effective S/N ratio of the CPT resonance signal while maintaining miniaturization, thus resolving the contradiction between size and measurement precision.
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 configuration allows for miniaturized, low-power atomic resonators with improved phase noise characteristics and stable frequency stabilization, overcoming the limitations of previous technologies.
Implementation Method 1
a high-frequency oscillator configured to receive the electric signal from the photodetector, frequency-divide the electric signal by two, and output a signal
Implementation Method 2
the high-frequency oscillator has an injection-locked frequency divider circuit including an acoustic resonator as an oscillation element
Implementation Method 3
causing CPT resonance by a quantum interference effect
Implementation Method 4
a photodetector configured to detect light having passed through the gas cell and convert the light to an electric signal
Data Source
AI summary
This atomic resonator for causing a resonance frequency by CPT resonance includes: a gas cell having alkali metal atoms enclosed; a photodetector configured to detect light having passed through the gas cell and convert the light to an electric signal; a high-frequency oscillator configured to receive the electric signal and output the signal after a frequency thereof is divided by two; and a laser light source configured to modulate and introduce, into the gas cell, light based on the signal output from the high-frequency oscillator. The high-frequency oscillator has an injection-locked frequency divider circuit including an acoustic resonator as an oscillation element.