Carrier-suppressed modulation and self-mixing demodulation for vibration measurement

Area of Science:

• Optical Physics
• Vibration Measurement
• Signal Processing

Background:

• Coherent detection typically requires a local oscillator for signal demodulation.
• Measuring small vibrations with high precision is crucial in various scientific and industrial applications.
• Existing methods for vibration measurement can be complex or require specialized equipment.

Purpose of the Study:

• To introduce a double-sideband suppressed-carrier (DSB-SC) technique for measuring small vibrations.
• To demonstrate an optical balanced detection approach for achieving carrier suppression.
• To recover the baseband signal without a local oscillator, simplifying the detection process.

Main Methods:

• Implementation of an optical balanced detection system.
• Generation of a double-sideband suppressed-carrier (DSB-SC) signal.
• Utilizing a self-mixing approach for demodulating the DSB-SC signal to recover the baseband signal.
• Experimental demonstration of carrier suppression and vibration measurement.

Main Results:

• Successful suppression of the optical carrier was achieved.
• Accurate measurement of small vibrations was demonstrated using the proposed technique.
• Experimental results showed close agreement with theoretical predictions, validating the method's effectiveness.

Conclusions:

• The developed optical balanced detection technique effectively measures small vibrations using DSB-SC modulation.
• The self-mixing demodulation approach eliminates the need for a local oscillator, offering a simpler alternative to traditional coherent detection.
• This method provides a promising solution for precise and simplified vibration sensing.