Vibration: history and measurement with an extrinsic Fabry-Perot sensor with solid-state laser interferometry

Area of Science:

• Optics and Photonics
• Mechanical Engineering
• Sensor Technology

Background:

• Vibration analysis is crucial in various scientific and engineering fields.
• Accurate microdisplacement measurement requires advanced sensing techniques.
• Existing methods may have limitations in noncontact or dynamic measurements.

Purpose of the Study:

• To develop and demonstrate a laser-based noncontact interferometric vibration sensor.
• To investigate the sensor's performance using Fabry-Perot cavity principles.
• To evaluate the sensor's capabilities with both multimode and single-mode fiber transmission.

Main Methods:

• Utilized a Fabry-Perot cavity formed by a gradient-index lens and a movable reflector.
• Employed laser interferometry to detect interference fringes modulated by phase changes.
• Calibrated the sensor using multimode fiber and performed dynamic tests with both fiber types.

Main Results:

• Achieved a displacement resolution of 0.034 microm over a 10.2 microm range with multimode fiber.
• Demonstrated a dynamic working range of at least 3.74 microm at frequencies up to 2 kHz.
• Observed a dynamic working range of at least 4.29 microm when using single-mode fiber.

Conclusions:

• The developed laser-based sensor effectively measures microdisplacement with high resolution.
• The sensor demonstrates robust performance in dynamic vibration testing.
• The system shows promise for noncontact vibration monitoring applications.