Sensitivity-improved microwave photonic fiber-ring temperature sensor with the self-Vernier effect

Area of Science:

• Photonics
• Optical Sensing
• Interferometry

Background:

• Fiber-ring (FR) interferometers are used for sensing applications.
• Microwave photonic (MWP) technology offers a method for signal processing in optical sensors.
• Enhancing sensor sensitivity is crucial for precise measurements.

Purpose of the Study:

• To propose and demonstrate a highly sensitive microwave photonic fiber-ring temperature sensor.
• To leverage the self-Vernier effect for enhanced sensitivity in temperature sensing.
• To simplify the sensor design by avoiding dual interferometers and precise optical path difference (OPD) control.

Main Methods:

• A fiber-ring interferometer was combined with a delay fiber to generate the Vernier effect.
• The Vernier effect was achieved by superimposing the interferometer's spectrum with its time-delayed version.
• Microwave photonic technology converted temperature-induced spectrum shifts into frequency shifts.

Main Results:

• The proposed sensor demonstrated enhanced sensitivity due to the self-Vernier effect.
• The experimental sensitivity reached -392.317 kHz/℃.
• This represents an approximate 15-fold increase in sensitivity compared to sensors without the self-Vernier effect.

Conclusions:

• A simple and highly sensitive microwave photonic fiber-ring temperature sensor was successfully demonstrated.
• The self-Vernier effect significantly amplifies temperature-induced frequency shifts, enhancing sensor performance.
• The proposed method offers a practical approach for developing advanced optical temperature sensors.