Evanescent Field Controllable MZ Sensor via Femtosecond Laser Processing and Mechanic Polishing

Area of Science:

• Photonics and optical sensing
• Integrated optics
• Materials science

Background:

• Optical sensors utilizing evanescent fields are crucial for environmental monitoring.
• Evanescent field depth directly impacts optical sensor accuracy, posing fabrication challenges for on-chip devices.

Purpose of the Study:

• To develop a high-accuracy on-chip optical sensor for refractive index detection.
• To address the challenge of controlling evanescent field depth for improved sensor performance.

Main Methods:

• Fabrication of a Mach-Zehnder interferometer waveguide structure in Corning Eagle 2000 glass using a femtosecond laser.
• Exposing a sensing window via mechanical polishing of the bulk material.

Main Results:

• Demonstrated an on-chip Mach-Zehnder interferometer refractive index sensor with small size, light weight, and good stability.
• Achieved high sensitivity of 206 nm/RIU or 337 dB/RIU.
• Established a theoretical measurement range of 1-1.508 refractive index units (RIU).

Conclusions:

• The developed on-chip sensor enables rapid and accurate refractive index measurements.
• The device shows excellent application prospects for use in extreme or complex environments.
• This work advances the field of integrated optical sensing for demanding applications.