Thermo-Tuning Fourier Transform Spectrometer Based on SU-8 Waveguide.

Area of Science:

• Photonics
• Spectroscopy
• Microfabrication

Background:

• On-chip Fourier transform spectrometers (FTS) offer miniaturization and cost-effectiveness for spectral analysis.
• Traditional spectrometers are often bulky and expensive, limiting their widespread application.
• Integrated photonic devices are crucial for developing compact sensing technologies.

Purpose of the Study:

• To design, fabricate, and characterize a novel Mach-Zehnder interferometer (MZI) based Fourier transform spectrometer (FTS) on a chip.
• To demonstrate the feasibility of using SU-8 polymer waveguides for integrated spectroscopy.
• To evaluate the performance metrics including footprint, spectral bandwidth, and resolution.

Main Methods:

• Fabrication of a Mach-Zehnder interferometer (MZI) using SU-8 polymer waveguide technology.
• Integration of a micro-heater for active tuning of the optical path length difference.
• Characterization of the device by analyzing interference signals using Fourier transform algorithms.
• Measurement of spectral bandwidth and resolution.

Main Results:

• A compact FTS device with a footprint of only 2 × 12 mm² was successfully fabricated.
• The device achieved a spectral bandwidth of approximately 100 nm.
• The spectral resolution was determined to be less than 20 nm.
• The MZI optical path length difference was effectively tuned by a heater with low power consumption (max 2.2 W).

Conclusions:

• The developed on-chip MZI FTS represents a promising technology for compact and cost-effective spectral analysis.
• SU-8 polymer waveguides are suitable for fabricating integrated Fourier transform spectrometers.
• The device's small size and performance metrics indicate potential for various applications requiring portable spectroscopy.