Bragg-Grating-Based Photonic Strain and Temperature Sensor Foils Realized Using Imprinting and Operating at Very Near...

Area of Science:

• Materials Science
• Photonics
• Sensor Technology

Background:

• Traditional electrical strain gages face limitations like electromagnetic interference.
• Optical sensors using Bragg gratings offer superior accuracy and multiplexing capabilities.
• Existing optical fiber Bragg gratings are less suitable for planar integration and dense sensor arrays.

Purpose of the Study:

• To develop thin, flexible polymer sensor foils for integrated strain and temperature monitoring.
• To demonstrate the fabrication and performance of multiplexed Bragg gratings in planar polymer waveguides.
• To enable the creation of photonic strain gage rosettes for multi-directional strain measurement.

Main Methods:

• Fabrication of single-mode polymer waveguides with imprinted Bragg gratings at 850 nm.
• Integration of multiple Bragg gratings with pitches of 280 nm, 285 nm, and 290 nm.
• Characterization of waveguide quality, bend loss, and cross-talk.

Main Results:

• High-quality, single-mode polymer waveguides with minimal residual layers were achieved.
• Multiplexed Bragg gratings were successfully imprinted for operation at 850 nm.
• Measured strain sensitivity of 0.85 pm/µε and temperature sensitivity of -150 pm/°C were obtained.

Conclusions:

• Thin polymer sensor foils with integrated Bragg gratings are viable for strain and temperature sensing.
• The planar approach enables dense, multi-directional sensor arrays (rosettes).
• Operation at 850 nm offers advantages in material loss for photonic integrated sensors.