Electrically tunable Bragg gratings in single-mode polymer optical fiber

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Polymer Science

Background:

• Fiber Bragg gratings (FBGs) are crucial optical components for sensing and telecommunications.
• Existing tunable FBG devices often involve complex or bulky mechanisms.
• Polymer optical fibers offer flexibility and cost-effectiveness but present unique fabrication challenges.

Purpose of the Study:

• To demonstrate the first tunable fiber Bragg grating (FBG) device fabricated on polymer optical fiber.
• To utilize a surface-deposited thin-film resistive heater for wavelength tuning.
• To characterize the performance of the polymer FBG device under joule heating.

Main Methods:

• Fabrication of a polymer optical fiber FBG.
• Deposition of a Palladium/Copper (Pd/Cu) metallic layer using photochemical deposition induced by vacuum-ultraviolet radiation at room temperature.
• Integration of a thin-film resistive heater onto the fiber surface.
• Wavelength tuning of the FBG using joule heating and characterization of its response.

Main Results:

• Successful fabrication of a tunable FBG device on polymer optical fiber.
• Achieved a wavelength shift of 2 nm with a moderate input power of 160 mW.
• Determined a wavelength-to-input power coefficient of -13.4 pm/mW.
• Measured a time constant of 1.7 s(-1) for the device response.

Conclusions:

• The developed device represents the first tunable FBG on polymer optical fiber using a surface-deposited thin-film heater.
• The device exhibits efficient wavelength tuning capabilities via joule heating.
• This technology holds promise for flexible, cost-effective tunable optical fiber devices.