Long-period gratings in polymer ridge waveguides

Area of Science:

• Photonics and optical engineering.
• Waveguide grating fabrication and characterization.
• Materials science of polymers for optical applications.

Background:

• Long-period waveguide gratings (LPWGs) are crucial components in optical signal processing.
• Benzocyclobutene (BCB) is a polymer with desirable optical properties for waveguide fabrication.
• Understanding LPWG behavior in BCB waveguides is essential for developing advanced photonic devices.

Purpose of the Study:

• To design and fabricate LPWGs in BCB ridge waveguides.
• To analyze the optical characteristics of these LPWGs using perturbation theory.
• To demonstrate a polarization-insensitive LPWG for specific applications.

Main Methods:

• Accurate perturbation theory for analyzing LPWG properties.
• UV-writing technique utilizing a KrF excimer laser for fabrication.
• Transmission spectra measurement and analysis of fabricated gratings.

Main Results:

• Successful design and fabrication of LPWGs in BCB ridge waveguides.
• Detailed analysis of phase-matching, coupling coefficients, and spectral properties.
• Demonstration of an LPWG with polarization-insensitive resonance wavelength at a specific temperature.
• Experimental results show excellent agreement with theoretical predictions.

Conclusions:

• The developed perturbation theory accurately predicts LPWG behavior in BCB waveguides.
• Fabricated LPWGs exhibit tunable characteristics, including polarization dependence.
• The demonstrated polarization-insensitive LPWG is a significant step towards practical photonic device realization.
• These findings provide valuable insights for designing LPWG-based optical devices.