Polymer/silica hybrid integration waveguide Bragg grating based on surface plasmon polaritons.

Area of Science:

• Photonics and Nanophotonics
• Integrated Optics
• Plasmonics

Background:

• Surface plasmon polaritons (SPPs) offer unique light confinement properties.
• Bragg gratings are essential for wavelength-selective optical devices.
• Integrating SPP waveguides with gratings enables advanced photonic functionalities.

Purpose of the Study:

• To design and fabricate a novel device integrating a Bragg grating with a long-range surface plasmon polariton waveguide.
• To characterize the optical transmission and reflection properties of the proposed device.
• To investigate the thermal tunability of the device's spectral response.

Main Methods:

• Fabrication of a corrugated silica substrate using contact lithography and ICP etching.
• Formation of a long-range SPP waveguide using a thin gold stripe embedded in SU-8 2005 photoresist.
• Transfer of the grating structure onto the SU-8 2005 film via spin coating.
• Optical characterization of transmission and reflection spectra, including thermal tuning experiments.

Main Results:

• Achieved a transmission peak with a 17 dB extinction ratio and 0.9 nm 3-dB bandwidth at 1575.2 nm.
• Observed a reflection peak with a 9.7 dB side-mode suppression ratio and 0.9 nm 3-dB bandwidth.
• Demonstrated a thermal shift of the reflection peak by 2.9 nm for a heating power range of 0-6 mW.
• Quantified the thermal dependence with an average slope of -0.48 nm/mW.

Conclusions:

• The proposed device successfully integrates Bragg grating and SPP waveguide functionalities.
• The device exhibits high-performance optical filtering characteristics.
• The demonstrated thermal tunability offers potential for active optical control and sensing applications.