Efficient coupling between dielectric-loaded plasmonic and silicon photonic waveguides.

Area of Science:

• Photonics
• Nanotechnology
• Materials Science

Background:

• Practical on-chip plasmonic devices require efficient light coupling into and out of surface plasmon waveguides.
• Achieving this over short length scales is a significant challenge in integrated photonics.

Purpose of the Study:

• To report on low insertion loss for polymer-on-gold dielectric-loaded plasmonic waveguides end-coupled to silicon-on-insulator waveguides.
• To determine the propagation loss of these plasmonic waveguides independently.
• To demonstrate efficient coupling to plasmonic ring resonators.

Main Methods:

• End-coupling of polymer-on-gold dielectric-loaded plasmonic waveguides to silicon-on-insulator waveguides.
• Measurement of transmission through plasmonic waveguides of varying lengths to determine propagation loss.
• Characterization of coupling to whispering-gallery modes in plasmonic ring resonators.

Main Results:

• Achieved a coupling efficiency of 79 ± 2% per transition at telecommunication wavelengths.
• Determined a characteristic surface-plasmon propagation length of 51 ± 4 μm at λ = 1550 nm.
• Demonstrated efficient coupling to whispering-gallery modes with an average bending-loss-limited quality factor of 180 ± 8.

Conclusions:

• The demonstrated low insertion and propagation losses are promising for practical on-chip plasmonic devices.
• Efficient coupling to plasmonic waveguides and resonators is achievable at telecommunication wavelengths.
• These findings contribute to the development of integrated photonic circuits utilizing surface plasmons.