Disorder effects in subwavelength grating metamaterial waveguides

Area of Science:

• Integrated photonics
• Metamaterials
• Silicon photonics

Background:

• Subwavelength grating (SWG) waveguides utilize pitches smaller than the wavelength to suppress diffraction.
• SWGs act as artificial metamaterials with tunable refractive indices based on geometry and polarization.
• SWG waveguides offer performance enhancements in silicon photonics for devices like couplers and sensors.

Purpose of the Study:

• To investigate the influence of disorder effects on SWG waveguides.
• To analyze the impact of segment position and size jitter on waveguide transmittance.
• To correlate disorder effects with modal confinement in SWG structures.

Main Methods:

• Electromagnetic simulations
• Experimental measurements
• Theoretical analysis of disorder effects

Main Results:

• A small jitter (~5 nm) in SWG segment position/size dramatically reduces transmittance in wide (multimode) SWG waveguides.
• The effect of jitter on transmittance is negligible for narrow (single mode) SWG waveguides.
• The impact of jitter is directly related to the modal confinement of the SWG waveguide.

Conclusions:

• Disorder, specifically jitter, is a critical factor affecting SWG waveguide performance.
• Modal confinement dictates the sensitivity of SWG waveguides to fabrication imperfections.
• Understanding these disorder effects is crucial for the reliable design of SWG-based photonic devices.