Optimization of Y-splitting antiresonant reflecting optical waveguides-based rib waveguides

Antiresonant reflecting optical waveguide power splitters, designed for use around the 635-nm wavelength, are characterized for multiple split angles ranging from 0.5 deg to 9 deg. Theoretical expectations and simulations predict lowest transmission losses at this split junction for the lowest angles. This is confirmed by the experimental structures built in SiO₂ films on silicon substrates. A fabrication nonideality affects the achievable splitting angle. Design considerations are discussed based on tradeoffs between loss and the required length for a Y-splitter.

Signal-to-noise Enhancement in Optical Detection of Single Viruses with Multi-spot Excitation

We present fluorescence detection of single H1N1 viruses with enhanced signal to noise ratio (SNR) achieved by multi-spot excitation in liquid-core anti-resonant reflecting optical waveguides (ARROWs). Solid-core Y-splitting ARROW waveguides are fabricated orthogonal to the liquid-core section of the chip, creating multiple excitation spots for the analyte. We derive expressions for the SNR increase after signal processing, and analyze its dependence on signal levels and spot number. Very good agreement between theoretical calculations and experimental results is found. SNR enhancements up to 5x10⁴ are demonstrated.