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We demonstrate two-dimensional optical lattice generation at 1064nm wavelength using vertically embedded multimode-interference (MMI) square-core polymer waveguides on a silicon chip. We demonstrate tuning of the effective waveguide length by longitudinally offsetting the waveguide input end-face from the input beam waist. Our measurement results of the waveguides with different cross-sectional dimensions at different effective waveguide lengths exhibit lattice patterns spanning from 4 × 4 to 10 × 10 arrays at the waveguide output end-face. Our theoretical analysis reveals that the offset causes additional mode-dependent phase changes. Our numerical modeling results using the three-dimensional beam-propagation method are consistent with our experimental results and theory.

We report on-chip optical lattice generation using SU8-filled vertically embedded multimode-interference waveguides in a silicon substrate. We show stretching of rabbit red blood cells using the generated optical lattices in a fluidic channel.

We illustrate a 2×2 quantum photonic switch fabric using two-photon quantum interference in an integrated silicon microring resonator array. Our modeling demonstrates phase- or wavelength-selective routing of single photons at different output states.

Silicon nitride (SiN) is a promising material platform for integrating photonic components and microfluidic channels on a chip for label-free, optical biochemical sensing applications in the visible to near-infrared wavelengths. The chip-scale SiN-based optofluidic sensors can be compact due to a relatively high refractive index contrast between SiN and the fluidic medium, and low-cost due to the complementary metal-oxide-semiconductor (CMOS)-compatible fabrication process. Here, we demonstrate SiN-based integrated optofluidic biochemical sensors using a coupled-resonator optical waveguide (CROW) in the visible wavelengths. The working principle is based on imaging in the far field the out-of-plane elastic-light-scattering patterns of the CROW sensor at a fixed probe wavelength. We correlate the imaged pattern with reference patterns at the CROW eigenstates. Our sensing algorithm maps the correlation coefficients of the imaged pattern with a library of calibrated correlation coefficients to extract a minute change in the cladding refractive index. Given a calibrated CROW, our sensing mechanism in the spatial domain only requires a fixed-wavelength laser in the visible wavelengths as a light source, with the probe wavelength located within the CROW transmission band, and a silicon digital charge-coupled device (CCD) / CMOS camera for recording the light scattering patterns. This is in sharp contrast with the conventional optical microcavity-based sensing methods that impose a strict requirement of spectral alignment with a high-quality cavity resonance using a wavelength-tunable laser. Our experimental results using a SiN CROW sensor with eight coupled microrings in the 680nm wavelength reveal a cladding refractive index change of ~1.3 × 10^-4 refractive index unit (RIU), with an average sensitivity of ~281 ± 271 RIU-1 and a noise-equivalent detection limit (NEDL) of 1.8 ×10^-8 RIU ~ 1.0 ×10^-4 RIU across the CROW bandwidth of ~1 nm.

Chip-scale, optical microcavity-based biosensors typically employ an ultra-high-quality microcavity and require a precision wavelength-tunable laser for exciting the cavity resonance. For point-of-care applications, however, such a system based on measurements in the spectral domain is prone to equipment noise and not portable. An alternative microcavity-based biosensor that enables a high sensitivity in an equipment-noise-tolerant and potentially portable system is desirable. Here, we demonstrate the proof-of-concept of such a biosensor using a coupled-resonator optical-waveguide (CROW) on a silicon-on-insulator chip. The sensing scheme is based on measurements in the spatial domain, and only requires exciting the CROW at a fixed wavelength and imaging the out-of-plane elastic light-scattering intensity patterns of the CROW. Based on correlating the light-scattering intensity pattern at a probe wavelength with the light-scattering intensity patterns at the CROW eigenstates, we devise a pattern-recognition algorithm that enables the extraction of a refractive index change, Δn, applied upon the CROW upper-cladding from a calibrated set of correlation coefficients. Our experiments using an 8-microring CROW covered by NaCl solutions of different concentrations reveal a Δn of ~1.5 × 10(-4) refractive index unit (RIU) and a sensitivity of ~752 RIU(-1), with a noise-equivalent detection limit of ~6 × 10(-6) RIU.