Generation of slow intense optical solitons in a resonance photonic crystal

We demonstrate interesting and previously unforeseen properties of a pair of gap solitons in a resonant photonic crystal which are predicted and explained in a physically transparent form using both analytical and numerical methods. The most important result is the fact that an oscillating gap soliton created by the presence of a localized population inversion inside the crystal can be manipulated by means of a proper choice of bit rate, phase and amplitude modulation. Developing this idea, we are able to obtain qualitatively different regimes of a resonant photonic crystal operation. In particular, a noteworthy observation is that both the delay time and amplitude difference must exceed a certain level to ensure effective control over the soliton dynamics

Polarization-entangled photon pair sources based on spontaneous four wave mixing assisted by polarization mode dispersion

Photonic-based qubits and integrated photonic circuits have enabled demonstrations of quantum information processing (QIP) that promises to transform the way in which we compute and communicate. To that end, sources of polarization-entangled photon pair states are an important enabling technology, especially for polarization-based protocols. However, such states are difficult to prepare in an integrated photonic circuit. Scalable semiconductor sources typically rely on nonlinear optical effects where polarization mode dispersion (PMD) degrades entanglement. Here, we directly generate polarization-entangled states in an AlGaAs waveguide, aided by the PMD and without any compensation steps. We perform quantum state tomography and report a raw concurrence as high as 0.91$\pm$0.01 observed in the 1100-nm-wide waveguide. The scheme allows direct Bell state generation with an observed maximum fidelity of 0.90$\pm$0.01 from the 800-nm-wide waveguide. Our demonstration paves the way for sources that allow for the implementation of polarization-encoded protocols in large-scale quantum photonic circuits

Highly Efficient Excitation of Surface Plasmons Using a Si Gable Tip

A compact and highly efficient technique to excite SPP mode at an Au/SiO2 interface by using an engineered high index (silicon) gabled tip at the 1550 nm wavelength has been proposed. The optimized geometry of the Si tip enables a highly efficient excitation of the single interface SPP mode through near field interaction in an ultra-compact setup. An experimental demonstration of the proposed scheme is also presented in the paper which converts 25.5% of the total input power to an SPP mode. With an improved fabrication, this efficiency can reach as high as 52%. The device is compact, facilitates on-chip excitation of the SPP, its fabrication is compatible with the standard Si fabrication processes, and, as such it is expected to be very useful in the design of future integrated photonic circuits as well as integrated sensors. Also, this scheme can find applications in studying nonlinear characteristics of materials

Polarization rotator based on augmented low-index-guiding waveguide on silicon nitride/silicon-on-insulator platform

Using a newly proposed augmented low-index-guiding scheme with silicon nitride/silicon dual-core waveguide, we have designed, fabricated, and characterized a transverse electric (TE) to transverse magnetic (TM) and TM-to-TE compact polarization rotator. The polarization rotation is realized in an asymmetric directional coupler. The measured peak conversion efficiencies for the TE-to-TM and TM-to-TE rotations are approximately 97%. The measured polarization extinction ratio for the TE-to-TM rotation is greater than 20 dB over 50-nm bandwidth, while for the TM-to-TE rotation it is greater than 15 dB over the C-band

Vertically integrated spot-size converter in AlGaAs-GaAs

We report on the demonstration of a spot size converter (SSC) for monolithic photonic integration at a wavelength of 850 nm on a GaAs substrate. We designed and fabricated a dual-waveguide AlGaAs chip. The design consists of a lower waveguide layer for efficient end-fire coupling to a single-mode fiber, an upper waveguide layer for high refractive index contrast waveguides, and a vertical SSC to connect the two waveguide layers. We measured a SSC conversion efficiency of 91% (or −0.4  dB) between the upper and lower waveguide layers for the TE mode at a wavelength of 850 nm

LED excitation of an on-chip imaging flow cytometer for bead-based immunoassay

A green LED is demonstrated to generate a uniform square illumination pattern for an on-chip imaging flow cytometer system. The proposed system is used to perform the detection of a bead-based immunoassay for a sepsis biomarker, procalcitonin

Microchip imaging cytometer: making healthcare available, accessible, and affordable

The Microchip Imaging Cytometer (MIC) is a class of integrated point-of-care detection systems based on the combination of optical microscopy and flow cytometry. MIC devices have the attributes of portability, cost-effectiveness, and adaptability while providing quantitative measurements to meet the needs of laboratory testing in a variety of healthcare settings. Based on the use of microfluidic chips, MIC requires less sample and can complete sample preparation automatically. Therefore, they can provide quantitative testing results simply using a finger prick specimen. The decreased reagent consumption and reduced form factor also help improve the accessibility and affordability of healthcare services in remote and resource-limited settings. In this article, we review recent developments of the Microchip Imaging Cytometer from the following aspects: clinical applications, microfluidic chip integration, imaging optics, and image acquisition. Following, we provide an outlook of the field and remark on promising technologies that may enable significant progress in the near future

Highly Efficient Excitation of Surface Plasmons Using a Si Gable Tip

A compact and highly efficient technique to excite SPP mode at an Au/SiO2 interface by using an engineered high index (silicon) gabled tip at the 1550 nm wavelength has been proposed. The optimized geometry of the Si tip enables a highly efficient excitation of the single interface SPP mode through near field interaction in an ultra-compact setup. An experimental demonstration of the proposed scheme is also presented in the paper which converts 25.5% of the total input power to an SPP mode. With an improved fabrication, this efficiency can reach as high as 52%. The device is compact, facilitates on-chip excitation of the SPP, its fabrication is compatible with the standard Si fabrication processes, and, as such it is expected to be very useful in the design of future integrated photonic circuits as well as integrated sensors. Also, this scheme can find applications in studying nonlinear characteristics of materials