Optical Micro/Nanofiber Enabled Multiaxial Force Sensor for Tactile Visualization and Human-Machine Interface.

Tactile sensors with capability of multiaxial force perception play a vital role in robotics and human-machine interfaces. Flexible optical waveguide sensors have been an emerging paradigm in tactile sensing due to their high sensitivity, fast response, and antielectromagnetic interference. Herein, a flexible multiaxial force sensor enabled by U-shaped optical micro/nanofibers (MNFs) is reported.

Fully forward mode training for optical neural networks.

Optical computing promises to improve the speed and energy efficiency of machine learning applications. However, current approaches to efficiently train these models are limited by in silico emulation on digital computers. Here we develop a method called fully forward mode (FFM) learning, which implements the compute-intensive training process on the physical system.

On-chip silicon electro-optical modulator with ultra-high extinction ratio for fiber-optic distributed acoustic sensing.

Ultra-high extinction ratio (ER) optical modulation is crucial for achieving high-performance fiber-optic distributed acoustic sensing (DAS) for various applications. Bulky acousto-optical modulators (AOM) as one of the key devices in DAS have been used for many years, but their relatively large volume and high power consumption are becoming the bottlenecks to hinder the development of ultra-compact and energy-efficient DAS systems that are highly demanded in practice. Here, an on-chip silicon electro-optical modulator (EOM) based on multiple coupled microrings is demonstrated with ultra-high ER of up to 68 dB while the device size and power consumption are only 260 × 185 μm and 3.

On-chip wavefront shaping in spacing-varied waveguide arrays.

The ability to manipulate light propagation sets the foundations for optical communication and information processing systems. With the ever-growing data capacity and data rate, photonic integrated circuits have attracted increasing attentions of researchers owing to their large-volume integration capacity and fast operation speed. In this work, we proposed and experimentally demonstrated a new wavefront shaping method using waveguide arrays with hyperbolic secant refractive index profiles.

Ultrafast dynamic machine vision with spatiotemporal photonic computing.

Ultrafast dynamic machine vision in the optical domain can provide unprecedented perspectives for high-performance computing. However, owing to the limited degrees of freedom, existing photonic computing approaches rely on the memory's slow read/write operations to implement dynamic processing. Here, we propose a spatiotemporal photonic computing architecture to match the highly parallel spatial computing with high-speed temporal computing and achieve a three-dimensional spatiotemporal plane.

Low loss, flexible single-mode polymer photonics.

Single-mode polymer photonics is of significant interest to short-reach data communications, photonic packaging, sensing, and biophotonic light delivery. We report here experimental demonstration of mechanically flexible waveguides fabricated by using commercial off-the-shelf biocompatible polymers that claim a record low propagation loss of 0.11 dB/cm near 850 nm wavelength.

CdTe microwires as mid-infrared optical waveguides.

Cadmium telluride (CdTe) has been proven to be an attractive mid-infrared (MIR) material with a large refractive index (~2.68 at 4.5 μm) and broadband transparency (~1 to 25 μm).

2D Materials for Optical Modulation: Challenges and Opportunities.

Owing to their atomic layer thickness, strong light-material interaction, high nonlinearity, broadband optical response, fast relaxation, controllable optoelectronic properties, and high compatibility with other photonic structures, 2D materials, including graphene, transition metal dichalcogenides and black phosphorus, have been attracting increasing attention for photonic applications. By tuning the carrier density via electrical or optical means that modifies their physical properties (e.g.

Single CdTe Nanowire Optical Correlator for Femtojoule Pulses.

On the basis of the transverse second harmonic generation (TSHG) in a highly nonlinear subwavelength-diameter CdTe nanowire, we demonstrate a single-nanowire optical correlator for femto-second pulse measurement with pulse energy down to femtojoule (fJ) level. Pulses to be measured were equally split and coupled into two ends of a suspending nanowire via tapered optical fibers. The couterpropagating pulses meet each other around the central area of the nanowire, and emit TSHG signal perpendicular to the axis of the nanowire.

Graphene decorated microfiber for ultrafast optical modulation.

We demonstrate ultrafast optical modulation using a single 1-μm-diameter graphene-decorated microfiber, which is fabricated with a convenient and controllable evanescent-field-induced deposition method. Benefitting from the significantly enhanced light-graphene interaction of the subwavelength transvers dimension of the microfiber and accumulation of the saturable absorption of the piled graphene flakes, the microfiber shows nonlinear saturable absorption with a peak power threshold down to 1.75 W (60 MW/cm(2)), with a measured response time of about 3.

Graphene coated ZnO nanowire optical waveguides.

We report the fabrication and characterization of freestanding graphene coated ZnO nanowires (GZNs) for optical waveguiding. The GZNs are fabricated using a tape-assist transfer under micromanipulation. Owing to the deep-subwavelength diameter and high index contrast of the ZnO nanowire waveguide, light-graphene interaction is significantly enhanced by the strong surface optical fields, resulting in a linear absorption as high as 0.

Hybrid photon-plasmon nanowire lasers.

Metallic and plasmonic nanolasers have attracted growing interest recently. Plasmonic lasers demonstrated so far operate in hybrid photon-plasmon modes in transverse dimensions, rendering it impossible to separate photonic from plasmonic components. Thus only the far-field photonic component can be measured and utilized directly.