Silicon photonics is increasingly used in an array of communications and computing applications. In many applications, photonic chips must be coupled to optical fibers, which remains challenging due to the size mismatch between the on-chip photonics and the fiber itself. Existing approaches suffer from low alignment tolerance, sensitivity to fabrication variations, and complex processing, all of which hinder mass manufacture.To address these problems, researchers at UC Berkeley have developed a coupling mechanism between a silicon integrated photonic circuit and an optical fiber which uses a microlens to direct and collimate light into the fiber. Researchers have demonstrated that this device can achieve low coupling loss at large alignment tolerances, with an efficient and scalable manufacturing process analogous to existing manufacture of electronic integrated circuits. In particular, because the beam is directed above the silicon chip, this method obviates dry etching or polishing of the edge of the IC and allows the silicon photonics to be produced by dicing in much the same way as present electronic integrated circuits.

Researchers at UC Irvine have developed a novel optical fiber technology that uses newly developed “zero-refractive index” material as a guiding medium, overcoming the significant limitations of conventional optical fiber where light properties are limited by glass core material. This novel technology will dramatically improve optical communication transmission speed and power by orders of magnitude.

The inventors have developed a scalable laser aperture that emits light perpendicular to the surface. The aperture can, in principal, scale to arbitrarily large sizes, offering a universal architecture for systems in need of small, intermediate, or high power. The technology is based on photonic crystal apertures, nanostructured apertures that exhibit a quasi-linear dispersion at the center of the Brillouin zone together with a mode-dependent loss controlled by the cavity boundaries, modes, and crystal truncation. Open Dirac cavities protect the fundamental mode and couple higher order modes to lossy bands of the photonic structure. The technology was developed with an open-Dirac electromagnetic aperture, known as a Berkeley Surface Emitting Laser (BKSEL).  The inventors demonstrate a subtle cavity-mode-dependent scaling of losses. For cavities with a quadratic dispersion, detuned from the Dirac singularity, the complex frequencies converge towards each other based on cavity size. While the convergence of the real parts of cavity modes towards each other is delayed, going quickly to zero, the normalized complex free-spectral range converge towards a constant solely governed by the loss rate of Bloch bands. The inventors show that this unique scaling of the complex frequency of cavity modes in open-Dirac electromagnetic apertures guarantees single-mode operation of large cavities. The technology demonstrates scaled up single-mode lasing, and confirmed from far-field measurements. By eliminating limits on electromagnetic aperture size, the technology will enable groundbreaking applications for devices of all sizes, operating at any power level. BACKGROUND Single aperture cavities are bounded by higher order transverse modes, fundamentally limiting the power emitted by single-mode lasers, as well as the brightness of quantum light sources. Electromagnetic apertures support cavity modes that rapidly become arbitrarily close with the size of the aperture. The free-spectral range of existing electromagnetic apertures goes to zero when the size of the aperture increases. As a result, scale-invariant apertures or lasers has remained elusive until now.  Surface-emitting lasers have advantages in scalability over commercially widespread vertical-cavity surface-emitting lasers (VCSELs). When a photonic crystal is truncated to a finite cavity, the continuous bands break up into discrete cavity modes. These higher order modes compete with the fundamental lasing mode and the device becomes more susceptible to multimode lasing response as the cavity size increases. 

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Researchers at the University of California, Davis have developed an optical transceiver that uses compressive sensing to reduce bandwidth requirements and improve signal resolution.

Researchers at the University of California, Davis have developed a reconfigurable radiator array that produces a high frequency directed beam via uninterrupted, scalable, electronic beam steering.

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Researchers at the University of California, Davis have developed a new class of lasers and amplifiers that uses a CMOS-compatible electronics platform - and can also be applied to nano-amplifiers and nano-lasers applications.

Electromagnetic noise from surfaces is one of the limiting factors for the performance of solid state and trapped ion quantum information processing architectures. This noise introduces gate errors and reduces the coherence time of the systems. Accordingly, there is great commercial interest in reducing the electromagnetic noise generated at the surface of these systems.Surface treatment using ion bombardment has shown to reduce electromagnetic surface noise by two orders of magnitude. In this procedure ions usually from noble gasses are accelerated towards the surface with energies of 300eV to 2keV. Until recently, commercial ion guns have been repurposed for surface cleaning. While these guns can supply the ion flux and energy required to prepare the surface with the desired quality, they are bulky and limit the laser access, making them incompatible with the requirements for ion trap quantum computing.To address this limitation, UC Berkeley researchers have developed an ion gun that enables in-situ surface treatment without sacrificing high optical access, enabling in situ use with a quantum information processor.

Researchers at the University of California, Davis have developed a nanolaser platform built from materials that do not exhibit optical gain.

Researchers at the University of California, Davis have developed a method for ultra-wideband and highly precise, photonic-electronic, signal processing. This technology is capable of high-speed, real-time signal correlation/processing by exploiting RF-photonics, ultra-stable optical frequency combs and high precision electronics.

Researchers at the University of California, Davis have developed a hierarchical optical switch architecture that is low latency and energy efficient.

Researchers at the University of California, Davis have developed a multi-wavelength, laser array that generates more precise wavelengths than current technologies. The array also delivers narrow linewidths and can operate athermally.

Researchers at the University of California, Davis have developed a nanophotonic-based platform for signal processing and optical computing in algorithm-based neural networks that is faster and more energy-efficient than current technologies.

Researchers at the University of California, Davis have developed nonreciprocal and reconfigurable phased-array antennas with demonstrated advantages over competing, current technologies.

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The widespread adoption of visible light communication (VLC) systems based on light emitting diode (LED) transmitters requires the simultaneous increase in efficiency and speed of the optical source. Efficiency is measured by the external quantum efficiency while speed is quantified by the 3dB modulation bandwidth. Most research on the indium gallium nitride (InGaN) system has focused on improving the EQE because this metric, and its dependence on injection current density is an important factor for the growth of LEDs as illumination source for general lighting purposes. The modulation rate of LEDs is however poised to grow in importance due to the need to couple information processing with illumination. An LED with GHz modulation bandwidth, incorporated as light source in an optical transceiver, can enable a plethora of VLC applications: from chip-to-chip wireless communications in data centers to smart automotive lighting, from safe and RF interference-free wireless local area networks in hospitals and offices to underwater optical communications for the exploration, inspection and maintenance of offshore oil

Hyperbolic metasurfaces (HMS) merge the exotic properties of hyperbolic metamaterials with the potential for lower losses and better device coupling offered by planar metasurfaces. Despite use of single-crystalline silver (Ag), HMS remain inherently lossy, limiting potential applications. Recent work has suggested that Ag could be combined with indium gallium arsenide phosphide (InGaAsP) multiple quantum wells (MQW) to enable transparent propagation of signals through waveguides and multilayers. Described here is the first experimental demonstration of a luminescent HMS (LuHMS) based on nanostructured (NS) Ag/InGaAsP MQW.  

Object detection and ranging is a fundamental task for several applications such as autonomous vehicles, atmospheric observations, 3D imaging, topography and mapping. UCI researchers have developed a light detection and ranging (LIDAR) system which makes use of frequency modulated continuous waves (FMCW) with several simultaneous radiofrequency tones for improved speed of measurement while maintaining robust spatial information. 

UCLA researchers in the Department of Physics have developed a plasma opening switch that enables quick diversion of multi-gigawatt pulses to a protective shunt circuit.

Researchers at the University of California, Davis and NHanced Semiconductors have developed a new optical interposer solution for embedded photonics that have higher energy efficiency than the current pluggable optics solutions

Researchers at UCI have developed a novel method for encrypting optical communications, which is simpler, less expensive, and less computationally-demanding than standard solutions.