| Tech ID |
Title |
|
| 23277 |
All-To-All Interconnection With Wavelength Routing Devices
A method that uses wavelength routing devices such as arrayed waveguide grating routers (AWGR) and Echelle grating routers to realize a passive interconnection network with a reduced number of wavelengths to implement all-to-all interconnection.
(more...) |
| | 23031 |
Universal Mobile Phone Adaptor For Taking Pictures Through Ocular Devices ("Eye Phone Dock")
The Eye Phone Dock is a universal smartphone adaptor for taking pictures or videos through an eyepiece of an optical device such as slit lamps, microscopes, and telescopes.
(more...) |
| | 22863 |
Sub-volt Electro-optic Modulator with 100 GHz Bandwidth
An electro-optic modulator with 100 GHz bandwidth that requires less than 1V to turn on and off.
(more...) |
| | 22745 |
Nanopillar Photonic Crystal Lasers
Currently, optical microcavity fabrication methods using nanowires require multiple material depositions and additional fabrication steps including precision alignment of the randomly placed nanowires. Further, such microcavities are relatively inefficient at trapping light and consequently require a threshold power of a factor of 1000 or more. Although there are lasers such as the vertical cavity surface emitting lasers (VCSELs) and "top-down" photonic-crystal lasers with higher performance measures, they require the use of thick semiconductor films and thus cannot be incorporated onto integrated circuits without extensive and low yield process steps.
(more...) |
| | 22739 |
Chromo-Modal Dispersive Device
The ability to control group velocity dispersion (GVD) is of paramount importance in applications where the width of an optical pulse is critical to the operation of an optical system. Typically, devices for generating large amounts (>100 ps/nm) of group velocity dispersion consist of either diffraction grating pairs spaced by large distances or long lengths of dispersion compensating optical fiber. Unfortunately, these types of dispersive elements often possess limited optical bandwidth, limited total dispersion, low peak power handling, or large spatial footprints.
(more...) |
| | 22683 |
Thresholdless Nanoscale Coaxial Lasers
Semiconductor lasers generate a large amount of undesired spontaneous emission before starting lasing oscillation, which degrades their efficiency and performance substantially. Therefore, lasers that emit almost no spontaneous emission have long been sought. Such 'thresholdless lasers', - where light output versus excitation power has no obvious threshold characteristic - lasing occurs at extremely low excitation powers. These lasers' superior performance is suited to optical applications. Currently there are two main approaches to designing nanolasers. The first utilizes dielectric based structures. Dielectrics have low loss at optical frequencies. There are, however, drawbacks in using dielectric-based nanolasers: they are either large in size or their mode extends far out of the gain region, and thus they exhibit poor gain-mode overlap. The other approach uses metal in a cavity. In recent years, nanoscale metallic, plasmonic, and metallo-dielectric cavities have shown to confine light in ultra-small volumes and to improve the gain-mode spatial overlap. However, existing metal-based nanolasers require high threshold pump power because of the significant absorption loss of the metals at optical frequencies.
(more...) |
| | 22640 |
Two All Optical Contention Resolution Solutions for Optical Networks
Two all-optical techniques for contention resolution in AWGR-based optical connections. Both inventions remove the need for electrical switches for contention resolution in an optical network.
(more...) |
| | 22639 |
Efficient Defragmentation Technique In Flexible Optical Networks
This invention achieves a highly efficient defragmentation of spectrum in an optical telecommunications network (quasi-hitless). Using this technique, spectrum may be completely defragmented between connections in less than 400 ns, regardless of how the spectrum is allocated initially and with ho need for global synchronization.
(more...) |
| | 22011 |
Removing Atmospheric Turbulence Effects For Videos
Atmospheric turbulence cause by variation of refractive index along the optical transmission path can strongly affect the performance of the long-distance imaging system. It produces geometric distortion, space-and-time-varient defocus blur, and motion blur (if the exposure time is not sufficiently short). Existing restoration algorithms for this problem can generally be divided into two main categories. The first is based on a multi-frame reconstruction framework and the other is known as “lucky exposure”. The main problem with multi-frame reconstruction algorithms is that in general they can hardly estimate the actual point spread function (PSF), which is spatially and temporally changing, hence limiting their performance. The “lucky exposure” approach employs image selection and fusion methods to reduce the blurring effects caused by turbulence. One shortcoming of this method is that even though turbulence caused blur is strongly alleviated through the fusion process, the output still suffers from blur caused by diffraction-limited PSF.
(more...) |
| | 22004 |
Micro Optical Waveguide Manufactured From Laminates
A cantilever waveguide fabricated from laminate materials and integrated onto a printed circuit board (PCB). New fabrication and packaging methods were also developed in creating an electro-optical sensor device.
(more...) |
| | 21880 |
Focus Stacking using Refined Index Map
Limited depth of field of a conventional imaging system can be a significant problem in many application areas, such as brightfield microscopy and macro photography. If the surface profile of an object is beyond the focal range, in a single shot only part of the surface can be sharp, while the rest areas are blurred. The spatially varying point-spread-function (PSF) is directly related with the depth map (object surface topography), the focal distance, and other camera settings. To extend the depth of field, a common method is to take a series of multi-focus images by gradually moving the focal plane, so that different parts of the object can be in focus in different images. Then a post process called focus stacking is carried out to generate an all-in-focus image by detecting and fusing the in-focus regions together from the observed multi-focus images. Generally such fusion algorithms take a similar scheme: (1) a local sharpness metric is defined and measured in every pixels within the image sequence; (2) at each position an image index is detected according to the highest sharpness measure, and an index map is then formed; (3) an all-in-focus image is generated based on the index map. However, most local sharpness metrics can be easily affected by image content and noise, producing an inaccurate index map that may affect the output image quality. For example, discontinuity of the index map frequently happens in the low signal-to-noise-ratio (SNR) regions (e.g. flat areas), and generates artifacts in the output. Smoothing the sharpness measure can somehow alleviate this problem, but also reduce the detection accuracy in the boundary regions leading to extra blur.
(more...) |
| | 21783 |
Novel Parametric Light Generator and Monochromator
Developed here is a fiber optical parametric amplifier to realize a wide-range tunable, high-sweep rate, frequency-swept light source. The invention provides for the following: Generation of fast, wide-band, wavelength swept light.Analysis of spectral content in arbitrary wavelength bands. Amplification and frequency conversion of selected spectral slices in a wideband optical signal.
(more...) |
| | 21459 |
Low-Voltage Near-Field Electrospinning Enables Controlled Continuous Patterning of Nanofibers on 2D and 3D Substrates
Researchers at the University of California, Irvine have developed a novel method to continuously pattern nanofibers on 2D and 3D substrates. A unique polymer ink formulation provides the right balance of viscosity and elasticity necessary to enable controlled, seamless near-field electrospinning of nanofibers at very low voltages.
(more...) |
| | 21295 |
Hybrid Silicon Integrated Optical Isolator and Circulator
A nonreciprocal ring resonator implemented in a ring isolator, which has the main advantages of miniaturization and integration with other optoelectronic devices. The isolator increases stability and reduces noise in optoelectronic circuits due to a high isolation ratio, which is measured at 9 dB in 1550 nm regime.
(more...) |
| | 21121 |
Inti Multiview - Real-Time Stereo Reconstruction Integration For 3D Teleimmersion
While teleimmersion has great potential, available algorithms for real-time stereo reconstruction require several seconds to several minutes to process two images and produce accurate stereo output. Available FPGA and GPU implementations have inherent drawbacks in ability to reconstruct homogenous regions or regions with repeating patterns. The time-of-flight cameras have low resolution, limited range, high noise, and albedo sensitivity. Therefore, a practical real-time stereo reconstruction is needed for a system enabling geographically distributed users to interact with each other in a shared virtual space. University of California investigators have responded to this challenge by developing INTI Multiview, a real-time stereo reconstitution integration for 3D telleimmersion. With INTI Multiview, each user is presented by their 3D avatar generated in real time. INTI Multiview focuses primarily on integrating multiple stereo reconstructions from different views. Levels of accuracy comparable to other methods are achieved at a much faster speed on CPU by taking a hybrid approach: performing a local optimization technique (the region matching) and using a global optimization approximation to improve the initial results (anisotropic diffusion). The investigators have implemented a novel multiscale representation that allows for the highly accurate reconstruction of a scene. The investigators have successfully tested INTI Multiview in many application areas, such as remote dance choreography, shared geoscientific and archeological applications, and training. This work has further extensions in other applications where real-time stereo data is necessary, e.g. full body motion capture, surveillance and tracking, foreground/background segmentation, autonomous vehicle control. Markerless 3D reconstruction for human movement analysis (motion capture, visual feedback for gaming, rehabilitation etc.)
(more...) |
| | 21120 |
Minimization Of 3D Distortion Through Frame Interpolation
Stereoscopic displays present different images to the two eyes by alternating the images on the display screen to be delivered to the left and right eyes. Even though the eyes do not receive images simultaneously, the presented images are typically captured simultaneously. This inconsistency between how the images are made and how they are presented can lead to undesirable effects, including motion jerkiness, flicker, and depth distortion. Investigators at University of California at Berkeley have addressed these challenges by developing a method that minimizes 3D distortions through frame interpolation. The 3D distortion minimization will yield a noticeable improvement in image appearance that will be sought after by consumers. The innovation uses motion-compensating frame-rate conversion (MCFRC) to offset the effective capture times of the incoming frames for one eye and thereby eliminate the inconsistency between the timing of capture and presentation to the two eyes. This yields images with less apparent flicker and jerkiness, but in particular, reduced depth distortion. UCB has a pending patent application on this technology.
(more...) |
| | 20919 |
Plasmon Laser at Deep Sub-Wavelength Scale
The data bandwidth needs of the 21st century rely on the progress of Photonic Integrated Circuits (PICs), which are able to provide ultra high bandwidths at low cost. PICs appeared as the result of miniaturization of discrete optical components, similar to the miniaturization of electrical components that caused a revolution in electronics. However, in case of PICs, the diffraction limit of light fundamentally restricts how small the components can be scaled. The most critical devices in PICs are electro-optical transducers, such as light sources and detectors, which convert electrical signals into optical ones and need to be fast, efficient, and integrable. While many PIC components have been successfully developed, the on-chip laser light source is still facing many challenges. Researchers at UC Berkeley invented a semiconductor plasmonic laser that surpasses the diffraction limit, offering true PIC scaling. The laser uses a hybrid plasmonic waveguide consisting of a semiconductor nanowire separated from a metal surface by a thin insulating gap. Because plasmonic modes have no cutoff, the lateral dimensions of both the device and the optical mode can be downscaled. This invention overcomes the difficulties encountered by previous attempts to use plasmons in creating a truly nano-scale laser and opens the door to constructing other types of optical transducers.
(more...) |
| | 20768 |
Snap-Action Bistable Micromechanism Actuated By Nonlinear Resonance
On a micro-scale, conventional switching devices using bistable structural elements are well-suited for relays and switches, addressable MEMS-based pixel arrays, tunable optical MEMS filters or microfluidic valves. However, the currently employed approaches all need high voltages applied to reach the threshold value force. A novel approach has been developed by researchers at UCI that address this need for high voltage.
(more...) |
| | 20396 |
Control Of Rogue Waves And Applications To Optical Supercontinuum Generation
Rogue waves are abnormally large, steep waves that appear unexpectedly in the open ocean. These waves are rare, and occur much more commonly than predicted by conventional wave models. Although the formation of these extreme waves is not fully understood, it is widely believed that nonlinearity plays a central role. In the past, the study of rogue waves has focused on hydrodynamic studies and experiments. However, there are other physical systems that possess similar nonlinear characteristics and may also support rogue waves. UCLA researchers have discovered that rogue waves can arise in optics, and can be harnessed for applications.
(more...) |
| | 18848 |
A Broadband Amplifier with Huge Gain-bandwidth Product and Low Power Consumption
Without a distributed amplifier, most broadband amplifier bandwidths can be achieved around 1/10 to 1/3 of their fT only. Therefore, a high bandwidth amplifier requires high fT (at least 3-10 times of the amplifier bandwidth) transistors in order to achieve high bandwidth. Unfortunately, the current device technology is limited and in very high fT transistors, yield is still low. This leads to high cost and low yield.Even if high gain-bandwidth product could be achieved by a distributed amplifier, the major disadvantages of the distributed amplifier are large area, and high dc power consumption. Transistors were operated with high current density for high fT in order to achieve high bandwidth amplification. However, the transistors would become highly stressed resulting in reliability problems and short lifetimes. 50 ohm terminations are currently employed at the input and output of broadband amplifiers in order to obtain desirable input and output broadband impedance matches (low S11 and S22). However, the disadvantage is 3-dB losses at theirs inputs and outputs.
(more...) |
| | 18509 |
Methods For Increased Channel Capacity Beyond Cdma
CDMA (Code-Division Multiple Access) was introduced in 1989 as an attractive method to increase the capacity per Hz of spectrum over TDMA (Time-Domain Multiple Access). Increased capacity per communication channel results in a greater number of users able to share the same bandwidth. This in turn enables communications service providers to handle more subscribers with the same bandwidth. Researchers at the University of California at Berkeley have advanced the CDMA technology to further increase channel capacity by a factor of 2. By applying non-linear digital signals to the carrier, the transmitted energy is spread more evenly and more densely over the bandwidth.
(more...) |
| | 18357 |
Method And Apparatus For Scheduling Cells In An Input Queued Switch
Researchers at the University of California, Berkeley have developed a new method and apparatus for scheduling cells in high-bandwidth input-queued switches used in arbitrary topology cell-based local area networks, such as ATM networks. The scheduling mechanism represents the performance bottleneck in most high throughput switches. The scheduler developed at Berkeley provides significant improvements over current scheduling techniques such as Parallel Iterative Matching (PIM). The PIM technique grants and selects input queue requests based upon randomness, whereas the UC Berkeley method is based upon a rotative priority iterative matching desynchronization (RPIMD) algorithm, which, as its name implies, selects the input request with the current highest priority and increments the designation of the highest priority after each iteration. This method results in substantially reducing computational overhead. It also allows the switch to operate at a higher rate than with a PIM scheduler, by converging in a single operation. Moreover the rotating principle reduces the burtiness at arriving traffic, thus reducing queuing delay.
(more...) |
| | 18056 |
Ultra-low Loss Hollow-core Waveguides
The ability to generate long optical delays with low intrinsic loss is useful for a wide range of applications including optical signal processors, RF filtering, optical buffers, and optical sensing. Optical fibers have been used for these applications with advantages such as ultra-low loss, dispersion and nonlinearity and an exceedingly large bandwidth. However, they are bulky, heavy, and lack of manufacturing scalability. Lithographically defined, chip-scale waveguides have been reported in SiO2/Si and III-V material systems. They are desirable because they are compact, light-weight, and can be integrated with other optoelectronic devices. The lowest reported loss achieved to-date in chip-based waveguides is on the order of 1 dB/m, three to four orders of magnitude higher than that of optical fibers. This loss is unacceptably high for most applications requiring 0.01 dB/m. The fundamental reasons for the high losses are direct band-edge absorption, free carrier absorption, and absorption due to interaction with optical phonons. In addition, these devices are expected to have high nonlinearity and dispersion. To address these limitations, Researchers at UC Berkeley have invented a novel ultra-low loss hollow-core waveguide structure. The new structure provides unprecedented mirror reflectivity and fabrication tolerance. The design can achieve exceedingly low propagation loss that cannot be achieved by conventional waveguide concepts. In addition, the researchers show a potential 2D design with loss estimated to be less than 0.01 dB/m.
(more...) |
| | 17311 |
Broad Bandwidth And Highly Reflective Gratings
Broadband mirrors with very high reflectivity are essential for applications such as telecommunications, surveillance, sensors and imaging. Among the various conventional mirror designs, metal mirrors have larger reflection bandwidths but lower reflectivities; as a result they are not suitable for fabricating transmission-type optical devices such as etalon filters. Dielectric distributed Bragg reflectors (DBRs) can achieve a higher reflectivity but deposition methods for DBRs are often not precise enough to yield the reflectivities of 99% or better needed for demanding applications, and typical material combinations constrain the mirror bandwidth and can be incompatible with conventional semiconductor processing technologies. In addition the tuning range is often limited for tunable etalon type devices such as MEM vertical cavity surface emitting lasers (VCSELs), filters, and detectors. There is a need for a mirror with broadband reflection, low loss, and compatibility with conventional optoelectronic processing methods. Researchers at the UC Berkeley have developed a single layer, sub-wavelength grating with a very broad reflection spectrum and very high reflectivity. The grating design facilitates monolithic integration of optoelectronic devices at a wide range of wavelengths from visible to far infrared, as well as integration with electronic circuits and other optoelectronic devices. Grating spectral characteristics can be tailored by choice of materials and structure to maximize both reflectivity and spectral coverage. The grating design developed at Berkeley has potential application in MEM tunable devices and reconfigurable focal plane arrays for such high value applications as optical communications, chemical/biological sensors, and imaging.
(more...) |
| | 17253 |
Electrostatic Microactuator For Phase Micromirror Arrays
Micromirror arrays represent a huge market opportunity in a variety of sectors from optical displays, scanners and communication switches, to maskless lithography and optical spectroscopy. In the conventional design of these arrays, mirrors are mounted on tiltable cantilevers. However, in high frequency and analog applications a phased-mirror approach would be more useful. In this design, mirrors are shifted perpendicular to plane of the array to produce an image by interference effects. Unfortunately, no practical solution has been proposed to fabricate an electrostatically actuated dense array of phase micromirrors of micrometer size. To address this problem, researchers at the University of California at Berkeley have developed a MEMS-based microactuator for phase micromirror arrays. This electrostatic microactuator supports a rigid micromirror that is compliant only in the vertical direction. The fundamental advantage of this Berkeley microactator is that it can be manufactured by conventional MEMS fabrication techniques using standard semiconductor patterning and thin-film deposition processes. This low voltage actuator is conducive to fabricating flat and dense mirror arrays -- which is highly desirable in optical systems. Moreover, the device limits the range of actuation to prevent snap-down, and also provides damping to suppress mirror vibration.
(more...) |
| | 17247 |
Optical Coupling Technology
The Regents of the University of California has available for licensing a significant portfolio of patents related to optical coupling technology. Patent No. 5,163,107 Fiber optic coupler/connector with GRIN lens: A robust, removable, optic fiber coupler which allows for a simple, passive optic fiber alignment without concern for large mechanical discrepancies of slight contamination between the couplers as found in severe environments within the manufacturing industries. Patent No. 5,666,448 Variable splitting optical coupler: An optical coupler with a movable deflecting element to vary the relative splitting of an optical signal. Patent No. 5,757,994 Three-part optical coupler: An optical coupler with deflecting element to passively couple fiber optic signals. Patent No. 5,761,357 Fiber optic "T"coupler in-line splitter: A fiber optic "T" coupler using cutoff portions of GRIN lenses. Patent No. 5,809,187 Multi-port network using passive optical couplers: A fiber optic network with passive optic fiber connections. Patent No. 5,883,993 Fiber Optic "T" Coupler Modulator: Two quarter wave length GRIN lenses with their collimated ends facing each other with a modulation device between them. The modulation device acts on the collimated light transmitted between the GRIN lenses. The modulator can be a filter, a polarizer, an optical switch, an amplifier or any other device for modulating light. Patent No. 5,892,868 Fiber optic coupler combiner: A fiber optic coupler having multiple small lens elements coupled to a larger lens element fo rtransferring collimated light at the interface for bilaterally combining or dividing light. Patent No, 5,894,534 Fiber optic "T" coupler single-path transceiver: Fober ptic couplers for two-way communications on the same fiber optic cable. Patent No. 6,219,477 Multiport single path optical system: An optic system for multiplexing on a single optic fiber. Patent No. 6,272,226 Multipath optical coupler: Methods and apparatus for transmitting an inserted optical signal into an optical coupler and transmitting an extracted optical signal from the optical coupler so that the extracted optical signal does not contain any aspect of the inserted optical signal.
(more...) |
| | 17064 |
Variable All-optical Shift Register
There has been tremendous progress in research and commercialization of dense wavelength division multiplexing (DWDM) optical fiber communications. Transmission capacity as high as 10 terabits/second through a single fiber has been demonstrated in the laboratory. This huge capacity can create enormous data traffic congestion at major interconnections. An all-optical packet switched network can potentially eliminate this major bottleneck by allowing the data packets to route through the network without optoelectronic conversion. One of the most important components in a router is a buffer. A buffer must be able to store data packets for a substantial period of time and must be able to release the data within an acceptable delay when the switch is clear for routing. Researchers at the University of California, Berkeley have developed a novel concept for an all-optical buffer with variable memory, based on slowing the group velocity of the optical data packet in the buffer wtih a controlled reduction, such that it is effectively an optical memory. By varying the group velocity reduction factor, the memory length and the delay time can be adjusted.
(more...) |
|
|