85 results about "Optical buffer" patented technology

A variable semiconductor all-optical buffer and method of fabrication is provided where buffering is achieved by slowing down the optical signal using a control light source to vary the dispersion characteristic of the medium based on electromagnetically induced transparency (EIT). Photonic bandgap engineering in conjunction with strained quantum wells (QWs) and quantum dots (QDs) achieves room temperature operation of EIT. Photonic crystals are used to sharpen the spectral linewidths in a quantum well structure due to its density of states and in a quantum-dot structure caused by the inhomogeneity of the dot size, typically observed in state-of-the-art QD materials. The configuration facilitates monolithic integration of an optical buffer with an amplifier and control laser to provide advantages over other material systems as candidates for optical buffers.

A polarization type optical buffer together with the adjusting method is designed for the low turning on and off speed and the instability of the avoiding polarization state, namely using the nonlinear rotation of the polarization state in a semiconductor optical amplifier or an optical fiber as a polarization control switch to realize the optical buffer to cache the data packet signal. The optical buffer consists of an input polarization controller, a polarization beam combiner, a nonlinear polarization rotation functional unit, a polarization beam splitter and a polarization maintaining fiber, wherein, the nonlinear polarization rotation functional unit consists of a front polarizer, a tail polarizer, the controllable non-linear rotation functional parts and an online monitoring unit of the polarization state composed by an optical fiber coupler and a polarization controller. The instability of the polarization can be avoided by adjusting the polarization type optical buffer to the polarized rotation. The polarization type optical buffer of the invention has the advantages that the reading and writing speed is high and the buffer depth of an optical fiber ring reaches above 90%, thereby being good for the cascade.

The invention discloses an optical delayer coupled through adopting multiple-mode interference, which adopts an all-pass filter structure; the all-pass filter structure is a structure of the sequent coupling of a plurality of micro ring resonant cavities and a bus waveguide, wherein the coupled segment between the micro ring resonant cavities and the bus waveguide is of a 2*2 multiple-mode interference coupler. Adopting the multiple-mode interference coupled structure, the invention can improve the coupling efficiency between the micro ring resonant cavities and the bus waveguide, and makes the optical delayer have wider operation bandwidth. The invention has high technical redundancy, is easy to manufacture, has small size, is suitable for dense integration, also has the characteristics of wide bandwidth and big time delay, the structural design with different splitting ratio increases the flexibility of the device application, and the delayer is suitable for being used as an optical buffer device of high-speed all-optical packet switching network in the future.

The invention discloses a silicon-based multimode helical waveguide delay line supporting low-loss fundamental mode transmission. A curvature gradual change type S bending multimode waveguide is placed at the centers of curvature gradual change type helical bending multimode waveguides; and two curvature gradual change type helical bending multimode waveguides are annularly and helically arranged,an inner end of one curvature gradual change type helical bending multimode waveguide is connected with one end of the curvature gradual change type S bending multimode waveguide through a bending waveguide, the other end of the curvature gradual change type S bending multimode waveguide is connected with the inner end of the other curvature gradual change type helical bending multimode waveguidethrough another bending waveguide, and the entire silicon-based multimode helical waveguide delay line is arranged in a central symmetry manner. The silicon-based multimode helical waveguide delay line disclosed by the invention can effectively avoid mode mismatch loss and inter-mode crosstalk caused by the abrupt curvature change of the traditional structure, and can reduce the scattering loss introduced by a waveguide sidewall, thereby obtaining low-loss fundamental mode transmission in the silicon-based multimode helical waveguide, and the silicon-based multimode helical waveguide delay line has the advantages of low loss and compact structure and the like, and can be applied to optical buffers, optical delay lines and other systems.

A recessed area formed on a substrate surface is filled with heat sink material to form a heat sink. The heat sink material has thermal conductivity greater than that of the substrate. The heat sink may have a substantially flat surface substantially flush with the substrate surface. The substrate may further include: a planar optical waveguide formed thereon positioned for optical coupling with an optical device mounted on the substrate in thermal contact with the heat sink; and/or an electrical contact layer formed thereon positioned for establishing electrical continuity with an optical device mounted on the substrate in thermal contact with the heat sink. The electrical contact may also provide thermal contact between the device and heat sink. The substrate may further include a low-index optical buffer layer formed on its surface. Materials for the substrate, buffer layer, and heat sink may include silicon, silica, and diamond, respectively.

The panoramic-reconstruction temporal imaging (PARTI) system is a single-shot optical waveform measurement apparatus that achieves scalable record length and sub-picosecond resolution simultaneously for ultrafast non-repetitive waveform characterization, in analogy with the wisdom of stitching multiple mosaic images to achieve larger-field-of-view in the spatial domain. It consists of a high-fidelity optical buffer, a low-aberration time magnifier and synchronization-control electronics. For specific measurement circumstances, the PARTI system can also be carried out based on a passive optical buffer, which reduces the system complexity. The PARTI system is configured for real-time single-shot characterization of non-repetitive optical dynamic waveform that evolves over a time scale much larger than that of its ultrafast temporal details, i.e., optical dynamics with large time-bandwidth product.

The invention relates to an all-optical buffer based on a photonic crystal fiber and pertains to the all-optical buffer devices in an optical network, which solves the problems that the existing optical buffers have high pump power and optical circuits are easy to be damaged. The invention comprises a data caching optical circuit which is composed of a highly-nonlinear photonic crystal fiber, etc., and a read and write control optical circuit. The invention is provided with a Mach-Zehnder switch at an input terminal and a Mach-Zehnder switch at an output terminal between which the data caching optical circuit and a direct data channel composed of the optical fiber pass through in parallel; the Mach-Zehnder switch at an input terminal and the Mach-Zehnder switch at an output terminal are controlled by a buffer on-off controller so as to select optical signals to pass through the direct data channel or the data caching optical circuit. The all-optical buffer of the invention can realize the continuous and controllable cache time of the optical signal under rather low pump optical power and has simple structure, low cost, a short signal storage medium, low energy consumption of the system as well as continuous and adjustable cache time, and has universality to the photonic crystal fiber of a small mode field.

The invention relates to a queue-type all-optical buffer, which belongs to the field of all-optical packet switching. The queue-type all-optical buffer is characterized in that the queue-type all-optical buffer is formed by cascade connection of a plurality of optical buffer units, and uplink output ends of each stage of the optical buffer units are sequentially connected with downlink input ends of the last stage, thereby constituting an uplink channel. Data packets which are input to each stage of the optical buffer units are determined to carry out the uplink output or the buffer at the stage by a control signal input end. A control signal output end of any i stage of the optical buffer units is connected with the control signal input end of the i+1 stage of the optical buffer units, thereby avoiding the situation that the i+1 stage of the optical buffer units output data to the i stage of the optical buffer units when the i stage of the optical buffer units have the buffer data packets. When two data packets simultaneously achieve the buffer, the data packet with high priority is directly output and the data packet with low priority is stored in the buffer. The queue-type all-optical buffer has the queue characteristics of first-in first-out and last-in last-out, can simultaneously process two data packets and has the advantages of easy expansion of storage capacity, no need of external control signals and the like.

The invention relates to an all-optical network quick-dynamic configurable optical packet buffer. M Sagnac interference rings with reflex-transmission functions and M optical fiber delay lines are mutually by interval welded and connected in series; the optical fibers at the head and tail ends are welded with an input end and an output end of a 2 times 2 quick optical switch to form a buffer fiber ring. The other couple of the input end and output end of the 2 multiplied by 2 quick optical switch are adopted as the input and output ends of optical packet signals. The optical buffer of the invention enhances the re-cycle optical fiber buffering capability and provides the diverse buffer path options by embedding the Sagnac interference rings and optical fiber delay lines by interval on the basis of the existing re-cycle optical fiber ring of the traditional 2 multiplied by 2 quick optical switch so as to realize the time-slot exchanging for a plurality of optical packets and the quick-dynamic configuration of buffering time while supplying a plurality of optical packets. The invention has the advantages that the optical buffering time dynamic scope is wide; the reconfiguration time is short; the physical volume is small; the power cost is low and the potential expansibility is high, etc.

The present invention relates to a stack type fully optical buffer, and belongs to the field of fully optical packet switching. The buffer is characterized by consisting of a plurality of cascading light guide units; the downlink output end of the light guide unit of each level is orderly connected with the downlink input end of lower level, so as to form a downlink channel; the uplink input end of each level is orderly connected with the uplink input end of higher level, so as to form an uplink channel. The data packet which is transmitted into the light guide unit of each level is controlled by a control end for uplink transmission or downlink transmission. The i-level downlink output end is connected with the control end of the level of i plus 2, so as to prevent the levels of i and i plus 2 from simultaneously transmitting the data to the level of i plus 1. When two data packets arrive to the buffer simultaneously, the data packet of higher priority is directly transmitted outwards, and the data packet of lower priority is stored in the buffer; and the storage depth of the original data packet in the buffer is deepened by one level. The fully optical buffer has the first-in but last-out, and last-in but first-out characteristics, the capability of simultaneously processing two data packets, and the advantages of easy expansion of the storage capacity, no requirement for additional control signals, and so on.