Abstract: In an example embodiment, an optical amplifier comprises a doped multi-core optical fiber and two optical couplers placed at the ends of the doped multi-core fiber, with each optical coupler having a respective plurality of optical waveguide cores optically coupled to the optical waveguide cores of the doped multi-core fiber. The spatial arrangement of the cores at the input end of the first optical coupler is configured for low-loss intake of the optical energy from the input transmission line. The spatial arrangement of the cores at the output end of the first optical coupler and the spatial arrangement of the cores at the input end of the second optical coupler match the spatial arrangement of the cores in the doped multi-core fiber. The spatial arrangement of the cores at the output end of the second optical coupler is configured for low-loss transfer of the optical energy into the output transmission line.

Abstract: An optical apparatus includes a front optics section and a spectrometer section. The front optics section includes a spot de-multiplexer configured to receive a plurality of multi-mode optical signals each having a plurality of modal components, and to output in a linear array of a corresponding plurality of optical beams for each multimode optical signal. The spectrometer section includes a wavelength steering element configured to separate each of the optical beams into a plurality of wavelength channels. A fiber steering element is configured to steer the wavelength channels between the optical beams.

Abstract: An optical amplifier includes a multi-mode pump laser module, a multi-mode waveguide, a multi-mode to multiple single-mode fiber converter module and a plurality of single-mode cores. The multi-mode pump laser module emits pump light having a plurality of modes to the multi-mode fiber or waveguide. The multi-mode waveguide propagates the emitted pump light to the converter module. The converter module receives the pump light and distributes the pump light approximately uniformly to a plurality of single-mode cores.

Abstract: Various exemplary embodiments relate to an optical amplifier, including: a multicore rare-earth doped optical fiber with a first plurality of cores associated with a first stage of the optical amplifier and a second plurality of cores associated with a second stage of the optical amplifier; a three dimensional (3D) waveguide configured to couple input space division multiplexed (SDM) channels into the first plurality of cores at a first end of the multicore rare-earth doped optical fiber and to couple channels from the second plurality of cores to output SDM channels; a reflector configured to optically interconnect the first plurality of cores to the second plurality of cores; and pump laser coupled to the multicore rare-earth doped optical fiber configured to produce laser pump light to pump the multicore rare-earth doped optical fiber.

Abstract: A small gap semiconductor system comprises: two parallel semiconductor sheets formed of atomically thin small gap semiconductor, one sheet containing electrons and the other containing holes; a dielectric insulating barrier arranged parallel to and separating the two semiconductor sheets; independent electrical contacts to each of the semiconductor sheets; two dielectric layers above and below the two semiconductor sheets respectively; and two conducting gates sandwiching the two semiconductor sheets and separated from the respective semiconductor sheets by the respective dielectric layers.

Abstract: In a method for dynamic buffer adjustment at a line card of router, a current buffer occupancy at the line card is compared with at least a first buffer occupancy threshold, the first buffer occupancy threshold being calculated based on a buffer occupancy threshold parameter and a capacity of at least a first buffer memory at the line card; and an active buffer capacity is adjusted by at least one of activating and deactivating buffer memory blocks at the line card based on the comparing step, the activating including switching on the buffer memory blocks, and the deactivating including causing the buffer memory blocks to enter a sleep state.

Abstract: Diverse semiconductor structures are fabricated on a single substrate or wafer by using a non-selective area growth technique involving deposition of material over the entire substrate. The fabricated structures are obtained by selective removal of portions of the deposited material layers. Single level and multi-level structures are possible.

Abstract: Duobinary and NRZ modulation of an X-Gb/s optical signal is achieved with a lumped element InP Mach-Zehnder device configured to operate at X/k-Gb/s where k>1 and arranged in a push-pull configuration.

Abstract: A monolithically integrated tunable wavelength converter and variable optical delay device(s) that is capable of providing optical delay(s) of any length. Advantageously, our devices are both compact and readily realized as a photonic integrated circuit (PIC) on a semiconductor substrate.

Abstract: A monolithically integrated tunable wavelength converter and variable optical delay device(s) that is capable of providing optical delay(s) of any length. Advantageously, our devices are both compact and readily realized as a photonic integrated circuit (PIC) on a semiconductor substrate.

Abstract: A tunable laser module having two or more tunable lasers exhibiting different, possibly contiguous or partially overlapping wavelength regions. The lasers are integrated into a single package, thereby extending a total wavelength range for the package that is substantially beyond that covered by a single laser while—at the same time—providing gap-free wavelength range coverage. Of further advantage, the laser module employs a locking mechanism that is relatively immune from backscatter.

Abstract: A method or apparatus for use in generating an information system, wherein an object-oriented model of the information system is provided, the model defining classes of information objects require to be supported by the information system in terms of their attributes, operations that maybe performed on the object, and an intended relationship (if any) between two or more of the objects. Built-in or predefined descriptions of the operations which maybe performed on the objects are provided in terms of conditions that should hold initially, data that might be affected, and the desired results. An operation referenced in a class definition is then automatically expanded by adding a respective built-in or predefined description thereto within the object-oriented model of the information system.

Abstract: The invention includes an apparatus for modulating an optical signal. The apparatus includes a modulating mechanism comprising a plurality of modulating component arrays, each modulating component array comprising a plurality of modulating components, wherein adjacent ones of the plurality of modulating components in each modulating component array are separated by gaps, and wherein adjacent ones of the plurality of modulating component arrays are offset along a dispersion direction of an incident optical signal such that the gaps associated with the adjacent ones of the plurality of modulating component arrays are offset. In one embodiment, rows of the modulating components in the modulating component arrays are offset along the dispersion direction of the incident optical signal by a fraction of the modulating component pitch.

Abstract: A dispersion compensator having relatively uniform transmission characteristics over the bandwidth of a communication channel. The compensator is designed to process an optical signal corresponding to the communication channel by decomposing that signal into spectral components, routing different components along different optical paths that impart relative delays between the components, and recombining the delayed components spatially and directionally to generate a processed optical signal with reduced chromatic dispersion. In one embodiment, the compensator is a waveguide circuit that includes four diffraction gratings operating in transmission and optically coupled to a tunable lens array, in which different tunable lenses receive light corresponding to different communication channels. For each channel, a desired group delay value is produced by selecting magnification strength of the corresponding tunable lens.

Abstract: A device employing at least one wavelength sieve/combiner that operates on discrete wavelength units and is optically interposed between an array of fibers and an array of micro mirrors which may be configured to act as in a multiplexing mode, a demultiplexing mode, a broadcast mode, and combinations of such modes. Each wavelength sieve/combiner can split a wavelength division multiplexed (WDM) beam into various discrete wavelength unit beams, combine various discrete wavelength unit beams into a WDM beam, or cause multiple copies of part or all of the wavelengths to be supplied as outputs. Typically, each fiber is associated with one wavelength sieve/combiner. Preferably, the beams between a wavelength sieve/combiner and the micro mirror array should be converging to the plane of the micro mirror array.

Abstract: An optical MEMS devices is imaged to a different location at which a second optical MEMS device is located in a manner that effectively combines the tilt angles of at least one micro mirror of each of the first and second optical devices. The imaging system may reproduce the angle of reflection of the light from the first micro mirror. This may be achieved using a telecentric system, also known as a 4 f system, as the imaging system. The physical size of the arrangement may be reduced by compacting the optical path, e.g., using appropriate conventional mirrors, and/or employing folded arrangements, i.e., arrangements in which there is only one MEMS device stage that does double duty for both input and output through the use of at least one conventional mirror.

Abstract: A ground anchorage testing arrangement having an impulse imparting apparatus connectable to a ground anchorage tendon (20) or element thereof to be tested, the impulse imparting apparatus comprising an attachment means (22) for attachment to the ground anchorage tendon (20), a movable mass (31), a guide (28, 34) for guiding movement of the mass in the direction substantially aligned with the axis 0 of the ground anchorage to be tested and a drive means for imparting a driving force to move the mass in said direction (not shown). A method of assessing the integrity of ground anchorages, the method comprising the steps of (a) imparting a load impulse to a ground anchorage tendon to be tested, (b) monitoring the vibrational response signal of the anchorage to the imparted load impulse, (c) conditioning the vibrational response signal and (d) applying the conditioned vibrational response signal to an artificial neural network.

Abstract: A ground anchorage testing arrangement having an impulse imparting apparatus connectable to a ground anchorage tendon (20) or element thereof to be tested, the impulse imparting apparatus comprising an attachment means (22) for attachment to the ground anchorage tendon (20), a movable mass (31), a guide (28, 34) for guiding movement of the mass in the direction substantially aligned with the axis 0 of the ground anchorage to be tested and a drive means for imparting a driving force to move the mass in said direction (not shown). A method of assessing the integrity of ground anchorages, the method comprising the steps of (a) imparting a load impulse to a ground anchorage tendon to be tested, (b) monitoring the vibrational response signal of the anchorage to the imparted load impulse, (c) conditioning the vibrational response signal and (d) applying the conditioned vibrational response signal to an artificial neural network.