Nec Corporation

Micron Technology Incorporated

Mitsubishi Electric Corporation

Elpida Memory, Inc.

Kohei Nakamura

Yoshihisa Inada

Takanori Inoue

Eduardo Rodriguez

Fatih Yaman

Hussam Batshon

Shaoliang Zhang

Katsuhiro Kitagawa

Takaaki Ogata

Akira Yamashita

Shinsuke Fujisawa

Kazuhiro Kurihara

Daisuke Mizuno

Yoshihiro Morimoto

Kazuhiko Fukushima

Shuichi Murai

Yuhei Kaneko

Ting Wang

Yue-Kai Huang

Shuichi Tsukada

Ezra Ip

Ryuji Aida

Minari Arai

Yoshinari Takigawa

Sachiko Kamisaki

Ryu Kurahashi

Wataru Nagaya

Hassam Batshon

Aspects of the present disclosure describe systems, methods. and structures in which guided acoustic Brillouin (GAWBS) noise is measured using a homodyne measurement technique and demonstrated using a number of optical fibers, such fibers being commonly used in contemporary optical communications systems. The measurements are made with single spans and determined to be consistent with separate multi-span long-distance measurements. Additionally, a technique for preparing an optical fiber exhibiting superior GAWBS noise characteristics by reducing coherence length of the optical fiber by spinning the fiber at a high rate during the drawing process such that birefringence coherence length is reduced.

Optical fiber exhibiting low guided acoustic Brillouin scattering (GAWBS) noise and measurement thereof

Earthquake detection via fiber sensing is provided using using a supervisory path of submarine cables wherein the supervisory system/path of a submarine optical cable conveys portion(s) of an optical signal back to an origin location periodically—i.e., at every repeater location. Advantageously, since it is known where a returning signal is coming from, a resolution equivalent to an undersea span length may be determined—which is sufficient for wide area disturbances such as earthquakes. The returned signal is sufficiently strong such that the signal-to-noise ratio of a returned/received signal is not limited by the ASE noise of the amplifiers. The returned signal is much larger as compared to a normal distributed acoustic sensing (DAS) return signal since the return signal according to aspects of the present disclosure is directed backward via an optical coupler/reflector/circulator having a much larger coupling ratio as compared to normal Rayleigh back scattering utilized in DAS.

Fiber sensing using supervisory path of submarine cables

Apparatuses, systems, and methods for input buffer data feedback equalization (DFE). An input buffer includes a DFE circuit which adjusts a threshold voltage of the input buffer based on a previously latched data bit. The DFE circuit includes a number of DFE legs coupled in parallel to a node of the input buffer. Each DFE leg is selectively activated by a DFE code. Each DFE leg includes a capacitance (e.g., a field effect transistor) which is coupled to the node in an active leg based on the previously latched data bit. The previously latched data bit may also be used to generate a reset signal which couples the capacitors to ground. Each DFE leg may also include a transistor coupled to a bias voltage, which is stable across a range of PVT variations.

Apparatuses and methods for input buffer data feedback equalization circuits

Aspects of the present disclosure are directed to systems, methods, and structures providing for the accurate measurement of guided acoustic-wave Brillouin scattering in optical fiber transmission systems and facilities.

Accurate measurement for guided acoustic-wave Brillouin scattering

In order to readily carry out communication between terminal stations, a submarine optical communication system includes a first terminal station including a first monitoring means for monitoring the signal quality of dummy light a first dummy light source that outputs dummy light to the second terminal station, and a first light transmitting means for transmitting an optical signal to the second terminal station, the optical signal including a first signal quality of the dummy light; and the second terminal station including a second dummy light source that outputs dummy light to the first monitoring means, a second monitoring means for monitoring the signal quality of the dummy light, and a light receiving means for receiving the optical signal.

Submarine optical communication system and communication method

Aspects of the present disclosure describe estimating/measuring core-cladding concentricity error in optical fibers. In sharp contrast to the prior art, our inventive method is based on measuring a seemingly unrelated property of fibers called guided acoustic wave Brillouin scattering (GAWBS). As we shall show and describe, by analyzing this GAWBS property we advantageously determine what level of CCCE is exhibited by the optical fiber.

Estimating core-cladding concentricity error in optical fibers using guided acoustic-wave Brillouin scattering

Aspects of the present disclosure describe methods for reducing guided acoustic wave Brillouin (GAWBS) noise in an optical fiber that may be included in an optical communications system by reducing the polarization diffusion length of the fiber by increasing the birefringence of the optical fiber, the increased birefringence of the optical fiber being increased with respect to its average magnitude. Additionally, the polarization diffusion length is reduced by reducing the coherence length of birefringence of the optical fiber.

Method for reducing GAWBS noise by reducing polarization diffusion length

Aspects of the present disclosure describe a three-way branching unit switch module having a small footprint suitable for application in an undersea application.

Three-way branching unit switch module having small footprint

Aspects of the present disclosure describe a method for estimating mode field distribution in optical fibers from guided acoustic-wave Brillouin scattering wherein light for which the optical mode-field distribution is determined remains in the optical fibers and the distribution is made for light inside the fiber, and not at a fiber/air interface or other perturbation points to the fiber resulting in a more accurate representation of the optical mode-field distribution in the fiber. Since light is always in the fiber during the determination, no complicated fiber preparation steps or procedures are required and the mode-field distribution is determined as an average distribution along the length of the fiber under test.

Estimating mode field distribution in optical fibers from guided acoustic wave brillouin scattering

In a wedge looseness diagnosis which is performed by striking wedges of a rotary electric machine, a variation of a wave form of a strike sound is reduced with respect to a variation of an amount of looseness of the wedges, and it is difficult that a slight difference of the amount of the looseness of the wedges is discriminated, so that the wedges are struck by a strike portion in a state where the wedges are pressed by a pressure portion which presses the wedges, and a strike sound at a high frequency is reduced, whereby an amount of a variation of magnitude of the strike sound is enlarged with respect to a valuation of the amount of the looseness of the wedges, and the amount of the looseness of the wedges is judged in accordance with the strike sound which is obtained by a strike sound measuring portion.

Wedge looseness inspection device of rotary electric machine

Aspects of the present disclosure describe a method for digital coherent transmission systems that advantageously provides low-complexity, single-step nonlinearity compensation based on artificial intelligence (AI) implemented in a deep neuron network (DNN).

Single-step nonlinearity compensation using artificial intelligence for digital coherent transmission systems

An excitation light source apparatus capable of assuring an excellent optical transmission characteristic even at occurrence of a gain tilt is provided. The excitation light source apparatus comprises an excitation light outputting means, a control signal detection means, a control signal detection means, an excitation light control means, and a multiplexing means. The excitation light outputting means outputs excitation light for Raman amplification. The control signal detection means detects a control signal of the excitation light outputting means from beams of WDM signal light transmitted through optical fibers in an upstream direction and a downstream direction. The excitation light control means controls the excitation light outputting means, based on the control signal. The multiplexing means multiplexes the excitation light and each of the beams of the WDM signal light, and outputs the respective multiplexed beams of light to the optical fiber.

Excitation light source apparatus and gain equalizing method

Apparatuses, systems, and methods for data strobe write timing. A memory device may receive a data strobe clock signal and serial write data during a write operation. A deserializer circuit of the memory may convert the serial write data into parallel write data using timing based on the data strobe clock signal. For example, one or more internal signals may be generated based on the data strobe clock signal and used to activate various operations of the deserializer circuit. The data strobe clock signal may also be used to activate bit lines of the memory device in order to write the parallel write data to memory cells along those activated bit lines. The memory may also receive a system clock, separate from the data strobe clock signal, which may be used for other operations of the memory. For example, in a read operation, the bit lines may be activated with timing based on the system clock.

Apparatuses, systems, and methods for data strobe write timing

Aspects of the present disclosure describe systems, methods, and structures that advantageously amplify optical signals through the effect of optical pump signals generated by a multicore laser diode and multicore rare-earth doped optical fiber in optical communication with a 3D waveguide structure and a multicore input signal fiber providing a plurality of optical signals for amplification.

Multicore fiber amplifier with high power efficiency

Aspects of the present disclosure describe systems, methods and structures for optical fiber nonlinearity compensation using neural networks that advantageously employ machine learning (ML) algorithms for nonlinearity compensation (NLC) that advantageously provide a system-agnostic model independent of link parameters, and yet still achieve a similar or better performance at a lower complexity as compared with prior-art methods. Systems, methods, and structures according to aspects of the present disclosure include a data-driven model using the neural network (NN) to predict received signal nonlinearity without prior knowledge of the link parameters. Operationally, the NN is provided with intra-channel cross-phase modulation (IXPM) and intra-channel four-wave mixing (IFWM) triplets that advantageously provide a more direct pathway to underlying nonlinear interactions.

Growing community of inventors

Tokyo, Japan

Kohei Nakamura