Abstract: An optical and electronic integrated switch includes a network processor that controls the functions of the packet switch, a plurality of optical transceivers having photoelectric conversion functions, and a plurality of optical switches. The optical switches include different types of optical core switch and a plurality of optical-path selection switches. The optical transceivers provided near the processor have a regenerative relay function that regenerates optical signals and turns back the optical signals, and perform optical communication with a communication counterpart via the optical switches. In the optical communication, optical switches of the different types can cooperate to set paths for optical cut-through in which path selection is performed such that inputted optical signals are outputted without the intervention of the processor. This optical cut-through can be effectively performed without imposing a signal processing burden that consumes electric power on the processor.

Abstract: An optical transmission system including an optical transmission device and an optical reception device that receives, via an optical transmission line, a signal transmitted from the optical transmission device, the optical transmission system including a transmission-mode selection unit that selects transmission mode information in descending order of priority out of transmission mode information, which is combinations of a plurality of parameters concerning transmission performance, the transmission mode information being a plurality of kinds of the transmission mode information common to the transmission performance of the optical transmission device and the optical reception device, a signal transmission unit that transmits, to the optical reception device, a signal modulated based on the selected transmission mode information, and a signal reception unit that receives the signal and modulates the received signal based on the transmission mode information selected by the transmission-mode selection unit.

Abstract: A photonics-electronics convergence switch with which, even if an optical network system is built by combining a plurality of packet switches, the amount of processing in the packet switches does not increase, the optical network system operates with low electric power consumption, and this enables wide-range optical communication between the nodes of a communication origin and of a communication partner, includes a network processor that is an electronic circuit configured to control the functions of the packet switch, a plurality of optical transmitter-receivers having photoelectric conversion functions, and a plurality of optical switches.

Abstract: A photo-electron fusion switch that can perform optical communications without any trouble, even when nodes of a communication source and a communication partner that are large in transmission capacity are connected, and makes it possible to realize a concentrated arrangement of devices having similar functions and reduce the communication processing time is connected to communication source's information processing devices and communication partner's information processing devices and information processing devices that are each different in transmission speed so as to configure an optical network system.

Abstract: An adaptive equalizer includes an updating unit that updates a step size of a vector of a tap coefficient used for controlling an adaptive filter based on a time-series update vector in accordance with a time-series input and output of the adaptive filter that tracks a polarization state of an optical signal received by a coherent optical receiver. The updating unit updates the step size based on a DC gain of the update vector. The updating unit may update the step size for each update vector component based on a DC gain for each update vector component.

Abstract: An aspect of the present invention is an adaptive equalization filter for an optical transmission system, including: a main signal filter; and a coefficient computation unit that updates the filter coefficient of the main signal filter. The pre-stage filter and the post-stage filter receive a sample of the main signal as an input. The pre-stage coefficient computation unit obtains the filter coefficient of the pre-stage filter by feedback control using the gradient method. The post-stage coefficient computation unit obtains the filter coefficient of the post-stage filter by feedforward control. The convolution computation unit obtains the filter coefficient of the main signal filter by convolution computation of the filter coefficient of the pre-stage filter obtained by the pre-stage coefficient computation unit and the filter coefficient of the post-stage filter obtained by the post-stage coefficient computation unit.

Abstract: A digital signal processing device includes: a delay means that delays audio data in units of sampling periods; and a control means that writes audio data to a first buffer memory one word at a time in sequence at a sampling period, performs control to burst transfer burst length audio data to a DRAM from the first buffer memory, performs control to burst transfer the burst length audio data to a second buffer memory from the DRAM, and outputs audio data to the delay means from the second buffer memory one word at a time in sequence at the sampling period, in which a delay time of audio data output by the delay means is determined by a combination of a delay time of multiple sampling period units depending on a burst length of the DRAM and a delay time of a sampling period unit of the delay means.

Abstract: A signal processing apparatus includes: a coefficient update unit configured to approximate a characteristic of a transmission line of an optical signal by a first tap coefficient vector of which an L0 norm is a predetermined value or less; a zeroing unit configured to generate a second tap coefficient vector by replacing, with 0, a tap coefficient of which an absolute value is less than a threshold among tap coefficients of the first tap coefficient vector; and an adaptive filter configured to perform, based on the second tap coefficient vector, adaptive equalization processing on a digital signal corresponding to an optical signal received via the transmission line.

Abstract: An optical reception device includes a coefficient update section which optimizes a dispersion coefficient used in compensation of wavelength dispersion of a received signal obtained by receiving an optical signal according to a coherent detection method and a phase rotation amount used in compensation of a nonlinear optical effect of the received signal, and a transmission characteristic estimation section which estimates a transmission characteristic of a transmission line by using the optimized dispersion coefficient and the optimized phase rotation amount.

Abstract: An electric digital received signal obtained from a received optical signal is segmented into blocks of a certain length with an overlap of a length determined in advance with an adjacent block. Fourier transformation is performed for each of the blocks. The blocks subjected to the Fourier transformation are stored consecutively in time series, a coefficient determined based on a wavelength dispersion compensation amount according to one of frequency positions and a delay amount according to one of the frequency positions and one of time positions is applied to each of frequency component values included in a plurality of the stored blocks, and the blocks to which the coefficient has been applied and which are obtained by adding up the frequency component values to which the coefficient has been applied for each of the frequency positions are generated. Inverse Fourier transformation is performed on the generated blocks to which the coefficient has been applied.

Abstract: A signal processing device includes a distributing unit and a plurality of correcting units with different processing performance, the distributing unit distributes a bit sequence having a first number of bits to the first correcting unit, and a bit sequence having a second number of bits less than the first number of bits to the second correcting unit having lower processing performance than the first correcting unit, the first correcting unit applies error correction processing to the bit sequence having the first number of bits distributed to the first correcting unit, and the second correcting unit applies error correction processing to the bit sequence having the second number of bits distributed to the second correcting unit.

Abstract: A high-performance optical and electronic integrated switch capable of effectively extending the transmission distance includes a network processor that controls the functions of the packet switch, a plurality of optical transceivers provided near the processor and having a photoelectric conversion function, and an optical relay switch. A plurality of optical waveguides are connected to the input and output sides of the optical relay switch. Each optical transceiver has a regeneration function that performs optical-electrical conversion on inputted optical signals, then turns back the converted signals, and performs signal conversion on them, and its input side is connected with a routing optical waveguide included in the optical waveguides on the output side of the switch and its output side is connected with a routing optical waveguide included in the optical waveguides on the input side of the switch. The optical waveguides include ones for connecting to an external communication counterpart.

Abstract: An optical reception apparatus includes a wavelength dispersion compensation unit that performs wavelength dispersion compensation individually on reception signals that are obtained by receiving, by a coherent detecting scheme, an optical signal modulated in a subcarrier modulation scheme and by performing division on a subcarrier-by-subcarrier basis, and a plurality of delay compensation units that compensate for a delay between reception signals at different subcarriers among the reception signals at subcarriers obtained by the wavelength dispersion compensation.

Abstract: A photo-electron fusion switch that can perform optical communications without any trouble, even when nodes of a communication source and a communication partner that are large in transmission capacity are connected, and makes it possible to realize a concentrated arrangement of devices having similar functions and reduce the communication processing time is connected to communication source's information processing devices and communication partner's information processing devices and information processing devices that are each different in transmission speed so as to configure an optical network system.

Abstract: A virtual environment optical communication network is generated by setting configuration parameters of physical packages of a real environment optical communication network in package emulators that a computer program has virtually constructed to implement the physical packages, the real environment optical communication network being constructed by a plurality of node devices in which the physical packages are mounted, pieces of configuration data are generated based on pieces of resource data indicating resources required for optical paths detected based on acquired configuration parameters and a requested transmission mode, optical paths are set in the virtual environment optical communication network based on the generated pieces of configuration data, and optical paths are set in the real environment optical communication network based on the pieces of configuration data that have been used to set the optical paths.

Abstract: An optical and electronic integrated switch includes a network processor that controls the functions of the packet switch, a plurality of optical transceivers having photoelectric conversion functions, and a plurality of optical switches. The optical switches include different types of optical core switch and a plurality of optical-path selection switches. The optical transceivers provided near the processor have a regenerative relay function that regenerates optical signals and turns back the optical signals, and perform optical communication with a communication counterpart via the optical switches. In the optical communication, optical switches of the different types can cooperate to set paths for optical cut-through in which path selection is performed such that inputted optical signals are outputted without the intervention of the processor. This optical cut-through can be effectively performed without imposing a signal processing burden that consumes electric power on the processor.

Abstract: A photonics-electronics convergence switch with which, even if an optical network system is built by combining a plurality of packet switches, the amount of processing in the packet switches does not increase, the optical network system operates with low electric power consumption, and this enables wide-range optical communication between the nodes of a communication origin and of a communication partner, includes a network processor that is an electronic circuit configured to control the functions of the packet switch, a plurality of optical transmitter-receivers having photoelectric conversion functions, and a plurality of optical switches.

Abstract: An optical transmission system including an optical transmitter and an optical receiver, wherein the optical transmitter includes a signal coding unit that performs non-linear block coding on an M (M is an integer greater than or equal to 1)-value symbol sequence or a bit sequence input as data information to generate an L (L is an integer greater than or equal to 2, L>M)-value symbol sequence that corresponds to the M-value symbol sequence or the bit sequence in one-to-one correspondence, a digital-to-analog conversion unit that converts the generated L-value symbol sequence to an analog signal, and a modulator that generates an optical modulation signal by performing modulation based on the analog signal, and the optical receiver includes a light receiving unit that receives the optical modulation signal transmitted from the optical transmitter and converts the optical modulation signal to an electrical signal, and a signal decoding unit that restores the M-value symbol sequence or the bit sequence by pe

Abstract: A digital signal processing device includes a control unit that performs control to alternately burst transfer burst length audio data in a first half area of a first buffer memory and burst length audio data in a second half area of the first buffer memory to a DRAM, in which the control unit performs control to burst transfer the burst length audio data in the first half area of the first buffer memory to the DRAM while writing audio data one word at a time to the second half area of the first buffer memory in sequence and performs control to burst transfer the burst length audio data in the second half area of the first buffer memory to the DRAM while writing audio data one word at a time to the first half area of the first buffer memory in sequence.

Abstract: An optical transmission system including an optical transmission device and an optical reception device that receives, via an optical transmission line, a signal transmitted from the optical transmission device, the optical transmission system including a transmission-mode selection unit that selects transmission mode information in descending order of priority out of transmission mode information, which is combinations of a plurality of parameters concerning transmission performance, the transmission mode information being a plurality of kinds of the transmission mode information common to the transmission performance of the optical transmission device and the optical reception device, a signal transmission unit that transmits, to the optical reception device, a signal modulated based on the selected transmission mode information, and a signal reception unit that receives the signal and modulates the received signal based on the transmission mode information selected by the transmission-mode selection unit.