Nec Corporation

Sumida Corporation

Nec C Orporation

Takehiro Nakano

Ryuji Aida

Fumihito Meguro

Tatsumi Nishino

Yutaka Yano

Yoshihisa Inada

Eduardo Rodriguez

Fumihoto Meguro

In order to avoid the phenomenon of communication being impeded and signals transmitted by the plurality of slave devices overlapping, a communication system according to the present invention has the first master device transmits a first pulsed light to the first transmission path and receives a return light of the first pulsed light from the second transmission path; each of the slave devices modulates the first pulsed light, and outputs the modulated first pulsed light as the return light of the first pulsed light; and the width of the first pulsed light is narrower than double the shortest distance from among the transmission distance between the slave device outputting the return light and the transmission distance between the first master device and the slave device outputting the return light.

Communication system and method for controlling communication system

Provided are an optical transmission line monitoring apparatus, an optical transmission line monitoring system, and an optical transmission line monitoring method capable of monitoring a plurality of optical transmission lines in parallel. A monitoring light output unit outputs monitoring lights with different frequencies to optical transmission lines. A local oscillation light source outputs a local oscillation light. An interference unit, to which return lights corresponding to the monitoring lights are input, configured to output an output light generated by interference between input lights and the local oscillation light. A conversion unit converts the output light into an electrical signal. A signal processing unit extracts, from the electrical signal, an intermediate-frequency signal based on each of the monitoring lights, and generates monitoring results of the optical transmission lines from the intermediate-frequency signal.

Optical transmission line monitoring apparatus, optical transmission line monitoring system, and optical transmission line monitoring method

The optical relay is a C+L-band relay which is inserted between a first transmission path fiber and a second transmission path fiber, and comprises: a first optical fiber amplification unit which is inserted in a first line and amplifies one of a C-band signal or an L-band signal; a second optical fiber amplification unit which is inserted in a second line and amplifies one of the C-band signal or the L-band signal; and an inserting means which inserts some or all of the wavelengths of light output from the first optical fiber amplification unit into the second optical fiber amplification unit, or which inserts some or all of the wavelengths of light output from the second optical fiber amplification unit into the first optical fiber amplification unit.

Optical relay, optical relay control method, and optical transmission system

Aspects of the present disclosure describe systems, methods and structures including high-density submarine/undersea reconfigurable optical add/drop multiplexers (ROADM) having remote wavelength selective switch (WSS) redundancy.

High-density submarine ROADM unit with remote WSS redundancy

To enable the transmission and reception of a super-channel optical signal to continue maintaining the possible transmission capacity without providing a redundant configuration in advance even though a failure occurs in a subcarrier, an optical transmitterof the present invention includes a splitting meansfor splitting an inputted client signal so as to make frequency efficiency in optical modulation means optimized; optical modulation meanstoN for modulating one of subcarriers having mutually different wavelengths with the client signal output; a multiplexing meansfor multiplexing the modulated signals and outputting a super-channel optical signal; and a control means, in a state where a failure occurs in one of the subcarriers, for making a split client signal output to modulation means corresponding to a subcarrier having no failure and applying a modulation method with a higher frequency efficiency to at least one of the modulation means.

Optical transmitter, optical transmission device, optical transmission/reception system, and optical transmission method

In order to provide a configuration for suppressing deterioration in the transmission quality of a signal light due to a nonlinear phenomenon in an optical fiber, a polarization dispersion adder is provided with: a polarization rotation unit which, with respect to each pulse of signal light generated by modulating a light carrier, rotates and outputs the polarization of the pulse during a period from a pulse rise start time (T) to a pulse fall completion time (T); and a delay addition unit which adds a delay of an amount corresponding to the rotation amount of the polarization added by the polarization rotation unit to the pulse outputted from the polarization rotation unit.

Polarization dispersion adder and optical receiver

An antenna coil may include a first coil portion wound with coil wire; a second coil portion wound with coil wire and intersecting with the first coil portion; and a case having a coil receiving portion receiving the first coil portion and the second coil portion, in which the first coil portion and the second coil portion are disposed so that extending directions of the respective coil portions are directed in diagonals direction of the coil receiving portion.

Antenna coil

In a transmission path monitoring system, a first add section adds a first add signal to a first wavelength division multiplexing signal. A first drop section separates a first drop signal from the first wavelength division multiplexing signal. A first loopback section transfers a monitor signal on a first drop optical transmission path onto a second add optical transmission path. A second add section adds a second add signal to a second wavelength division multiple signal. A second drop section separates a second drop signal from the second wavelength division multiplexing signal. A first communication section transmits the first add signal and the monitor signal and receive the second drop signal and the monitor signal.

Transmission line monitoring system

A coil part used in a antenna coil has a cross shape core that includes: a first winding frame part extending a first direction and being provided with a coil, and a second winding frame part extending a direction crossing the first direction and being provided with a coil. A first core including the first winding frame part is interlocked with a second coreincluding the second winding frame part.

Growing community of inventors

Tokyo, Japan

Takehiro Nakano