Kddi Corporation

Other

Nec Platforms, Ltd.

Kdd Submarine Cable Systems, Inc.

Kddi Submarine Cable Systems Inc.

Takehiro Tsuritani

Masatoshi Suzuki

Noboru Edagawa

Tomohiro Otani

Keiji Tanaka

Hidenori Takahashi

Shohei Beppu

Noboru Yoshikane

Hidenori Taga

Yuichi Yamada

Jun Haeng Lee

Yuta Wakayama

Masahiro Shigihara

Koji Igarashi

Masahiro Kikuta

Daiki Soma

An optical coupler includes N members. A Kth (K is an integer of 1 to N) member includes a MCF including P (P is an integer of N or greater) cores, and a marker disposed at a position closest to a first core, and at least one SCF. A core of the SCF of the Kth member is coupled to a coupled core other than the first core. Cores of the MCF of an Mth (M is an integer of 1 to N−1) member are connected to cores of the MCF of an (M+1)th member. A total number of SCF included in the N members is P. Each of P cores of the MCFs configured through the connection of the N members is connected to a core of one of the SCFs.

Optical coupler and optical amplifier

A communication device includes: a switching unit connected to a transmission unit, a reception unit, a transmission port, and a reception port, the switching unit being set in a first state in which the transmission unit and the transmission port are connected and the reception unit and the reception port are connected or a second state in which the transmission unit and the reception port are connected and the reception unit and the transmission port are connected; a monitoring unit configured to monitor a light level of light input from the reception port or the transmission port; and a control unit configured to set the switching unit in the first state or the second state based on the light level monitored by the monitoring unit.

Communication device and communication system

A reception apparatus includes: a receiving unit configured to coherently detect an optical signal and output an electrical signal containing a modulated signal and a pilot signal; a first compensating unit configured to detect a frequency of the pilot signal by performing a DFT of the electrical signal, and determine and compensate for frequency error in the electrical signal based on a reference frequency; a frequency converting unit configured to convert the frequency of the pilot signal after the compensating such that the frequency of the pilot signal is lowered by the reference frequency; and a second compensating unit configured to determine frequency error in the modulated signal after the compensating by performing a DFT on the pilot signal after the frequency converting and detecting a frequency of the pilot signal after the frequency converting.

Reception apparatus and non-transitory computer readable medium

A measurement apparatus includes: a light source unit configured to generate optical signals of, from among n+1 frequencies (n is an integer of 3 or larger) at a predetermined frequency interval, n frequencies except for a target frequency, and output the generated optical signals to an optical transmission path that is a measurement target; an optical power measurement device configured to measure of an optical signal of the target frequency output from the optical transmission path and generated in the optical transmission path as a result of four-wave-mixing of the optical signals of the n frequencies; and a processor configured to determine a power spectrum density of non-linear interference noise that occurs in the optical transmission path, by multiplying the power of the optical signal of the target frequency by an adjustment value.

Measurement apparatus of optical communication system

The present invention relates to the quality monitoring of optical signals, which have different symbol rates and generated by different modulation schemes, used for example in a wavelength division multiplexing network. The apparatus according to the invention includes an optical splitter for outputting the input optical signal to a first optical route and a second optical route, an optical coupler for coupling a optical signal from the first optical route with a optical signal from the second optical route, a delay unit provided on the first optical route, and a phase shift unit provided on the first optical route or the second optical route.

Optical signal quality monitoring apparatus

A link connectivity verification message to recognize a physical link connection state is transmitted from the WDM to the PXC on a C-plane. The PXC transmits a link connectivity verification ACK message including information representing a physical link connection state, and the WDM transmits a cross-connect instruction message to cross-connect a transmission side and a reception side of a port (port) of the PXC. Probe light transmitted from the port (port a) of the WDM is turned back by a cross-connect of the port (port) of the PXC. The WDM receives the probe light to verify a link connectivity.

Link connectivity verification method

An optical signal is transmitted via a transponder, an all-optical node, and a WDM deviceincluding an optical filter. A control means which includes a route and wavelength selecting functional part, transmits a request band information and a wavelength information based on a requested band information, link information of a network, and band limitation information with respect to each filter wavelength of the optical filter. A multi-rate functional partsends a bit rate varying request to set a band to be requested to the network side according to the requested band information. A wavelength varying functional partsends a wavelength varying request to set a wavelength of the optical signal according to the wavelength information. The optical filterincludes a bit rate (band) dependent wavelength multiplexing and demultiplexing functional part

Wavelength service providing apparatus in all-optical network

Between photonic cross connects (PXCs)andan in-use system path passing through transmission apparatus (WDMs)andare set, and a backup system passing through transmission apparatus (WDMs)andis set. The WDMsandlink to the PXCsandand release masking therebetween when the in-use system path is set, and set masking therebetween when the in-use system path is deleted. The WDMsandincluded in the in-use system path transmit an alarm to a monitoring system when an input light is turned off, and the WDMsandincluded in the backup system path do not transmit an unintended alarm to the monitoring system even when the input light is turned off.

Link system for photonic cross connect and transmission apparatus

An optical transmitter outputs WDM signal lights comprising signal lights with 100 wavelengths of 10 Gbit/s, onto an optical transmission fiber. In the optical transmission line, a transmission fiber and a local area dispersion compensation fiber are disposed per repeater span defined by an optical amplification repeater, the local area dispersion compensation fiber is for compensating the average chromatic dispersion in the repeater span to become 2 ps/nm/km as well as a dispersion slope to become zero, and a wide area dispersion compensation fiber for compensating the average chromatic dispersion to become &minus;0.2 ps/nm/km as well as the dispersion slope to become zero is disposed per predetermined number of optical repeater spans. The optical transmission fiber comprises a single mode optical fiber with large core diameter having a zero dispersion wavelength at a 1.3 &mgr;m band and plus chromatic dispersion at a signal wavelength band (a 1.55 &mgr;m band). The optical amplification repeater comprises an erbium-doped optical fiber to be pumped by a 0.98 &mgr;m band pumping light.

Optical transmission system, optical transmission line and optical transmitter

An optical fiber transmission line for realizing satisfactory long haul transmission characteristics using two kinds of optical fibers. The optical fiber transmission line includes a plurality of local dispersion compensating spans, wide dispersion compensating spans disposed at predetermined intervals, and optical repeating amplifiers to connect each span. The local dispersion compensating span includes a first optical fiber with positive dispersion having an effective core area of 130 &mgr;m or more and a second optical fiber with a negative dispersion value of &minus;50 ps/nm/km or less to transmit the light output from the first optical fiber. The wide dispersion compensating span consists of a third optical fiber having the same configuration and composition with the first optical fiber.

Optical fiber transmission line

An object of this invention is to improve transmission characteristics in WDM transmission. An optical transmitter ( ) wavelength-multiplexes signal lights of wavelengths &lgr; through &lgr;n and outputs them onto an optical transmission line ( ). Optical powers of the signal lights of the respective wavelength through &lgr;n are identical or become smaller proportional to the wavelength. One repeater span of the optical transmission line ( ) is composed of an optical fibers ( ) and an optical amplifier ( ), and a gain equalizer ( ) is dispersed every several repeater spans. The optical amplifier ( ) in the repeater span amplifies each signal light so that optical power of a signal on the shorter wavelength side becomes smaller than that of a signal on the longer wavelength side. The gain equalizer ( ) equalizes optical powers of the respective signal lights.

Optical transmission system, its method, and optical amplification transmission line

To realize an optical demultiplexer with a constant chromatic dispersion value, an optical signal of wavelength (&lgr; ) enters a port (A) of an optical circulator ( ), and an optical signal of wavelength (&lgr; ) enters a port (A) of an optical circulator ( ). A port (B) of the optical circulator ( ) connects to a port (X ) of an interleaved optical filter ( ), and a port (B) of the optical circulator ( ) connects to a port (X ) of the optical filter ( ). A port (Y ) of the optical filter ( ) connects to a port (Y ) of the optical filter ( ) through an optical isolator ( ). The optical isolator ( ) allows the optical propagation from the port (Y ) to the port (Y ) of the optical filter ( ) and refuses the optical propagation from the port (Y ) to the port (Y ). An optical coupler ( ) combines the input lights of the input ports (X and X1) from ports (C) of the optical circulators ( and ) and outputs from the output port (Y ). The optical filter ( ) transmits wavelength (&lgr; ) in the straight propagation between the ports (X , Y ) and between the ports (X , Y ) and transmits wavelength (&lgr; ) in the cross propagation between the ports (X Y ) and between the ports (X Y ).

Optical multiplexer and demultiplexer

A dispersion compensating optical transmission line comprises a plurality of optical transmission fibers for transmitting signal light, at least one first dispersion compensator disposed at a first dispersion compensating cycle for compensating an accumulated chromatic dispersion of the signal light so that an average chromatic dispersion is equal to a first desired value, and a plurality of second dispersion compensators disposed at a second dispersion compensating cycle shorter than the first dispersion compensating cycle for compensating the accumulated chromatic dispersion of the signal light so that an average chromatic dispersion is equal to a second desired value which absolute value is larger than that of the first desired value.

Growing community of inventors

Kamifukuoka, Japan

Takehiro Tsuritani