JP2006246104A - Optical wavelength division multiplex transmitter, optical wavelength division multiplex transmission system, and optical transmission circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To transmit a wavelength division multiplex optical signal of which the transmission speed based on a spectrum-sliced WDM transmission system is ≥10.0 [Gbit/s] through an optical fiber transmission line consisting of a single mode fiber having zero-dispersion wavelength of 1,300-1,324 nm over 1.5 km. <P>SOLUTION: Each of a plurality of optical transmission circuits 11 modulates output light from a wade-band light source in a wide-band optical signal transmission means 112 by an electric signal to which forward error correction encoding is applied by an FEC coding circuit 111 to output a wide-band modulation optical signal having optical spectrum full width half maximum of ≥2 nm and random polarization, and a wavelength multiplexing means 12 segments respective wide-band modulation optical signals by slice width with full width half maximum of 37-160 GHz, arranges wavelength division multiplex optical signals at center frequency intervals of ≤357 GHz in a range of 1,450-1,650 nm wavelength and sends these optical signals to an optical fiber transmission line 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a configuration of an optical wavelength division multiplexing transmission apparatus, an optical wavelength division multiplexing transmission system, and an optical transmission circuit.

  In order to increase the transmission capacity in an optical fiber network, an optical wavelength division multiplexing (WDM) transmission system that multiplexes and transmits optical signals having different wavelengths on one optical fiber has been realized. As a method for realizing this system, a method including a light source that outputs light of a different wavelength for each of a plurality of transmitters can be considered. However, this method requires many types of transmitters, which is economical and easy to maintain. There is a problem in terms. Therefore, in an optical WDM transmission system, a spectrum slice WDM transmission system has been studied as a system that can realize a single type of transmitter and improve economy and maintenance operability.

  FIG. 1 shows an example of an optical WDM transmission system based on the spectrum slice WDM transmission system disclosed in Patent Document 1. In FIG. The plurality of transmitters (user devices) 1 include a broadband light source that generates broadband spontaneous emission (ASE), and transmits a broadband modulated optical signal by direct modulation or external modulation. The remote node 2 inputs the broadband modulated optical signal transmitted from each transmitter 1 through the access optical fiber transmission line, and optically wavelength-division-multiplexes optical signals obtained by spectrally slicing predetermined wavelengths, and transmits the optical fiber. Output to path 3. The wavelength division multiplexed optical signal transmitted through the optical fiber transmission line 3 is demultiplexed by the wavelength demultiplexer 4 and received by a plurality of receivers 5.

In this spectrum slice WDM transmission system, the transmission signal is error-corrected and the code error rate (BER) threshold value is set to 10 ⁻⁴ , so that the transmission spectrum half-width Δf [Hz] and optical wavelength division multiplexed spectrum slice are obtained. When the normalized spectral width Δf / ΔF, which is the ratio to the optical signal center frequency (wavelength) interval ΔF [Hz], is 0.45 to 0.7, the transmission speed of the optical signal is BR [bit / s]. Then, it is shown that good transmission characteristics can be obtained by setting BR / ΔF to 0.028 [bit / s / Hz] or less.
JP 2000-314507 A

  However, when the transmission speed BR of the optical signal is 10.0 [Gbit / s], it is necessary to make Δf thicker than 160 GHz (1.2 nm), and the wavelength range of the wavelength division multiplexed optical signal is set to the low loss wavelength of the optical fiber. If the 1.55 μm band (1450 nm or more and 1650 nm or less) is used, and the optical fiber transmission line is a single mode fiber having a zero dispersion wavelength at 1300 to 1324 nm, the waveform deteriorates due to the influence of fiber dispersion because Δf is large. There is a problem that optical fiber transmission exceeding 1.5 km is impossible.

  Further, there has been no broadband optical signal transmission means composed of a semiconductor optical integrated circuit capable of transmitting 10.0 [Gbit / s] broadband signal light having a random polarization component.

  In order to solve this, in the present invention, a plurality of optical transmission circuits that output a wideband modulated optical signal having a full width at half maximum of 2 nm or more and whose polarization is random, and a wideband from the plurality of optical transmission circuits Wavelength multiplexing means for optically wavelength-division-multiplexing the modulated optical signal, and at least one of the optical transmission circuits encodes an input signal having a transmission rate of 10.0 [Gbit / s] or more using a forward error correction code. Forward error correction encoding circuit and broadband optical transmission means for modulating the output light from the broadband light source by the FEC encoded signal, and the wavelength multiplexing means is output from a plurality of optical transmission circuits A broad-band modulated optical signal is cut out with a full width at half maximum of 37 GHz (0.3 nm) or more and a slice width of 160 GHz (1.2 nm) or less, and ranges from 1450 nm to 1650 nm. Suggest optical wavelength division multiplexing transmission apparatus having a characteristic of wavelength division multiplexed optical signals arranged at 357GHz (2.8 nm) or less of the center frequency (wavelength) intervals.

  Further, the present invention is an optical wavelength division multiplexing transmission system comprising the optical wavelength division multiplexing transmitter, the optical wavelength division multiplexing receiver, and an optical fiber transmission line connecting them together, wherein the optical wavelength The division multiplexing receiver includes wavelength demultiplexing means for separating a transmitted wavelength division multiplexed optical signal for each center frequency (wavelength) and a plurality of optical reception circuits, and at least one of the optical reception circuits is And an optical signal receiving means for converting the received optical signal into an electrical signal and a forward error correction decoding circuit for decoding the FEC-encoded electrical signal. The optical fiber transmission line has a zero dispersion wavelength of 1300 to 1324 nm. We propose an optical wavelength division multiplexing transmission system consisting of single-mode fibers.

  Also, in the present invention, a plurality of optical transmission circuits that output a broadband modulated optical signal having a full width at half maximum of 2 nm or more and a random polarization, and the broadband modulated optical signals from the plurality of optical transmission circuits are converted into optical wavelengths. An optical wavelength division multiplexing transmission system comprising wavelength multiplexing means for division multiplexing, an optical wavelength division multiplexing receiver, and an optical fiber transmission line connecting them together, wherein at least one of the optical transmission circuits Comprises a forward error correction encoding circuit that encodes an input signal with a forward error correction code, and a broadband optical transmitter that modulates output light from a broadband light source with the FEC encoded signal, and the wavelength multiplexing The means outputs a wideband modulated optical signal having a transmission speed of 10.0 [Gbit / s] or more output from a plurality of optical transmission circuits and transmitted through an optical fiber at a full width at half maximum of 37 GHz (0.3 n ) The characteristics are cut out with a slice width of not less than 160 GHz (1.2 nm) and disposed at a center frequency (wavelength) interval of not more than 357 GHz (2.8 nm) in a wavelength range of 1450 nm to 1650 nm to obtain a wavelength division multiplexed optical signal. And the optical wavelength division multiplexing receiver comprises wavelength demultiplexing means for separating the transmitted wavelength division multiplexed optical signal for each center frequency (wavelength) and a plurality of optical reception circuits, and the optical reception At least one of the circuits comprises an optical signal receiving means for converting a received optical signal into an electrical signal, and a forward error correction decoding circuit for decoding the FEC-encoded electrical signal, and the optical fiber transmission line includes: An optical wavelength division multiplexing transmission system composed of a single mode fiber having a zero dispersion wavelength of 1300 to 1324 nm is proposed.

  In the present invention, the forward error correction encoding circuit that encodes the input signal with the forward error correction code, and the output light from the broadband light source having an output spectrum full width at half maximum of 2 nm or more are FEC-encoded. A broadband optical signal transmitting means for modulating a signal and outputting a broadband modulated optical signal having a full width at half maximum of 2 nm or more and having a random polarization and a transmission speed of 10.0 [Gbit / s] or more; And an optical wavelength filter disposed at a subsequent stage of the signal transmitting means, and the optical wavelength filter transmits a full width at half maximum of 37 GHz (0.3 nm) or more and 160 GHz (1.2 nm) or less in a wavelength range of 1450 nm to 1650 nm. An optical transmission circuit having a width is proposed.

  In the present invention, a broadband optical signal transmitting means for outputting a broadband optical signal having an optical spectrum full width at half maximum of 2 nm or more and random polarization, and a full width at half maximum of 37 GHz (0.3 nm) in the wavelength range from 1450 nm to 1650 nm. A plurality of optical transmission circuits including at least an optical wavelength filter having a transmission width of 160 GHz (1.2 nm) or less, an optical coupler for optical wavelength division multiplexing of broadband optical signals from the plurality of optical transmission circuits, and optical wavelength division 8. An optical wavelength division multiplexing transmission system comprising a multiplex receiver and an optical fiber transmission line connecting them together, wherein at least one of the optical transmission circuits is an optical transmission circuit according to claim 6 or 7. The optical coupler combines a wideband modulated optical signal output from a plurality of optical transmission circuits and transmitted through an optical fiber to divide the wavelength. The optical wavelength division multiplex receiver is a multiplexed optical signal, and includes a wavelength demultiplexing unit that separates the transmitted wavelength division multiplexed optical signal for each center frequency (wavelength), and a plurality of optical receiver circuits. At least one of the receiving circuits comprises an optical signal receiving means for converting the received optical signal into an electric signal, and a forward error correction decoding circuit for decoding the FEC encoded electric signal, and the optical fiber transmission line is An optical wavelength division multiplexing transmission system that is a single mode fiber having a zero dispersion wavelength of 1300 to 1324 nm is proposed.

  According to the present invention, in the optical wavelength division multiplexing transmission apparatus, the optical wavelength division multiplexing transmission system, or the optical transmission circuit, the broadband optical signal transmission means is a semiconductor optical in which a semiconductor optical amplifier and an electroabsorption optical modulator are integrated. It is proposed to configure the circuit.

  According to the present invention, in a spectrum slice WDM transmission system with a transmission rate of 10.0 [Gbit / s] or higher, the center frequency (wavelength) interval of wavelength division multiplexed optical signals can be 357 GHz (2.8 nm) or less. In the case of transmitting an optical signal having a spectral width of 37 GHz (0.3 nm) or more and 160 GHz (1.2 nm) or less in a 55 μm band on a single mode fiber having a zero dispersion wavelength at 1300 to 1324 nm, it was impossible in the past. Transmission exceeding 1.5 km is possible.

  In addition, it is possible to realize a broadband optical signal transmission unit composed of a semiconductor optical integrated circuit capable of transmitting broadband signal light having a random polarization component and a transmission rate of 10.0 [Gbit / s] or more.

<First Embodiment>
FIG. 2 shows an optical wavelength division multiplexing (WDM) transmission system according to the first embodiment of the present invention. This system includes an optical wavelength division multiplexing transmitter 10, an optical wavelength division multiplexing receiver 20, and The optical fiber transmission line 3 connects these components to each other.

  The optical wavelength division multiplexing transmission apparatus 10 includes a plurality of optical transmission circuits 11 and wavelength multiplexing means 12, and each optical transmission circuit 11 further includes a forward error correction (FEC) encoding circuit 111. And broadband optical signal transmission means 112.

  The FEC encoding circuit 111 encodes an input (electrical) signal with a forward error correction code. The broadband optical signal transmission unit 112 modulates the output light from the broadband light source with the FEC encoded signal, and outputs a broadband modulated optical signal having an optical spectrum full width at half maximum of 2 nm or more and random polarization.

  As shown in FIG. 3, the broadband light source has a full width at half maximum of the optical spectrum with an output spectrum of 2 nm or more, and a broadband optical signal that can secure two or more wavelength channels when sliced at 100 GHz (0.8 nm) intervals. Shall be output. For example, spontaneous emission light (ASE) of an optical amplifier such as a super luminescent diode (SLD), a semiconductor optical amplifier (SOA), an erbium-doped optical fiber amplifier (EDFA), or the like corresponds to this.

  Random polarization means that the power difference between the polarization components of the output light is 3 dB or less, and as shown in FIG. 4 (a), the polarization independent optical amplifier (SOA, EDFA) is used. By directly modulating the driving current of the broadband light source, or as shown in FIG. 4B, the ASE from the polarization independent optical amplifier (SOA, EDFA) is not dependent on the polarization of an electroabsorption optical modulator or the like. By performing external modulation with an external modulator, a broadband modulated optical signal with random polarization can be obtained.

  As shown in FIG. 5, the wavelength multiplexing means 12 cuts out a wideband modulated optical signal from a plurality of optical transmission circuits 11, performs optical wavelength division multiplexing, and sends it to the optical fiber transmission line 3. A lattice (AWG) or the like corresponds to this. As will be described later, the wavelength multiplexing unit 12 cuts out the broadband modulated optical signal output from the plurality of optical transmission circuits 11 with a full width at half maximum of 37 GHz (0.3 nm) or more and a slice width of 160 GHz (1.2 nm) or less, The wavelength division multiplexed optical signal has a characteristic of being arranged at a center frequency (wavelength) interval of 357 GHz (2.8 nm) or less in a wavelength range of 1450 nm to 1650 nm.

  The optical wavelength division multiplexing receiver 20 includes a wavelength demultiplexing unit 21 and a plurality of optical receiving circuits 22, and each optical receiving circuit 22 further includes an optical signal receiving unit 221 and a forward error correction (FEC) decoding circuit. 222.

  The wavelength demultiplexing means 21 separates the wavelength division multiplexed optical signal transmitted through the optical fiber transmission line 3 for each central frequency (wavelength) and sends it to a plurality of optical receiving circuits 22. This is the case. The optical signal receiving means 221 receives the modulated optical signal from the wavelength demultiplexing means 21, converts it into an FEC-encoded electrical signal, and outputs it. The FEC decoding circuit 222 decodes the FEC encoded electric signal and outputs the original electric signal (input signal).

  When the input (electrical) signal to the optical transmission circuit 11 is 10.0 [Gbit / s], the relationship between the slice width Δf [Hz] in the wavelength multiplexing means 12 and the transmission power and reception sensitivity per channel is shown. As shown in FIG.

Curve (1) shows the transmission power when a broadband optical signal from a broadband light source with an output power of −10 [dBm / nm] is sliced with each slice width. Curve (2) represents the reception sensitivity at which the code error rate (BER) is 1 × 10 ⁻¹² when the forward error correction code is not applied. Curve (3) shows that when Reed-Solomon (255, 239) FEC is applied as the FEC code and the BER threshold value is 1.8 × 10 ⁻⁴ , the BER is 1 × 10 after FEC decoding. ^The reception sensitivity is ^-12 . Curve (4) is the FEC code as a reference by T. Mizuochi et al. (“Forwad Error Correction Based on Block Turbo Code With 3-bit Soft Decision for 10-Gb / s Optical Communication Systems,” “IEEE Journal Selected Topics in When FEC (hereinafter referred to as BTC-FEC) described in Quantum Electronics, Vo.10, No.2, pp.376-386, 2004) is assumed, BER becomes 1 × 10 ⁻¹² after FEC decoding The transmission speed of the encoded signal is 12.4 [bit / s].

  The difference between the curve (1) and the curves (2), (3) and (4) is the loss allowed between the transmission side and the reception side.

In Patent Document 1, in a spectrum slice WDM transmission system (corresponding to Reed-Solomon (255, 239)) in which a BER threshold is set to 10 ⁻⁴ by a forward error correction code, the slice width is obtained in order to obtain good transmission characteristics. When the normalized spectral width Δf / ΔF, which is the ratio of Δf [Hz] and the center frequency (wavelength) interval ΔF [Hz] of the wavelength slice multiplexed spectrum slice optical signal, is 0.45 to 0.7, It has been shown that the ratio BR / ΔF between the optical signal transmission rate BR [bit / s] and ΔF [Hz] needs to be 0.028 [bit / s / Hz] or less. That is, for example, when BR is 10.0 [Gbit / s], it is described that ΔF should be thicker than 357 GHz (2.8 nm). However, the polarization component of the optical signal is not clear, and the optical signal spectrum is sliced by wavelength multiplexing means having a Gaussian transmission spectrum.

  In obtaining the result of FIG. 6, the calculation was performed on the assumption that the polarization component of the optical signal is random and the spectrum of the optical signal is sliced by wavelength multiplexing means having a flat transmission spectrum in the full width at half maximum range. .

  Reed-Solomon (255, 239) or BTC-FEC-encoded 1.55 μm band (1450-1650 nm) broadband optical signal, single mode fiber (1.55 μm band) with zero dispersion wavelength at 1300-1324 nm FIG. 7 shows the calculation result of the dispersion tolerance with respect to the slice width Δf when the dispersion value is transmitted at about 17 ps / nm / km. This is the fiber length with a dispersion penalty of 1 dB.

In Patent Document 1, when the threshold value of BER is set to 1 × 10 ⁻⁴ by a forward error correction code (corresponding to Reed-Solomon (255, 239)), when Δf / ΔF is 0.45 to 0.7, In order to set BR / ΔF to 0.028 [bit / s / Hz] or less, when BR is 10.0 [Gbit / s], if Δf is thicker than 160 GHz (1.2 nm), good transmission characteristics can be obtained. As shown in FIG. 7, if the wavelength band of the wavelength division multiplexed optical signal is 1.55 μm band and the optical fiber transmission line is a single mode fiber having a zero dispersion wavelength in 1300 to 1324 nm, Δf is 160 GHz from FIG. It can be seen that when the thickness is larger than (1.2 nm), the dispersion resistance becomes 1.5 km or less.

  6 that Δf can be set to 37 GHz (0.3 nm) or more and 160 GHz (1.2 nm) or less when FEC is applied. From FIG. 7, Δf is 160 GHz (1.2 nm). It can be seen that, for the first time, optical fiber transmission exceeding 1.5 km is possible for the first time. At this time, since ΔF is thicker than Δf, it can be set to 357 GHz (2.8 nm) or less.

  A dispersion compensation circuit can be arranged at any location in the system (for example, between the optical fiber transmission line and the optical wavelength division multiplexing receiver) to further increase the optical fiber transmission distance. In this case, according to the present invention, an error in the amount of dispersion compensated by the dispersion compensation circuit can be allowed by 1.5 km in terms of the length of the single mode fiber providing dispersion.

<Second Embodiment>
FIG. 8 shows an optical WDM transmission system according to the second embodiment of the present invention, here, in the optical WDM transmission system of the first embodiment, a plurality of optical transmission circuits and wavelength multiplexing means transmit optical fibers to each other. An example in which a wavelength splitter type PON (Passive Optical Network) is connected by a path, and the same components are arranged in the opposite direction and bidirectional communication is performed by carrying out the communication in the opposite direction. Show.

  That is, in FIG. 8, reference numeral 31 denotes a plurality of optical transmission / reception circuits including the optical transmission circuit 11 and the optical reception circuit 22, 32 denotes wavelength multiplexing / demultiplexing means, and 33 and 34 denote optical fiber transmission lines. A multiplex transmitter / receiver 30 is configured. Reference numeral 41 denotes wavelength multiplexing / demultiplexing means, and reference numeral 42 denotes a plurality of optical transmission / reception circuits including the optical transmission circuit 11 and the optical reception circuit 22, and the other optical wavelength multiplexing transmission / reception apparatus 40 is constituted by these. In the wavelength splitter type PON, AWG or the like is used as wavelength multiplexing / demultiplexing means (wavelength multiplexing / demultiplexing means).

  Also in this case, as in the case of the first embodiment, the optical signal transmission speed is 10.0 [Gbit / s] or more, and the slice width Δf is not less than 37 GHz (0.3 nm) full width at half maximum and 160 GHz (1. 2 nm) or less. Therefore, when transmitting a polarization-independent broadband signal in the 1.55 μm band with a single mode fiber having a zero dispersion wavelength at 1300 to 1324 nm, it is possible to transmit an optical fiber exceeding 1.5 km, which has been impossible in the past. Become.

  A dispersion compensation circuit can be arranged at any place in the system (for example, between the optical fiber transmission line and the optical wavelength division multiplexing transmitter / receiver) to further increase the optical fiber transmission distance. In this case, according to the present invention, the distance difference between the plurality of optical fiber transmission lines connecting the optical transmission circuit and the wavelength multiplexing / demultiplexing means can be allowed by 1.5 km in terms of the length of the single mode fiber that gives dispersion.

<Third Embodiment>
FIG. 9 shows an example in which an optical wavelength filter is added to the optical transmission circuit according to the third embodiment of the present invention, here the optical transmission circuit used in the first or second embodiment. 113 are optical wavelength filters having a full width at half maximum of 37 GHz (0.3 nm) or more and a transmission width of 160 GHz (1.2 nm) or less in the wavelength range of 1450 nm to 1650 nm.

  The optical wavelength filter 113 is disposed at the subsequent stage of the broadband optical signal transmission unit 112, and constitutes the optical transmission circuit 11A together with the FEC encoding circuit 111 and the broadband optical signal transmission unit 112.

  According to the above-described configuration, the full width at half maximum of 37 GHz (0.3 nm) or more and 160 GHz (with a full width at half maximum of 2 nm output from the broadband optical signal transmission unit 112 and having a random polarization whose polarization is random is 160 GHz ( 1.2 nm) or less as a modulated light signal.

<Fourth embodiment>
FIG. 10 shows an optical WDM transmission system according to a fourth embodiment of the present invention, here an optical WDM transmission system according to the second embodiment, which is shown in the third embodiment instead of the optical transmission circuit 11. Using the optical transmission circuit 11A, an optical transmission / reception circuit 31A using the optical reception circuit 22A in which an optical wavelength filter 223 similar to the optical wavelength filter 113 is disposed in front of the optical signal reception means instead of the optical reception circuit 22, is used. An example is shown in which an optical coupler (power splitter) 35 is used in place of the wavelength multiplexing / demultiplexing means 32 to configure a power splitter type PON (Passive Optical Network) optical wavelength division multiplexing transmitter / receiver 30A.

  Also in this case, similarly to the second embodiment, the transmission speed of the optical signal is 10.0 [Gbit / s] or more, and the spectral width Δf of the wavelength division multiplexed optical signal is 37 GHz (0.3 nm) or more and 160 GHz. (1.2 nm) or less is possible. Therefore, when transmitting a polarization-independent broadband signal in the 1.55 μm band with a single mode fiber having a zero dispersion wavelength at 1300 to 1324 nm, it is possible to transmit an optical fiber exceeding 1.5 km, which has been impossible in the past. Become.

  A dispersion compensation circuit can be arranged at any place in the system (for example, between the optical fiber transmission line and the optical wavelength division multiplexing transmitter / receiver) to further increase the optical fiber transmission distance. In this case, according to the present invention, the distance difference between the plurality of optical fiber transmission lines connecting the optical transmission circuit and the wavelength multiplexing / demultiplexing means or the optical coupler by 1.5 km in terms of the length of the single mode fiber giving dispersion is obtained. acceptable.

<Fifth embodiment>
An optical wavelength division multiplexing transmission apparatus, an optical wavelength division multiplexing transmission system, and an optical transmission circuit according to a fifth embodiment of the present invention are configured by a semiconductor optical circuit in which a semiconductor optical amplifier and an electroabsorption optical modulator are integrated. The broadband optical signal transmitting means is used.

  Conventionally, this semiconductor optical circuit has been used for the purpose of amplifying signal light incident from an electroabsorption optical modulator and outputting signal light from the electroabsorption optical modulator by a semiconductor optical amplifier.

  By modulating the spontaneous emission light of the semiconductor optical amplifier by an electroabsorption optical modulator, this semiconductor optical circuit transmits a broadband optical signal having a random polarization component and a transmission rate of 10.0 [Gbit / s] or more. It can be used as a possible broadband optical signal transmission means, whereby the devices, systems and circuits described in the first to fourth embodiments can be realized in a small size.

Configuration diagram showing an example of an optical WDM transmission system based on a conventional spectrum slice WDM transmission system 1 is a configuration diagram of an optical WDM transmission system according to a first embodiment of the present invention. Spectrum diagram of broadband optical signal from broadband light source Configuration diagram showing a specific example of broadband optical signal transmission means Spectral diagram showing how a wideband modulated optical signal is cut out by wavelength multiplexing means Graph showing the relationship between slice width, transmission power per channel and reception sensitivity in wavelength multiplexing means The graph which shows the result of having calculated the dispersion tolerance with respect to the slice width in the wavelength multiplexing means at the time of transmitting the optical signal by which FEC encoding was carried out with the single mode fiber 1 is a configuration diagram of an optical WDM transmission system according to a second embodiment of the present invention. Configuration diagram of an optical transmission circuit according to a third embodiment of the present invention The block diagram of the optical WDM transmission system concerning the 4th Embodiment of this invention

Explanation of symbols

  3: optical fiber transmission line, 10: optical wavelength division multiplexing transmitter, 11, 11A: optical transmission circuit, 12: wavelength multiplexing means, 20: optical wavelength division multiplexing reception apparatus, 21: wavelength demultiplexing means, 22, 22A : Optical receiver circuit, 30, 30A, 40: Optical wavelength division multiplexing transmitter / receiver, 31, 31A, 42: Optical transmitter / receiver circuit, 32, 41: Wavelength multiplexing / demultiplexing means, 33, 34: Optical fiber transmission line, 35: Light Coupler: 111: FEC encoding circuit; 112: broadband optical signal transmission means; 113, 223: optical wavelength filter; 221: optical signal reception means; 222: FEC decoding circuit.

Claims (8)

A plurality of optical transmitter circuits that output a broadband modulated optical signal having a full width at half maximum of 2 nm or more and a random polarization; and a wavelength combination for optical wavelength division multiplexing of the broadband modulated optical signals from the plurality of optical transmitter circuits. Wave means,
At least one of the optical transmission circuits includes a forward error correction encoding circuit that encodes an input signal having a transmission rate of 10.0 [Gbit / s] or more with a forward error correction code, and output light from a broadband light source. A broadband optical transmitter that modulates with an FEC-encoded signal;
The wavelength multiplexing means cuts out a wideband modulated optical signal output from a plurality of optical transmission circuits with a full width at half maximum of 37 GHz (0.3 nm) or more and a slice width of 160 GHz (1.2 nm) or less, and has a wavelength from 1450 nm to 1650 nm. An optical wavelength division multiplexing transmitter characterized by having a wavelength division multiplexed optical signal arranged in a range with a center frequency (wavelength) interval of 357 GHz (2.8 nm) or less. The optical wavelength division multiplexing transmitter according to claim 1,
The broadband optical signal transmission means is composed of a semiconductor optical circuit in which a semiconductor optical amplifier and an electroabsorption optical modulator are integrated. An optical wavelength division multiplexing transmission system comprising the optical wavelength division multiplexing transmission device according to claim 1, an optical wavelength division multiplexing reception device, and an optical fiber transmission line connecting them to each other,
The optical wavelength division multiplexing receiver is composed of wavelength demultiplexing means for separating the transmitted wavelength division multiplexed optical signal for each central frequency (wavelength), and a plurality of optical receiving circuits,
At least one of the optical receiving circuits comprises an optical signal receiving means for converting a received optical signal into an electric signal, and a forward error correction decoding circuit for decoding the FEC encoded electric signal,
The optical fiber transmission line is composed of a single mode fiber having a zero dispersion wavelength of 1300 to 1324 nm. An optical wavelength division multiplexing transmission system. A plurality of optical transmission circuits that output a broadband modulated optical signal having a full width at half maximum of 2 nm or more and a random polarization, and wavelength multiplexing for optical wavelength division multiplexing of the broadband modulated optical signals from the plurality of optical transmission circuits An optical wavelength division multiplex transmission system comprising means, an optical wavelength division multiplex receiver, and an optical fiber transmission line connecting them together,
At least one of the optical transmission circuits includes a forward error correction encoding circuit that encodes an input signal with a forward error correction code, and a broadband optical transmission that modulates output light from a broadband light source using the FEC encoded signal. Consisting of means,
The wavelength multiplexing means outputs a wideband modulated optical signal having a transmission speed of 10.0 [Gbit / s] or more output from a plurality of optical transmission circuits and transmitted through an optical fiber to a full width at half maximum of 37 GHz (0.3 nm) or more and 160 GHz (1 .2 nm) with a slice width of less than or equal to, and arranged at a center frequency (wavelength) interval of not more than 357 GHz (2.8 nm) in a wavelength range of 1450 nm to 1650 nm to have a wavelength division multiplexed optical signal,
The optical wavelength division multiplexing receiver is composed of wavelength demultiplexing means for separating the transmitted wavelength division multiplexed optical signal for each central frequency (wavelength), and a plurality of optical receiving circuits,
At least one of the optical receiving circuits comprises an optical signal receiving means for converting a received optical signal into an electric signal, and a forward error correction decoding circuit for decoding the FEC encoded electric signal,
The optical fiber transmission line is composed of a single mode fiber having a zero dispersion wavelength of 1300 to 1324 nm. An optical wavelength division multiplexing transmission system. The optical wavelength division multiplexing transmission system according to claim 4,
The broadband optical signal transmission means is composed of a semiconductor optical circuit in which a semiconductor optical amplifier and an electroabsorption optical modulator are integrated. An optical wavelength division multiplex transmission system, wherein: A forward error correction encoding circuit that encodes an input signal with a forward error correction code, and an output light from a broadband light source having an output spectrum full width at half maximum of 2 nm or more is modulated by the FEC-encoded signal, and 2 nm Broadband optical signal transmitting means for outputting a broadband modulated optical signal having a full width at half maximum of the optical spectrum and having a random polarization and a transmission rate of 10.0 [Gbit / s] or higher, and a subsequent stage of the broadband optical signal transmitting means And an arranged optical wavelength filter,
The optical wavelength filter has a full width at half maximum of 37 GHz (0.3 nm) or more and a transmission width of 160 GHz (1.2 nm) or less in a wavelength range of 1450 nm to 1650 nm. The optical transmission circuit according to claim 6,
The broadband optical signal transmission means is composed of a semiconductor optical circuit in which a semiconductor optical amplifier and an electroabsorption optical modulator are integrated. Broadband optical signal transmitting means for outputting a broadband optical signal having a full width at half maximum of 2 nm or more and a random polarization, and a full width at half maximum of 37 GHz (0.3 nm) or more and 160 GHz (1. A plurality of optical transmission circuits including at least an optical wavelength filter having a transmission width of 2 nm) or less, an optical coupler for optical wavelength division multiplexing of broadband optical signals from the plurality of optical transmission circuits, an optical wavelength division multiplexing receiver, and these An optical wavelength division multiplexing transmission system composed of optical fiber transmission lines that connect each other,
At least one of the optical transmission circuits is an optical transmission circuit according to claim 6 or 7,
The optical coupler combines a wideband modulated optical signal output from a plurality of optical transmission circuits and transmitted through an optical fiber to form a wavelength division multiplexed optical signal,
The optical wavelength division multiplexing receiver is composed of wavelength demultiplexing means for separating the transmitted wavelength division multiplexed optical signal for each central frequency (wavelength), and a plurality of optical receiving circuits,
At least one of the optical receiving circuits comprises an optical signal receiving means for converting a received optical signal into an electric signal, and a forward error correction decoding circuit for decoding the FEC encoded electric signal,
The optical fiber transmission line is a single mode fiber having a zero dispersion wavelength of 1300 to 1324 nm. An optical wavelength division multiplexing transmission system, wherein:

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