JP3481456B2 - Bidirectional WDM optical transmission system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention particularly relates to NZ-DSF
And belongs to a suitable bidirectional WDM optical transmission system . [0004] Conventionally, in recent years, the transmission capacity of the network enlarging, improved reliability, research ring system to which the WDM technology from the request, such as a lower cost has been actively conducted. [0003] The present invention is, however, in the wavelength division multiplexing (WDM) optical transmission system, WDM optical signals in the dispersion-shifted fiber of 1550nm band; long-distance transmission by (DSF zero-dispersion wavelength 1551 nm) In the case, Four Wave Mixing (FWM; Four Wave Mixing)
There is a problem that the reception sensitivity is deteriorated due to the influence of. [0004] The present invention has been made in view of such problems and situations, and an object, turn the reception sensitivity degradation due to four-wave mixing even when long-distance transmission
Another object of the present invention is to provide a bidirectional WDM optical transmission system that can avoid such a situation. [0005] The present invention is described in claim 1 of the present invention.
The gist of the invention described above is that WDM optical transceivers are used as optical transmission paths.
A two-way WDM optical transmission system
WDM optical transmission and reception as one of the WDM optical transceivers
Transmitter (1) and WD as the other WDM optical transmitter
An M optical transceiver (6), the WDM optical transceiver
(1) The WDM optical transceiver (6) is an optical transmission line
The one optical transmission line is connected one-to-one by (5).
(5) is configured to perform bidirectional WDM optical transmission,
The WDM optical transceiver (1) is a WD for the 1550 nm band.
M optical transmitter (2) and 1580nm band WDM optical receiver
(3) wavelength division multiplexing of 1550 nm band and 1580 nm band
A WDM coupler (4) for transmitting and receiving the WDM light.
The transmitter (6) is a WDM optical transmitter for 1580nm band
(9) and 1550 nm band WDM optical receiver (8) and 15
WD for wavelength division multiplexing of 50nm band and 1580nm band
An M coupler (7) is provided, and the single optical transmission line (5)
An optical transmission line configured to perform one-way WDM optical transmission;
(5) shows that the zero dispersion wavelength is 1550 nm band and 1580 nm.
The zero-dispersion wavelength created so as not to be in the nm band is 150
Consisting of 0 nm zero dispersion shifted fiber (NZ-DSF)
Bidirectional WDM optical transmission system characterized by the following:
Live in Embodiments of the present invention will be described below in detail with reference to the drawings. First Embodiment As shown in FIG. 1, an optical transmission system according to a first embodiment includes a WDM optical transceiver 1 and a WDM optical transceiver 6.
And The WDM optical transceiver 1 and the WDM optical transceiver 6 are connected one-to-one by an optical transmission line 5, and bidirectional WDM optical transmission is performed on the single optical transmission line 5. The WDM optical transceiver 1 comprises a WDM optical transmitter 2 for the 1550 nm band and a WDM optical receiver 3 for the 1580 nm band.
And a WDM coupler 4 for performing wavelength division multiplexing in the 1550 nm band and the 1580 nm band. The WDM optical transmitter / receiver 6 includes a WDM optical transmitter 9 for the 1580 nm band and a WDM optical receiver 8 for the 1550 nm band.
And a WDM coupler 7 that performs wavelength division multiplexing in the 1550 nm band and the 1580 nm band. The WDM optical transceiver 1 and the WDM optical transceiver 6 are connected one-to-one by an optical transmission line 5, and bidirectional WDM optical transmission is performed by the single optical transmission line 5. The optical transmission line 5 has a zero dispersion wavelength of 1550 n.
Nonzero-disp having a zero dispersion wavelength of 1500 nm prepared so as not to be in the m band and the 1580 nm band.
version shifted fiber (NZ-D
By applying SF), it is possible to avoid the influence of four-wave mixing caused by transmitting a WDM optical signal over a long distance. The WDM optical transmitter / receiver 6 is similar to the WDM optical transmitter / receiver 1 in that the WDM optical receivers 8 and 1 for the 1550 nm band are used.
580 nm band WDM optical transmitters 9 and 1550 nm band and 1
It comprises a WDM coupler 7 that performs wavelength division multiplexing in the 580 nm band. (Second Embodiment) Next, a second embodiment will be described with reference to FIG. Second
The embodiment is a point-to-point WDM optical transmission system.
It relates to a point system. This system performs bidirectional WDM optical transmission between the WDM optical transceivers 10 and 14 as in FIG. In FIG. 2, the WDM optical transceiver 10 is a WDM optical transceiver 10 for a 1550 nm band.
DM optical transmitter 15 and WDM optical receiver 1 in 1580 nm band
6, a WDM coupler 17 for performing wavelength division multiplexing in the 1550 nm band and the 1580 nm band. The WDM optical transmitter / receiver 14 has WDM optical transmitters 24 and 155 for the 1580 nm band.
0nm band WDM optical receiver 23, 1550nm band and 15
The WDM coupler 22 performs wavelength division multiplexing in the 80 nm band. The WDM optical transmitters 15 and 24 have a wavelength of 1550 nm.
Transmission unit 2 for transmitting optical signals in the band or 1580 nm band
5-1 to 25-n, 40-1 to 40-n;
Optical multiplexing units 26 and 39 for performing optical wavelength multiplexing of optical signals from 5-1 to 25-n and 40-1 to 40-n, and optical direct amplifying units 27 and 38 for amplifying multiplexed optical signals. And a dispersion compensating fiber (DC
F) 28, 37. The WDM optical receivers 16 and 23 are provided with a dispersion compensating fiber (DCF) for compensating a dispersion amount generated during long-distance transmission.
32, 33; optical direct amplifiers 31 and 34 for amplifying WDM optical signals; optical demultiplexers 30 and 35 for demultiplexing optical wavelengths of WDM optical signals; and optical demultiplexers 30 and 35 Optical receivers 29-1 to 29-n, 36-1 to 3-3 for performing reception
6-n. In order to amplify a bidirectional WDM optical signal,
Optical direct amplifiers 19 and 1580n for amplification in 1550 nm band
Optical direct amplifier 20 for m-band amplification, 1550 nm band and 15
WDM for wavelength division multiplexing of WDM optical signal in 80nm band
A bidirectional linear repeater 12 composed of couplers 18 and 21 is used. The WDM optical transmitters 15 and 24 are provided with an optical transmission unit 25 for transmitting an optical signal in a 1550 nm band or a 1580 nm band.
-1~25-n, 40 -1~ 40 -n and optical multiplexing unit 26 for performing optical wavelength multiplexing optical signal from the optical transmission section 25-1~25-n, 40 -1~ 40 -n , 39 , an optical direct amplifier 27, 38 for amplifying the multiplexed optical signal, and a dispersion compensating fiber (D
CF) 28, 37. WDM optical receiver 1
Reference numerals 6 and 23 denote dispersion compensating fibers (DCFs) 32 and 33 for compensating for the amount of dispersion generated during long-distance transmission, and an optical direct amplifying unit 31 for amplifying a WDM optical signal on the transmission line 11 or 13.
34 and an optical separation unit 3 for performing optical wavelength separation of the WDM optical signal
And 0,35, the optical receiver 29-1 to 29-n for receiving a respective optical signal from the optical separation unit 30, 35, 36 -1 3
6- n. The 1550 nm band and 158
The WDM couplers 17, 18, 21, and 22 that perform wavelength division multiplexing of WDM optical signals in the 0 nm band may be replaced by 3 dB couplers. Next, the operation of the second embodiment will be described. In FIG. 2, a 1550 nm band WDM optical signal (λ1 to λ) transmitted from the WDM optical transmitter 15 is shown.
i) is transmitted to the optical transmission line 11 via the WDM coupler 17. The WDM optical signal (λ
1 to λi) are input to the bidirectional linear repeater 12, and WD
After being wavelength-divided by the M coupler 18 and amplified by the optical direct amplifier 19 for amplification in the 1550 nm band, it is transmitted to the transmission line 13 via the WDM coupler 21. The WDM optical signals (λ1 to λi) propagated through the optical transmission line 13 are
After being input to 2 and wavelength-division-divided, it is received by the WDM optical receiver 23 on the opposite side. On the other hand, a WDM optical signal (λi + 1 to λi + 1) in the 1580 nm band output from the WDM optical transmitter 24.
λn) is transmitted to the optical transmission line 13 via the WDM coupler 22. The WDM optical signals (λi + 1 to λn) propagated through the optical transmission line 13 are input to the bidirectional linear repeater 12, wavelength-divided by the WDM coupler 21, and amplified by the optical direct amplifier 20 for amplifying the 1580 nm band. The light is transmitted to the optical transmission line 11 via the WDM coupler 18. The WDM optical signals (λi + 1 to λn) propagated through the optical transmission line 11 are:
After being input to the WDM coupler 17 and subjected to wavelength division, it is received by the WDM optical receiver 16 on the opposite side. The WDM couplers 17, 18, used in the WDM optical transceivers 10, 14 and the bidirectional linear repeater 12,
FIG. 3 shows the operations of 21 and 22. The 1550 nm band WDM optical signals (λ1 to λi)
The 80 nm band WDM optical signals (λi + 1 to λn) are wavelength-divided by the wavelength division multiplexing unit 41, and the 1550 nm band WDM optical signals (λ1 to λi) are
The nm-band WDM optical signals (λi + 1 to λn) are
Is output to Conversely, 1550 input from port 43
nm band WDM optical signal (λ1 to λi) and the 1580 nm band WDM optical signal (λi + 1
To λn) are wavelength-multiplexed by the wavelength division multiplexing unit 41,
WDM in both wavelength bands of 1550 nm band and 1580 nm band
An optical signal is output from port 42. Thus, the 1550 nm band and 158
Thus, bidirectional optical transmission of the WDM optical signal in the 0 nm band is realized. Also, since NZ-DSF having a zero dispersion wavelength of 1500 nm is used for the optical transmission lines 11 and 13,
In both the 50 nm band and the 1580 nm band, W
It is possible to avoid the deterioration of the receiving sensitivity due to the four-wave mixing of the DM optical signal. Further, by performing bidirectional optical transmission in the 1550 nm band and the 1580 nm band, it is possible to increase the transmission capacity and reduce the cost of laying the optical transmission line. The optical direct amplifier used for the WDM linear repeater uses a WDM coupler or a 3 dB coupler at the input / output end for the 1550 nm band,
By dividing for the nm band, a broadband one is not required
One for the 550 nm band and one for the 1580 nm band may be used. Third Embodiment A third embodiment will be described with reference to FIG. In the third embodiment, an optical ADM (Add / Drop) of a WDM optical transmission system is used.
Optical switch 45, 4 for self-healing ( self-line recovery ) in a Multiplex ring system.
7 is provided at the input / output end of the node, during which the optical ADM unit 4
6 are arranged. The optical ADM unit 46 includes an optical ADM unit for an operation system and an optical ADM unit for a standby system. The optical ADM unit for the operation system separates / adds (Add / Add) WDM optical signals (λ1 to λi) in the 1550 nm band.
And a separation / insertion (Ad) of a WDM optical signal (λi + 1 to λn) in the 1580 nm band.
d / Drop), 1550n
The WDM couplers 48 and 51 perform wavelength division multiplexing of WDM optical signals in the m band and the 1580 nm band. The optical ADM unit for the standby system separates / adds (Add / Add) WDM optical signals (λ1 to λi) in the 1550 nm band.
And a separation / insertion (Ad) of WDM optical signals (λi + 1 to λn) in the 1580 nm band.
d / Drop), 1550n
It is composed of WDM couplers 52 and 55 which perform wavelength division multiplexing of WDM optical signals in the m band and the 1580 nm band. Normally, the optical switches 45 and 47 are controlled so as to connect the optical ADM unit for operation system and the optical transmission line for operation system, and the transmission is performed by the optical transmission line for operation system. Light A
If the optical transmission line between the DM nodes is disconnected, the optical switch of the optical ADM node connected to the disconnected optical transmission line is controlled, and the transmission line is restored by switching to the standby optical transmission line. Plan. The light separating / inserting sections 49, 50, 53, 54
As shown in FIG. 5, a WDM optical direct amplifier 57 for amplifying a 1550 nm band WDM optical signal, an optical demultiplexer 58 for demultiplexing the WDM optical signal, and an optical demultiplexer 58 for demultiplexing each optical signal from the optical demultiplexer 58. OE / EO converter 5 that performs OE / EO conversion
9-1 to 59-n and the OE / EO conversion units 59-1 to 59-n
Optical switch 60 for separating and inserting an optical signal from 59-n
-1 to 60-n and the optical switches 60-1 to 60-n
OE / EO converters 61-1 to 61-n for performing OE / EO conversion of the optical signal from the OE / EO converter, and the OE / EO converter 61-1
It comprises an optical multiplexing unit 62 for performing optical wavelength multiplexing of each optical signal from -61-n, and an optical direct amplifying unit 63 for amplifying the multiplexed optical signal. The WDM optical signal input to the port 56 is
After the optical amplification by the WDM optical direct amplifier 57 , the optical separation unit 58
OE / EO converters 59-1 to 59-n
Performs OE / EO conversion. OE / EO converter 59-1
Optical signals of respective wavelengths through the through 59-n optical switch 60
-1 to 60-n to perform separation / insertion of an arbitrary wavelength. The optical signals of each wavelength passing through the optical switches 60-1 to 60-n are converted into OE / EO converters 61-1 to 61-n.
Is input to the optical multiplexing unit 62 via The optical multiplexing section 62 multiplexes the optical signals of the respective wavelengths into optical wavelengths and performs WDM optical direct amplification 63
Is output from the port 64 via the. The optical ADM nodes 65-1 to 65-6 shown in FIG.
FIG. 6 shows a configuration example of an optical ADM ring system in which 5-n are connected in a ring shape. Each optical ADM node 65-1
65-n are connected by two optical transmission lines of an operation system and a standby system, and a 1550 nm band WDM optical signal and a 1580 nm band WDM optical signal are bidirectionally transmitted to each optical transmission line. FIGS. 7 and 8 show an example of a self-healing function of an optical ADM ring network in which optical ADM nodes 65-1 to 65-n are connected in a ring. In FIG. 7, 1550 n is normally provided between the optical ADM node 66 and the optical ADM node 69.
It performs bidirectional optical transmission in the m and 1580 nm bands. In this case, the optical switch of each optical ADM node 66 and optical ADM node 69 controls the optical switch so that the optical ADM unit performing separation / insertion is connected to the active optical transmission line. The solid line indicates the transmission path in the 1550 nm band, and the dashed line indicates the transmission path in the 1580 nm band. In FIG. 8, the optical ADM node 71 and the optical A
When the optical transmission path between the DM node 72 becomes cross switches the optical switch of the optical ADM node 71 and the optical ADM node 72 as shown in FIG. 8, bypassing using reverse rotation protection optical transmission line The transmission between the optical ADM node 71 and the optical ADM node 74 is restored. In the figure, reference numerals 73 and 75 are optical ADMs.
Node. (Fourth Embodiment) A fourth embodiment will be described with reference to FIG. The fourth embodiment relates to an optical cross-connect system of a WDM optical transmission system, and performs transmission in the opposite direction to the positive optical cross-connect node 76 and the positive optical cross-connect node 76 for performing optical cross-connect processing in the 1550 nm band and the 1580 nm band. It comprises a backlight cross-connect node 77. The positive light cross-connect node 76 has 155
An optical cross-connect unit 80 for performing cross-connect processing for each wavelength in the 0-nm band, an optical cross-connect unit 81 for performing cross-connect processing for each wavelength in the 1580-nm band, and 1550;
WDM couplers 79-1 to 79-n and 82-1 to 8 that perform wavelength division multiplexing of WDM optical signals in the nm band and the 1580 nm band.
2-n. The backlight cross-connect node 77 has a
An optical cross-connect unit 86 for performing cross-connect processing for each wavelength in the 0 nm band, an optical cross-connect unit 87 for performing cross connect processing for each wavelength in the 1580 nm band, and 1550
WDM couplers 85-1 to 85-n and 88-1 to 8 that perform wavelength division multiplexing of WDM optical signals in the nm band and the 1580 nm band.
8-n. In the figure, reference numerals 84-1 to 84-
n, 89-1 to 89-n are ports. In FIG. 9, ports 78-1 to 78-n
Are input to the optical cross-connect unit 80 via the WDM couplers 79-1 to 79-n. The optical cross-connect unit 80 converts the optical signals of each wavelength into arbitrary WDM couplers 82-1 to 82-n.
Is switched to be connected to port 83-1 to port 83-1.
83-n. The WDM optical signal of the 1580 nm band input to the ports 83-1 to 83-n is converted to a WDM coupler 82-n.
The signals are input to the optical cross-connect unit 81 via 1 to 82-n. The optical cross-connect unit 81 switches the optical signal of each wavelength so as to be connected to an arbitrary WDM coupler 79-1 to 79-n, and transmits the optical signal from the ports 78-1 to 78-n. Similarly, the backlight cross connect node 77
However, optical cross-connect processing in the opposite direction of the 1550 nm band and the 1580 nm band is performed. The optical cross connect units 80 and 8 in FIG.
The configuration of 1, 86, 87 is shown in FIG. The optical cross-connect units 80, 81, 86, and 87, as shown in FIG.
WDM optical direct amplifier 91-1 for amplifying WDM optical signal
To 91-n, optical demultiplexers 92-1 to 92-n for demultiplexing optical wavelengths of WDM optical signals, and optical demultiplexers 92-1 to 92-n.
OE / EO for performing OE / EO conversion of each optical signal from -n
Conversion units 93-1 to 93-n, 94-1 to 94-n, and OE / EO conversion units 93-1 to 93-n, 94-1 to 9
4-n, an optical full-matrix switch 95 for switching the destination node of the optical signal of each wavelength, and OE / E of the optical signal from the optical signal from the optical full-matrix switch 95
OE / EO converters 96-1 to 96-n, 9 for performing O conversion
7-1 to 97-n and the OE / EO conversion units 96-1 to 96-n
96-n, optical multiplexing units 98-1 to 98-n for performing optical wavelength multiplexing of optical signals from 97-1 to 97-n, and WDM optical signals from optical multiplexing units 98-1 to 98-n And WDM optical direct amplifiers 99-1 to 99-n for amplifying the signals. The WDM optical signal from each node input to the ports 90-1 to 90-n is converted to a WDM optical direct amplifier 91-n.
The light is input to the light splitting units 92-1 to 92-n via 1 to 91-n, and is split into each wavelength. The separated optical signals are output to OE / EO converters 93-1 to 93-n and 94-1.
After the OE / EO conversion by .about.94-n, it is input to the optical full matrix switch 95. The optical full-matrix switch 95 controls switching so that optical signals of each wavelength from each optical cross-connect node are transmitted to any optical cross-connect node. Each optical signal output from the optical full matrix switch 95 is converted into an OE / EO converter 96-1 to 96-.
n, 97-1 to 97-n, and the optical multiplexing units 98-1 to 98-1.
Optical multiplexing is performed by 98-n. Optical multiplexing units 98-1 to 98
-N output from the WDM optical amplifiers 99-1 to 99-n,
Output from -1 to 100-n. In this way, an optical signal of an arbitrary wavelength input to an arbitrary port is wavelength-multiplexed and output from an arbitrary output port. The optical cross-connect node 10 shown in FIG. 10
FIG. 11 shows a schematic diagram of an optical cross-connect system in which a mesh network system is formed using 1-1 to 101-n. Each optical cross connect node 101-
1 to 101-n, two optical transmission lines for performing bidirectional WDM optical transmission in the 1550 nm band and the 1580 nm band are connected to each other for the reverse direction, and each optical cross-connect node 101 -1 to 101-n are connected in a mesh. Each optical cross-connect node 101-1 to 101-1
In 01-n, the optical full-matrix switch 95 shown in FIG. 10 can perform control so that an optical signal of an arbitrary wavelength can be transmitted to any of the optical cross-connect nodes 101-1 to 101-n. In the fourth embodiment, the same effects as in the above embodiment can be obtained. The number, position, shape and the like of the above-mentioned constituent members are not limited to the above-mentioned embodiment, but can be set to suitable numbers, positions and shapes for carrying out the present invention. In each drawing, the same components are denoted by the same reference numerals. As described above, according to the present invention, the NZ-DSF is applied to the optical transmission line, and the A
The following effects can be obtained by performing bidirectional optical transmission in the band (1550 nm band) and the B band (1580 nm band). By applying a wavelength different from that of the optical transmitter and the optical receiver to the optical transmission line, the A band (1550 nm band) and the B band (1580 nm band) can be used even when long-distance transmission is performed.
It is possible to avoid the deterioration of the receiving sensitivity due to the four-wave mixing of the WDM optical signal.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a bidirectional WDM according to a first embodiment of the present invention.
It is a basic block diagram of the optical transmission method. 2 is a diagram illustrating a point-to-point system of the WDM optical transmission system according to a second embodiment of the present invention. FIG. 3 is a diagram illustrating an operation of a WDM optical transceiver and a WDM coupler used in a bidirectional linear repeater of the WDM optical transmission system illustrated in FIG. 2; FIG. 4 is a diagram illustrating an optical ADM ring system of a WDM optical transmission system according to a third embodiment of the present invention. FIG. 5 is a configuration diagram of an optical ADM unit used shown in FIG. 6 is a configuration diagram of an optical ADM ring system in which the optical ADM nodes illustrated in FIG. 4 are connected in a ring shape. 7 is a diagram illustrating an example of a self-healing function of an optical ADM ring network in which the optical ADM nodes illustrated in FIG. 4 are connected in a ring shape. 8 is a diagram illustrating an example of a self-healing function of an optical ADM ring network in which the optical ADM nodes illustrated in FIG. 4 are connected in a ring shape. FIG. 9 is a diagram illustrating an optical cross-connect system of a WDM optical transmission system according to a fourth embodiment of the present invention. FIG. 10 is a configuration diagram of an optical cross-connect unit in FIG. 9; 11 is a schematic diagram of an optical cross-connect system using the optical cross-connect node shown in FIG. 9 to form a mesh network system. [Description of Signs] λ1 to λi : WDM optical signal in 1550 nm band λi + 1 to λn : WDM optical signal in 1580 nm band 1: WDM optical transceiver 2: WDM optical transmitter 3: WDM optical receiver 4: WDM coupler 5: Optical Transmission path 6: WDM optical transmitter / receiver 7: WDM coupler 8: WDM optical receiver for 1550 nm band 9: WDM optical transmitter for 1580 nm band 10: WDM optical transmitter / receiver 11, 13: Optical transmission path ( NZ-DSF ) 12 : WDM optical transmitter / receiver 15 : WDM optical transmitter 16 : WDM optical receivers 17, 18, 21, 22: WDM couplers 19, 20: Optical direct amplifier 23: WDM optical receiver 24: WDM Optical transmitters 25-1 to 25-n, 39-1 to 39-n, 40-1 to 40-1
40-n: optical transmitters 29-1 to 29-n, 36-1 to 36-n: optical receivers 26, 39: optical multiplexers 27, 31, 34, 38: direct optical amplifiers 28, 32, 33. , 37: dispersion compensating fiber (DCF) 30, 35: optical separation unit 41: WDM couplers 42, 43, 44: ports 45, 47: optical switch 46: optical ADM units 49, 50: optical separation and insertion units 53, 54: Optical separation / insertion units 48, 51, 52, 55: WDM coupler 56: Port 57: WDM optical direct amplifier 58: Optical separation units 59-1 to 59-n: OE / EO conversion units 60-1 to 60-n: Optical Switches 61-1 to 61-n: OE / EO converter 62: optical multiplexing unit 63: WDM optical direct amplifier 64: ports 65-1 to 65-n: optical ADM nodes 66, 69: optical ADM nodes 71, 72, 73, 74, 75; optical ADM node 76 : Positive light cross connect node 77: Reverse light cross connect node 78-1 to 78-n, 83-1 to 83-n: Ports 79-1 to 79-n, 82-1 to 82-n: WDM couplers 80, 81: Optical cross connect units 84-1 to 84-n, 89-1 to 89-n: ports 85-1 to 85-n, 88-1 to 88-n: WDM couplers 86, 87: Optical cross connect units 90-1 90-n: Ports 91-1 to 91-n: WDM optical direct amplifiers 92-1 to 92-n: Optical separation units 93-1 to 93-n, 94-1 to 94-n: OE / EO
Conversion unit 95: optical full matrix switches 96-1 to 96-n, 97-1 to 97-n: OE / EO
Conversion units 98-1 to 98-n: optical multiplexing units 91-1 to 99-n: WDM optical direct amplifiers 100-1 to 100-n: ports 101-1 to 101-n: optical cross-connect nodes

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-186933 (JP, A) JP-A-54-144801 (JP, A) JP-A-4-302549 (JP, A) JP-A-4- 57418 (JP, A) 8 Sakamoto et al., "Wavelength multiplexing transmission technology in 1580mm band", Proc. Of the IEICE 1997 Society Conference, 2, 377-380, September 6, 1997 (58) Field (Int. Cl. ⁷ , DB name) H04B 10/00

Claims (1)

(57) [Claims] [Claim 1] WDM optical transceivers are connected by an optical transmission line.
A bidirectional WDM optical transmission system connected , comprising: a WDM optical transceiver as one of said WDM optical transceivers
(1) and WDM light as the other WDM optical transmitter
A transmitter / receiver (6), the WDM optical transceiver (1) and the WDM optical transceiver
(6) is connected one-to-one by an optical transmission line (5),
Bidirectional WDM optical transmission is performed on the single optical transmission line (5).
The WDM optical transceiver (1) is configured as a WDM optical transceiver for the 1550 nm band.
DM optical transmitter (2) and WDM optical receiver in 1580nm band
(3) wavelength division multiplexing of 1550 nm band and 1580 nm band
The WDM optical transceiver (6) includes a WDM coupler (4) that performs W multiplexing.
DM optical transmitter (9) and 1550nm WDM optical receiver
(8) wavelength division multiplexing of 1550 nm band and 1580 nm band
The optical transmission line (5) has a zero-dispersion wavelength in the 1550 nm band.
And zero dispersion created so as not to be in the 1580 nm band
Zero-dispersion shift fiber with a wavelength of 1500 nm (NZ-D
Bidirectional WDM , comprising: SF)
Optical transmission system.