WO2005008925A9 - 光信号分岐回路及び光通信ネットワーク - Google Patents
光信号分岐回路及び光通信ネットワークInfo
- Publication number
- WO2005008925A9 WO2005008925A9 PCT/JP2004/010036 JP2004010036W WO2005008925A9 WO 2005008925 A9 WO2005008925 A9 WO 2005008925A9 JP 2004010036 W JP2004010036 W JP 2004010036W WO 2005008925 A9 WO2005008925 A9 WO 2005008925A9
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- Prior art keywords
- wavelength
- optical
- port
- optical signal
- add
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
- H04J14/0278—WDM optical network architectures
- H04J14/0283—WDM ring architectures
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
- H04J14/0201—Add-and-drop multiplexing
- H04J14/0215—Architecture aspects
- H04J14/0216—Bidirectional architectures
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
- H04J14/0201—Add-and-drop multiplexing
- H04J14/0215—Architecture aspects
- H04J14/0219—Modular or upgradable architectures
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
- H04J14/0227—Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
- H04J14/0241—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths
- H04J14/0242—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths in WDM-PON
- H04J14/0245—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths in WDM-PON for downstream transmission, e.g. optical line terminal [OLT] to ONU
- H04J14/0246—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths in WDM-PON for downstream transmission, e.g. optical line terminal [OLT] to ONU using one wavelength per ONU
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
- H04J14/0227—Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
- H04J14/0241—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths
- H04J14/0242—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths in WDM-PON
- H04J14/0245—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths in WDM-PON for downstream transmission, e.g. optical line terminal [OLT] to ONU
- H04J14/0247—Sharing one wavelength for at least a group of ONUs
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
- H04J14/0227—Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
- H04J14/0241—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths
- H04J14/0242—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths in WDM-PON
- H04J14/0249—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths in WDM-PON for upstream transmission, e.g. ONU-to-OLT or ONU-to-ONU
- H04J14/025—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths in WDM-PON for upstream transmission, e.g. ONU-to-OLT or ONU-to-ONU using one wavelength per ONU, e.g. for transmissions from-ONU-to-OLT or from-ONU-to-ONU
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
- H04J14/0227—Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
- H04J14/0241—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths
- H04J14/0242—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths in WDM-PON
- H04J14/0249—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths in WDM-PON for upstream transmission, e.g. ONU-to-OLT or ONU-to-ONU
- H04J14/0252—Sharing one wavelength for at least a group of ONUs, e.g. for transmissions from-ONU-to-OLT or from-ONU-to-ONU
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
- G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
- G02B6/29346—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by wave or beam interference
- G02B6/29361—Interference filters, e.g. multilayer coatings, thin film filters, dichroic splitters or mirrors based on multilayers, WDM filters
- G02B6/2937—In line lens-filtering-lens devices, i.e. elements arranged along a line and mountable in a cylindrical package for compactness, e.g. 3- port device with GRIN lenses sandwiching a single filter operating at normal incidence in a tubular package
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
- H04J14/0227—Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
- H04J14/0278—WDM optical network architectures
- H04J14/0282—WDM tree architectures
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
- H04Q11/0005—Switch and router aspects
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
- H04Q11/0005—Switch and router aspects
- H04Q2011/0007—Construction
- H04Q2011/0009—Construction using wavelength filters
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
- H04Q11/0005—Switch and router aspects
- H04Q2011/0007—Construction
- H04Q2011/0016—Construction using wavelength multiplexing or demultiplexing
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
- H04Q11/0005—Switch and router aspects
- H04Q2011/0052—Interconnection of switches
- H04Q2011/006—Full mesh
Definitions
- the present invention relates to a wavelength router and an optical add-drop multiplexer (OADM) used for optical fiber communication. Further, the present invention relates to an optical signal branch circuit used for optical fiber communication and an optical fiber-one communication network.
- FIG. 44 shows a conventional optical add-drop multiplexer.
- Fig. 44 (a) shows an optical add-drop multiplexer using an optical fiber grating (FBG) 601 and an optical circulator 602.
- the optical signal incident from the port 603 is reflected by the optical fiber grating (FBG) 601 only at the wavelength ⁇ i, and the reflected optical signal is guided to the add drop port 605 by the optical circulator 602.
- Light having a wavelength other than ⁇ i is guided to port 604.
- FIG. 44 (b) shows an optical drop multiplexer using three-port devices 611 and 612 of a dielectric thin film filter type.
- the optical signal among the optical signals incident from the port 613 is guided to the drop port 615 by the dielectric thin film filter type three port device 611.
- the optical signal having the wavelength from the add port 616 is guided to the port 614 by the dielectric thin film filter type three port device 612.
- FIG. 45 (a) shows the structure of a dielectric thin film filter type three-port device ⁇ ⁇ .
- the light from the incident port (optical fiber) 621 passes through the collimator 624 and the dielectric thin film filter 625, and the light of the wavelength ⁇ i passes through the collimator 626 to the transmission port (optical fiber) 623.
- Light other than the wavelength i is reflected by the dielectric thin film filter 625, passes through the collimator 624 again, and is guided to the reflection port (optical fiber) 622.
- Fig. 46 shows a conventional passive optical fiber communication network (PON passive Qptical Fiber Network).
- the optical signal from the base station 1210 was split by a passive tree-type splitter (tree power plastic) 1200 and sent to a large number of client stations 1213 via an optical fiber group 1201. Also, optical signals from the client station group 1213 to the base station 1210 were transmitted by time division multiple access (TDM).
- TDM time division multiple access
- the branching ratio of the tree-type splitter 1200 was often selected to be about 32.
- a wavelength router includes, for example, a first input port, a first optical add-drop multiplexer, a first output port, and a second input port. Port, a second optical add-drop multiplexer, and a second output port, for a predetermined number of nodes N, the first add-drop multiplexer is (N-1) A second optical head dropper comprising a set of head means drop means pairs. The multiplexer is characterized by having N-1) sets of add means and drop means.
- the number of branches is increased by applying an optical add-drop multiplexer (OADM) using a wavelength multiplexing technique to an optical signal branch circuit unit.
- OADM optical add-drop multiplexer
- various network topologies including a phonoremesh can be flexibly constructed on a ring-shaped optical fiber communication network by using wavelength multiplexing.
- problems such as insufficient isolation that occur at that time can be solved.
- it is possible to reduce the amount of optical fiber used in a passive optical fiber communication network (P ⁇ N).
- a redundant optical communication network can be realized.
- FIG. 1 shows the internal configuration of the wavelength router according to the first embodiment of the present invention.
- FIG. 2 shows a configuration of a double ring optical communication network constructed using four wavelength routers 21 to 24 based on the wavelength router 20.
- FIG. 3 shows how an optical signal of wavelength ⁇ 1 is routed between the wavelength routers 21 and 22.
- FIG. 4 is a diagram illustrating a wavelength routing path realized by the present embodiment.
- the wavelength router is a three-port device with a dielectric thin film filter. And 12 and has a so-called optical add-drop filter structure.
- the wavelength router ⁇ When used on the optical communication network shown in FIG. 2, the wavelength router ⁇ has the same basic configuration for each node (station) of the optical communication network, but has the wavelength of each dielectric thin film filter type three-port device. However, different wavelength routers 21, 22, 23, 24 are used.
- FIG. 1 shows an add-drop state of an optical signal of each wavelength in the case of the wavelength router 21.
- the wavelength router 21 will be described.
- the dielectric thin-film filter type three-port device 1 extracts the light of wavelength; 11 input from the optical fiber 25a and outputs it to the local port group (corresponding to 31 in FIG. 2).
- the dielectric thin-film filter type three-port device 2 guides light having a wavelength ⁇ input from the local port group (corresponding to 31 in FIG. 2) to the optical fiber 25b.
- the dielectric thin-film filter type three-port device 3 extracts the light of wavelength ⁇ 2 input from the optical fiber 25a and outputs the light to the local port group 2 ⁇ (corresponding to 31 in FIG. 2).
- the dielectric thin film filter type three-port device 4 guides the light of wavelength ⁇ 2 input from the local port group (corresponding to 31 in FIG. 2) to the optical fiber 25b.
- the dielectric thin-film filter type three-port device 5 extracts the light of wavelength 3 input from the optical fiber 25a and outputs it to the local port group ⁇ (corresponding to 31 in FIG. 2).
- the dielectric thin-film filter type three-port device 6 guides the light of wavelength ⁇ 3 input from the mouth-portal group K (corresponding to 31 in FIG. 2) to the optical fiber 25b.
- the dielectric thin-film filter type three-port device 8 extracts the light of wavelength ⁇ 1 input from the optical fiber 26a and outputs the light to the local port group (corresponding to 31 in FIG. 2).
- the dielectric thin film filter type three-port device 7 guides the light of wavelength ⁇ 1 input from the local port group (corresponding to 31 in FIG. 2) to the optical fiber 26b.
- the dielectric thin-film filter type three-port device 10 extracts the light of wavelength ⁇ 2 input from the optical fiber 26a and outputs the light to the local port group (corresponding to 31 in FIG. 2).
- the dielectric thin-film filter type three-port device 9 guides light having a wavelength of 12 input from the local port group ⁇ (corresponding to 31 in FIG. 2) to the optical fiber 26b.
- the dielectric thin-film filter type three-port device 12 extracts the light of wavelength ⁇ 3 input from the optical fiber 26a and outputs it to the local port group (corresponding to 31 in FIG. 2).
- the dielectric thin-film filter type three-port device 11 guides the light of wavelength ⁇ 3 input from the local port group (corresponding to 31 in FIG. 2) to the optical fiber 26b.
- the other wavelength routers 22 to 24 operate in the same manner as the wavelength router 21.
- the wavelengths handled are different.
- the wavelength router 22 operates by replacing ⁇ 2 of the wavelength router 21 with ⁇ 4 and replacing 3 with 3 and 5.
- the wavelength router 23 operates by replacing ⁇ 1 of the wavelength router 21 with ⁇ 1, ⁇ 2 of the wavelength nolator 21 with 15; and ⁇ 3 with ⁇ 6.
- Wavelength router 24 ⁇ ⁇ ⁇ .
- FIG. 2 is a diagram showing a configuration of a double-ring optical communication network which is composed of the wavelength routers 21 to 24 and the outer optical fiber 25 to the inner optical fiber 26.
- the optical signal of the wavelength ⁇ 1 to ⁇ 6 is transmitted clockwise, and on the inner optical fiber 26, the optical signal of the wavelength; 11 to ⁇ 6 is transmitted counterclockwise.
- the wavelength router 21 the optical signals of the wavelengths 11, ⁇ 2 and ⁇ 3 are added and dropped, and the optical signals of the wavelengths ⁇ 4, ⁇ 5 and ⁇ 6 are bypassed.
- the optical signals of the wavelengths ⁇ 1, ⁇ 4, and ⁇ 5 are added and dropped, and the optical signals of the wavelengths ⁇ 2, ⁇ 3, and 66 are bypassed.
- the optical signals of wavelengths 2, ⁇ 4 and ⁇ 6 are added and dropped, and the optical signals of wavelengths ⁇ 1, ⁇ 3 and ⁇ 5 are bypassed.
- the optical signals of wavelengths 3, ⁇ 5, and 6 are added and dropped, and the optical signals of wavelengths 1, 1, 2, and ⁇ 4 are bypassed.
- the wavelength routers 21, 22, 23, and 24 are provided with local ports 31, 32, 33, and 34, respectively, and these ports are provided with switches (tree-like architectures). Or routers) 41, 42, 43, and 44 are connected correspondingly. These switches (or routers) 41, 42, 43, and 44 have detachable optical transceivers 45 mounted thereon.
- An example of the detachable optical transceiver 45 is an optical transceiver called GBIC or SFP. These optical transceivers are designed to output optical signals with wavelengths compatible with CWDM (low density wavelength multiplexing) or DWDM (high density wavelength multiplexing).
- the optical transceivers 45 can individually output different wavelengths, the optical transceivers 45 can be switched so that the wavelength corresponds to each of the dielectric thin film filter type three-port devices in the wavelength router. Or router) 41, 42, 43, and 44.
- a detachable optical although a transceiver is used, a wavelength conversion mechanism may be interposed between the switches (or routers) 41, 42, 43, and 44 and the corresponding wavelength routers 21, 22, 23, and 24.
- the specific wavelength of each optical signal is, for example, from among the CWDM wavelengths defined by the ITU, ⁇ 1: 1490, ⁇ 2: 1510, ⁇ 3: 1530, ⁇ 4: 1550. ,: 5: 1570 nm, 6: 1590 nm, and the like.
- this wavelength could be any other combination of wavelengths, for example, six from the medium-strength C-band 100 GHz grid in the DWDM wavelength band defined by the ITU.
- the two wavelengths from the local port 31 of the wavelength router 21; the optical signal of 11 is one of the wavelengths ( ⁇ la) propagating clockwise on the outer optical fiber 25 and The other system ( ⁇ lc) propagates counterclockwise on the inner optical fiber 26 and bypasses the wavelength routers 24 and 23 in that order, again reaching the wavelength router 22, and both to the local port 32. Is output.
- the two wavelengths from the local port 32 of the wavelength router 22; 11 The optical signal of 1 (one lb) propagates counterclockwise on the inner peripheral optical fiber 26 to reach the wavelength router 21.
- the other system (e) propagates on the outer optical fiber 25, bypasses the wavelength routers 23 and 24 in that order, and reaches the wavelength router 21 again, and outputs both to the local port 31. That is, two full-duplex signal paths, clockwise and counterclockwise, are formed between the wavelength router 21 and the wavelength router 22 by the optical signal of the wavelength ⁇ 1. For this reason, even if a single cut of the optical fiber occurs at some point in the double-ring optical fiber communication network shown in Fig. 3, either the clockwise or counterclockwise system survives and the communication Network reliability can be improved.
- FIG. 4 shows a wavelength routing path formed by the double ring optical fiber communication network of the present embodiment shown in FIG.
- the double ring optical fiber communication network of the present embodiment forms a full mesh and redundant wavelength routing path indicated by ⁇ in FIG. 4 between the switches (or routers) 41, 42, 43, and 44.
- the wavelength routing path 51 is a full-duplex wavelength routing path composed of a set of optical signals having the wavelengths ⁇ la and ⁇ lb shown in FIG.
- the wavelength routing path 52 is a full-duplex wavelength routing path composed of optical signals having wavelengths ⁇ lc and ⁇ Id shown in FIG.
- the wavelength routing path 50 has a wavelength ⁇ 1 between the switches 41 and 42, and has a wavelength ⁇ 1 between the switches 41 and 43. At wavelength ⁇ 2, between switches 41 and 44 at wavelength ⁇ 3, between switches 42 and 43 at wavelength 4, between switch 42 and switch 44 at wavelength ⁇ 5, and between switch 43 and switch 44. It is shown in Fig. 4 that they are connected at wavelength ⁇ 6.
- each path corresponds to each wavelength.
- each route is provided with clockwise and counterclockwise redundant routes.
- the full-mesh communication path is a path with high communication efficiency, and each path is redundant, so that one path can be secured even in the event of an accident such as physical disconnection of optical fiber.
- each wavelength router optical signals other than the wavelength router being added / dropped are optically bypassed, so that the processing of these bypassed optical signals is performed by the switches 41 to 44. It reduces the processing power of switches that do not need to be performed.
- each node wavelength router
- the hardware size of the switch is half that of the case where all of these are processed electrically. Will be.
- Embodiment 2 of the present invention will be described with reference to FIGS. 5 to 7.
- the power S was used to construct a double ring using two optical fibers.
- the dual ring was constructed by performing bidirectional transmission of different wavelengths on one optical fiber. are doing.
- FIG. 5 shows the internal configuration of the wavelength router IS according to the second embodiment of the present invention.
- FIG. 6 shows the configuration of a double-ring optical communication network constructed using three wavelength routers 71 to 73 based on the wavelength router 70.
- FIG. 7 is a diagram illustrating a wavelength routing path realized by the present embodiment.
- the wavelength router IS is made up of a dielectric thin film filter type three-port device 61 to 68 and has a so-called optical add-drop filter structure.
- the wavelength router ⁇ is used on the optical communication network shown in Fig. 2, the basic configuration is the same for each node (station) of the optical communication network, but the wavelength of each dielectric thin film filter type three-port device is the same. Different wavelength routers 71, 72 and 73 are used.
- Fig. 5 shows the state of add-drop of the optical signal of each wavelength in the case of the wavelength router 71. Has been.
- the wavelength router 71 will be described.
- the dielectric thin-film filter type three-port device 71 outputs an optical signal of wavelength ⁇ 1 from the local port side to the optical fiber 75a side.
- the dielectric thin film filter type three-port device 62 extracts the light of wavelength ⁇ 2 input from the optical fiber 75a and outputs the light to the local side.
- a set of full-duplex optical signal transmission lines is formed by optical signals of wavelengths ⁇ 1 and ⁇ 2.
- the dielectric thin-film filter type three-port device 63 outputs light of wavelength ⁇ 1 from the local port side to the optical fiber 75b side.
- the dielectric thin film filter type three-port device 64 outputs the light of wavelength ⁇ 2 input from the optical fiber 75b to the local port side.
- the dielectric thin film filter type three-port device 65 outputs light of wavelength ⁇ 3 from the local port side to the optical fiber 75a.
- the dielectric thin-film filter type three-port device 66 outputs light having a wavelength of 14 from the optical fiber 75a side to the local port side.
- the thin-film three-port device 67 outputs the light of wavelength ⁇ 3 from the local port side to the optical fiber 75b.
- the thin film three-port device 68 outputs light of wavelength ⁇ 4 from the optical fire 75b to the local port.
- the other wavelength routers 72 and 73 operate similarly to the wavelength router 71.
- the wavelengths handled are different from each other as shown in FIG.
- FIG. 6 is a diagram showing a configuration of a ring-shaped optical communication network composed of the wavelength routers 71 to 73 and the optical fiber 75.
- Switches (or routers) 81, 82, and 83 having a tree-like architecture are connected to the wavelength routers 71, 72, and 73, respectively.
- Switches 81, 82, and 83 have detachable optical transceivers 85 mounted thereon.
- An example of the detachable optical transceiver 85 is an optical transceiver called GBIC or SFP. These optical transceivers are designed to output optical signals of wavelengths compatible with CWDM (low-density wavelength division multiplexing) and DWDM (high-density wavelength division multiplexing).
- two systems of optical signals ⁇ la and ⁇ lb having the wavelength ⁇ 1 are sent to the wavelength router 72.
- two systems of optical signals ⁇ 2a and ⁇ 2b having a wavelength ⁇ 2 are sent to the wavelength router 71.
- One full two at wavelength ⁇ la and wavelength ⁇ 2a A double communication path is formed, and another full-duplex communication path is formed by the wavelength ⁇ lb and the wavelength 2b.
- two redundant communication paths (clockwise and counterclockwise) are formed.
- FIG. 7 shows a wavelength routing path formed by the ring-shaped optical fiber communication network of the present embodiment shown in FIG.
- a full-mesh and redundant wavelength routing path shown by in FIG. 8 is formed between the switches 81, 82, and 83.
- FIG. 8 shows the internal configuration of the wavelength router dish according to the third embodiment of the present invention.
- a high-density wavelength division multiplexing (DWDM) is used and an optical fiber amplifier is provided inside.
- the wavelength router 100 of this embodiment is composed of optical add-drop multiplexers (OADMs) 101 and 102 and enormous beam doped fiber optical amplifiers (EDFAs) 103 and 104.
- OADMs optical add-drop multiplexers
- EDFAs beam doped fiber optical amplifiers
- OADM optical add-drop multiplexers
- a dielectric thin film filter type three-port device group (not shown) is incorporated, and a predetermined wavelength is added or added (added). Drop) power to do S.
- the optical signal from the optical fiber 107a is first amplified by an erbium-doped fiber optical amplifier (EDFA) 103, and then an add-drop of a predetermined optical signal is performed by an optical add-drop multiplexer 1 (OADM) 101. Thereafter, the signal is output to the optical fiber 107b.
- the optical signal from the optical fiber 108a is first amplified by an erbium-doped fiber optical amplifier (EDFA) 104, and then added to a predetermined optical signal by an optical add-drop multiplexer (OADM) 102. Thereafter, the light is output to the optical fiber 108b.
- EDFA erbium-doped fiber optical amplifier
- OADM optical add-drop multiplexer
- the local port groups 105 and 106 are connected to a switch (not shown).
- An optical signal connected to another wavelength router is input / output to / from the port group 105 on the left side.
- the optical signal extracted (dropped) from the optical signals input from the optical fiber 107a is sent to the oral-side port group 105.
- An optical signal group input to a switch port (not shown) to the local port group 105 is added (added) to the optical signal transmitted to the optical fiber 108b.
- An optical signal group connected to another wavelength router is input / output to / from the local port group 106 in a counterclockwise direction. Extracted from the optical signal input from the optical fiber 108a (the The dropped optical signal is sent to the local port group 106.
- the optical signal group input from the switch side, not shown in the local port group 106 is added (added) to the optical signal transmitted to the optical fiber 107b side.
- FIG. 9 shows a configuration of a double ring optical communication network formed using the wavelength router of the present embodiment.
- This double ring optical communication network comprises wavelength routers 111, 118, an outer optical fiber 121, and an inner optical fiber 122.
- the optical signal is transmitted clockwise in the outer optical fiber 121, and the optical signal is transmitted counterclockwise in the inner optical fiber 122.
- 28 types of optical signals having wavelengths of ⁇ 1 to ⁇ 28 are used, and a redundant full-duplex communication path of 28 paths is formed in a full mesh between the wavelength routers 111 and 118. ing.
- a total of 28 types of wavelengths are used. At each node (wavelength router), only 7 wavelengths unique to each node are added and dropped, and the remaining 21 wavelengths are bypassed. In other words, the hardware size of the switches and routers connected to the wavelength router is 25% smaller than when all of this is processed electrically.
- the ⁇ paths can be realized with ⁇ wavelengths if two optical fibers are used as shown in FIGS. 2 and 9, and one optical fiber can be realized as shown in FIG. If the communication path is formed by changing the upstream and downstream wavelengths, 20 wavelengths are required.
- ⁇ 1 is a vector having eight elements, and its elements ⁇ 1 to ⁇ 7 indicate wavelengths forming a communication path from node 1 to another node.
- the element ⁇ of ⁇ 1 is the “wavelength” that indicates the communication path from node 1 to node 1, but since it does not actually need to be provided, ⁇ , a concept representing an empty set, is introduced. If the communication path between node 1 and node 2 is formed with the wavelength ⁇ 1, the wavelength; 11 is always included in the vector path indicating the communication path from node 2 to other nodes. Is [ ⁇ 1, ⁇ , ⁇ 8, ⁇ 9, ⁇ 10, ⁇ 11, ⁇ 12, ⁇ 13]. That is, the matrix of the equation (2) is a transposed matrix.
- the wavelength used as the communication path from node 2 to node 1 is the communication path from node 1 to node 2. This is because it must match the wavelength used as the path.
- forming a communication path from node 1 to node 2 with a wavelength of 11 means that the wavelength of the optical signal transmitted from node 1 is ⁇ 1, and the optical signal of ⁇ 1 is received by node 2. Which indicates that.
- the empty set is included.
- the wavelength represented by the force-empty set does not need to be implemented. Therefore, the implemented wavelength is a full mesh between N nodes.
- the wavelength router in which N is provided only needs to implement N-1 wavelengths. Also, since different wavelengths are mounted on each node, N types of optical add-drop multiplexers corresponding to ⁇ 1 to ⁇ are mounted.
- a network may be configured without matching the wavelength of the communication path from node 1 to node 2 with the wavelength of the communication path from node 2 to node 1. In this case, the number of wavelengths used is doubled, but there is an advantage that the wavelength arrangement becomes free.
- a wavelength arrangement as shown in Expression (3) can be adopted.
- 56 wavelengths are required to form a full mesh between nodes.
- a full mesh is formed by providing 2M wavelengths between N nodes.
- M is a value represented by the equation (1).
- the wavelength arrangement that can be washed by the equations (5) and (6) can also be used when bidirectional transmission is realized by changing the upstream and downstream wavelengths with one optical fiber.
- wavelengths are arranged in the optical add-drop multiplexer 1 so as to realize a full mesh communication path, and some of the communication paths are not used. Since a full mesh has all possible paths between N nodes, a full mesh To realize a star topology by not using some of the routes.
- an optical signal for clockwise and an optical signal for counterclockwise are further wavelength-multiplexed to be realized by one optical fiber.
- an erbium-doped fiber optical amplifier 103 uses a C-band (1530_1560 nm) optical amplifier
- an erbium-doped fiber optical amplifier 10L uses an L-band (1565_1605 nm) optical amplifier
- clockwise and counterclockwise signals This is an embodiment in which a single optical fiber is multiplexed by a wavelength multiplexer (not shown).
- the input port 107a of the erbium-doped fiber optical amplifier 103 and the output port 108b of the optical add-drop multiplexer 102 are multiplexed by a wavelength multiplexer (not shown), and similarly, the input port 108a of the erbium-doped fiber optical amplifier 104
- the output port 107b of the optical add-drop multiplexer 101 may be multiplexed with a wavelength multiplexer (not shown).
- the same C-band erbium-doped fiber optical amplifier may be used to divide the C-band into a short wavelength side and a long wavelength side.
- the force S that realizes the optical add-drop multiplexer by the dielectric thin film filter type three-port device is S, which is another means such as a fiber Bragg grating filter (FBG) and an optical circulator. Can be combined to realize an optical add-drop multiplexer.
- FBG fiber Bragg grating filter
- the optical amplifier is not limited to the erbium-doped fiber optical amplifier, but may be another rare-earth doped fiber optical amplifier, a Raman optical amplifier, a semiconductor laser optical amplifier, a rare-earth-doped planar waveguide optical amplifier, or the like.
- FIG. 10 shows the internal structure of the wavelength router according to the fourth embodiment of the present invention.
- This embodiment is a modification of the wavelength router of FIG.
- FIG. 10A shows the case of the third embodiment, in which an erbium-doped optical fiber amplifier 103 is arranged in front of an optical add-drop multiplexer 101 (OADM) 101 as a preamplifier.
- OADM optical add-drop multiplexer 101
- an erbium-doped optical fiber amplifier 105 is disposed as a boost amplifier after the optical add-drop multiplexer 1 (OADM) 101.
- Figure 10 (c) The erbium-doped optical fiber amplifier 103 is arranged as a preamplifier, and the erbium-doped optical fiber amplifier 105 is arranged as a boost amplifier.
- FIGS. 10 (a), (b), and (c) are all operable. Considering the isolation characteristics of the optical add-drop multiplexer (OADM) 101, FIGS. Masley. From the viewpoint of long-distance transmission characteristics, FIG. 10 (c) in which a preamplifier and a booster amplifier are arranged is most desirable. On the other hand, Fig. 10 (a) or (b) is desirable from the viewpoint of cost.
- OADM optical add-drop multiplexer
- An optical add-drop multiplexer (OADM) 101 is provided with a dielectric thin-film filter type three-port device 131 and 132.
- the optical signal 133 from the port 136 side is added by the dielectric thin-film filter type three-port device 131, and the optical signal 134 is dropped by the dielectric thin-film filter type three-port device 131.
- FIG. 1 An optical add-drop multiplexer (OADM) 101 is provided with a dielectric thin-film filter type three-port device 131 and 132.
- the optical signal 133 from the port 136 side is added by the dielectric thin-film filter type three-port device 131, and the optical signal 134 is dropped by the dielectric thin-film filter type three-port device 131.
- the optical signal 134 when there is no erbium-doped optical fiber amplifier in all stages of the optical add-drop multiplexer (OADM) 101, the optical signal 134 may be attenuated due to long-distance transmission.
- the added optical signal 133 is strong.
- the optical signal 134 is capable of attenuating up to about 25 dBm.
- the optical signal 133 is about OdBm. Then, the amount of light 135 that the optical signal 133 leaks from the dielectric thin film filter type three-port device 132 to the port 137 may not be ignored.
- isolation 138 The force at which the dielectric thin-film filter-type three-port device does not leak light signals of other wavelengths is referred to as isolation 138. This value is usually about 25 to 30 dB. Here, the isolation of 25 dB means that the leakage light power is attenuated to S-25 dB. In the case of “isolation”, “minus” is usually expressed as “saving”.
- the received optical signal 134 dropped to the port 137 is _25dBm
- the amount of leaked light 135 reaches -30dB
- the difference is only 5dB.
- the difference between the signal component (in this case, the received signal 134) and the noise signal (in this case, the amount of leakage 135) is required to be at least 20 dB, and preferably 25 dB. Unable to receive (see Figure 11 (b)).
- the signal attenuated from the distant node by passing through the optical add-drop multiplexer in a number of stages When receiving a signal, strong signals from nearby nodes can cause crosstalk.
- FIG. 10 (a) As shown in Fig. 10 (a), when the erbium-doped optical fiber amplifier 103 is arranged in all stages of the optical add-drop multiplexer ( ⁇ ADM) 101, the received optical signal dropped is also close to Od Bm. Therefore, the problem of a decrease in the signal-to-noise ratio as described above does not occur. Therefore, from this viewpoint, a configuration as shown in FIG. 10 (a) or FIG. 10 (c) is desirable. In other words, if the configuration shown in Fig. 10 (a) or 10 (c) is used, an optical add-drop multiplexer (OAD M) with an isolation value of 25 and about 30dB can be used. There is no need to use an optical add-drop multiplexer (OADM) with specially enhanced isolation.
- OAD M optical add-drop multiplexer
- FIG. 12 shows a case where the gain control mechanism of the erbium-doped fiber optical amplifier 103 is further attached to the present embodiment.
- a part of an optical signal dropped from a port 141 of an optical add-drop multiplexer (OADM) 101 is taken out by an optical fiber coupler 142 and inputted to a port 143 of an erbium-doped fiber optical amplifier 103.
- the erbium-doped fiber optical amplifier 103 changes the gain according to the input optical signal at the port 143, and operates to keep the optical signal intensity from the port 143 substantially constant.
- OADM optical add-drop multiplexer
- the branch ratio of the optical fiber coupler 142 is preferably selected such that the branch toward the port 143 is about 1/10 to 1/100.
- a normal optical signal may be used, but it is particularly preferable to use an optical signal of a monitor channel (or a supervisor channel) for network monitoring.
- a light amount detection mechanism is provided in the erbium-doped fiber optical amplifier 103.
- a light amount detection mechanism to be connected to the optical add-drop multiplexer 1 (OADM) 101 has a light amount detection mechanism.
- the detection result may be sent to the erbium-doped fiber optical amplifier 103 in the form of an electric signal to perform gain control.
- This method has an advantage that the light amount loss is small, though the structure of the optical transceiver is complicated.
- FIG. 14 shows a wavelength router (an optical add-drop multiplexer) according to a fifth embodiment of the present invention.
- the following three-port device with a duplicate dielectric thin film filter was used. Is a major feature.
- FIG. 13 shows such a duplicate dielectric thin film filter type three-port device! It is a figure which shows the structure of ⁇ .
- the entrance port 151, reflection port 152, and transmission port 153 form one dielectric thin-film filter type three-port device, and the entrance port 161, reflection port 162, and transmission port 163 form another dielectric three-port device.
- the collimator lenses 154 and 156 and the dielectric thin film filter 155 are shared. Since the dielectric thin film filter is shared, the transmission wavelengths of the two dielectric thin film filter type three-port devices formed as described above are the same.
- the wavelength router ⁇ shown in Fig. 1 uses a large number of dielectric thin film filter type three-port devices having the same wavelength.
- a dielectric thin film filter type three port device 1, 2, 7, and 8 has a wavelength of 11; Therefore, by using a three-port device with a duplicated dielectric thin-film filter 150 as shown in Fig. 13 for these three-port dielectric thin-film filters, the number of actually used dielectric thin-film filters and collimator lenses can be reduced. And thus reduce costs.
- a dielectric thin film filter type three-port device may be provided in duplicate at a port for dropping an optical signal.
- Fig. 14 shows a configuration in which such a double filter configuration is provided at the drop port of the wavelength router m in Fig. 5. If the isolation of one filter is 25 dB, the isolation will be doubled to 50 dB if two filters are stacked. Therefore, the lack of isolation can be eliminated.
- the dielectric thin film filter type three-port device 62a and 62b by the duplicate dielectric thin film filter type three port device shown in FIG. In this way, the number of dielectric thin-film filters and collimator lenses actually used can be reduced, and the cost can be reduced.
- the dielectric thin-film filter type three-port devices 64a and 64b, the dielectric thin-film filter type three-port devices 66a and 66b, and the dielectric thin-film filter type three-port devices 68a and 68b are each a duplicate type. It can be constituted by an electric thin film filter type three-port device.
- the dielectric thin-film filter type three-port devices 61 and 63 and the dielectric thin-film filter type three-port devices 65 and 67 can be replaced with a duplex dielectric thin-film filter type three-port device in pairs.
- FIG. 15 (a) shows a double-pass type dielectric thin-film filter three-port device. This is because the light from the entrance port 181 is guided to the dielectric thin film filter 185 via the collimator 184, the reflected light is guided to the reflection port 182, the transmitted light is reflected by the mirror 186, and then the dielectric thin film filter This is a method of transmitting the transmitted light through the collimator 184 to the transmission port 183 via the collimator 184. Since the transmitted light passes through the dielectric thin film filter twice (double pass), the isolation is doubled. Further, there is a feature that only one collimator lens is required, and all of the entrance port, the reflection port, and the transmission port can be provided on the same side with respect to the dielectric thin film filter 185.
- FIG. 15 (b) further shows a three-port device of a double-pass dielectric film filter having a duplicate structure according to a sixth embodiment of the present invention! Indicates ⁇ .
- the input port 181, the reflection port 182, and the transmission port 183 form one double-pass dielectric thin-film filter
- the input port 191, reflection port 192, and transmission port 193 form another double-pass dielectric thin-film filter.
- Forming a three-port device Since the two double-pass type dielectric thin film filter three-port devices share the collimator lens 184, the dielectric thin film filter 185, and the mirror 186, the number of parts is reduced, and the cost can be reduced.
- the double-pass type dielectric thin-film filter filter three-port device can solve the problem of insufficient isolation as shown in Fig. 11 by using it as a port for dropping an optical signal of an optical add-drop multiplexer. it can.
- the double-pass type dielectric thin-film filter three-port device having a duplicate structure can replace the dielectric thin-film filter three-port devices 62 and 64 in FIG. 5, for example.
- An optical add-drop multiplexer uses a plurality of dielectric thin film filter three-port devices of the same wavelength to add and drop an optical signal of the same wavelength.
- the use of a duplex dielectric thin film filter three-port device can reduce the number of components and the cost.
- FIG. 16 shows an embodiment plate in which the wavelength router (optical add-drop multiplexer 1) US of FIG. 14 is mounted on a box. Since it is necessary to use a port using a two-stage filter as a drop port, the misuse of the drop port and the add port must be prevented. Therefore, in the present embodiment, a drawing 201 showing the wavelength routing path is provided on the upper surface of the box, and each port (receptacle) 210 to 219 on the front face 202 of the box is provided with a symbol indicating the distinction between wavelength and transmission / reception, and the distinction between clockwise and counterclockwise. Is displayed. Each symbol on the front 202 of the box represents the wavelength as ⁇ 1, e2, e3, ⁇ 4, ⁇ for transmission, Rx for reception, Right for clockwise, Left for counterclockwise, and C for common port. I have.
- Receptacle 210 is a counterclockwise common port
- receptacle 211 is a transmission port of counterclockwise wavelength ⁇ 1
- receptacle 212 is a reception port of counterclockwise wavelength 2
- receptacle 213 is a transmission port of counterclockwise wavelength 3.
- the receptacle 214 is a counterclockwise wavelength 4 receiving port.
- the receptacle 215 is a clockwise transmission port of the wavelength ⁇ 1
- the receptacle 216 is a clockwise reception port of the wavelength ⁇ 2
- the receptacle 217 is a transmission port of the clockwise wavelength ⁇ 3
- the receptacle 218 is a clockwise wavelength;
- the receiving port 14 and the receptacle 219 are clockwise common ports.
- FIG. 17 shows another embodiment ⁇ in which the wavelength router (optical add-drop multiplexer 1) US of FIG. 14 is mounted on a box.
- Another drawing 221 showing the wavelength routing path is provided on the top of the box.
- This drawing shows how the own station (Station_l) and other stations (Station_2, Statio n-3) are routed. From the user's point of view, the logical connection form may be more important than the physical connection of each station, and the embodiment of Fig. 17 is useful in such a case. Display method.
- the symbols on the front face 222 of the box represent wavelengths as ⁇ 1, 22, 3, 44, ⁇ for transmission, Rx for reception, Right for clockwise, Right for left, and C for common port.
- the display of Station-2 and Station_3 indicates the destination of the communication path.
- the connection of each receptacle provided on the box front 222 is different from that in FIG.
- Receptacle 230 is a counterclockwise common port
- receptacle 231 is a transmission port of wavelength ⁇ 1, which is counterclockwise directed toward Station-2
- receptacle 232 is a counterclockwise reception port of wavelength ⁇ 2, which receives from Station-2.
- Receptacle 233 is a transmission port having a wavelength of ⁇ 1 directed clockwise to Station-2, and receptacle 234 is a reception port of a wavelength ⁇ 2 received clockwise from Station-2.
- Receptacle 235 turns counterclockwise to Station-3.
- Direction toward 3 Reception port of wavelength ⁇ 3, receptacle 238 is a reception port of wavelength ⁇ 4 received from clockwise Station-3, and receptacle 239 is a clockwise common port.
- FIG. 18 shows a case where the wavelength router (optical add-drop multiplexer 1) US of FIG. 14 is implemented as a patch code ⁇ .
- the patch path is shown on the upper surface 241 of the main unit.
- An optical connector 242 is provided at the end of the optical fiber cord 244 coming out of the patch cord, and a tag 243 is provided near the optical connector 242.
- Each tag has a wavelength, a role, a communication path, etc. of each optical connector. It is shown.
- FIG. 19 shows an optical fiber communication network in which bidirectional transmission is realized on one optical fiber 270 by changing the upstream wavelength and the downstream wavelength.
- the wavelength multiplexer ⁇ ⁇ includes a dielectric thin film filter type three-port device 251 to 254.
- the wavelength multiplexer ⁇ includes a dielectric thin film filter type three-port device 261 and 264.
- An optical signal of wavelength ⁇ 1 for transmission is added to port 255 of the wavelength multiplexer ⁇ , and an optical signal of wavelength 2 for transmission is added to port 256.
- the optical signals multiplexed by the dielectric thin film filter type three-port devices 251 and 252 are sent to the common port 259, the optical fiber 270, and the common port 269 of the wavelength multiplexer.
- the multiplexed optical signal is applied to the dielectric thin film filter type three-port device 261 and 261 in the wavelength multiplexer ⁇ .
- the optical signals are separated into the original wavelength 1 and 2 optical signals, respectively, and output to ports 265 and 266, respectively.
- An optical signal of wavelength 3 for transmission is added to port 267 of the wavelength multiplexer, and an optical signal of wavelength 14 for transmission is added to port 268.
- the optical signals multiplexed by the dielectric thin film filter type three-port devices 263 and 264 are sent to the common port 269, the optical fiber 270, and the common port 259 of the wavelength multiplexer.
- the multiplexed optical signal is separated into the optical signals of the original wavelengths of 13 and 14 by the dielectric thin film filter type three-port devices 253 and 254 in the wavelength multiplexer, respectively. And 258 are output.
- wavelength multiplexers 250 to 260 can be regarded as wavelength routers having the simplest functions. This is because point-to-point wavelength routing is performed.
- the wavelength multiplexer 250 it is meaningful to arrange the dielectric thin film filter type three-port devices 251 to 252 for transmission at a position near the common port 259. This will be described with reference to FIG.
- port 281 is an input port
- port 282 is a reflection port
- port 283 is a transmission port.
- the ports, the collimator 284, the dielectric thin film filter 285, and the collimator 285 constitute a dielectric thin film filter type three-port device.
- the dielectric thin film filter type three-port device it is known that when a transmission optical signal is incident from the transmission port 283 side, crosstalk hardly occurs on the reflection port 282 side. This is because, among the light incident from the transmission port 283 side, a component that causes crosstalk is reflected in the direction 287 side, and almost no component propagates in the direction 288 side coupled to the reflection port 282.
- FIG. 19 also shows a case where an optical connector or the like is provided in the immediate vicinity of the entrance port 281 and large reflection (reflectance caused by Fresnel reflection at the air-glass interface, so-called _13 dB reflection) occurs. Is effective. It is known that most of the Fresnel reflected light from the vicinity of the incident port 281 is guided to the transmission port 283, and the amount of light reflected toward the direction 288 attenuates to -15 dB to 120 dB with respect to the incident light. The amount of this attenuation is It will be added to the isolation of the membrane filter type three port device 253, 254, 261 or 262. Therefore, an effective isolation of about 40 to 50 dB in total can be realized, and the problem of crosstalk can be eliminated.
- the transmitting dielectric thin-film filter type three-port devices 251 to 252 are arranged near the common port 259.
- bidirectional transmission using different wavelengths for upstream and downstream can be realized on one optical fiber without causing the problem of insufficient isolation as described in FIG.
- a two-channel full-duplex communication path is realized using four wavelengths.
- One-channel full-duplex communication path is realized using two wavelengths, and four channels are realized using eight wavelengths.
- a full-duplex communication path for the channel can also be realized.
- the three-port dielectric thin film filter device for transmission must be placed closer to the common port than the three-port dielectric thin film filter device for reception.
- FIG. 21 shows an example in which the wavelength router (wavelength multiplexer) according to the eighth embodiment of the present invention is mounted on a box and a box.
- an isolation problem may occur unless the transmission port and the reception port are distinguished from each other to prevent misuse. Therefore, drawings 291 and 301 showing wavelength routing paths are provided on the upper surfaces of the boxes 290 and, respectively. The wavelength routing paths shown in the drawings 291 and 301 are different from the actual connection of the dielectric thin film filter type three-port device shown in FIG.
- Each port (receptacle) 255 to 258 on the front face 292 of the box corresponds to the port shown in FIG. 19 (a).
- channels (full-duplex communication path) with Tx for transmission and Rx for reception are shown as CH1 and CH2, respectively.
- the wavelengths are expressed as ⁇ 1, ⁇ 2, ⁇ 3, ⁇ 4.
- the common port is represented as common port C.
- the ports (receptacles) 265 to 268 on the front surface 302 of the box plate correspond to the ports in Fig. 19 (b).
- the transmission is indicated by ⁇
- the reception is indicated by Rx
- the channel full-duplex communication path
- CH1 and CH2 respectively.
- the wavelengths are expressed as ⁇ 1, ⁇ 2, ⁇ 3, ⁇ 4.
- the common port is represented as common port C.
- the wavelength multiplexing device is mounted on the box. It is safe to implement it as a card.
- FIG. 22 shows a wavelength router (optical add-drop multiplexer 1) according to Embodiment 9 of the present invention.
- a method for compensating for the lack of isolation by arranging the dielectric thin-film filter type three-port devices 321, 322, 327, and 328 for transmission described in the eighth embodiment near the output port and devising a wavelength arrangement.
- the wavelength routers 311 to 313 are realized without using a double filter or a double-pass structure.
- the dielectric thin film filter type three-port devices 323, 324, 235, and 326 are used for reception.
- Reference numeral 315 indicates an optical fiber, and reference numerals 331 to 338 indicate at-drop ports.
- the wavelength router 311 uses wavelengths ⁇ 1, ⁇ 2, e4, and e5.
- the wavelength router 312 uses the wavelengths ⁇ 1, ⁇ 2, e 7, and e 8 to check.
- the wavelength nolator 313 uses wavelengths 4, 4, 5, ⁇ 7, and ⁇ 8.
- the paired wavelengths as the transmission wavelength and the reception wavelength, respectively, and using the technique described in the eighth embodiment for the wavelength filter, the lack of isolation between the paired wavelengths is first compensated. Insufficient isolation is further compensated for by leaving one wavelength between the paired wavelengths.
- a problem of crosstalk 340 as shown in FIG. 23 occurs, for example.
- the optical signal of wavelength ⁇ 2 is dropped on the wavelength router 311, and the light of wavelength 3 is bypassed.
- an optical signal having a wavelength of 12 is greatly attenuated from a distant node, and the optical intensity thereof is, for example, -30 dBm.
- the optical signal of the wavelength ⁇ 3 is from the neighboring node and hardly attenuated and has an OdBm intensity. Since the isolation between wavelengths ⁇ 2 and ⁇ 3 is only about 3 OdB if it is a one-stage filter, the crosstalk from wavelength ⁇ 3 and the optical signal intensity at wavelength 2 are almost equal, and reception should be straight. Can not.
- a three-port dielectric thin film filter device for low-density wavelength division multiplexing has There is only about 25 to 30 dB of isolation, but for non-adjacent wavelengths there is about 50 to 60 dB of isolation. Therefore, if the wavelength 3 is not used as in the present embodiment, the wavelengths bypassing the wavelength router 311 are all non-adjacent wavelengths, so that the above problem does not occur.
- the wavelength router in Fig. 22 can be used to configure a full mesh communication path on a ring-shaped optical fiber communication network as shown in Figs. 6 and 7. Further, by combining with the wavelength router shown in FIG. 24, a star-type communication path can be formed on a ring-shaped optical fiber communication network.
- Fig. 24 shows a wavelength router ⁇ for forming a star-type communication path.
- the transmitting dielectric thin film filter type three-port devices 361 and 364 are arranged on the outside, and the receiving dielectric thin film filter type three-port devices 362 and 363 are arranged on the inside.
- Reference numeral 355 indicates an optical fiber, and reference numerals 365 to 368 indicate an add-drop port.
- the wavelength router 351 uses the wavelengths ⁇ 1, ⁇ 2.
- the wavelength router 352 uses wavelengths ⁇ 4 and ⁇ 5.
- the wavelength nolator 353 uses wavelengths ⁇ 7 and ⁇ 8.
- the wavelength router 354 uses wavelengths ⁇ 7 and ⁇ 8, but the wavelength for transmission and the wavelength for reception are opposite to those of the wavelength router 353.
- FIG. 25 shows an optical communication network formed by the wavelength routers 311, 351, 352, 353, and 354.
- One optical fin 361 connects the wavelength nolators 311, 351, 352, 353, and 354.
- the wavelength routers 351 and 352 around the wavelength router 311 are connected in a star type. Redundant full-duplex communication paths 362 and 363 are formed between the wavelength router 311 and the wavelength routers 351 and 352, respectively.
- a full-duplex communication path 364 at the point "one point" is formed.
- the network consisting of the wavelength nolators 311, 351 and 352 and the network consisting of the wavelength nolators 353 and 354 are logically independent.
- FIG. 26 shows a wavelength router (wavelength multiplexer) according to Embodiment 10 of the present invention.
- This embodiment is a wavelength multiplexer for performing bidirectional transmission using different wavelengths with one optical fiber.
- This embodiment is an application of the method of using the CWDM wavelengths shown in Embodiment 9 step by step. is there.
- the dielectric thin film filter type three-port device 370 transmits a wavelength ⁇ 6 (1570 nm). Further, the dielectric thin film filter type three-port device 380 transmits a wavelength of 4 (1530 nm).
- the transmission optical signal of wavelength ⁇ 4 is input to the reflection port 372 of the dielectric thin film filter type three port device 370. Further, a transmission light signal having a wavelength of 14 is input to the reflection port 382 of the three-port device 370 of the dielectric thin film filter type.
- the optical signal of wavelength ⁇ 6 that has propagated through the optical fiber 378 is guided to the transmission port 373 via the input port 371 of the three-port dielectric film filter type device 370.
- the optical signal of wavelength ⁇ 4 transmitted through the optical fiber 378 is guided to the transmission port 383 via the entrance port 381 of the dielectric thin film filter type three-port device 380.
- the optical signal incident on the reflection port almost leaks to the transmission port 373 due to the positional relationship of the optical system.
- the transmitted optical signal 376 has a light of 377 reflected at the reflection point 374 of 25 dB or more at the adjacent wavelength and 50 dB or more at the non-adjacent wavelength. Isolation is obtained.
- the amount of reflection at the reflection point 374 can reach 4% (-13 dB) of the Fresnel reflection at the glass-air interface.
- the optical signal input to the reflection port 372 is an optical signal of OdBm
- the crosstalk reaches up to -38 dBm for adjacent wavelengths.
- the optical signal transmitted from the dielectric and other filter type three-port device 380 has the power S to attenuate to ⁇ 35 dBm while propagating through the optical fiber 378.
- the signal-to-noise ratio (signal-to-noise ratio) is only 3 dB, and it cannot be received properly.
- the isolation can be taken more than 50dB.
- the S / N ratio can be increased to 28 dB or more, and the conditions for good reception, the SZN ratio of 2 OdB or more (preferably 25 dB or more) can be realized.
- one bidirectional transmission is realized by one optical fiber using two wavelengths, so that one dielectric thin film filter type three-port device is used for each, thereby reducing costs.
- FIG. 27 shows an example in which the present embodiment is applied to the case of four wavelengths.
- the wavelength multiplexer 390 is made up of a dielectric thin film filter type three port device 391, 392, and 393 forces.
- the wavelength multiplexer 400 is composed of a dielectric thin film filter type three-port device 401, 402, and 403.
- the wavelength division multiplexing device 390 has four ports 395 and 398 398.
- the optical signal of wavelength ⁇ 4 input from port 398 is multiplexed with the optical signal of wavelength ⁇ 3 input from port 397 by the dielectric thin film filter type three-port device 393, and the dielectric thin film filter type is used.
- the light is output to the port 399 via the three-port devices 392 and 391, and reaches the port 409 of the wavelength multiplexer 400 via the optical fiber 410.
- the optical signals of wavelengths 6 and 7 from the port 409 of the wavelength multiplexer 400 pass through the optical fiber 410 and reach the port 399 of the wavelength multiplexer 390, and then the dielectric thin film filter type three-port device. 391 and 392 lead to ports 395 and 396 respectively.
- the wavelength multiplexer 400 has four ports 405 to 408.
- the optical signal of wavelength ⁇ 6 input from the port 408 is multiplexed with the optical signal of wavelength 7 input from the port 407 by the dielectric thin film filter type three-port device 403, and the dielectric thin film filter type three
- the light is output to the port 409 via the port devices 402 and 401, and reaches the port 399 of the wavelength multiplexer 390 via the optical fiber 410.
- the optical signals of wavelengths ⁇ 4 and ⁇ 3 from the port 409 of the wavelength multiplexer 390 reach the port 409 of the wavelength multiplexer 400 via the optical fiber 410, and then the dielectric thin film filter type three-port device. 401 and 402 lead to ports 405 and 406, respectively.
- FIG. 28 shows a wavelength multiplexer ⁇ according to Embodiment 11 of the present invention.
- This wavelength multiplexer 4Q is a wavelength multiplexer for performing bidirectional transmission by changing the wavelength between upstream and downstream with one optical fiber.
- CWDM provides high isolation at non-adjacent wavelengths, and can be used to solve the problem of isolation during bidirectional transmission.
- the wavelength multiplexer 421 is composed of seven dielectric thin film filter type three-port devices 431 to 437. Further, a local port for reception corresponding to the wavelength of port 441 to 444f; 11 for the wavelength ⁇ 4, and ports 445 to 448 are a single port of the transmission port corresponding to the wavelength ⁇ 5 to ⁇ 18. A port 449 is a remote port for transmission and reception.
- the double-pass type dielectric thin film filter type three-port device has a structure as shown in FIG. 15 (a), and has a high isolation for adjacent wavelengths. This is because in the case of wavelength ⁇ 4, an optical signal of adjacent wavelength ⁇ 5 is used, and if reflection occurs near the transmission / reception remote port 449, a problem of insufficient isolation may occur. This is because ⁇ 4 needs to have a particularly high adjacent wavelength isolation.
- a normal dielectric thin film filter type three-port device is used because there is no fear that adjacent wavelengths will be reflected back. Also, in the wavelength multiplexer 422 used in pairs with the wavelength multiplexer 421, The double-pass dielectric thin-film filter type three-port device is used as the dielectric thin-film filter type three-port device with a wavelength of 5 mm.
- a simple two-stage filter is used instead of the double-pass type dielectric thin-film filter type three-port device, or a two-stage filter using the duplicated dielectric thin-film filter type three-port device shown in Fig. 15 (b). Good to use ,.
- a dielectric thin film filter type three-port device having high adjacent wavelength isolation may be provided only at the reception port of the boundary wavelength. It is.
- FIG. 29 shows an embodiment in which the wavelength multiplexer is mounted as a patch cord.
- An optical fiber is fused and connected between the dielectric thin film filter type three-port devices.
- a force fuser requires a certain length of optical fiber. Therefore, a dielectric thin film filter type three-port device group is usually provided in a rectangular box, and the optical fibers are arranged in an arc shape.
- the dielectric thin film filter type three-port device group 431, 433, 435, and 437 are mounted on the housing 451, and the dielectric thin-film finoleta type three-port device group 432 is mounted.
- 434, and 436 are mounted on a housing 453, and the two housings are connected by a cord 452.
- FIG. 29 (a) is a diagram corresponding to the circuit diagram of the wavelength multiplexer shown in FIG. 28, and FIG. 29 (b) is a diagram showing a state of actual mounting.
- the housing 451 is provided with a hook 454, and the housing 453 is provided with a hook 455. These hooks are equipment to be hooked and held by optical connectors and appropriate fittings on the front panel of devices such as routers and switches.
- the patch cord-type wavelength multiplexer shown in Fig. 29 (b) has the advantage that it can be mounted flexibly on the front panel of a router or switch because the two housings are connected by a cord. There is. Also, there is an advantage that the size is smaller than when mounted in a rectangular box as before.
- a wavelength router such as a wavelength multiplexer or an optical add-drop multiplexer is mounted on a housing by dividing a dielectric thin film filter type three-port device group into two groups as shown in Fig. 29, and a space between the housings is provided. Needless to say, you can connect them with a code. That is, the configuration in FIG. 29 is not limited to the circuit configuration in FIG.
- a wavelength router and an optical communication network according to the twelfth embodiment of the present invention will be described with reference to FIGS. 30 to 32.
- a plurality of logical network topologies can be formed on a ring-shaped optical fiber network.
- a flexible network structure is formed by using high-density wavelength division multiplexing (DWDM), which can use more wavelengths.
- DWDM high-density wavelength division multiplexing
- wavelength routers 461 to 468 are connected in a double ring shape by two optical fibers 471 and 472.
- the structure is similar to that of the network described with reference to FIGS. The difference from the third embodiment is that a full mesh network is not formed between all the wavelength routers.
- a funnel mesh network is formed between the wavelength routers 461, 464, 465, and 468 using a wavelength ⁇ 1 having a wavelength ⁇ 1.
- a first star-shaped network (star 1) is formed between the wavelength nolators 462 and 463 around the wavelength nolator 461 using the wavelengths ⁇ 7 and ⁇ 8.
- a second star-shaped network (star 2) is formed around the wavelength router 468 and between the wavelength routers 466 and 467 using the wavelength; 19 and the wavelength;
- Fig. 30 (b) Such a wavelength arrangement is shown in Fig. 30 (b).
- an optical add-drop multiplexer that can add and drop the number of wavelengths of the number of slave stations N is arranged in the wavelength router serving as the center (master station), and the slave station wavelength router is arranged in the wavelength router of the slave station.
- An optical add-drop multiplexer that add-drops only one wavelength that specifies the wavelength is placed. Therefore, a master station in a star topology accommodating up to N slave stations is equipped with an N-wavelength optical add-drop multiplexer.
- 2N wavelengths are required.
- FIG. 31 shows the internal structure of the wavelength router 461 as an example.
- the optical signal from the input port 492a is amplified by the erbium-doped fiber optical amplifier 491a, and then the first optical add-drop multiplexer ( ⁇ ADM) 481a and the second optical add-drop multiplexer ( ⁇ ADM) 482a Via output port 493a.
- the first optical add-drop multiplexer ( ⁇ ADM) 481a has a wavelength arrangement that forms a full mesh using wavelengths ⁇ 1 to I6.
- the second optical add-drop multiplexer (OADM) 482a has a wavelength arrangement that forms a star 1 using the wavelengths ⁇ 7 and ⁇ 8.
- an optical add-drop multiplexer having an appropriate wavelength arrangement may be vertically connected as necessary. Les ,.
- the erbium-doped fiber optical amplifier 491b and the optical add-drop multiplexers 481b and 482b perform the same optical amplification and add-drop on the optical signal from the port 492b.
- FIG. 32 shows a wavelength router according to a modification of the present embodiment. This figure shows only half of the wavelength router, that is, only the functional part that amplifies the optical signal from the left side in FIG. 32, adds the optical add drop, and sends it to the right side.
- the wavelength router is provided with an optical amplifier and an optical add-drop multiplexer (not shown) that amplify and add optical signals from the right side in FIG.
- a first optical add-drop multiplexer 483 is connected downstream of the erbium-doped fiber optical amplifier 491c.
- This optical add-drop multiplexer 483 has a structure similar to that of the optical add-drop multiplexer 101 shown in FIG. 8, and uses wavelengths ⁇ 1 to 128 to transmit signals between eight nodes (wavelength routers). Form a full mesh network.
- a second optical add-drop multiplexer 484 is connected to the subsequent stage of the optical add-drop multiplexer 483.
- the second optical add-drop multiplexer 484 has a structure as shown in FIG. 32 (b).
- This is an optical add-drop multiplexer composed of two arrayed waveguide diffraction gratings 485a and 485b.
- the two arrayed waveguide gratings 485a and 485b can multiply and demultiplex the 16 wavelengths of wavelength ⁇ 29 power, etc .; 144; Atdodo
- the wavelength that does not drop is a short circuit between the corresponding ports of the two arrayed waveguide gratings 485a and 485b with an optical fiber, and the wavelength that adds and drops drops the corresponding port to the outside.
- a wavelength multiplexer formed by multiplexing and connecting dielectric thin film three-port devices, a wavelength multiplexer that multiplexes fiber Bragg grating filters and the like are used. Good to use ,. The point is that the wavelength multiplexers (multiplexers and demultiplexers) should be faced to each other.
- a wavelength arrangement as shown in FIG. 32 (c) can be realized.
- a full-mesh network can be constructed using the wavelengths ⁇ 1 to; 128, and further additional communication paths can be arbitrarily set using the wavelengths 129 to 144.
- Various communication paths on a ring-shaped optical fiber network can be established by arbitrarily connecting the optical add-drop multiplexer for full mesh, the optical add-drop multiplexer for star, the optical add-drop multiplexer for free, etc. Can be realized by wavelength multiplexing.
- a continuous wavelength arrangement is shown as a wavelength used for each topology form (full mesh, star, free, etc.). However, this wavelength arrangement does not need to be continuous.
- Each topology can be realized by a set consisting of the required number of wavelengths, and each wavelength does not have to be physically contiguous
- FIG. 33 shows a wavelength router according to the thirteenth embodiment of the present invention.
- the wavelength router optical add-drop multiplexer for the full-mesh type or the star type described above can be realized by connecting the basic components shown in FIG. 33 vertically.
- FIG. 33 (a) shows a basic component 500 of an optical add-drop multiplexer for a network constituted by using two optical fibers.
- Basic component 500 consists of four dielectric thin film Filter-type three-port device 501-504 force
- the four dielectric thin film filter type three-port devices 501 to 504 are provided with a dielectric thin film filter having a wavelength of i.
- the reflection port of the dielectric thin film filter type three-port device 501 is connected to the reflection port of the dielectric thin film filter type three port device 502.
- the reflection port of the dielectric thin-film filter type three-port device 504 is connected to the reflection port of the dielectric thin-film filter type three-port device 503.
- the input port of the dielectric thin-film filter type three-port device 501 is one of the input ports of this basic element, and the input port of the dielectric thin-film filter type three-port device 504 is another input port of this basic element ⁇ .
- the input port of the dielectric thin-film filter type three-port device 502 and the input port of the dielectric thin-film filter type three-port device 503 are output ports of the basic element ⁇ , respectively.
- the transmission ports of the dielectric thin-film filter type three-port devices 501 to 504 are add-drop ports.
- Fig. 33 (b) shows an optical add-drop multiplexer applied to a ring-type optical fiber communication network that performs bidirectional transmission using different wavelengths for upstream and downstream using a single optical fiber.
- the basic component ⁇ consists of four dielectric thin film filter-type three-port devices 501-504.
- the dielectric thin film filter type three-port devices 511 and 513 are provided with a dielectric thin film filter of wavelength i
- the dielectric thin film filter type three-port devices 512 and 514 are provided with a dielectric thin film filter of wavelength j.
- the reflection port of the dielectric thin film filter type three-port device 511 is connected to the incident port of the dielectric thin film filter type three port device 512.
- the reflection port of the dielectric thin-film filter type three-port device 512 is connected to the reflection port of the dielectric thin-film filter type three-port device 513.
- the input port of the dielectric thin-film filter type three-port device 513 is connected to the reflection port of the dielectric thin-film filter type three-port device 514.
- the input port of the dielectric thin-film filter type three-port device 511 is one of the input / output ports of this basic element fi, and the input port of the dielectric thin-film filter type three-port device 514 is another input / output port of this basic element. Become one. Dielectric thin film
- the transmission ports of the filter type three-port devices 511 to 514 are added drop ports.
- a point-to-point redundant communication path can be realized on a double ring optical fiber communication network using two optical fibers.
- Point-to-point can be compared to a "line", and by combining these lines, an arbitrary topology can be constructed, whether it is a full mesh or a star.
- a point-to-point redundant communication path can be realized on a ring-shaped optical fiber communication network using one optical fiber.
- Point-to-point can be compared to a "line”. By combining these lines, it is possible to construct an arbitrary topology whether it is a full mesh or a star.
- an optical circuit equivalent to the basic element ⁇ or in FIG. 33 is formed from a free-space optical system, a free-space optical system using a structure in which a dielectric thin film filter is mounted on a glass block, glass, plastic, or the like. It is needless to say that the present invention also includes such a realization example.
- FIG. 34 shows an optical communication network according to Embodiment 14 of the present invention.
- a base station 1002 and optical signal branching circuit units 1001a to 1001d are connected in series by an optical fiber 1004.
- Client station groups 1003a to 1003d are connected to the optical signal branch circuit units 1001a to 1003d, respectively.
- FIG. 35 shows the internal structure of the optical signal branch circuit unit 1001.
- the optical signal branching circuit unit 1001 is a dielectric thin film filter type three-port device 1011 and 1012, a CWDM optical transceiver 1013 having a transmission wavelength of CWDM (low density wavelength multiplexing), and a transmission wavelength of 1.5.
- Port 1017 is a port on the other side of the base station, and port 1018 is a port connected to the next-stage optical signal branch circuit unit.
- the port group 1021 is a port connected to the client station group.
- FIG. 45 (a) Three-port devices 1011 and 1012 of the dielectric thin film filter type are shown in Fig. 45 (a). It has the same internal structure as that shown in FIG. 45, and is represented by simplified symbols as shown in FIG. 45 (b).
- FIG. 36 is a diagram showing a wavelength multiplexing apparatus IS provided in the base station 1002. It consists of local optical transceivers 1041a through 1041d, remote CWDM (low-density wavelength multiplexing) optical transceiver 1042a, 1042d, and wavelength multiplexer 43. On the left side of the local optical transceivers 1041a to 1041d, a P ⁇ N switch (not shown) is connected. CH1 and CH4 show each channel of P ⁇ N.
- the optical signals of CH1 to CH4 from the P ⁇ N switch are converted into electrical signals by local optical transceivers 1041a to 1041d, and then the remote CWDM (low-density wavelength multiplexing) optical transceiver 1042a Or the internal force of the CWDM wavelength determined by the ITU-T according to 1042d or converted to the selected wavelengths of ⁇ 1, ⁇ 3, ⁇ 5, and ⁇ 7, and wavelength-multiplexed by the wavelength multiplexer 43. After that, they are sent to the optical signal branching circuit units 1001a to 1001, respectively.
- CWDM low-density wavelength multiplexing
- R of the optical transceiver is the receiving port of the optical signal
- T is the transmitting port of the optical signal
- Rx is the output port of the electrical signal corresponding to the receiving signal of the optical signal
- Tx is the electrical signal corresponding to the transmitting signal of the optical signal. Input port.
- optical signals of wavelengths ⁇ 2, ⁇ 4, ⁇ 6, and 8 are transmitted from the optical signal branch circuit units 1001 a to 1001 via the optical fiber 1004, respectively.
- the wavelengths 2, 4, 6, and ⁇ 8 also use the selected wavelength of the CWDM wavelength defined by ITU- ⁇ .
- the CWDM wavelength is set every 20nm from 1270nm to 1610nm.
- the CWDM wavelengths specified by the ITU-T eight wavelengths from 1470 nm to 1610 nm are particularly frequently used.
- ⁇ 1 1470 ⁇
- 2 2 1490nm
- ⁇ 3 1510nm
- ⁇ 4 1530
- ⁇ 5 1550
- ⁇ 6 1570
- ⁇ 7 1590nm
- ⁇ 8 1610 111 ⁇ ⁇ Review.
- the optical signal transmitted via the optical fiber 1004 is dropped by the optical signal branch circuit unit 1001 as shown in FIG.
- the optical signal branch circuit unit 1001a drops an optical signal of wavelength ⁇ 1 by the dielectric thin film filter type three-port device 1011.
- an optical signal of wavelength ⁇ 2 is added by the dielectric thin film filter type three-port device 1012 and sent to the base station 1002 side.
- CW in optical signal branch circuit unit 1001a The DM (Low Density Wavelength Division Multiplexing) optical transceiver 1013 transmits an optical signal of ⁇ 2.
- the CWDM (low density wavelength multiplexing) optical transceiver 1013 and the 1.5 / im optical transceiver 1014 are combined back to back.
- the optical signal received by the CWDM (Low Density Wavelength Multiplexing) optical transceiver 1013 is converted into an electrical signal and sent to a 1.5 xm optical transceiver 1014 to be converted to a wavelength of 1.5 zm and converted into a WDM optical fiber. It is sent to the client station group 1003a via the plastic and the tree coupler 1016.
- CWDM Low Density Wavelength Multiplexing
- the optical signal branching unit 1001b drops the optical signal of wavelength ⁇ 3 and adds the optical signal of wavelength ⁇ 4.
- the optical signal branching unit 1001c drops the optical signal of wavelength ⁇ 5 and adds the optical signal of wavelength ⁇ 7.
- the optical signal branching unit 100D drops the optical signal of wavelength ⁇ 7 and adds the optical signal of wavelength ⁇ 8.
- An optical signal having a wavelength of 1.3 ⁇ m from the client station group 1003a is sent to the receiving port (R) of the 1.5 x m optical transceiver 1014 via the tree coupler 1016 and the WDM coupler 1015.
- the optical signal having the wavelength of 1.3 ⁇ ⁇ ⁇ is converted into an electric signal by the 1.5 ⁇ optical transceiver 1014 and then converted into an optical signal of wavelength ⁇ 1 by the CWDM (low-density wavelength multiplexing) optical transceiver 1013.
- the signal is sent to the base station 1002 via the dielectric thin film filter type three-port device 1012.
- each channel can accommodate up to 32 client stations, a total of up to 128 client stations can be accommodated. Therefore, it is effective in reducing the optical fiber installation cost.
- FIG. 37 shows optical signal branching circuits according to Embodiment 15 of the present invention.
- the optical signal branching circuit unit 5 is composed of a dielectric thin film filter type three-port device 1011 and 1012, a CWDM (low density wavelength multiplexing) optical transceiver 1013, a WDM (wavelength multiplexing) optical fiber coupler 1015, and a 32-branch tree coupler 1016.
- the port 1017 is a port on the side different from the base station, and the port 1018 is a port connected to the next-stage optical signal branch circuit unit.
- the port group 1021 is a port connected to the client station group.
- optical signal branch circuit unit The difference between the optical signal branch circuit unit and the optical signal branch circuit unit 1001 is that the optical signal branch Circuit unit! ⁇ Is not equipped with a 1.5 ⁇ optical transceiver 1014. Wavelength conversion of upstream optical signals from a tree coupler 1016 to a base station is performed only by a CWDM (low-density wavelength multiplexing) optical transceiver 1013 (1.3 im ⁇ CWDM wavelength).
- CWDM low-density wavelength multiplexing
- the Tx and Rx terminals of the CWDM (low-density wavelength division multiplexing) optical transceiver 1013 are short-circuited, and the 1.3 ⁇ m wavelength input to the optical signal input port (R) of the CWDM (low-density wavelength division multiplexing) optical transceiver 1013 is The optical signal is converted into an optical signal ⁇ j of the CWDM wavelength, and is sent to the base station via the dielectric thin film filter type three-port device 1012.
- the optical signal of CWDM wavelength ⁇ i transmitted from the base station is transmitted to a tree coupler 1016 via a dielectric thin film filter type three-port device 1011, a WDM optical fiber coupler 1015, and a tree coupler 1016.
- photodiodes used to receive optical signals have sensitivity over a wide wavelength range over the entire CWDM wavelength range (1270_1610 nm), so even if configured as described above, there will be problems with reception at the client station. Absent.
- the main feature of the present embodiment is that the 1.5 / im optical transceiver 1014 is omitted to reduce the cost by utilizing this feature of the photodiode.
- a clock recovery retiming circuit (not shown) may be provided between the Rx terminal and the Tx terminal of the CWDM (low-density wavelength multiplex) optical transceiver 1013. By providing the clock recovery retiming circuit, distortion of the optical signal can be corrected. Further, other wavelength multiplexing means such as a dielectric / thin film filter type three-port device may be used instead of the WDM optical fiber coupler 1015.
- the 1.5 / m optical transceiver can be omitted from the optical signal branching unit as compared with the case of the fourteenth embodiment, resulting in an effect of cost reduction.
- FIG. 38 shows the internal structure of the optical signal branch circuit units 1050a and 1050b. 1050c. And an optical communication network including these optical signal branch circuit units.
- FIG. 39 shows a wavelength multiplexing device provided in a base station.
- the optical signal branch circuit is composed of a completely passive circuit.
- the reference numerals 1051a, 1051b, and 1051d denote a three-port dielectric thin film filter device having transmission wavelengths of 1, 1, ⁇ 2, and ⁇ 3, respectively.
- reference numbers 1055a, 1055b, and 1055c are optical fiber power plugs with branch ratios of 3: 1, 2: 1, and 1: 1 respectively, and reference numbers 1056a through 1056d are 8-branch tree couplers.
- the optical signal of wavelength ⁇ 1 is dropped by the dielectric thin film filter type three-port device 1051a in the optical signal branch circuit unit 1050a, and the dielectric thin film filter type three
- the data is branched by the tree coupler 1056a via the port device 1052a and sent to the client station group, not shown.
- the optical signal of wavelength ⁇ 2 is dropped by the dielectric thin film filter type three-port device 1051b in the optical signal branch circuit unit 1050b, and the dielectric thin film filter type three After being branched by the tree coupler 1056b via the port device 1052b, it is sent to the client station group (not shown).
- the optical signal of wavelength ⁇ 3 is dropped by the dielectric thin film filter type three-port device 5cb in the optical signal branch circuit unit 1050c, and the dielectric thin film filter type is used. After being branched by the tree coupler 1056c via the three-port device 1052c, it is sent to the client station group (not shown).
- the optical signal of wavelength ⁇ 4 is branched by the tree coupler 1056d in the optical signal branch circuit unit 1050d and sent to a client station group (not shown).
- an optical signal of an upstream wavelength ⁇ Od from a client station group (not shown) connected to the optical signal branch circuit unit 1050d passes through a tree power plug 1056d in the optical signal branch circuit unit 1050d, and It is dropped by the dielectric thin film filter type three-port device 1054c in the branch circuit unit 1050c and sent to the optical fiber coupler 1055c.
- Optical signal An optical signal with an upstream wavelength of 0c from a group of client stations (not shown) connected to the branch circuit unit 1050c is a tree force bra 1056c, a dielectric thin film filter type three-port device. The light is sent to the optical fiber coupler 1055c through the reflection port of the chair 1052c.
- the upstream signal of the optical signal branch circuit unit 1050d and the upstream signal of the optical signal branch circuit unit 1050c are joined by the optical fiber coupler 1055c.
- the combined upstream signal is transmitted to the base station side by the dielectric thin film filter type three-port device 1053c.
- the combined signal of the upstream signals of the optical signal branch circuit units 1050d and 1050c is dropped by the dielectric thin film filter type three-port device 1054b in the optical signal branch circuit unit 1050b, and sent to the optical fiber force bra 1055b.
- the optical signal of the upstream wavelength ⁇ Ob from the client station group (not shown) connected to the optical signal branch circuit unit 1050b passes through the tree coupler 1056b and the reflection port of the dielectric thin film filter type three-port device 1052b, and the optical fiber cover Sent to 1055b.
- the upstream signals of the optical signal branch circuit units 1050d and 1050c and the upstream signal of the optical signal branch circuit unit 1050b are merged by the optical fiber force bra 1055b.
- the combined upstream signal is sent to the base station side by the dielectric thin film filter type three-port device 1053b.
- the combined signal of the upstream signals of the optical signal branch circuit units 1050d, 1050c, and 1050b is dropped by the dielectric thin film filter type three-port device 1054a in the optical signal branch circuit unit 1050a and sent to the optical fiber coupler 1055a.
- the optical signal of the upstream wavelength ⁇ 0a from the client station group is connected to the optical signal branch circuit unit 1050a, and the optical signal of the upstream wavelength ⁇ 0a is connected to the reflection coupler 1056a and the reflection port of the dielectric thin film filter type three port device 1052c.
- the light is then sent to the optical fiber coupler 1055a.
- the optical fiber coupler 1055a By the optical fiber coupler 1055a, the upstream signals of the optical signal branch circuit units 1050d, 1050c, and 1050b and the upstream signal of the optical signal branch circuit unit 1050a are combined.
- the combined upstream signal is sent to the base station side by the dielectric thin film filter type three-port device 1053a.
- the wavelength ⁇ 0 is a wavelength in a range of about 1310 nm ⁇ 40 nm. This is because a cheap Fabry-Perot laser with low wavelength accuracy is used for the client station.
- the wavelengths ⁇ 0a to ⁇ 0d are distinguished only for explaining the flow of the optical signal, and the wavelength is included in a range of about 1310 nm ⁇ 40 nm.
- the optical communication network of Fig. 38 since the optical communication network of Fig. 38 operates, from the wavelength ⁇ 1; the downlink signal of 14 is divided into eight, each of which is transmitted to the client station, and transmitted from a maximum of 32 client stations. Optical signals of wavelength ⁇ 0 are combined into one and sent to the base station.
- FIG. 39 shows the structure of a wavelength multiplexing device incorporated in the base station. It consists of CWDM optical transceivers 1057a to 1057d and a wavelength multiplexer 1058.
- the CWDM optical transceivers 1057a to 1057d the Rx terminal and the Tx terminal are short-circuited, and wavelength conversion is realized by one optical transceiver.
- the downlink signals from CH1 to CH4 and the uplink signal from CH0 are multiplexed by the wavelength multiplexer 1058.
- the optical signal branch circuits are composed of passive components, there is no need to supply power to the optical signal branch circuit, and the reliability is high. Further, since four waves are used for the downstream signal and one wave is used for the upstream signal, a wide downstream bandwidth can be obtained. For example, if the transmission speed is 100 Mbps per wave, 32 stations share 100 Mbps on the upstream and 8 stations share 100 Mbps on the downstream. In general, a downlink signal from a base station often requires a wider band, and therefore, such a transmission capacity arrangement has a large economic effect.
- FIG. 40 shows the internal structure of the optical signal branch circuit units 1060a to 1060d according to the seventeenth embodiment of the present invention, and the optical communication network including these optical signal branch circuit units.
- Wavelength 11 Dielectric thin-film filter type with transmission wavelengths of 1, ⁇ 2, ⁇ 3, reference number 1063a, 1063b, 1064a, and 1064cf; Dielectric thin-film filter type with transmission wavelength of 10
- reference number 1063c is a dielectric thin-film filter type three-port device having a transmission wavelength of ⁇ 5
- reference numbers 1065a and 1065c are optical fiber power plugs having a 1: 1 branching ratio, reference numbers 1066a, 1066d. Is an 8-branch pulley plastic
- reference numeral 1067 is a CWDM optical transceiver.
- the optical signal branch circuit unit 1060a has the same configuration as the optical signal branch circuit unit 1050a according to the sixteenth embodiment. Only the point where the branch ratio of the optical fiber coupler 1065a is 1: 1 is the optical signal branch. Different from circuit unit 1050a.
- the optical signal branch circuit unit 1060d has the same structure as the optical signal branch circuit unit 1050d of the sixteenth embodiment.
- Optical signal branch circuit unit 1 060b and 1060c have a structure different from that of Example 16.
- the upstream signals of the optical signal branch circuits 1060d and 1060c are joined to the optical fiber coupler 1065c by the same mechanism as in the sixteenth embodiment.
- the combined optical signal is converted into an optical signal having a wavelength of ⁇ 5 by the CWDM transceiver 1067, and then transmitted to the base station through the dielectric thin film filter type three-port device 1063c.
- the main difference from the sixteenth embodiment is that only the upstream signals of the optical signal branch circuit units 1060d and 1060c are combined and wavelength-converted and sent to the base station.
- the upstream signal of the wavelength ⁇ Ob from the tree coupler 1066b passes through the reflection port of the dielectric thin film filter type three-port device 1062b, the dielectric thin film filter type three-port device 1063b, and the base station side.
- Sent to In the optical signal branch circuit unit 1060a the optical signal of wavelength ⁇ Ob sent from the optical signal branch circuit unit 1060b is dropped by the dielectric thin film filter type three-port device 1064a, and then sent to the optical fiber coupler 1065a.
- an upstream signal of wavelength 0a from the tree coupler 1066a is sent to the optical fiber coupler 1065a via the reflection port of the dielectric thin film filter type three-port device 1062a.
- the optical signals of ⁇ Ob and ⁇ 0a are combined, then added by the dielectric thin film filter type three-port device 1063a, and sent to the base station side.
- the downstream optical signal is ⁇ 1
- the optical signal of four wavelengths ⁇ 4 is divided into eight, and is transmitted to the client station side.
- the upstream signals of 16 client stations are combined with the optical signals of two wavelengths ⁇ 0 and ⁇ 5, respectively, and sent to the base station.
- FIG. 41 is a diagram showing the configuration of the optical communication network of this embodiment.
- FIG. 42 is a diagram showing the internal structure of the optical signal branch circuit unit 1071 of this embodiment.
- reference numerals 1071a, 1071b, 1071c, and 1071d denote optical signal branching circuit units of the present embodiment
- reference numeral 1072 denotes a base station.
- the base station 1072 and the optical signal branch circuit units 1071a to 1071d are connected in a ring by an optical fiber 1074.
- Each of the optical signal branch circuit units 1071a to 1071d is connected to a client station group 1073a or 1073d, respectively.
- reference numerals 1081 and 1083 denote three-port dielectric thin-film filter devices with transmission wavelengths
- Ii and reference numerals 1082 and 1084 denote three-port dielectric film finolators with transmission wavelengths
- Devices, reference numbers 1085 and 1086 are CWDM optical transceivers with transmission wavelength j
- reference number 1087 is a crosspoint switch and control unit
- reference numbers 1088 and 1089 are optical transceivers with a transmission wavelength of 1.5 zm.
- Reference numbers 1090 and 1091 are WDM optical fiber couplers
- reference numbers 1092 and 1093 are 32-branch tree couplers.
- Reference numeral 1096 denotes an input / output port for a clockwise transmission path
- reference numeral 1097 denotes an input / output port for a clockwise transmission path
- reference numerals 1094 and 1095 denote input / output ports to a client station group.
- the communication path is routed from the base station 1072 to the optical signal branch circuit unit 1071 in two directions, clockwise and counterclockwise, using two wavelengths, wavelength and wavelength. Able to shape. Therefore, as compared with the case of Example 14, etc., even if one point of a ring-shaped fiber that can be connected by force can be cut off if it can achieve twice the communication capacity with the same number of wavelengths, it can rotate clockwise or counterclockwise. Either route survives, and there is an advantage that a redundant communication network can be realized.
- the optical signal having the wavelength from the input / output port 1096 for the clockwise transmission path is dropped by the dielectric thin-film filter type three-port device 1081, and the reception port (R) of the CWDM optical transceiver 1085 is Sent.
- the optical signal of the wavelength converted into the electric signal is transmitted from the Rx terminal of the CWDM optical transceiver 1085 to the optical transceiver 1088 through the crosspoint switch and the control unit 1087. Then, it is converted to the wavelength of wavelength 1.
- the wavelength is then sent to the input / output port 1094 to the client station group via the WDM optical fiber coupler 1090 and the tree coupler 1092.
- the wavelength 1 passes through a tree coupler 1092, a WDM optical fiber coupler 1090, an optical transceiver 1088, a crosspoint switch and a controller 1087, and is usually sent to a CWDM optical transceiver 1085, where it is converted into an optical signal having a wavelength j.
- the optical signal of this wavelength j is added by the dielectric thin film filter type three port device 1082 and sent to the input / output port 1096 for the clockwise transmission path.
- the optical signal of the wavelength from the input / output port 1097 for the counterclockwise transmission path is dropped by the dielectric thin film filter type three-port device 1083, and the reception port (R) of the CWDM optical transceiver 1086 is dropped.
- Sent The optical signal of the wavelength converted into the electric signal is transmitted from the Rx terminal of the CWDM optical transceiver 1086 to the optical transceiver 1089 through the crosspoint switch and the control unit 1087. Then, it is converted into the wavelength of wavelength 1.
- the wavelength is then sent to the input / output port 1095 to the client station group via the WDM optical fiber coupler 1091 and the tree coupler 1093.
- the optical signal of wavelength 1.3 / im sent from the client station group to the input / output port 1095 is a tree coupler 1093, a WDM optical fiber coupler 1091, an optical transceiver 1089, a cross point switch and a control unit. After passing through 1087, it is usually sent to the CWDM optical transceiver 1086, where it is converted into an optical signal of wavelength j.
- the optical signal of the wavelength j is added by the dielectric thin film filter type three port device 1084 and sent to the input / output port 1097 for the clockwise transmission path.
- the crosspoint switch and the control unit 1087 provide a live communication path.
- the optical transceivers 1088 and 1089 operate in parallel.
- the interruption of the communication path can be detected by a link signal detection mechanism (not shown) from the CWDM optical transceivers 1085 to 1086. It should be noted that two systems corresponding to the wavelength multiplexing device 1040 shown in FIG. 36 are provided in the base station 1072 in FIG.
- the dielectric thin film filter type three-port devices 1081 and 1083 can be configured by one duplicate dielectric type filter three-port device.
- the dielectric thin film filter type three-port device 1082 and 1084 should be composed of one duplicated dielectric filter type three-port device. Advertise.
- the duplicate dielectric filter type three-port device has been described in the fifth embodiment with reference to FIG.
- duplex dielectric thin film filter type three-port device in the optical signal branch circuit unit of this embodiment has an advantage that the number of components can be reduced and the cost can be reduced.
- an optical signal from the base station side communication device 1501 passes through a 2 ⁇ 2 optical switch 1502, passes through an optical fiber (normal path) 1505, passes through an optical fiber (backup path) 1504, and passes through a 2 ⁇ n splitter 1508.
- a monitoring device (OTDR) device 1503 is connected to the 2 ⁇ 2 optical switch 1502, and a monitoring light (OTDR light) is cut between the optical fiber (normal path) 1505 and the 2 ⁇ n splitter 1508.
- a filter 1507 is provided.
- a monitor light (OTDR light) cut filter 1506 is provided between the optical fiber (backup path) 1504 and the 2 ⁇ n splitter 1508.
- the base station side communication device 1501 is a device called OLT (Optical Line Terminal) in P ⁇ N (Passive Optical Network), and the client station 1509 communicates with ⁇ NU (Optical Network Unit) in P ⁇ N.
- OLT Optical Line Terminal
- ⁇ NU Optical Network Unit
- a device called is provided.
- a signal from the base station communication device ( ⁇ LT) 1501 is distributed to a large number (about 32 stations) of client stations (ONUs) 1509 by a 2 ⁇ n splitter 1508.
- Signals from the client station ( ⁇ NU) 1509 are collected by a 2 ⁇ n splitter 1508 and sent to the base station side communication device (OLT) 1501.
- a so-called protection mechanism is realized by the 2 ⁇ 2 optical switch 1502. If a disconnection or the like occurs in the optical fiber (normal path) 1505, the signal transmission path can be switched to the optical fiber (backup path) 1504 by the 2 ⁇ 2 optical switch 1502.
- the monitoring device (OTDR) device 1503 is an optical fiber (usually The path is connected to 1505, so the optical fiber disconnection can be checked by OTDR (Optical Time Domain Reflectometry). Since the monitor light (OTDR light) is cut by the monitor light (OTDR light) cut filter 1506 or 1507, it is impossible for the monitor light (OTDR light) to be sent to the client station 1509 through the 2 ⁇ n splitter 1508. Nagu It is possible to detect optical fiber breakage while operating P ⁇ N.
- the monitoring device (OTDR) device 1503 is not essential for performing protection. This is because even if the monitoring device (OTDR) device 1503 is omitted using a 1 ⁇ 2 optical switch, switching to the backup route can be performed when the normal route is disconnected. In addition, protection can be realized by switching using an electrical switch instead of switching using an optical switch. Two optical transceivers can be prepared in the base station communication device (@LT) 1501, and each transceiver can be connected to the normal route and the backup route, and the route can be switched when an error occurs.
- the optical fiber (normal path) 1505 and the optical fiber (backup path) 1504 is provided to enable switching (protection) from the normal path to the backup path when an error such as a broken optical fiber occurs.
- a monitoring device (OTDR) device 1503 at one end of the 2X2 optical switch, it is possible to detect the disconnection location of the abnormal path without stopping the operation of the PON.
- FIG. 1 is a diagram showing an internal configuration of a wavelength router according to Embodiment 1 of the present invention.
- FIG. 2 is a diagram illustrating a double ring optical communication network according to a first embodiment of the present invention.
- FIG. 3 is a diagram showing wavelength routing between a wavelength router 21 and a wavelength router 22.
- FIG. 4 is a diagram showing a wavelength routing path in Embodiment 1 of the present invention.
- FIG. 5 is a diagram illustrating an internal configuration of a wavelength router according to a second embodiment of the present invention.
- FIG. 6 is a diagram showing a ring-shaped optical communication network according to a second embodiment of the present invention.
- FIG. 7 is a diagram showing a wavelength routing path in Embodiment 2 of the present invention.
- FIG. 10 is a diagram showing the internal structure of a wavelength router according to a fourth embodiment of the present invention.
- FIG. 11 is a diagram showing a problem of insufficient isolation of an optical add-drop multiplexer.
- FIG. 12 is a diagram illustrating a gain control mechanism of the optical amplifier according to the fourth embodiment of the present invention.
- FIG. 13 is a diagram showing the structure of a duplicate dielectric thin film filter type three-port device.
- FIG. 14 is a diagram illustrating a wavelength router according to a fifth embodiment of the present invention.
- FIG. 15 is a diagram showing a duplicated double-pass type dielectric thin film finolatus port device which is Embodiment 6 of the present invention.
- FIG. 16 is a diagram showing a wavelength router mounted on a box according to Embodiment 7 of the present invention.
- Garden 18 is a diagram showing a wavelength router implemented as a patch cord.
- Garden 19 is a diagram showing a bidirectional transmission optical fiber communication network.
- Garden 20 is a diagram showing the relationship between transmitted light and reflected light in a dielectric thin film filter type three-port device.
- FIG. 21 is a diagram showing a wavelength router (wavelength multiplexer) mounted on the box of the eighth embodiment.
- FIG. 22 is a diagram illustrating a wavelength router (optical add-drop multiplexer 1) according to a ninth embodiment of the present invention.
- FIG. 23 is a diagram illustrating a problem of crosstalk in the wavelength router 311.
- FIG. 24 is a diagram showing a wavelength router for forming a star-type communication path.
- FIG. 25 is a diagram showing an optical communication network formed by wavelength nolators 311, 351, 352, 353, and 354.
- FIG. 26 is a diagram showing a wavelength router (wavelength multiplexer) according to Embodiment 10 of the present invention.
- FIG. 27 illustrates a four-wavelength wavelength router (wavelength multiplexer) according to a tenth embodiment of the present invention.
- FIG. 28 is a diagram showing a wavelength router (wavelength multiplexer) according to Embodiment 11 of the present invention.
- FIG. 29 is a diagram showing an embodiment in which the wavelength multiplexer according to the eleventh embodiment of the present invention is implemented as a patch cord.
- FIG. 30 is a diagram illustrating an optical communication network according to Embodiment 12 of the present invention.
- FIG. 31 is a diagram showing the internal structure of a wavelength router according to Embodiment 12 of the present invention.
- FIG. 32 is a diagram showing a modification of the wavelength router of the twelfth embodiment of the present invention.
- FIG. 33 is a diagram showing a wavelength router according to Embodiment 13 of the present invention.
- FIG. 34 is a diagram showing an optical communication network according to Embodiment 14 of the present invention.
- FIG. 35 is a diagram showing the internal structure of the optical signal branch circuit unit 1001.
- FIG. 36 is a diagram showing a wavelength multiplexing apparatus 1 Q provided in a base station 1002.
- FIG. 37 is a diagram showing an internal structure of an optical signal branch circuit according to Embodiment 15 of the present invention.
- FIG. 38 is a diagram showing an optical signal branch circuit and an optical communication network according to Embodiment 16 of the present invention.
- FIG. 39 is a diagram illustrating a structure of a wavelength multiplexing device incorporated in a base station in Embodiment 16 of the present invention.
- FIG. 40 is a diagram showing an optical signal branch circuit unit and an optical communication network according to Embodiment 17 of the present invention.
- FIG. 41 is a diagram illustrating a configuration of an optical communication network according to Embodiment 18 of the present invention.
- FIG. 42 is a diagram showing the internal structure of an optical signal branch circuit unit 1071 according to an embodiment of the present invention.
- FIG. 43 is a diagram illustrating an optical communication network according to Embodiment 19 of the present invention.
- FIG. 44 is a diagram showing a conventional optical add-drop multiplexer.
- FIG. 45 is a view showing the structure of a conventional dielectric thin film filter type three-port device ⁇ Q.
- FIG. 46 is a diagram showing a conventional passive optical fiber communication network (P ⁇ N).
- Optical fiber 31-34: Locale report group 44: Switch or router ... Removable optical transceiver, 51, 52- Wavelength / rating /, ° S
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Abstract
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JP2009038650A (ja) * | 2007-08-02 | 2009-02-19 | Osaka Prefecture Univ | OADM(OpticalAddDropMultiplexer)モジュールおよびそれが装着されてなるOADMユニット |
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