KR20090071922A - Wdm/tdm hybrid optical network system and apparatus thereof - Google Patents

Abstract

A WDM/TDM hybrid optical network system and an apparatus thereof are provided to increase the transmission distance, remotely the network state and realize the duplication of an optical line. An H-OLT(Hybrid Optical Line Termination)(100) comprises a WDM wavelength branching coupler(140). The WDM wavelength branching coupler combines the M number of downlink WDM optical signals received from a WDM optical transceiver. An RTD(Remote Terminal for Distribution)(200) changes the downlink WDM optical signals into the M number of downlink TDM optical signals. Optical splitters(310, 320) branch the downlink TDM optical signals into optical signals.

Description

Wavelength division multiplexing / time division multiplexing composite optical network system and device therefor {WDM / TDM HYBRID OPTICAL NETWORK SYSTEM AND APPARATUS THEREOF}

The present invention relates to a composite optical network system combining a time division multiplexing-passive optical network (TDM-PON) with a wavelength division multiplexing (WDM) technique and an apparatus used therein.

With the recent rapid increase in traffic and the convergence of broadcasting and telecommunication services, the speed of subscriber networks has been increasing rapidly. Among these technologies, passive optical network (PON) technology is introduced due to the advantages of not only providing high bandwidth to subscribers but also greatly reducing the operating cost of the network because the OSP (outside plant) consists only of passive components. This is spreading. The PON technology is classified into two types according to the difference between multiplexing and multiple access methods. The first is TDM-PON based on time division multiplexing, and the second is WDM-PON based on wavelength division multiplexing.

1 is a diagram illustrating a configuration of a conventional general TDM-PON.

TDM-PON is a structure in which subscribers share the optical fiber with the optical line terminal (OLT) 10 of a national company using a time division technique, and B-PON and G-PON standardized by ITU-T and E standardized by IEEE PON is currently in use. Looking at the current transmission method of the general TDM-PON, from the perspective of the downlink signal, one optical transceiver is installed in the OLT 10 of the office side to broadcast the traffic delivered to each subscriber, and the remote node. (RN, remote node) is used to distribute the downlink optical signal transmitted from the OLT 10 to N subscriber lines by simply using a 1xN optical splitter 20 for splitting the optical power, the ONT ( The optical network terminations 31, 32, and 33 receive downlink signals from the OLT 10 and selectively transmit only the frames allocated to the subscribers.

Looking at the transmission of the uplink signal, the subscriber's ONT (31, 32, 33) OLT (10) of its own dedicated time slot (slot) through the ranging (ranging) and dynamic bandwidth allocation (DBA) process ), And then transmit the uplink data only when the time slot allocated to it arrives, and turn off the optical transmitter completely when not in its own slot, and the uplink signal from each subscriber is the optical splitter (20) of the remote node. ) Is transmitted to the OLT (10).

Typically, a fixed wavelength light source of 1480 nm to 1500 nm band is used for the OLT 10, and a fixed wavelength light source of 1260 nm to 1360 nm band is used for the ONT (31, 32, 33) at the subscriber side, but an upward wavelength is used in the next-generation TDM-PON. The possibility of changing the downlink wavelength, and increasing the bandwidth by transmitting the downlink signal to optical transceivers of various wavelengths are discussed in the standardization organization. However, TDM-PON has a problem that the transmission loss increases with the increase of the branch rate because the remote node is composed of the optical power splitter. As a result, TDM-PON has a limited bandwidth and branching rate of about 64 quarters at 2.5Gb / s shared bandwidth.

However, in the aforementioned time division multiplexing scheme, bandwidth and branching rate are limited, and transmission loss due to branching rate increases.

2 is a diagram illustrating a conventional general WDM-PON network.

Unlike TDM-PON, which shares an optical line using time division multiplexing, the WDM-PON illustrated in FIG. 2 has a difference in sharing an optical line using a wavelength division multiplexing technique.

As shown in FIG. 2, the WDM-PON logically implements point-to-point connection by allocating dedicated uplink (λum) and downlink wavelengths (λdm) to M subscribers, thereby complex ranging in the TDM-PON. And the time slot allocation process through the DBA. In the OLT 40, M optical transceivers 41, 42, and 43 assigned to each subscriber are installed, which are combined in the WDM wavelength branch combiner 44 and transmitted to the optical line, and WDM installed in the remote node 50. The wavelength branch combiner 55 again has a simple multiplexing structure distributed to each subscriber for each wavelength channel.

Although FIG. 2 illustrates a WDM-PON system for transmitting an Ethernet frame, the WDM system basically provides multiplexing at the physical layer (PHY), and thus guarantees transparency of transmission at a higher layer. It is also possible to transmit a hierarchy / synchronous network (SONET), an asynchronous transfer mode (ATM), a generic frame procedure (GFP), and the like. WDM-PON provides logical point-to-point connectivity through wavelength assignment, provides greater security than broadcast-based TDM-PON, and increases bandwidth and fiber bandwidth per fiber simply by adding wavelength. There are advantages such as relatively easy to increase, but also has the disadvantage that the light source required for WDM is relatively expensive compared to the TDM-PON light source. Also, since N optical transceivers of the wavelength division method are required for each, there is a problem in that the cost for wavelength selection increases accordingly to provide a high branching rate.

As a WDM light source for WDM-PON, CWDM (coarse WDM), DWDM (dense WDM) fixed wavelength light source and DWDM wavelength independent light source are used. As a DWDM wavelength independent light source technology, a wavelength tunable laser can be used. In addition, seed seeding is used in a FP (Fabry-Perot) laser or a reflective semiconductor optical amplifier (RSOA) in a method using a seed light source such as a broadband light source or a laser array. And a method of spectrally dividing and injecting a light source. In addition, an optical link configuration method for generating uplink signals by remodulating downlink signals to RSOA is being researched and developed.

On the other hand, Korean Patent Registration 10-0584419 discloses a structure that combines the WDM method and the TDM method, but causes the transmission loss by optically splitting individual wavelengths to be point-to-point communication through the optical splitter by demultiplexing, There was a problem that can not use the TDM-PON and WDM equipment as it is.

In order to solve the above-mentioned problems of the prior art, an embodiment of the present invention provides an optical network and a device for a subscriber network having low construction and operation costs by increasing the transmission bandwidth and branch rate per optical fiber.

In addition, another embodiment of the present invention provides an apparatus for easily providing the existing equipment to the switch to the above-described WDM / TDM composite optical network.

Further, another embodiment of the present invention provides a WDM / TDM composite optical network system that can be flexibly applied to a user environment through a bus system.

In addition, another embodiment of the present invention provides a WDM / TDM composite optical network system that increases the transmission distance of the above-described system, remotely monitors network conditions and provides optical fiber redundancy.

As a technical means for achieving the above technical problem, according to the first aspect of the present invention, WDM / TDM (wavelength division multiplexing / time division multiplexing) composite optical network system, M TDM-PON optical line terminal (OLT) The hybrid OLT converts a single wavelength optical signal generated from the M WDM optical signals, and combines and outputs the M WDM optical signals, and converts the WDM optical signals output from the hybrid OLT into M TDM-PON optical signals. A WDM-TDM conversion device for converting in an optical-to-optical manner; And an optical splitter for power splitting each of the converted M single wavelength TDM-PON optical signals into N optical signals, wherein the hybrid OLT is connected to each of the TDM-PON OLTs to perform TDM-WDM conversion. It includes a TDM-WDM conversion terminal.

In addition, according to a second aspect of the present invention, a TDM-WDM conversion terminal for converting a single wavelength TDM signal from M TDM-PON OLT and M WDM signals is connected to the TDM OLT and is connected to a TDM optical signal. M TDM optical transceivers for performing mutual conversion of electrical signals, M WDM optical transceivers for performing mutual conversion of electrical signals and M WDM optical signals of M divided wavelengths, and the conversion between the TDM optical transceivers and WDM optical transceivers. Combining the WDM-TDM matching unit and the M WDM optical signals from the M WDM optical transceivers, and performing the matching of the WDM optical transceivers to the M WDM optical transceivers. And a WDM wavelength branching coupler for branching the signal.

Further, according to a third aspect of the present invention, a WDM / TDM composite optical network system includes a hybrid OLT for wavelength-combining and outputting a plurality of WDM optical signals, and some WDM optical signals of an input wavelength-coupled WDM optical signal. At least one drop type WDM-TDM conversion device for converting and outputting a PON optical signal in an optical-to-optical manner, and outputting the remaining WDM optical signals by wavelength combining; And at least one optical splitter connected to the drop type WDM-TDM converter for power branching the converted TDM-PON optical signal, wherein the drop type WDM-TDM converter is connected in series to form a bus structure network. Form.

Further, according to the fourth aspect of the present invention, a drop type WDM-TDM conversion apparatus used to implement a bus structured WDM / TDM composite optical network enables wavelength-divided combined WDM optical signals. A first WDM wavelength branch combiner for generating M WDM individual wavelength optical signals, a first WDM optical transceiver for receiving and converting some of the WDM individual wavelength optical signals into an electrical signal, converting the electrical signal into a TDM-PON optical signal A first TDM optical transceiver for converting, a first WDM-TDM matching unit performing matching between the first WDM optical transceiver and the first TDM optical transceiver and the remaining WDM wavelength optical signals of the M WDM individual wavelength optical signals It includes a second wavelength branch coupler for coupling.

In addition, according to a fifth aspect of the present invention, a WDM / TDM composite optical network system includes a hybrid OLT for wavelength-coupled output of a plurality of WDM optical signals and a first optical power for branching a WDM optical signal output from the hybrid OLT. A splitter, a WDM-TDM converter for converting each WDM optical signal branched by the first optical splitter into a TDM optical signal in an optical-to-optical manner, and a TDM optical signal converted by the WDM-TDM And a second optical splitter for power branching.

According to the problem solving means of the present invention described above, it is possible to provide a WDM-TDM composite optical network that can increase the transmission bandwidth and the branch rate per optical fiber.

In addition, the problem solving means of the present invention can easily switch to the above-described WDM / TDM composite optical network to the existing equipment, by providing a WDM-TDM composite optical network in a bus method to be flexibly applied to the user environment It can have the effect.

In addition, the problem solving means of the present invention can increase the transmission distance in the WDM-TDM composite optical network system, remotely monitor the network status and provide optical fiber redundancy.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to be "connected" to another part, it is not only "directly connected" but also "electrically connected" or "optically connected" with another element in between. It also includes the case. In addition, when a part is said to "include" a certain component, which means that it may further include other components, except to exclude other components unless otherwise stated.

First Example

3 is a diagram illustrating the configuration of a WDM / TDM composite network according to a first embodiment of the present invention.

In the WDM / TDM composite optical network shown in FIG. 3, M downlink WDM individual wavelength optical signals received from M WDM optical transceivers 110, 12, and 130 including a WDM light source are wavelength-coupled to generate a downlink WDM optical signal. A hybrid optical line termination (H-OLT) 100 comprising a WDM wavelength branch coupler (WDM MUX) 140; A WDM-TDM conversion device (RTD) for converting a downlink WDM optical signal into M downlink TDM optical signals (RTD) 200; And M optical splitters 310 and 320 for power branching each of the downlink TDM optical signals into N optical signals and for power coupling the uplink TDM optical signals.

In the first embodiment, since the WDM / TDM composite optical network is wavelength-divided into M in the WDM scheme and then the power branching is repeated in the N in the TDM scheme, the total branching rate is M × N. Compared to the optical network composed of -PON or WDM-PON alone, it is possible to obtain a significant branching rate increase.

For example, when the WDM 16 branch and the TDM-PON 32 branch are combined, the total branch rate is 512 branches, which can accommodate 512 subscribers simultaneously on one fiber. In addition, since the optical link is divided into a WDM-PON section and a TDM-PON section centering on the WDM-TDM converter, it is easy to increase the transmission distance compared to the existing TDM-PON or WDM-PON. The subscriber unit ONT 311, 312, 313 is compatible with the existing TDM-PON and easily upgrades the subscriber network composed of the existing TDM-PON to the WDM / TDM composite optical network of the present invention. Therefore, the cost of building a WDM / TDM composite optical network can be reduced.

4 is a diagram showing the configuration of the WDM-TDM conversion apparatus according to the first embodiment of the present invention.

The WDM-TDM converter 200 includes a WDM wavelength branch combiner (WDM MUX) 21, a WDM optical transceiver 221, 231, and 241, a WDM-TDM matching unit (WTA) 222, 232, and 242. Optical transceivers 223, 233, and 243.

The wavelength branch combiner (WDM MUX) 210 splits / combines the WDM optical signals (uplink wavelengths: λu1 to λuM and downward wavelengths: λd1 to λdM) connected to the H-OLT 100 in up and down directions for each wavelength channel. .

The branched M WDM wavelength channels (uplink wavelength λum, downward wavelength λdm) are WDM optical transceivers 221, 231, and 241, WDM-TDM matching units (WTAs) 222, 232, and 242, and TDM optical transceivers ( Through 223, 233, and 243, the light-to-optical conversion is performed to convert the phase and the downlink wavelengths λuT and λdT of the TDM-PON OLT standard to be connected to M optical splitters and channels through an optical path.

More specifically, in the case of downlink signal transmission, the downlink WDM optical signal is received by the WDM wavelength branch combiner 210 in the WDM-TDM converter 200. In the WDM wavelength branch combiner 210, the downlink WDM optical signal is branched for each wavelength and divided into M downlink WDM individual wavelength optical signals having different wavelengths λd1 to λdM. The downlink WDM discrete wavelength optical signal is transmitted to the WDM optical transceivers 221, 231, 241. The downlink WDM individual wavelength optical signal received by the WDM optical transceivers 221, 231, 241 is converted into an electrical signal and transmitted to the WDM-TDM matching unit 222, 232, 242.

The WDM-TDM matching unit 222, 232, 242 receives an electrical signal and transmits it to the TDM optical transceivers 223, 233, and 243. The TDM optical transceivers 223, 233, and 243 convert the received electrical signals into downlink TDM optical signals and transmit them to the optical splitter. The TDM optical transceivers 223, 233, and 243 may use optical transceivers used in conventional TDM-PON OLTs.

At this time, the WDM-TDM matching units 222, 232, and 242 serve to mediate optical-to-optical conversion between the WDM optical transceivers 221, 231, and 241 and the TDM optical transceivers 223, 233, and 243. .

On the other hand, in the upward direction, the uplink TDM optical signal is received by the TDM optical transceivers 223, 233, and 243. The uplink TDM optical signals received by the TDM optical transceivers 223, 233, and 243 are converted into electrical signals and transmitted to the WDM-TDM matching units 222, 232, and 242. The WDM-TDM matching unit 222, 232, 242 receives an electrical signal and transmits it to the WDM optical transceivers 221, 231, 241. The WDM optical transceivers 221, 231, 241 convert the received electrical signal into an uplink WDM individual wavelength optical signal and transmit it to the WDM wavelength branch combiner 210. The WDM wavelength branch combiner 210 wavelength-combines M uplink WDM individual wavelength optical signals having different wavelengths (λu1 to λuM) into an uplink WDM optical signal and transmits them to the H-OLT 100.

In the WDM / TDM composite optical network according to the first embodiment of the present invention, since the power branched to N in the TDM method again after the wavelength is branched into the M in the WDM method, the total branching rate is M × N, Compared to the conventional optical network composed of TDM-PON or WDM-PON alone, it is possible to obtain a significant branching rate increase. For example, when the WDM 16 branch and the TDM-PON 32 branch are combined, the total branch rate is 512 branches, which can accommodate 512 subscribers simultaneously on one fiber.

In addition, since the optical link is divided into a WDM-PON section and a TDM-PON section centering on the WDM-TDM converter, the end-to-end distance is reduced, thereby increasing the transmission distance compared to the conventional TDM-PON or WDM-PON. It is easy to make.

In addition, according to the first embodiment, the TDM signal that has undergone the photo-to-optical conversion is converted to the up and down wavelengths (λuT, λdT) of the TDM-PON OLT standard so that the subscriber device ONT is compatible with the existing TDM-PON. It is easy to upgrade the existing subscriber network composed of TDM-PON to the WDM / TDM composite optical network of the present invention. Therefore, the cost of building a WDM / TDM composite optical network can be reduced.

2nd Example

A second embodiment of the present invention is provided with means for connecting existing TDM-PON OLT equipment to the WDM / TDM composite optical network of the first embodiment.

5 is a diagram illustrating a configuration of an H-OLT according to a second embodiment of the present invention.

According to the second embodiment of the present invention, the H-OLT 100 is a TDM-PON OLT (101, 102, 103), each TDM-PON OLT (101, 102, 103) connected to the TDM-WDM conversion terminal ( RTT) 150.

The TDM-WDM conversion terminal (RTT) 150 attaches to the WDM / TDM composite optical network without modifying the existing OLT in order to evolve the area where the TDM-PON is already installed into the WDM / TDM composite optical network. Support access to

Functionally, the TDM optical transceivers 151a, 151b, 151c of the TDM-WDM conversion terminal (RTT) 150, the WDM-TDM matching units 152a, 152b, 152c, and the WDM optical transceivers 153a, 153b, 153c , WDM-TDM converter 200 has a reverse function. Therefore, the configuration of the TDM-WDM conversion terminal (RTT) 150 also has a shape in which the WDM-TDM conversion device 200 shown in FIG. 4 is turned upside down.

First, referring to a downlink signal transmission process, the TDM-PON downlink optical signals transmitted from M conventional TDM-PON OLTs are respectively received by the TDM optical transceivers 151a, 151b, and 151c, and converted into electrical signals. The converted electrical signal is input to the WDM optical transceivers 153a, 153b, and 153c via the WDM-TDM matching units 152a, 152b, and 152c, and then converted into M downlink WDM individual wavelength optical signals λd1 to λdM. WDM wavelength branch combiner 140 is wavelength-coupled into the downlink WDM optical signal.

The uplink signal transmission process is the reverse of the downlink signal transmission process. After the uplink WDM optical signal is converted into M uplink WDM individual wavelength optical signals λu1 to λuM through the WDM wavelength branch combiner 140, the WDM optical transceiver ( 153a, 153b, 153c are converted into electrical signals. The converted electrical signal is input to the TDM optical transceivers 151a, 151b, and 151c through the WDM-TDM matching units 152a, 152b, and 152c, and is converted into a TDM-PON uplink optical signal to be transmitted to the existing TDM-PON OLT. do.

Through the optical-to-optical conversion process in the TDM-WDM conversion terminal 150, M optical signals having the standard phase and the downlink wavelengths λuT and λdT of the TDM-PON are converted into M different phase and downlink wavelengths λu1 ˜. It becomes possible to convert into a WDM optical signal having lambda uM and lambda d1 to lambda dM).

Therefore, the combined form of the M existing TDM-PON OLT and the TDM-WDM conversion terminal 150 is functionally equivalent to the H-OLT shown in FIG. 3, and thus, a WDM / TDM composite optical network to which the H-OLT is connected. It can be applied as it is.

FIG. 6 is a diagram showing the configuration of an H-OLT in which a remote monitoring function and an optical line function are added to a second embodiment of the present invention.

FIG. 6 shows a configuration of a TDM-WDM conversion terminal 150 required for connecting the existing TDM-PON OLTs 101, 102, and 103 to a WDM / TDM hybrid optical network having a remote monitoring function and an optical fiber redundancy function. Doing. In the components illustrated in FIG. 6, the same process of transmitting and converting the uplink and downlink optical signals performed by the components having the same reference numerals as in FIG. 5 is omitted.

On the other hand, the 1x2 optical switch 156 is added to the rear end of the TDM-WDM conversion terminal 150 to perform the line redundancy function. The 1x2 optical switch 156 is responsible for control in the embedded micro-controller unit (MCU) 154. In addition, an optical supervisory channel (OSC) 155 is mounted in the MCU 154 to collect the optical module monitoring information of the WDM-TDM conversion device 200 and the remote junction to be described later and transmit control information.

The combination of this RTT and the existing TDM-PON OLT becomes functionally equivalent to the H-OLT shown in FIG. 2A, and thus can be connected to a WDM / TDM hybrid optical network having a remote monitoring function and a fiber redundancy function. .

In a WDM / TDM composite optical network with optical monitoring, the H-OLT 100 can control the remote node, so even if hundreds to thousands of subscribers are accommodated in a trunk, the H-OLT 100 can control it. Do. Therefore, the reliability of the optical link portion is improved.

Through the redundancy function in addition to the control and control, when a failure occurs in the operation line, the MCU 154 controls the optical switch 156 to communicate through the protection line.

Through the configuration shown in the second embodiment, the WDM / TDM composite optical network can be easily configured without modifying the existing TDM-PON OLT equipment, and the reliability of the optical link unit is improved by using the remote monitoring function and the redundancy function. You can.

3rd Example

A third embodiment of the present invention relates to a WDM / TDM composite optical network configured with a bus in the form of a bus and a WDM-TDM conversion apparatus therefor.

7 is a diagram illustrating a WDM-TDM composite optical network system according to a third embodiment of the present invention.

The WDM / TDM composite optical network described so far has been aimed at the point-to-multipoint network structure. However, when the subscribers are distributed in small groups, the cost of the optical fiber infrastructure can be reduced through the bus type network structure rather than the point-to-multipoint network. .

FIG. 7 illustrates a configuration diagram of a WDM / TDM hybrid optical network configured with a bus in a network form. The H-OLT 100, the optical splitters 301, 302, 303, and 304, and the ONT are shown in FIG. Using the element as it is, drop type WDM-TDM converters (RTDM) 400, 410, and 420 are inserted to branch and transmit a specific wavelength or bundle of wavelengths to the splitter.

In the third embodiment, (L-1) drop type WDM-TDM converters (RTDMs) 400, 410, and 420 are inserted to form a bus type network, and each drop type WDM-TDM converter 400 is provided. , 410 and 420 branch the M1 to ML-1 wavelength channels, respectively, and deliver the rest to the next drop type WDM-TDM converter 400, 410, and 420.

That is, in the case of the drop type WDM-TDM conversion apparatus 400 of the third embodiment, M1 branches of the total M WDM optical signals are branched and transferred to the optical splitter, and the remaining (M-M1) pieces are dropped WDM-TDM conversion. Transfer to device 410. Finally, the branching is finally completed in the drop type WDM-TDM conversion device 420 that accepts ML wavelengths.

8 is a diagram showing the configuration of a drop type WDM-TDM conversion device according to a third embodiment of the present invention.

The drop type WDM-TDM converter 400 for branching a specific wavelength or wavelength bundle may be configured through photo-to-optical conversion as shown in FIG. 8.

 The WDM optical transceivers 421, 431, 441, 451, WDM-TDM matching units 422, 432, 442, 452, and TDM optical transceivers 423, 433 are illustrated in FIG. 4. The configuration is the same as that of the converter 200.

However, WDM optical song receivers 443 and 453 recover electrical signals back to WDM optical signals, and WDM wavelength branch combiner 460 combines the WDM signals.

That is, in the embodiment shown in FIG. 8, Ma wavelengths are input, and the Ml wavelengths are split, transmitted to the optical splitter, and the rest of the WDM-TDM conversion apparatus is illustrated. To this end, the WDM wavelength branch combiner 460 is connected to the WDM optical transmission receivers 443 and 453.

More specifically, in the embodiment, the downlink WDM optical signal to which Ma wavelengths are allocated is converted into Ma downlink WDM individual wavelength optical signals (λd1 to λdMa) via a WDM branch combiner, and then assigned to each WDM optical transceiver 421. , 431, 441, 451. The downlink WDM individual wavelength optical signals received by the WDM optical transceivers 421, 431, 441, 451 are converted into electrical signals and transmitted to the WDM-TDM matching units 422, 432, 442, 452. The WDM-TDM matching unit receives an electrical signal and, in the case of Ml channels to be transmitted and branched to the optical splitter, transmits to the TDM optical transmission receivers 423 and 433, or to the next WDM-TDM conversion device (Ma-Ml ) Channels are sent to the WDM optical transmission receivers 443 and 453.

Thereafter, the TDM optical signals output from the TDM optical transmitters 423 and 433 are branched by the optical splitter and transmitted to the ONT.

On the other hand, the (Ma-Ml) individual wavelength WDM optical signals output from the WDM optical transmission receivers 443 and 453 are again combined at the WDM wavelength branch combiner to generate a downlink WDM optical signal having (Ma-Ml) wavelengths. Then it is sent to the next WDM-TDM conversion device.

Since the uplink signal transmission process is the inverse of the downlink signal transmission process, description thereof will be omitted.

8 illustrates a structure in which wavelengths are sequentially branched from wavelength 1, it is natural that arbitrary wavelength branching combinations are possible according to the convenience of the network configuration.

In addition, it is natural that the H-OLT 100 and the drop type WDM-TDM converter (RTDM) 400, 410, and 420 can increase the transmission distance of a specific section by using a remote junction, which will be described later.

9 is a diagram illustrating a configuration in which a remote management function and a duplication function are added to a third embodiment of the present invention.

In the WDM / TDM composite optical network configured as a bus, it is possible to apply the remote management function and the optical fiber redundancy function. Of the components illustrated in FIG. 9, the H-OLT 100, the optical splitters 301, 302, 303, and 304, and the ONT may use the components illustrated in FIG. 3 as they are.

Meanwhile, the remote management function and the optical fiber redundancy function may be added to the drop type WDM-TDM converter (RTDM) 400, 410, and 420 of FIG. 7. Drop-type WDM-TDM converters (RTDM) 400, 410, and 420 are redundantly connected to the interworking line and the protection line.

FIG. 10 is a diagram showing the configuration of a drop type WDM-TDM conversion apparatus having a remote management function and a duplication function according to a third embodiment of the present invention.

Compared with FIG. 8, the transmission and branching characteristics of the uplink and downlink optical signals of the drop type WDM-TDM converter 400 shown in FIG. 10 are the same, and the 1x2 optical switch is applied to the WDM wavelength branch coupling device 310 of the previous stage. 411 is added, and a 1x2 optical switch 461 is added to the WDM wavelength branch coupling device 460 at the rear end.

The MCU 480 is responsible for the control of the optical switches 411 and 461. In addition, MCU 480 is responsible for monitoring and controlling the status of the optical module embedded in the drop-type WDM-TDM converter, and through the OSC (471, 472) to the H-OLT 100 of its own optical module The monitoring information is transmitted and the control information of the H-OLT 100 is received.

In addition, the WDM-TDM converter connected to the rear end of the WDM-TDM converter 400 and the monitoring information of the remote junction to be described later are relayed to the H-OLT 100, and the WDM of the other end from the H-OLT 100 is relayed. It performs a function of relaying control information to a TDM conversion device and a remote junction to be described later.

Based on the monitoring information, the MCU 480 controls the 1x2 optical switches 411 and 461 to switch the communication to the protection line when a failure occurs in the operation line.

According to the third embodiment described above, the WDM / TDM composite optical network of the present invention can be designed in a bus structure, flexibly adapted to the environment, and cost reduction can be performed.

In addition, it will provide remote monitoring and redundancy of the bus-structured WDM / TDM composite optical network.

4th Example

In a fourth embodiment, a WDM / TDM composite optical network is further provided, which further improves the branching rate.

FIG. 11 is a diagram illustrating a WDM / TDM optical network system having improved branching rate according to a fourth embodiment of the present invention.

In the WDM / TDM composite optical network described so far, the optical splitter has been used only for branching and combining a plurality of ONTs in a TDM interval. However, it is also possible to use the optical splitter in the WDM section to connect the H-OLT and a plurality of RTDs.

In the embodiment shown in FIG. 11, the K WDM-TDM conversions are performed via the optical splitter 500 having a 1xK branching rate without directly connecting the H-OLT 100 and the WDM-TDM conversion devices 201, 202, and 203. The devices 201, 202, 203 are connected.

Here, since the H-OLT 100, the WDM-TDM converters 201, 202, and 203 and the optical splitters 310, 320, and 330 are the same as those shown in FIGS. 3 and 4, repeated descriptions thereof will be omitted.

Meanwhile, in the embodiment shown in FIG. 11, the m-th TDM-PON MAC device in the H-OLT 100 simultaneously rangings K optical signals having phase and downward wavelengths λum and λdm. Or TDM-PON MAC functions such as dynamic bandwidth allocation (DBA). That is, by using the 1xK optical splitter 500, the effect of improving the utilization rate of the H-OLT 100 by K times can be obtained.

If the 1xK optical splitter 500 is inserted between the H-OLT 100 and the WDM-TDM converters 201, 202, and 203, as in the embodiment, then M x N x K with the same H-OLT 100 Although an improved final branching rate can be obtained, the transmission distance between the H-OLT 100 and the WDM-TDM converters 201, 202, and 203 due to the branching losses occurring in the 1xK optical splitter 500 results in a 1xK optical splitter ( It may be reduced compared to the absence of 500).

However, it is possible to improve the transmission distance by inserting a remote junction, which will be described later, between the H-OLT 100 and the WDM-TDM conversion apparatus 201, 202, and 203.

It is obvious that the embodiment shown in FIG. 11 can be applied to the WDM-TDM composite optical network of the bus structure shown in FIG.

12 is a diagram showing a configuration in which a remote monitoring function and a dual function are added to a fourth embodiment of the present invention.

In FIG. 12, WDM / TDM improves the branching rate by inserting optical splitters 500 and 510 into the H-OLT 100 and the WDM-TDM converters 201, 202, and 203 while maintaining line redundancy and remote monitoring. The composite optical network is shown.

However, the optical splitter 500 and the optical splitter 510 were installed in each of the two optical lines connected to the work line port and the protective line port at the rear end of the H-OLT 100. In this embodiment, the optical splitter 500 is used as the main optical splitter, and the optical splitter 510 is applied as the preliminary optical splitter.

Thereafter, the optical splitter 500 and the output ports of the optical splitter 510 were connected to the WDM-TDM converters 201, 202, and 203 one by one to complete the optical line redundancy.

As a result, data is normally transmitted to the optical line connected to the optical splitter 500, but when an abnormality occurs in the main optical line, the optical splitter 510 takes charge of data transmission while the line is switched to the preliminary optical line. In addition to the optical fiber duplication, the operation of the remote monitoring function may be applied in the same manner as illustrated in FIG. 6.

The embodiment shown in FIG. 12 can also improve the transmission distance by inserting a remote junction, which will be described later, between the H-OLT 100 and the WDM-TDM conversion apparatus 201, 202, and 203, and the bus shown in FIG. 7. Naturally, it can be applied to the WDM-TDM composite optical network of structure.

5th Example

In the fifth embodiment, a WDM-TDM composite optical network system having an increased transmission distance is provided.

13 shows a WDM-TDM composite optical network system having an increased transmission distance according to a fifth embodiment of the present invention.

Since the H-OLT 100, the optical splitters 310 and 320, the WDM-TDM converter 200 ONT and the like shown in FIG. 13 have the same functions as those shown in FIGS. Omit.

In the fifth embodiment, a remote terminal for concatenation (RTC) 600, 610 is additionally introduced to increase the transmission distance and is installed between the H-OLT 100 and the WDM-TDM converter 200. .

One or more remote junctions 600 and 610 may be used in some cases, and FIG. 13 assumes a situation in which L series units are connected in series.

The remote junctions 600 and 610 can be implemented in two ways. The first method is to use the optical-to-optical conversion similar to the WDM-TDM conversion apparatus 200, and the second is to use the optical amplifier. to be.

FIG. 14A is a diagram illustrating a configuration of a remote junction that performs light-to-light conversion.

The remote junction 600 includes a first WDM optical transceiver 621, 631, 641 and a WDM-TDM matcher 622 disposed between the first wavelength branch coupler 610 and the second wavelength branch coupler 650. 632, 642, and second WDM optical transceivers 623, 633, 643.

Looking at the transmission of the downlink signal, first, the downlink WDM optical signal received at the H-OLT 100 or another remote junction is received by the first WDM wavelength branch combiner 610. In the first WDM wavelength branch combiner 610, the downlink WDM optical signal is branched for each wavelength and divided into M downlink WDM individual wavelength optical signals having different wavelengths λd1 to λdM.

The downlink WDM discrete wavelength optical signal is transmitted to the first WDM optical transceivers 621, 631, 641. Downlink WDM individual wavelength optical signals received by the first WDM optical transceivers 621, 631, and 641 are converted into electrical signals and transmitted to the WDM-TDM matching units 622, 632, and 642.

The WDM-TDM matching units 622, 632, and 642 receive the electrical signals and transmit them to the second WDM optical transceivers 623, 633, 643. The WDM individual wavelength optical signals output from the second WDM optical transceivers 623, 633, 643 are combined at the second WDM wavelength branch combiner 650 to generate a downward WDM optical signal.

Through this process, the downlink WDM optical signal is compensated for the loss and distortion generated in the optical path and transmitted to the next remote junction or the WDM-TDM converter.

Since the uplink signal transmission process is the inverse of the downlink signal transmission process, description thereof will be omitted.

FIG. 14B is a diagram illustrating a photo-electric-optic remote junction with a remote monitoring function and a redundancy function.

Compared to FIG. 14A, the optical-to-optical remote junction shown in FIG. 14B has the same process of transmitting up and down optical signals, and 1x2 optical switches 611 and 651 are provided at the front and rear ends of the remote junction. Is added

The control of these optical switches 611, 651 is performed by the MCU 680. In addition, the MCU 680 is responsible for monitoring and controlling the state of the optical module embedded in the remote junction 600, the optical of the remote junction 600 to the H-OLT 100 through the OSC (660, 670) Delivers the monitoring information of the module and receives the control information of the H-OLT (100).

Furthermore, monitoring information of another remote junction or WDM-TDM converter connected to the rear end of the remote junction 600 is relayed to the H-OLT 100, and another remote junction or WDM of the rear end from the H-OLT 100 is relayed. It relays the control information to the TDM converter.

15A is a diagram illustrating a configuration of a remote junction using an optical amplifier.

The optical amplification remote junction 700 is different from the configuration of FIG. 14A in that optical amplification is performed without an optical-to-optical conversion process.

First, the transmission process of the downlink optical signal, first, the downlink WDM optical signal received from the H-OLT 100 or another remote junction is passed through the first wavelength band filter 710 to the downlink optical amplifier (GD) 740. After transmission, the signal strength is amplified. Then, the downlink WDM optical signal is transmitted to the next remote junction or the WDM-TDM conversion device through the second wavelength band filter 720 again.

Since the transmission of the uplink optical signal is the reverse of the transmission of the downlink optical signal, description thereof will be omitted.

However, due to the characteristics of the TDM-PON signal accommodated in the WDM optical signal, since the uplink optical signal has a burst mode characteristic, the uplink optical amplifier (GU) 730 must have a fast gain recovery capability in order to process it. The uplink optical amplifier having this characteristic may use an SOA or Raman optical amplifier, or an EDFA having fast automatic gain control.

On the other hand, since the downlink optical signal has a continuous characteristic rather than a burst mode, a conventional optical amplifier may be used which is not related to gain recovery capability. The wavelength band filters 710 and 720 separate and combine the wavelength band of the uplink optical signal and the wavelength band of the downlink optical signal.

In addition, in order to remove unnecessary noise components generated by the optical amplifier, a band pass filter may be installed at the rear of each of the upper and lower optical amplifiers 730 and 740. Through this, when the optical amplification remote junction is connected in series, it is possible to prevent signal degradation and optical amplification efficiency degradation due to accumulation of optical noise.

15B is a diagram illustrating a remote junction using an optical amplifier to which a remote monitoring function and a redundancy function are added.

Compared to the embodiment shown in FIG. 15A, the embodiment illustrated in FIG. 15B has the same process of transmitting the uplink and downlink optical signals, but 1x2 optical switches 711 and 721 are added to the front and rear ends of the remote junction.

The MCU 750 is responsible for controlling the optical switches 711 and 721. In addition, the MCU 750 is responsible for monitoring and controlling the state of the optical module embedded in the remote junction 700, the optical of the remote junction 700 to the H-OLT 100 through the OSC (730, 740) Delivers monitoring information of the module and receives control information of the H-OLT 100.

Ports corresponding to OSC wavelengths must be added to the wavelength band filters 710 and 711 to branch and couple the OSC channels 730 and 740.

In order to remove unnecessary noise components generated by the optical amplifiers 730 and 740, a band pass filter may be installed at the rear ends of the upper and lower optical amplifiers 730 and 740, respectively. Through this, when the optical amplification remote junction is connected in series, it is possible to prevent signal degradation and optical amplification efficiency deterioration due to the accumulation of optical noise.

Furthermore, monitoring information of another remote junction or a WDM-TDM converter connected to the rear end of the remote junction 700 is relayed to the H-OLT 100, and another remote junction or WDM-TDM of the rear end from the H-OLT 100 is relayed. The control device relays the control information.

FIG. 16A is a view showing still another configuration of a remote junction using an optical amplifier. FIG.

The optical amplification remote junction 800 is similar to the configuration of FIG. 15A in that optical amplification is performed without the optical-to-optical conversion process.

In FIG. 16A, when the wavelength of the uplink optical signal and the wavelength of the downlink optical signal are interleaved instead of being divided into bands, the optical splicer 810 and 820 may be used instead of the wavelength band filter to implement a remote junction more economically. To be.

Instead of the wavelength bandpass filter, the optical rotators 810 and 820 are three-port devices that perform a function of outputting a specific port of an optical signal introduced in a specific direction. Except that is used as the optical rotator 810, 820, the required characteristics of the remaining signal transmission process or the optical amplifier used is the same as the remote junction of Figure 15a.

FIG. 16B is a diagram illustrating a configuration of another optical amplification remote splicing unit to which a remote monitoring function and a redundancy function are added.

In the embodiment shown in FIG. 16B, the transmission process of the uplink and downlink optical signals is the same, but 1x2 optical switches 811 and 821 are added to the front and rear ends of the remote junction.

The MCU 850 is responsible for controlling the optical switches 811 and 821. In addition, the MCU 850 is responsible for monitoring and controlling the state of the optical module embedded in the remote junction 800, the optical of the remote junction 800 to the H-OLT 100 through the OSC (830, 840) Delivers monitoring information of the module and receives control information of the H-OLT 100.

When the optical rotators 811 and 812 are used as shown in FIG. 16B, separate wavelength filters 812 and 813 may be added for branching and combining the OSC 830 and 840 wavelengths.

In order to remove unnecessary noise components generated by the optical amplifiers 830 and 840, a band pass filter may be installed at the rear end of each of the upper and lower optical amplifiers 830 and 840. Through this, when the optical amplification remote junction is connected in series, it is possible to prevent signal degradation and optical amplification efficiency deterioration due to the accumulation of optical noise.

Furthermore, monitoring information of another remote junction or a WDM-TDM converter connected to the rear end of the remote junction 800 is relayed to the H-OLT 100, and the other remote junction or WDM-TDM of the rear end from the H-OLT 100 is relayed. The control device relays the control information.

The foregoing description of the present invention is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents are included in the scope of the present invention. Should be.

1 is a diagram illustrating a configuration of a conventional general TDM-PON.

2 is a diagram illustrating a conventional general WDM-PON network.

3 is a diagram illustrating the configuration of a WDM / TDM composite network according to a first embodiment of the present invention.

4 is a diagram showing the configuration of the WDM-TDM conversion apparatus according to the first embodiment of the present invention.

5 is a diagram illustrating a configuration of an H-OLT according to a second embodiment of the present invention.

FIG. 6 is a diagram showing the configuration of an H-OLT in which a remote monitoring function and an optical line function are added to a second embodiment of the present invention.

7 is a diagram illustrating a WDM-TDM composite optical network system according to a third embodiment of the present invention.

8 is a diagram showing the configuration of a drop type WDM-TDM conversion device according to a third embodiment of the present invention.

9 is a diagram illustrating a configuration in which a remote management function and a duplication function are added to a third embodiment of the present invention.

FIG. 10 is a diagram showing the configuration of a drop type WDM-TDM conversion apparatus having a remote management function and a duplication function according to a third embodiment of the present invention.

FIG. 11 is a diagram illustrating a WDM / TDM optical network system having improved branching rate according to a fourth embodiment of the present invention.

12 is a diagram showing a configuration in which a remote monitoring function and a dual function are added to a fourth embodiment of the present invention.

13 shows a WDM-TDM composite optical network system having an increased transmission distance according to a fifth embodiment of the present invention.

FIG. 14A is a diagram illustrating a configuration of a remote junction that performs light-to-light conversion.

FIG. 14B is a diagram illustrating a photo-electric-optic remote junction with a remote monitoring function and a redundancy function.

15A is a diagram illustrating a configuration of a remote junction using an optical amplifier.

15B is a diagram illustrating a remote junction using an optical amplifier to which a remote monitoring function and a redundancy function are added.

FIG. 16A is a view showing still another configuration of a remote junction using an optical amplifier. FIG.

FIG. 16B is a diagram illustrating a configuration of another optical amplification remote splicing unit to which a remote monitoring function and a redundancy function are added.

Claims (36)

In wavelength division multiplexing / time division multiplexing (WDM / TDM) composite optical network system, Hybrid OLT converting a single wavelength optical signal generated from M TDM-PON optical line terminal (OLT) into M WDM optical signals and wavelength-combining the M WDM optical signals, WDM-TDM conversion device for converting the WDM optical signal output from the hybrid OLT to M TDM-PON optical signal in the optical-to-optical method and An optical splitter for power branching each of the converted M single wavelength TDM-PON optical signals into N optical signals, The hybrid OLT includes a TDM-WDM conversion terminal connected to each of the TDM-PON OLTs to perform TDM-WDM conversion.  WDM / TDM composite optical network system. The method of claim 1, The TDM-WDM conversion terminal, A TDM optical transceiver connected to the TDM-PON OLT to convert a TDM-PON optical signal into an electrical signal; A WDM optical transceiver for converting the electrical signal into a WDM optical signal, A WDM-TDM matching unit for performing matching using the electrical signal between the TDM optical transceiver and WDM optical transmission and reception; A WDM wavelength branch combiner for combining M WDM optical signals from the WDM optical transceiver and for branching a combined WDM optical signal to the WDM optical transceiver WDM / TDM composite optical network system comprising a. The method of claim 2, The TDM-WDM conversion terminal, A switch connected to the WDM wavelength branch combiner for switching between an operating line and a protective line; Further comprising a micro-controller unit (MCU) for controlling the switching of the switch WDM / TDM composite optical network system The method of claim 2, The TDM-WDM conversion terminal, MCU to perform remote monitoring and remote control And an optical monitoring channel transceiver for collecting optical module monitoring information and transmitting control information to the MCU in the WDM / TDM composite optical network system. The method according to any one of claims 1 to 4, And a remote junction connected between the hybrid OLT and a WDM-TDM converter to increase a transmission distance of a WDM signal. The method of claim 5, wherein Wherein said remote junction performs optical-to-optical conversion. The method of claim 5, wherein The remote splicing unit separates the up and down signals with a first wavelength band filter to amplify the signal strength, respectively, and combines the up and down signals again with the second wavelength band filter. The method of claim 5, wherein The remote splicing unit separates up and down signals using a first rotator to amplify the signal strength, respectively, and combines the up and down signals again with a second rotator. In the TDM-WDM conversion terminal which converts a single wavelength TDM signal from M TDM-PON OLT and M WDM signals, M TDM optical transceivers connected to the TDM OLT to perform mutual conversion of a TDM optical signal and an electrical signal, M WDM optical transceivers for performing mutual conversion between the WDM optical signal of the M divided wavelength and the electrical signal, A WDM-TDM matching unit performing matching of a WDM signal and a TDM signal by using the converted electrical signal between the TDM optical transceiver and WDM optical transmission and reception; A WDM wavelength branch combiner for combining M WDM optical signals from the M WDM optical transceivers and for branching a combined WDM optical signal to the M WDM optical transceivers TDM-WDM conversion terminal comprising a. The method of claim 9, A switch connected to the WDM wavelength branch combiner for switching between an operating line and a protective line; MCU to control the switching of the switch The TDM-WDM conversion terminal further comprises The method of claim 9, MCU to perform remote monitoring and remote control And an optical monitoring channel transceiver for collecting optical module monitoring information and transmitting control information to the MCU in a WDM / TDM composite optical network system. In a WDM / TDM composite optical network system, Hybrid OLT that combines and outputs a plurality of WDM optical signals, At least one drop type WDM-TDM which converts some WDM optical signals among the wavelength-coupled WDM optical signals into TDM-PON optical signals and converts them to optical-to-optical modes, and outputs the remaining WDM optical signals by wavelength combining. A conversion device; And At least one optical splitter connected to the drop type WDM-TDM conversion device to power branch the converted TDM-PON optical signal; And the drop type WDM-TDM conversion device is connected in series to form a bus structure network. The method of claim 12, The drop type WDM-TDM converter, A first WDM wavelength branch combiner for wavelength-dividing the combined WDM optical signal to generate M WDM individual wavelength optical signals, A first WDM optical transceiver for receiving some of the WDM individual wavelength optical signals and converting them into electrical signals; A first TDM optical transceiver for converting the electrical signal into a TDM-PON optical signal, A first WDM-TDM matching unit performing matching between the first WDM optical transceiver and the first TDM optical transceiver; A second wavelength branch combiner for combining the remaining WDM wavelength optical signals among the M WDM individual wavelength optical signals; WDM / TDM composite optical network system comprising a. The method of claim 13, The drop type WDM-TDM converter, A second WDM optical transceiver for receiving and converting the remaining WDM optical signals among the WDM individual wavelength optical signals into electrical signals; A third WDM optical transceiver for converting the electrical signal into a WDM optical signal; And a second WDM-TDM matching unit performing matching between the second WDM optical transceiver and the third WDM optical transceiver. And wherein the second WDM optical transceiver, the third WDM optical transceiver and the second WDM-TDM matching portion are disposed between the first wavelength branch coupler and the second wavelength branch coupler. The method of claim 13, The drop type WDM-TDM converter, A first switch connected to the first WDM wavelength branch combiner for switching between an operating line and a protective line, A second switch connected to said second WDM wavelength branch combiner for switching between an operating line and a protective line; WDM / TDM composite optical network system further comprises a MCU for controlling the switching of the first and second switch The method of claim 13, The drop type WDM-TDM converter, MCU that transmits and relays monitoring information and receives and relays control information A first optical monitoring channel transceiver for collecting optical module monitoring information in the WDM / TDM composite optical network system and transmitting control information to the MCU; And a second optical monitoring channel transceiver for relaying monitoring information and control information corresponding to a drop-type WDM-TDM conversion apparatus connected to a rear stage. The method according to any one of claims 12 to 16, And a remote junction connected between any one of the hybrid OLT and a drop type WDM-TDM converter to increase a transmission distance of a WDM signal. The method of claim 17, Wherein said remote junction performs optical-to-optical conversion. The method of claim 17, The remote splicing unit separates the up and down signals with a first wavelength band filter to amplify the signal strength, respectively, and combines the up and down signals again with the second wavelength band filter. The method of claim 17, The remote splicing unit separates up and down signals using a first rotator to amplify the signal strength, respectively, and combines the up and down signals again with a second rotator. In the drop type WDM-TDM conversion apparatus used to implement a bus structured WDM / TDM composite optical network, Wavelength diverge the combined WDM optical signal. A first WDM wavelength branch combiner for generating M WDM individual wavelength optical signals, A first WDM optical transceiver for receiving some of the WDM individual wavelength optical signals and converting them into electrical signals; A first TDM optical transceiver for converting the electrical signal into a TDM-PON optical signal, A first WDM-TDM matching unit performing matching between the first WDM optical transceiver and the first TDM optical transceiver; A second wavelength branch combiner for combining the remaining WDM wavelength optical signals among the M WDM individual wavelength optical signals Drop type WDM-TDM conversion device comprising a. The method of claim 21, A second WDM optical transceiver for receiving and converting the remaining WDM optical signals among the WDM individual wavelength optical signals into electrical signals; A third WDM optical transceiver for converting the electrical signal into a WDM optical signal; And a second WDM-TDM matching unit performing matching between the second WDM optical transceiver and the third WDM optical transceiver. And the second WDM optical transceiver, the third WDM optical transceiver and the second WDM-TDM matching unit are disposed between the first wavelength branch coupler and the second wavelength branch coupler. The method of claim 22, A first switch connected to the first WDM wavelength branch combiner for switching between an operating line and a protective line, A second switch connected to said second WDM wavelength branch combiner for switching between an operating line and a protective line; MCU to control switching of the first and second switches Drop type WDM-TDM converter further comprising The method of claim 22, MCU that transmits and relays monitoring information and receives and relays control information A first optical monitoring channel transceiver for collecting optical module monitoring information and transmitting control information to the MCU in the WDM / TDM composite optical network system; Second optical monitoring channel transceiver for relaying monitoring information and control information corresponding to the drop type WDM-TDM converter connected to the rear stage Drop type WDM-TDM converter further comprising. In a WDM / TDM composite optical network system, Hybrid OLT that combines and outputs a plurality of WDM optical signals, A first optical splitter for power branching the WDM optical signal output from the hybrid OLT; A WDM-TDM conversion device for converting each WDM optical signal branched by the first optical splitter into a TDM optical signal in an optical-to-optical manner; A second optical splitter for power branching the TDM optical signal converted by the WDM-TDM converter; WDM / TDM composite optical network system comprising a. The method of claim 25, And a third optical splitter for power branching the WDM optical signal output from the hybrid OLT. And the third optical splitter is connected to the hybrid OLT and the WDM-TDM conversion device through a protective line. The method of claim 25 or 26, And a remote junction connected between the first optical splitter and the WDM-TDM conversion device to increase a transmission distance of a WDM signal. The method of claim 27, Wherein said remote junction performs optical-to-optical conversion. The method of claim 27, The remote splicing unit separates the up and down signals with a first wavelength band filter to amplify the signal strength, respectively, and combines the up and down signals again with the second wavelength band filter. The method of claim 27, The remote splicing unit separates up and down signals using a first rotator to amplify the signal strength, respectively, and combines the up and down signals again with a second rotator. In a WDM / TDM composite optical network system, Hybrid OLT that combines and outputs a plurality of WDM optical signals, WDM-TDM converter converts WDM optical signal output from hybrid OLT into TDM optical signal An optical splitter for power branching the TDM optical signal converted by the WDM-TDM converter; At least one remote junction connected between the hybrid OLT and the WDM-TDM conversion device to increase a transmission distance of a WDM signal WDM / TDM composite optical network system comprising a. The method of claim 31, wherein Wherein said remote junction performs optical-to-optical conversion. The method of claim 31, wherein The remote splicing unit separates the up and down signals with a first wavelength band filter to amplify the signal strength, respectively, and combines the up and down signals again with the second wavelength band filter. The method of claim 31, wherein The remote splicing unit separates up and down signals using a first rotator to amplify the signal strength, respectively, and combines the up and down signals again with a second rotator. The method according to any one of claims 31 to 34, wherein The remote junction A first switch for switching between an operation line and a protection line at the front end of the remote junction; A second switch for switching between an operation line and a protection line at the rear end of the remote junction; MCU to control switching of the first and second switches WDM / TDM composite optical network system further comprising The method according to any one of claims 31 to 34, wherein The remote junction MCU that transmits and relays monitoring information and receives and relays control information A first optical monitoring channel transceiver for collecting optical module monitoring information and transmitting control information to the MCU in the WDM / TDM composite optical network system; Second optical supervisory channel transceiver for relaying supervisory information and control information corresponding to a WDM-TDM converter or other remote junction connected at a later stage; WDM / TDM composite optical network system that further comprises.

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