KR100665694B1 - Wavelength division multiplexing passive optical network system of ring type - Google Patents

Abstract

The present invention relates to a ring-type WDM Wavelength Division Multiplexing Passive Optical Network (PON) system using a low water peak optical fiber having a wide wavelength range. Such a system,

An optical communication line employing a low water peak optical fiber having a wavelength range of 1280 nm to 1620 nm to form a ring type distribution network;

The downlink optical signal of different wavelengths output from the multiplexer / demultiplexer in the central base station is branched to the local base station through the ring-type optical communication line, and the uplink optical signal output from the local base station is output through the optical communication line. And an optical coupler that receives the input and outputs the multiplexer / demultiplexer in the central base station.

Used wavelength, coupler, ring type.

Description

WAVELENGTH DIVISION MULTIPLEXING PASSIVE OPTICAL NETWORK SYSTEM OF RING TYPE}

1 is a diagram illustrating loss characteristic curves for each wavelength of a quartz-based optical fiber.

Figure 2 is a general ring type WDM PON system configuration diagram.

3 is a configuration of a ring-type WDM PON system according to an embodiment of the present invention.

4 is a block diagram of a 4-port optical splitter / combiner 120 of FIG.

FIG. 5 is a detailed configuration diagram of the switching media converter 130 of FIG. 3.

Figure 6 is a configuration of a ring-type WDM PON system according to another embodiment of the present invention.

7 is a diagram illustrating a configuration of the signal compensator 500 of FIG. 6.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to optical communication systems, and more particularly, to a ring-type WDM PON (Wavelength Division Multiplexing Passive Optical Network) system using a low water peak optical fiber having a wide wavelength range.

Single Mode Fiber (SMF) refers to an optical fiber having only one number of propagation modes that can be transmitted in a wavelength of use. Such a single mode optical fiber has a wider bandwidth than a multimode optical fiber because there is no dispersion between modes, and has an advantage that wideband long distance transmission is possible due to excellent loss and dispersion characteristics. Therefore, it is the most widely used as the main transmission medium in the current optical transmission system.

The single mode optical fiber widely used as the main transmission medium in the optical transmission system is almost quartz-based. The loss characteristic curve of each quartz-based optical fiber is shown in FIG. 1.

Referring to FIG. 1, in the general quartz optical fiber (ITU-T G.652.AB), since the absorption peak due to hydroxyl (OH-) appears in the vicinity of 1385 nm wavelength, that is, the wavelength of 1340-1460 nm in the vicinity. There is a restriction that a band cannot be used as a communication band.

As a technique for overcoming this limitation, there is a patent application No. 2000-31179 published and filed in the Korean Patent Office. The invention disclosed in the exemplified patent publication completely removes hydroxyl (OH-) ions remaining in the optical fiber through two dehydration and sintering processes, and thus attenuation loss (dB / km) lower than that of the 1310 nm wavelength band even in the 1340-1460 nm wavelength band. It describes a method for producing a base material for optical fibers showing. The wavelength loss characteristic curve (ITU-T G.652C) of the quartz-based optical fiber manufactured by this manufacturing method is also shown in FIG. 1.

That is, the invention disclosed in the exemplified patent publication provides a method of manufacturing an optical fiber (usually referred to as a "low water peak optical fiber") in which a wavelength range of use (1280 to 1620 nm) is increased by 100 nm or more than an existing optical fiber. In addition, they overcome the technical limitations of conventional quartz optical fibers.

Meanwhile, as shown in FIG. 2, the ring-type WDM PON system includes a first multiplexer / demultiplexer (MUX1) for multiplexing / demultiplexing a steady state signal, and a second multiplexer / demultiplexer for multiplexing / demultiplexing a recovery signal. A central base station (CO) having MUX2). Each multiplexer / demultiplexer generates an optical signal having N different wavelengths and then multiplexes the optical signals to a local base station through a single optical fiber, or demultiplexes a signal multiplexed and received from a local base station (RN). It plays a role.

As shown in FIG. 2, the central base station CO includes two transmission / reception units (Tx and Rx) for each wavelength to implement redundancy. Transmit / receive (Tx1, .Rx1) section for steady state is connected to one multiplexer / demultiplexer (MUX1), and another transmit / receive section (Tx2, Rx2) for redundancy is another multiplexer / demultiplexer (MUX2). It has a structure that is connected to.

However, in the conventional ring-type WDM PON system configured as described above, redundancy is prepared for fiber switching or failure of a transmit / receive (Tx / Rx) module of a specific channel and two transmit / receive (Tx, Rx) modules and redundancy for each wavelength. Since the MUX is provided, the structure of the central base station CO is complicated.

In addition, in the above-mentioned conventional ring-type WDM PON system, since the optical fiber used as the optical transmission line is the ITU-T G.652.AB series (the wavelength range is 1280 to 1360 nm and 1530 to 1620 nm), the data transmission amount continuously increases. Given the expected future technology trends, there are limitations that cannot be adequately prepared.

Therefore, an object of the present invention is to provide a ring-type WDM PON system that can simplify the structure of the central base station as well as transmitting a large amount of multi-data by using an optical fiber with a wider wavelength range than the conventional optical fiber as an optical communication line. ,

Furthermore, by adopting a plurality of ring-type optical communication lines, but using optical fibers having a wider wavelength range than conventional ones as optical communication lines, accommodating a large number of subscribers using the same system as well as transmitting large amounts of multi-data. At the same time, it provides a ring-type WDM PON system that can adequately compensate for the losses caused by various environmental factors.

Ring type WDM PON system according to an embodiment of the present invention for achieving the above object,

An optical communication line employing an optical fiber having a wavelength range of 1280 nm to 1620 nm to form a ring type distribution network;

The downlink optical signals of different wavelengths output from the multiplexer / demultiplexer in the central base station are branched to the local base station through the ring-type optical communication line, and the uplink optical signals output from the local base station through the optical communication line are output. And an optical coupler that receives the input and outputs the multiplexer / demultiplexer in the central base station.

In addition, the signal compensator for amplifying the up and down optical signals transmitted and received between the multiplexing / demultiplexer and the optical coupler of the central base station to mutually amplify the signal loss compensation;

According to the characteristics of the present invention as described above, since the downlink optical signal output from the multiplexer / demultiplexer in the central base station is transmitted through the optical coupler to the ring-type optical communication line, the central base station due to the use of one multiplexer / demultiplexer Can simplify the structure.

In addition, the present invention employs an optical communication line that uses an optical fiber with a wavelength range of 100 nm or more larger than that of an existing optical fiber (ITU-T G.652.AB series). It will have the advantage of transmitting.

In addition, the present invention employs a plurality of ring-type optical communication lines and signal compensators while maintaining the system of the central base station side, thereby accommodating a larger number of subscribers and at the same time inserting loss caused by interfacing various devices on the optical communication lines, It is possible to appropriately compensate for losses such as fiber degradation.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

First, FIG. 3 is a block diagram of a ring-type WDM PON system according to an embodiment of the present invention. FIG. 4 is a block diagram of the four-port optical splitter / coupler 120 of FIG. 3, and FIG. Each of the detailed diagrams of the media converter 130 for the city is shown.

Referring to FIG. 3, a ring-type WDM PON system according to an exemplary embodiment of the present invention is a bidirectional optical branch / combiner 120 connected to a central base station CO and an optical communication line F to the central base station CO. ) And redundancy media converters 130.

The central base station CO converts and outputs an electrical signal into an optical signal, and includes a pair of transceivers TX and RX that receive and output an optical signal having the same wavelength as the output optical signal. Multiplexed optical signals of different wavelengths generated by each of the converters (GENERAL MC) and the media converter (GENERAL MC) are output to the optical communication line (F) and the uplink multiplexed signal input from the optical communication line (F). And a multiplexer / demultiplexer (WDM MUX / DEMUX: 100) for demultiplexing and outputting the demultiplexer to the converters (GENERAL MC). A 3 dB optical coupler is coupled between the media converters (GENERAL MC) of the central base station (CO) and the multiplexer / demultiplexer 100.

The optical coupler serves as a splitter for distributing the uplink optical signal demultiplexed by the multiplexer / demultiplexer 100 to the transmitter TX and the receiver RX of the media converter GE. Such an optical coupler may be replaced with an optical circulator to protect the optical transmitter.

Meanwhile, a 3dB optical coupler 110 is coupled to a signal output terminal (also referred to as a signal input terminal) of the central base station CO. The optical coupler 110 branches and transmits downlink multiplexed signals output from the multiplexer / demultiplexer 100 to different optical communication lines F, and upwards transmitted from any one of the optical communication lines F. It transmits the optical signal of the multiplexer / demultiplexer (100).

The reason for distributing and transmitting the output of the central base station (CO) through two paths through the optical coupler 110 is to secure an extra channel in case of line switching or failure of a transmitter (Tx) and a receiver (Rx) of a specific channel. To do this.

Although not shown in FIG. 3, a signal compensator for compensating up and down optical signals transmitted and received may be operated between the multiplexer / demultiplexer 100 of the central base station CO and the optical coupler 110. The signal compensation unit appropriately compensates for losses such as insertion loss and optical cable degradation caused by interfacing various devices on the optical communication line, and its detailed configuration and operation will be described later with reference to FIG. 7.

Meanwhile, the optical communication lines F of different directions connected to the optical coupler 110 form a ring distribution network as shown in FIG. 3. The optical communication line F, which forms a ring distribution network, is manufactured using anhydrous optical fibers having a wavelength range of 1280 nm to 1620 nm. The anhydrous optical fiber is capable of transmitting a large amount of multi-data as the use wavelength region is extended to 100 nm or more than the existing ITU-T G.652.A, B series (use wavelength region is 1280-1360 nm, 1530-1620 nm).

가스가 함유된 분위기의 로속에서 1차 탈수시키면서 수산기(OH-)를 제거하는 제2과정과; 상기의 수산기(OH-)기가 제거된 코아용 수우트 퇴적체를 적절한 온도에서 1차 소결하여 투명 유리화하는 제3과정과; 상기의 유리화된 코아용 수우트 퇴적체를 설계된 외경으로 연신하여 코아용 유리봉을 만드는 제4과정과; 상기의 코아용 유리봉의 외주부에 다시 화염가수분해 반응을 시켜 크래드용 수우트를 퇴적시키는 2차 퇴적의 제5과정과; 상기의 크래드용 수우트 퇴적체를

가스가 함유된 분위기의 로속에서 2차 탈수시키면서 수산기(OH-)기를 제거하는 제6과정과; 상기의 탈수가 수행된 크래드용 수우트 퇴적체를 2차 소결하는 제7과정을 포함하는 공정에 의해 제조 가능하다. 이러한 제조공정에 대해서는 대한민국 특허청에 선출원된 공개특허번호 2000-31179호에 상세히 기재되어 있으므로 그에 대한 부연 설명은 생략하기로 한다.The optical fiber includes a first process of primary deposition in which a porous glass fine particle having a core and a clad composition is deposited on a prepared glass rod while flame-hydrolyzing a glass raw material to form a core soot deposit; The core suot sediment

A second process of removing hydroxyl groups (OH-) while dehydrating primary in a furnace containing a gas; A third process of firstly sintering the core soot deposits from which the hydroxyl group (OH-) group has been removed and transparent vitrification at an appropriate temperature; A fourth step of stretching the vitrified core suit stack for the designed outer diameter to make a glass rod for the core; A fifth process of secondary deposition in which a flame hydrolysis reaction is again performed on the outer circumference of the glass rod for cores to deposit the clad suits; The clad suit stacks

A sixth step of removing hydroxyl (OH-) groups while secondary dehydration in a furnace containing a gas; The dewatering can be produced by a process including a seventh step of secondary sintering the clad soot deposit. Such a manufacturing process is described in detail in Korean Patent Application Publication No. 2000-31179 filed with the Korean Intellectual Property Office.

The optical fiber also has a deposited cladding / core ratio of less than 7.5, forming a core rod having a hydroxyl (OH—) content by weight less than 0.8 p.p.b; Extending the core rod using an anhydrous plasma torch; Overcladding the core rod with a glass tube having an inner diameter slightly greater than the outer diameter of the extended core rod and having an appropriately low hydroxyl (OH-) content; Breaking the glass tube on the core rod to preform; And exposing the tube to a heat source moving in the longitudinal direction with respect to the glass tube and the core rod to draw the optical fiber from the preform. This is also described in detail in the already published Patent Application No. 1999-7119 filed by the Lucent Technologies Co., Ltd. in the Republic of Korea Patent Office will also be omitted. In addition to the illustrated examples, all of the optical fibers disclosed before the filing date of the present invention and having a wavelength range of 1280 nm to 1620 nm may be employed in the present invention.

Meanwhile, as described above, bidirectional optical branching allows a signal to flow normally in a bidirectional direction at a predetermined position of an optical communication line F having an extended use wavelength range, and allows an optical signal having a wavelength corresponding to each subscriber to branch. The combiner 120 is installed.

) 신호만을 후술할 리던던시 미디어 변환기(130)의 마스터 채널로 드롭시키고, 그 드롭된 신호와 동일파장(

)의 신호를 상기 마스터 채널로부터 전송받아 상기 제1광통신 선로로 반사시키는 제1WDM 박막필터와; 또 하나의 입력포트(Com out Port)에 연결된 제2광통신 선로로부터 입력되는 신호중 상기 특정 대역의 파장(

) 신호만을 후술할 리던던시 미디어 변환기(130)의 슬레이브 채널로 드롭시키고, 그 드롭된 신호와 동일파장의 신호를 상기 슬레이브 채널로부터 전송받아 상기 제2광통신 선로로 반사시키는 제2WDM 박막필터;를 포함한다.The bidirectional optical splitter / combiner 120 has a signal flow in opposite directions between the first and second optical communication lines F on both sides of the ring, and as shown in FIG. 4, the first optical communication line ( Com in Prot), the wavelength of a specific band

) Signal is dropped to the master channel of the redundancy media converter 130 to be described later, and the same wavelength as the dropped signal (

A first WDM thin film filter for receiving a signal from the master channel and reflecting the signal from the master channel to the first optical communication line; The wavelength of the specific band among the signals input from the second optical communication line connected to another Com out Port (

And a second WDM thin film filter which drops only a signal to a slave channel of the redundancy media converter 130 to be described later, and receives a signal having the same wavelength as the dropped signal from the slave channel and reflects the signal to the second optical communication line. .

By the bidirectional optical splitter / combiner 120, the local base station RN can transmit an uplink optical signal transmitted from the subscriber device in a clockwise or counterclockwise direction in a ring type distribution network.

Meanwhile, each of the bidirectional optical splitters / combiners 120 is coupled with a redundancy media converter 130 that detects a line switching state and transmits an optical signal only in a clockwise or counterclockwise direction. The redundancy media converter 130 may be connected to the subscriber device directly or through an Ethernet network.

The redundancy media converter 130 will be described in more detail with reference to FIG. 5. The redundancy media converter 130 serves as a transceiver for a master channel, a transceiver for a slave channel, a CPU 136, and an interface unit. And PHY chips 135 and 145.

3dB optocouplers are connected to each of the master and slave channels. Such an optocoupler may be included in the media converter 130 and may be located externally. It can be assumed that the master channel is connected to the drop port of the bidirectional optical splitter / combiner 120 shown in FIG. 4 (which becomes an add port in the case of an upward signal), and the slave channel is bidirectional shown in FIG. It may be assumed that it is connected to the add port of the optical splitter / coupler 120. According to this assumption, the optical signal transmitted through the drop port and the master channel is branched by the optical coupler to the LD 131 which is the transmitter of the master channel and the PD 133 which is the receiver, and is transmitted from the LD 131 which is the transmitter of the master channel. The generated optical signal is transmitted to the central base station (CO) through the optical coupler and the drop port.

The transceiver of the master channel and the transceiver of the slave channel respectively include LDs 131 and 143 which are light sources as transmitters, LD drivers 132 and 144 for driving them, and PDs 133 and 141 and PD drivers 134 and 142 as receivers. Each of these master / slave transceivers converts electrical signals into optical signals and transmits them to the connected optical couplers, and converts the optical signals transmitted through the connected optical couplers into electrical signals, through the interface units 135 and 145 to be described later. Output to the device.

The CPU 136 controls the overall operation of the media converter 130. For example, the CPU 136 detects a state and a circuit switching state of the master and slave transceivers based on the control program data stored in the internal memory and activates only one transceiver of the master and slave transceivers. .

Finally, the media converter 130 further includes interface units 135 and 145 connected to the master and slave transceivers to perform data interfacing with subscriber devices. PHY chips may be used as the interface units 135 and 145. For reference, the rear end of the interface unit 145 connected with the slave transceiver may further include a buffer 137 for data buffering.

Hereinafter, a circuit switching flowchart performed by the CPU 136 of the redundancy media converter 130 will be described.

First, when the initial power is turned on, the CPU 136 of the redundancy media converter 130 switches to an initial state. In the initial state, the CPU 136 sets the master channel as the first channel. In the initializing state, the CPU 136 having set the master channel as the first channel checks whether there is an alarm. The presence or absence of an alarm can be checked by reading the states of the master and slave LDs 131 and 143 and the master and slave PDs 133 and 141. In the embodiment of the present invention, as shown in Table 1 below, it is assumed that the alarm state except for the case where the LD 131 and the PD 133 of the master or slave are normal. In Table 1, “0” indicates fault or disable, and “1” indicates active or enable.

MLD Status SLD Status MPD Link SPD Link Current Status Remarks 0 0 0 0 alarm 0 0 0 One alarm 0 0 One 0 alarm 0 0 One One alarm 0 One 0 0 alarm 0 One 0 One Slave 0 One One 0 alarm 0 One One One Slave One 0 0 0 alarm One 0 0 One alarm One 0 One 0 master Reflective check One 0 One One master One One 0 0 alarm Do not both work at the same time One One 0 One Slave One One One 0 master One One One One master

If the alarm state check result is an alarm state, the state is recorded in the internal memory for later management, and then the state of the system is continuously monitored.

If not in the alarm state, the CPU 136 switches the set first channel to the current channel. The CPU 136 then checks if an error event occurs while maintaining the current state. If an error event occurs in the current channel that is not an alarm condition, the channel must be moved, and it is necessary to check whether it is a link error due to reflection or a system error. For reference, when the circuit switching is cut in the vertical section, reflection occurs at the switched portion, and thus the transmission signal returns to itself and as a result, the switching is not recognized. It is necessary to confirm the error caused by such reflection.

Accordingly, when an error occurs, the CPU 136 determines whether the error is a system error. If the pilot packet is not received within a certain time, it may be determined as a system error. If it is not a system error, the CPU 136 “turns on” redundancy. That is, it disables the master which is the current channel and enables the slave which is a spare channel.

On the other hand, if a system error occurs, the CPU 136 disables the LD of the current channel, that is, the LD 131 of the master channel, to determine whether the error is caused by reflection, and then the PD of the current channel is “linked on”. Check it out. If the test shows that the PD link of the current channel is on, it "turns on" redundancy because it is not a reflection error. However, if the PD link of the current channel is not "on", the error indicates an error due to reflection, so that the external device is notified of the reflection of the current channel. The CPU 136 then controls the system in such a way as to " on " the redundancy.

When the redundancy of the spare channel is “on” according to the circuit switching detection and the detection result of the CPU 136 as described above, in the normal state, the central base station (CO) and each local base station can normally perform optical transmission through the master channel. Can be.

However, if a failure such as a circuit change occurs, the CPU 136 in the redundancy media converter 130 of each local base station detects this and turns on the redundancy, so that the central base station (CO) and the corresponding local base station are slaves, not master channels. The optical transmission can be normally performed through the channel.

As described above, the present invention branches the downlink optical signal output from the multiplexer / demultiplexer 100 in the central base station CO through the optical coupler to the ring-type optical communication line F, thereby implementing redundancy. It is possible to simplify the structure of the central base station due to the use of multiplexing / demultiplexing.

In addition, the present invention adopts the optical communication line (F) by using an optical fiber having a wavelength range of 100 nm or more larger than that of the existing optical fiber (ITU-T G.652.AB series), while using the existing system equipment even when the data transmission amount is increased in the future. It will be able to transfer large amounts of multi data.

Hereinafter, another embodiment of the present invention will be described with reference to FIGS. 6 and 7.

First, FIG. 6 illustrates a ring type WDM PON system configuration diagram according to another embodiment of the present invention, and FIG. 7 illustrates a configuration diagram of the signal compensator 500 of FIG. 6.

As shown in FIG. 6, the WDM PON system of the multi-ring type according to another embodiment of the present invention includes a plurality of ring-type optical communication lines 100a and 100b, a central base station 200, and a plurality of regional base stations. 300, an optical coupler 400, and a plurality of signal compensators 500, wherein the central base station 200 includes a plurality of local base stations 300 through ring-shaped optical communication lines 100a or 100b. Networked with them.

In FIG. 6, reference numerals 210 and 220 denote optical transceivers in the central base station described in FIG. 3, and reference numeral 230 denotes a multiplexer / demultiplexer coupled to the optical coupler 400. In FIG. Since this configuration has already been described in detail with reference to FIG. 3, duplicate description thereof will be omitted. However, reference numeral 240 denotes an optical circulator, and the optical circulator 240 outputs a downlink optical signal output from the optical transmitter 210 in the central base station 200 to the multiplexer / demultiplexer 230. The uplink optical signal demultiplexed by the multiplexer / demultiplexer is output to the optical receiver 220 paired with the optical transmitter 210. This optical circulator 240 may also be replaced with a 3 dB coupler.

In FIG. 6, each optical communication line 100a, 100b forming a plurality of ring-shaped distribution networks is fabricated using anhydrous optical fibers having a wavelength range of 1280 nm to 1620 nm. As described in the first embodiment, such anhydrous optical fiber has a large-capacity multi-function because the wavelength range is 100 nm or more than the existing ITU-T G.652.A, B series (the wavelength range is 1280 to 1360 nm and 1530 to 1620 nm). Data transfer is possible.

In addition, a bidirectional optical splitter / combiner 310 connected to a predetermined position of each optical communication line 100a and 100b forming the ring distribution network, and a redundancy media converter coupled to the optical splitter / combiner 310 320 is also the same as the optical splitter / combiner 120 and the media converter 130 described with reference to FIG. 3, and a description thereof will be omitted.

Unexplained reference numerals 321a and 321b are optical circulators described above, which can also be replaced by 3 dB couplers.

On the other hand, the optical coupler 400 having one side connected to the multiplexer / demultiplexer 230 in the central base station 200 is connected to each of the plurality of signal compensators 500 and is output downward from the multiplexer / demultiplexer 230. Branching an optical signal and outputting it to each signal compensator 500 or outputting an upward optical signal output from each signal compensator 500 to the multiplexer / demultiplexer 230 in the central base station 200. Play a role.

Each of the signal compensators 500 amplifies up and down optical signals transmitted and received between the optical communication lines 100a and 100b and the optical coupler 400 to compensate for signal loss.

The signal compensator 500 includes a first light circulator 510, a 1 × 2 coupler 520, a second light circulator 530, and a pair of amplifiers 540 as shown in FIG. 7. .

The first optical circulator 510 is a downlink optical signal output from the multiplexer / demultiplexer 230 in the central base station 200 and output through the optical coupler 400 and the optical coupler 400. The uplink optical signals inputted to the multiplexer / demultiplexer 230 in the central base station 200 are transmitted and received through different paths.

The 1 × 2 coupler 520 branches and outputs a downlink optical signal to be transmitted to the optical communication line 100a or 100b and receives an uplink optical signal transmitted from the optical communication line 100a or 100b to be described later. Output to the second light circulator 530.

The second optical circulator 530 transmits an uplink optical signal input from the 1 × 2 coupler 520 and a downlink optical signal output to the 1 × 2 coupler 520 through different paths.

The amplifier 540 is installed on two paths between the first optical circulator 510 and the second optical circulator 530 in opposite directions, and amplifies signals transmitted and received through these two paths to compensate for signal loss. State plays a role.

By placing the signal compensator 500 having the above-described configuration in each of the optical coupler 400 and the optical communication lines 100a and 100b, up and down optical signals transmitted and received between the central base station 200 and the optical communication lines 100a and 100b. The signal is amplified and transmitted by the two optical circulators 510 and 530 and amplifiers with different transmission paths.

Therefore, it is possible to compensate for losses caused by various environmental factors such as insertion loss caused by interface of various devices on the optical communication line, loss due to optical cable degradation, and the like.

In addition, the system according to the second embodiment of the present invention also employs an optical communication line (F) as an optical communication line (F) by using an optical fiber having a wavelength range of 100 nm or more larger than that of an existing optical fiber (ITU-T G.652.AB series). Even when using existing system equipment, it is possible to transmit large amounts of multi-data.

As described above, in the present invention, since the downlink optical signal output from the multiplexer / demultiplexer in the central base station is transmitted through the optical coupler to the ring type optical communication line, the structure of the central base station can be reduced by using one multiplexer / demultiplexer. There is an advantage to simplify,

Furthermore, the present invention employs an optical fiber having a wavelength range of 100 nm or more larger than that of an existing optical fiber (ITU-T G.652.AB series) as a transmission medium of a ring-type WDM PON system. It has the advantage of being able to transmit large amounts of multi-data while using it.                     

In addition, the present invention employs a plurality of ring-type optical communication lines and signal compensators having a wide wavelength range while maintaining the system of the central base station side, thereby accommodating a larger number of subscribers and simultaneously interfacing various devices on the optical communication lines. There is an advantage that it is possible to properly compensate for losses such as insertion loss, optical cable degradation, etc. that occur.

On the other hand, the present invention has been described with reference to the embodiments shown in the drawings, which are merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention should be defined only by the appended claims.

Claims (11)

delete delete delete delete An optical communication line employing an optical fiber having a wavelength range of 1280 nm to 1620 nm to form a ring type distribution network; The downlink optical signal of different wavelengths output from the multiplexer / demultiplexer in the central base station is branched to the local base station through the ring-type optical communication line, and the uplink optical signal output from the local base station is output through the optical communication line. An optical coupler which receives the input and outputs the multiplexer / demultiplexer in the central base station; A signal compensator for compensating an uplink and a downlink optical signal connected between the multiplexer / demultiplexer of the central base station and the optical coupler and transmitted / received to each other; A first optical circulator for transmitting and receiving downlink optical signals inputted from the multiplexer / demultiplexer of the central base station and uplink optical signals inputted to the multiplexer / demultiplexer of the central base station through different paths; A 1 × 2 coupler for branching the downlink optical signal transmitted to the optical communication line and receiving the uplink optical signal transmitted from the optical communication line; A second optical circulator for transmitting and receiving an uplink optical signal input from the 1 × 2 coupler and a downlink optical signal output to the 1 × 2 coupler through different paths; And a pair of amplifiers installed on two paths of the first optical cycle and the second optical cycle in opposite directions to amplify the up and down optical signals transmitted and received through the respective paths for loss compensation. Ring type WDM PON system. The method according to claim 5, At least one optical splitter / combiner for dropping only signals having a wavelength of a specific band among the downlink optical signals transmitted through the optical communication line and outputting them to the subscriber device side, and outputting the uplink optical signal transmitted from the subscriber device side to the optical communication line. ; A ring-type WDM PON system further comprising: a redundant media converter connected to the optical splitter / coupler for detecting a circuit switching state and accordingly transmitting an uplink optical signal in either a clockwise or counterclockwise direction. . delete delete delete delete delete

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