KR20010113286A - A connection device with multi frequency for optical communication system - Google Patents

Abstract

The present invention relates to a device capable of connecting and operating a plurality of optical relay stations using a single optical fiber in a straight line in a mobile communication system. Particularly, a plurality of optical relay stations located at remote locations are classified and operated using multiple wavelengths. In a mobile communication system in which a base station and a plurality of optical relay stations are connected to each other by a straight line of light, the master module of the base station connected to the light line includes an electrical signal of a first wavelength. A first LED for converting and outputting an optical signal, a first PD for converting and outputting an optical signal applied at a different wavelength into an electrical signal, and an optical signal applied from the first LED to an optical path, and receiving an optical signal received from the optical path It is characterized in that it comprises a multi-wavelength division multiplexer for detecting the wavelength for each wavelength and apply to each of the first PD corresponding to the wavelength; The add / drop unit which extracts the transmitted optical signal with a small loss and at the same time applies the optical signal to the optical path by high separation, and the electrical signal that the optical relay station transmits to the base station as the optical signal having a wavelength distinct from other optical relay stations. And an optical relay station including a slave for converting and outputting to an add / drop unit and converting an optical signal applied from the add / drop unit to an electrical signal, and an optical ray station for connecting the add / drop unit and the slave. .

Description

Multi-wavelength optical relay station connection device {A CONNECTION DEVICE WITH MULTI FREQUENCY FOR OPTICAL COMMUNICATION SYSTEM}

The present invention relates to a device capable of connecting and operating a plurality of optical relay stations using a single optical fiber in a straight line in a mobile communication system. Particularly, a plurality of optical relay stations located at remote locations are classified and operated using multiple wavelengths. And a multi-wavelength optical relay station connecting device.

In a wireless communication system such as mobile communication, a wireless signal transmitted from one base transceiver subsystem (BTS) is reflected by a high-rise building, a mountain or a functional area, or blocked like an underground area. In this area, the wireless communication between the base station and the mobile phone is impossible, which is called a shadow area.

In the shaded area as described above, by operating and operating a relay station which is operated under the control of the base station and whose output may be lower than that of the base station, the shaded area is eliminated and the quality of wireless service is improved.

The relay station as described above is connected to the base station using an optical cable line having a low transmission loss and having a broadband frequency characteristic, and is operated under control thereof.

Hereinafter, an apparatus for connecting a base station and a relay station line according to the prior art will be described with reference to the accompanying drawings.

1 is a connection diagram of a general base station and a relay station system according to an example, FIG. 2 is a detailed functional block diagram of a master and a slave according to an example of the prior art, and FIG. Is a connection diagram of a general base station and a relay station system according to another example, and FIG. 4 is a detailed functional block diagram of a master and a slave according to another example of the prior art.

Referring to FIG. 1, a connection configuration of a general base station and an optical relay station system includes a base station (BTS) 10 that receives a signal from a switching center (not shown), and transmits and receives a signal to a cellular phone;

Under the control of the base station 10, a plurality of optical relay station 40 for transmitting and receiving to and from the mobile phone in the shadow area (Shadow Area),

The optical path 30 is configured to transmit a signal between the base station 10 and the optical relay station 40 with low loss and wideband characteristics.

The base station 10 having the above-described configuration processes the signal received from the switching center by the control unit 15, converts it into a radio frequency (RF) signal, and transmits it through an antenna, thereby providing a service area of the base station 10 itself. Wirelessly transmitted to a cellular phone located in the (Service Area), a signal output from the cellular phone is received via an antenna, and the control unit 15 converts the signal into a baseband band and outputs the signal to the switching center.

The base station 10 is located in a shaded area that does not serve itself, and communicates with a relay station that eliminates the shaded area, and a plurality of master modules 20 equal to the number of relay stations are connected to the controller 15. At the same time, it is connected to the relay station 40 via a plurality of optical paths 30.

In addition, the relay station 40 receives a signal by the slave module 50 connected to the master module 20 through the optical path 30, and through the control unit 41 and the antenna, the received signal When the signal received from the mobile phone is received by the slave module 50 through the control unit 41, and transmitted to the master module 20 through the optical path 30, the control unit 15 It is sent to the switching center.

According to an example of the prior art, referring to FIG. 2 for the configuration of the master module 20 and the slave module 50 as described above, the master module 20 of the base station 10 is controlled from the control unit 15. 1550 LD (Laser Diode) 22 which converts into an optical signal by using a laser diode that receives an electrical high frequency (RF) signal and outputs a signal having a wavelength of 1550 nm,

A first wavelength division multiplexer (WDM) for outputting an optical signal applied from the 1550 LD 22 to the optical path 30 and separating and detecting an optical signal having a 1310 nm wavelength applied from the optical path 30. Division Multiplexer) 24,

A first photodiode (PD) 26 for converting a 1310 nm wavelength laser signal or an optical signal applied from the first WDM 24 into a radio frequency (RF) signal, which is an electrical signal, and applying the same to the control unit 15. Made up of

The slave module 50 of the relay station 40 uses a laser diode that outputs a high frequency (RF) signal, which is applied from the control unit 41, to a signal having a 1310 nm wavelength, and converts the signal into an optical signal. LD 52,

A second WDM 54 for outputting the optical signal applied from the 1310 LD 52 to the optical path 30 and separating and detecting the optical signal of 1550 nm applied from the optical path 30;

It consists of a 2nd photodiode (PD) 56 which converts an optical signal of 1550 nm applied from the second WDM 54 into a radio frequency (RF) signal of an electrical signal and applies it to the control unit 41.

In the master 20 and slave 50 modules having the above-described configuration, the signal applied from the base station 10 is converted into an optical signal of 1550 nm by the master 20, and is slaved through the optical path 30. By applying to 50, the high frequency output can be output from the relay station 40, and the signal to be transmitted to the base station 10 by the relay station 50 is converted into an optical signal of 1310 nm and applied to the master 20. 10) is delivered.

The base station 10 is provided with a plurality of master modules 20, as many as the number of relay stations 40, each relay station is provided with one slave module 50, each relay station 40 is an independent one The optical path 30 is allocated to communicate with the base station 10.

The prior art as described above can transmit and receive between the base station 10 and the relay station 40 by using one optical path 30 by using the first WDM 24 and the second WDM 54, When the first WDM 24 and the second WDM 54 are not used, the transmission-only optical path 30 and the reception-only optical path must be used separately.

According to the prior art according to the above example, a plurality of optical paths 30 by the number of relay stations 40 are required, and a plurality of master modules 20 are required.

The prior art, which partially solves the above problems, uses one master module 20 'for the base station 10, as shown in FIG. 3, and multiple relay stations 40 on a straight line of the optical cable 30. FIG. The slave 50's are connected in order.

In order to use the above configuration, the master 20 'and the slave 50' modules should use different intermediate frequencies, and the master 20 'and slave 50' modules of FIG. Detailed functional blocks are shown.

The master module 20 'includes a first LD 23 for converting an electrical signal applied from the controller 15 into an optical signal;

A first WDM (24) for outputting an optical signal applied from the first LD (23) to the optical path (30) and separating and detecting optical signals of different wavelengths applied from the optical path (30);

The first photoelectric conversion unit 25 receives the optical signal detected by the first WDM 24, modulates different intermediate frequencies (IF), and outputs the modulated signals.

In addition, each relay station 40 extracts the optical signal transmitted to the optical path 30 to a predetermined level, and simultaneously outputs the optical signal generated from each of the relay stations 40 to the optical path 30 at a predetermined level. Applying an optocoupler (35, 35 '),

Each slave module 50 'and control unit 41,

The slave module 50 'detects and outputs an optical signal applied from the optical coupler 35, 35', and simultaneously transmits a signal to be transmitted from the relay station 40 to the base station 10 by the optical coupler 35, 35 '. Second WDM (54,54 '),

Second photoelectric converters 55 and 55 'for converting the optical signal detected by the second WDM 54 and 54' into an electrical signal;

It is a unique intermediate frequency (IF1, IF2, IF3 ...) distinguished for each relay station 40, and is composed of second LDs 53, 53 'for converting a signal to be transmitted to the base station 10 into an optical signal. .

In the above-described configuration, the improved prior art will be described in detail. As a result, the plurality of relay stations 40, which are installed in the shaded area of the base station 10, must use signals of the same channel as the base station 10, One LD 23 converts the same electrical signal into an optical signal and applies it to the first WDM 24, and through the optical path 30, the optocouplers 35 and 35 'of each relay station 40. At the proper level.

In the above configuration, instead of the relay station 40, when a plurality of base stations 10 are connected in series, the channel and the signal to be transmitted must be distinguished for each base station 10, and thus different intermediate frequencies IF You can also use

The optical signal extracted at an appropriate level from the optocouplers 35 and 35 'of the respective relay stations 40 is detected by the second WDMs 54 and 54', and the second photoelectric converters 55 and 55 'are used. Is converted into an electrical signal and applied to the controller 41, and is transmitted to the mobile phone through an antenna, and the electrical signal received from the mobile phone is applied to the second LDs 53 and 53 'through the controller 41. And down-modulated to the unique intermediate frequencies IF1, IF2, IF3, ..., which are allocated to each relay station 40 at the same time, are converted into optical signals, and the second WDM 54, 54 ' By being applied to the optocouplers 35 and 35 ', it is applied to the first WDM 24 via the optical path 30.

The first WDM 24 detects the optical signals of all the relay stations 10 to which different intermediate frequencies IF are applied from each relay station 40, that is, the bandwidth is extended, and is applied. The first photoelectric conversion unit 25 is applied.

The first photoelectric conversion unit 25 converts an optical signal applied from the first WDM 24 into an electrical signal and is divided into intermediate frequencies IF assigned to the plurality of relay stations 40. By modulating, the signals applied from the respective relay stations 40 can be distinguished.

However, the above-described conventional technology is complicated by additionally requiring an intermediate frequency conversion device for dividing the relay station 40, and requires different slave modules 50 'to be used for each relay station 40. There is a problem that is not easy.

In addition, the structure of the master module 20 'is very complicated, and the cost increases, and since the optocouplers 35 and 35' need to be used for each relay station 40, the optocouplers 35, Due to the inherent optical loss caused by 35 '), there is a problem that long-distance or long-distance transmission is difficult and subsequent expansion is difficult.

In addition, each intermediate frequency IF passes through the master 20 'and the slave 50', and there is a problem that the active elements may act as harmonics with each other.

According to the present invention, a plurality of relay stations are connected by using a straight optical path, and each relay station transmits a signal to a base station using an optical signal having a different wavelength, and each relay station transmits and receives to and from the base station through an add / drop unit. The purpose of the present invention is to provide a multi-wavelength optical relay connection device capable of reducing optical loss, improving signal separation, and manufacturing at low cost by dividing a signal applied from each base station using a wavelength division multiplexer.

In order to achieve the above object, the present invention provides a mobile communication system in which a base station and a plurality of optical relay stations are connected to each other by a straight optical path. A first LED for converting and outputting an optical signal having a wavelength, a plurality of first PDs for converting and outputting an optical signal applied at a different wavelength into an electrical signal, and an optical signal applied from the first LED to the optical path; And a multi-wavelength division multiplexer which detects the optical signal received from the optical path for each wavelength and divides and applies the split signal to the corresponding first PD.

In addition, the present invention is to extract the optical signal transmitted to the optical path with a small loss, and at the same time the add / drop unit for applying the optical signal to the optical path by a high degree of separation, and the electrical signal that the optical relay station transmits to the base station, and other optical relay station An optical relay station which converts an optical signal having a different wavelength to be output to the add / drop unit, and simultaneously converts an optical signal applied from the add / drop unit into an electrical signal, and an optical relay station connecting the add / drop unit and the slave. And an optical relay station comprising an internal light path.

1 is a connection diagram of a general base station and a relay station system according to an example;

2 is a detailed functional block diagram of a master and a slave according to an example of the prior art;

3 is a connection diagram of a general base station and a relay station system according to another embodiment;

4 is a detailed functional block diagram of a master and a slave according to another example of the prior art;

5 is a detailed functional block diagram of a master and a slave according to the present invention;

6 is a detailed functional block diagram of an add / drop unit according to the present invention.

** Explanation of symbols on the main parts of the drawing **

10: base station 15,41: control unit 20,20 ', 70: master module

22: 1550 LD 23, 72: 1st LD 24: 1st WDM

25: first photoelectric conversion unit 26,76: first PD 30: optical path

33: optical relay station internal light path 35,35 ': optical coupler 40: optical relay station

50,50 ', 90,90': Slave module 52: 1310 LD

53,53 ', 96,96': 2nd LD 54,54 ': 2nd WDM

55,55 ': second photoelectric converter 56,94,94': second PD

74: multi-wavelength division multiplexer 80,80 ': add / drop section

82: first WDM 84: optical splitter 86: second WDM

88: third WDM 89: optical mixer 92: multiple wavelength division multiplexer

Hereinafter, a multi-wavelength optical relay station connecting apparatus according to the technique of the present invention with reference to the accompanying drawings.

5 is a detailed functional block diagram of a master and a slave according to the present invention, and FIG. 6 is a detailed functional block diagram of an add / drop unit according to the present invention.

Referring to FIG. 5, in the multi-wavelength optical relay station connecting apparatus according to the present invention, the base station 10 and the plurality of optical relay stations 40 are connected to each other by a continuous optical path 30 in a straight line. In the communication system, the master module 70 of the base station 10 connected to the optical path 30 is a first laser diode (LD) 72 for converting and outputting an electrical signal into an optical signal having a first wavelength. )Wow,

A plurality of first photo diodes (PD) 76 for converting and outputting optical signals applied at different wavelengths into electrical signals;

Multi-wavelength division multiplexing, which transmits an optical signal applied from the first LED 72 to the optical path, classifies and detects an optical signal received from the optical path by wavelength, and divides and applies the optical signal to the corresponding first PD 76, respectively. Firearm 74 is included and configured.

In addition, the present invention, in the mobile communication system in which the base station 10 and the plurality of optical relay station 40 is connected in series by a single optical line 30, the relay station 40, the optical path 30 Detects and outputs the transmitted optical signal, and separates the optical signal applied to the optical path 30 with high isolation and applies the first optical signal to the optical path 30 through another path. Division multiplexer 82; An optical splitter (84) for dividing the optical signal applied from the first wavelength division multiplexer (82) into two optical signals having a predetermined size; A second wavelength division multiplexer (86) which transmits an optical signal applied from the optical splitter (84) to the optical path (30), and at the same time outputs the optical signal received from the optical path (30) to another path; The optical signal applied from the optical splitter 84 is output to the relay station internal light paths 33 and 33 ', and at the same time, the optical signal received from the relay station internal light paths 33 and 33' is output to another path. A three wavelength division multiplexer 88; An optical mixer 89 for mixing the optical signals applied from the second wavelength division multiplexer 86 and the third wavelength division multiplexer 88 and outputting the mixed optical signals to the first wavelength division multiplexer 82. By extracting the optical signal transmitted from the base station 10 to the optical path 30 with a small loss, and simultaneously applying the optical signal to the optical path 30 by a high isolation (High Isolation) Add / Drop section (80,80 '),

Second LEDs 96, 96 'for transmitting an electrical signal from the optical relay station 40 to the base station 10 into an optical signal having a wavelength distinct from other optical relay stations 40; Second PDs 94 and 94 'for converting an optical signal applied from the base station 10 into an electrical signal; The optical signals applied from the second LEDs 96 and 96 'are output to the optical relay internal light paths 33 and 33', and the optical signals applied from the optical relay internal light paths 33 and 33 '. Is a wavelength division multiplexer (92, 92 ') to be applied to the second PD (94, 94') by using another path, so that the optical relay station 40 is connected to the base station 10. Converts an electrical signal to be transmitted to an optical signal having a wavelength different from that of the other optical relay station 40 and outputs the optical signal to the add / drop units 80 and 80 ', and simultaneously Slaves 90 and 90 'for converting an applied optical signal into an electrical signal;

The optical relay station internal light paths 33 and 33 'connecting the add / drop units 80 and 80' and the slaves 90 and 90 'are included.

Hereinafter, a multi-wavelength optical relay station connection apparatus according to the present invention having the above configuration will be described in detail with reference to the accompanying drawings.

The base station 10 and the plurality of optical relay stations 40 are connected by an optical line 30 continuously connected in a straight line, and transmit and receive necessary signals as optical signals.

The base station 10 transmits the electric signal applied from the control unit 15 as a wireless signal through the base station antenna and simultaneously applies the first signal to the first LD 72 of the master module 70.

The first LD 72 converts an applied electric signal into an optical signal having a wavelength of 1310 nm and outputs the result to the multiple wavelength division multiplexer 74. ) Is applied to the optical path 30 and simultaneously applied to the respective add / drop units 80 and 80 'of the plurality of optical repeaters 40.

The add / drop units 80 and 80 'transmit the transmission signal of the base station 10 transmitted by the first wavelength division multiplexer (WDM) 82 at a 1310 nm wavelength to the optical path. To apply.

The optical splitter 84 splits and extracts an optical signal having a predetermined predetermined level from the applied optical signal, and the split-extracted and remaining large level 1310 nm optical signal is applied to the second WDM 86 and simultaneously The optical signals divided into predetermined levels are applied to the third WDM 88, respectively.

The second WDM 86 outputs the appropriate level of the 1310 nm wavelength optical signal to the optical path 30 connected to the next optical relay station 40 in the straight line, and adds / adds the next optical relay station 40 to the next optical relay station 40. In the same process as the above by the drop unit 80 ', all the optical relay stations connected to the optical path 30 are repeated by repeating the process of dividing and extracting the optical signal of a predetermined level and outputting the optical signal to the optical path 30 again. At 40, an optical signal of 1310 nm wavelength output from the base station 10 is applied.

Further, a 1310 nm wavelength optical signal of a predetermined level applied to the third WDM 88 is outputted to the optical relay station internal light paths 33 and 33 ', and corresponding slaves 90 and 90' of the optical relay station 40 are provided. Are applied to

The wavelength division multiplexers 92 and 92 ', which correspond to the slaves 90 and 90', respectively, output a 1310 nm wavelength optical signal applied from the optical relay internal light paths 33 and 33 '. It is applied to the PD (94, 94 '), is converted into an electrical signal by the second PD (94, 94'), and applied to the control unit 41 of each optical relay station 40, the radio through the optical relay station antenna Is sent.

The signal received from the cellular phone located in the service area of each optical relay station 40 is applied to the second LDs 96 and 96 'of the slaves 90 and 90' through the control unit 41.

The second LDs 96 and 96 'convert an electrical signal into an optical signal, thereby converting each optical relay station 40 into an optical signal having a different wavelength.

As an example, the second LD 96 of the optical relay station 40 connected to the optical path 30 in the first order converts an electrical signal into an optical signal having a wavelength of 1530 nm, and the optical path ( The second LD 96 'of the optical relay station 40 connected in a second order to 30 converts an electrical signal into an optical signal having a wavelength of 1510 nm, and also a third of the optical path 30. The second LD 96 ′ of the optical relay stations 40 connected in sequence converts an electrical signal into an optical signal having a wavelength of 1550 nm, that is, each optical relay station 40 has a wavelength unit of about 20 nm. Second LDs 96 and 96 'which are divided and converted into optical signals having different wavelengths are used.

The use of the second LD having a wavelength difference in units of 20 nm as described above is relatively easy to manufacture LD (laser diode) and inexpensive.

As another example, when the number of optical relay stations 40 connected in series increases, it is possible to use LDs having wavelength differences in units of 1 nm, but the manufacturing of the LDs is difficult and expensive.

As described above, the optical signals generated at the specific wavelengths from the second LDs 96 and 96 'are applied to the wavelength division multiplexers 92 and 92', and are applied to the internal optical paths 33 and 33 'of the optical relay station. Is output and applied to the third WDM 88 of the add / drop portions 80 and 80 '.

The third WDM 88 outputs the applied optical signal to the optical path 30 by applying the applied optical signal to the first WDM 82 through the optical mixer 89.

When the optical path 30 is directly connected to the base station 10, the optical path 30 is input to the multi-wavelength division multiplexer 74 of the master module 70, and is classified according to wavelengths of the optical signal to generate the corresponding wavelength. 1 is applied to the PD 76, and converted into an electrical signal by the first PD 76 of the corresponding wavelength, and transmitted to the switching center through the control unit 15 of the base station 10.

As an example, the optical path 30 that receives the signal output from the first WDM 82 of the add / drop unit 80 ′ is added to another optical relay station 40 of the optical path 30 connected in a straight line. In the case of via the drop unit 80, the second WDM 86 of the other add / drop unit 80 receives the optical signal, and the second WDM 86 receives the corresponding optical mixer ( 89) to the optical signal.

For example, the optical mixer 89 mixes an optical signal having a wavelength of 1510 nm applied from the second WDM 86 and an optical signal having a wavelength of 1530 nm applied from the third WDM 88. After that, the first WDM 82 is applied, and the first WDM 82 outputs an optical signal having a wavelength of 1510 nm and 1530 nm to the optical path 30, thereby performing the same process as described above. Is passed on.

As an example, when three optical signals of different wavelengths, that is, three optical signals of 1510 nm, 1530 nm, and 1550 nm wavelengths are applied from three optical relay stations 40, the ad / drop closest to the base station 10 is applied. The optical mixer 89 of the unit 80 mixes the optical signals having the wavelengths of 1510 nm, 1530 nm, and 1550 nm and applies them to the corresponding first WDM 82, thereby providing a master module of the base station 10. The multiple wavelength division multiplexer 74 provided at 70 demultiplexes the optical signals of the wavelengths 1510 nm, 1530 nm, and 1550 nm, and outputs them through different paths, respectively, and outputs the optical signals of the corresponding wavelengths, respectively. By the first PD 76 converting the electric signal, it is possible to distinguish the signals applied from the respective optical relay stations 40.

In more detail, the multi-wavelength division multiplexer 74 of the master module 70 uses optical signals of different wavelengths because a plurality of optical relay stations 40 connected to the same optical path 30 use different wavelengths. The optical signals of different wavelengths corresponding to the numbers of the relay stations 40 must be classified, and the number of the first PDs 76 connected to the multi-wavelength division multiplexer 74 is also classified. As many as should be provided.

Although the multi-wavelength division multiplexer 74 is easy to manufacture and relatively inexpensive, the multi-wavelength division multiplexer 74 is used to classify optical signals at 20 nm wavelength unit intervals, but the number of optical relay stations 40 to be connected is large. In this case, DWDM (Dense WDM) of 1 nm wavelength unit used for ultra high-speed transmission may be used, and Micro Optics type WDM manufactured by thin film interference process is good in terms of function and size, but the price is high. Since it is expensive, it is preferable to use an inexpensive fiber fusion type WDM.

According to the present invention having the above-described configuration, the signals of the optical relay stations can be distinguished by optical signals having different wavelengths, are easy to manufacture, have excellent optical signal separation, and use an add / drop unit with low insertion loss. Thus, the separation of optical signals having different wavelengths is improved, and there is an effect that it can be manufactured at low cost.

In addition, there is an industrial and industrial use effect that can connect a plurality of optical relay stations by a single optical path, and can reduce the optical loss of the optical signal.

Claims (4)

In a mobile communication system in which a base station and a plurality of optical relay stations are connected by a straight optical path, The master module of the base station connected to the optical path includes a first LED for converting an electrical signal into an optical signal having a first wavelength and outputting the optical signal; A plurality of first PDs for converting and outputting optical signals applied at different wavelengths into electrical signals; And a multi-wavelength division multiplexer which transmits an optical signal applied from the first LED to the optical path, detects an optical signal received from the optical path for each wavelength, and divides and applies the optical signal to a corresponding first PD. Multi-wavelength optical relay station device. In a mobile communication system in which a base station and a plurality of optical relay stations are connected by a line of light, The optical relay station comprises: an add / drop unit for extracting an optical signal transmitted to an optical path with a small loss and at the same time applying the optical signal to the optical path by a high degree of separation; Slave for converting the electrical signal to be transmitted to the base station by the optical signal of the wavelength distinct from other optical relay station and output to the add / drop unit, and at the same time converts the optical signal applied from the add / drop unit into an electrical signal Wow, The optical wavelength station connection apparatus, characterized in that the optical relay station includes an internal optical path for connecting the add / drop unit and the slave. The method of claim 2, The add / drop unit detects and outputs an optical signal transmitted to an optical path, and a first wavelength division multiplexer for applying an optical signal applied to the optical path to another path by high separation degree; An optical splitter for dividing an optical signal applied from the first wavelength division multiplexer into two optical signals having a predetermined size; A second wavelength division multiplexer which transmits an optical signal applied from the optical splitter to an optical path and simultaneously outputs an optical signal received from the optical path to another path; A third wavelength division multiplexer for outputting an optical signal applied from the optical splitter to an internal optical path of the optical relay station and simultaneously outputting an optical signal received from the optical relay internal light path to another path; And a light mixer for mixing the optical signals applied from the second wavelength division multiplexer and the third wavelength division multiplexer and outputting the optical signals to the first wavelength division multiplexer. The method of claim 2, The slave may include: a second LED for converting an electrical signal to be transmitted from the optical relay station to the base station into an optical signal having a wavelength distinguished from other optical relay stations; A second PD for converting an optical signal applied from a base station into an electrical signal. The optical signal applied from the second LEDs is output to the internal optical path of the optical relay station, and the optical signal applied from the internal optical path of the optical relay station includes a wavelength division multiplexer for applying to the second PD using another path. Multi-wavelength optical relay station connection device characterized in that.