JP2003188832A - Optical transmitter and receiver for two-way optical wavelength division multiplex transmission system having broadcast communication function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical transmitter and receiver for a two-way optical wavelength division multiplex transmission system having a broadcast communication function suitable for an optical access network. <P>SOLUTION: This invention provides: an optical receiver and an optical transmitter for one-to-one communication with an external device by means of 2-way optical wavelength division multiplex transmission; and an optical receiver for broadcast communication with the external device by means of the optical wavelength division multiplex transmission. The optical transmitter and receiver for the two-way optical wavelength division multiplex transmission system is characterized in that the wavelengths for first and second optical signals for the one-to-one communication are selected to be a set of wavelengths satisfying a circulation characteristic of an AWG, the wavelength of an optical signal for the broadcast communication is selected to be a prescribed wavelength, the optical transmitter transmits one of the second optical signals to an external star coupler connected to the AWG, the optical receiver selectively extracts one of the first optical signals from the external star coupler, the optical receiver for the broadcast communication selectively extracts the optical signal for the broadcast communication from the external star coupler. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bidirectional optical wavelength division multiplexing transmission system for bidirectional transmission using an optical fiber as a transmission medium, and particularly to a short distance bidirectional connection between a subscriber's home and a station. A fixed wavelength light source and an arrayed waveguide diffraction grating type multiplexer / demultiplexer (AWG) applicable to a one-core bidirectional optical multiplex wavelength division transmission system for subscribers as an optical transmission system;
The present invention relates to an optical transmitter / receiver for a bidirectional optical wavelength division multiplexing transmission system having a broadcast communication function suitable for an optical access network using a star coupler.

[0002]

2. Description of the Related Art FIG. 1 is a single-core bidirectional optical wavelength division multiplexing system which uses a single-core optical fiber as a transmission medium and performs bidirectional transmission of one channel by using different wavelength bands in a down direction and an up direction. 1 shows the basic configuration of a transmission system.

That is, an optical signal of, for example, a nominal wavelength λ1 = 1300 nm (actual wavelength λ = 1300 to 1320 nm) transmitted from the transmitter 1 on the sender side goes down through the optical fiber 3 of one core via the filter 2. After being transmitted as a signal to the other party, it is received by the receiving apparatus 5 of the other party via the filter 4.

On the other hand, the optical signal of, for example, the nominal wavelength λ2 = 1550 nm (actual wavelength λ = 1540 to 1560 nm) transmitted from the transmission device 6 on the other side is filtered by the filter 7.
After being transmitted as an upstream signal by the single optical fiber 3 via the optical fiber, the signal is received by the receiver 9 on the sender side via the filter 8.

FIG. 2A is a diagram illustrating the transmission characteristics of the filters 2 and 4.

In other words, the filters 2 and 4 have the nominal wavelength λ1 = 1300 nm (actual wavelength λ = 1300 to 13) transmitted from the transmitter 1 on the sender side.
Although the optical signal of 20 nm) is transmitted, the nominal wavelength λ2 transmitted from the other side is = 1550 nm (actual wavelength λ =
1540 to 1560 nm) to prevent the downstream optical signal and the upstream optical signal from interfering with each other, for example, a low pass filter (LPF) or a band pass filter having a transmission characteristic as shown in the figure. Filter (B
PF).

FIG. 2B is a diagram illustrating the transmission characteristics of the filters 7 and 8.

In other words, the filters 7 and 8 have the nominal wavelength λ1 = 15 transmitted from the other side.
An optical signal of 50 nm (actual wavelength λ = 1540 to 1560 nm) is passed, but the nominal wavelength λ1 = 1300 nm (actual wavelength λ = 1) transmitted from the transmitter 1 on the sender side.
In order to prevent the interference between the downstream optical signal and the upstream optical signal by preventing the passage of the optical signal of 300 to 1320 nm), for example, a high-pass filter (HPF) or band having the transmission characteristics as shown in the drawing is used. Pass filter (B
PF).

FIG. 3 shows a single-fiber bidirectional optical wavelength division multiplexing transmission system which uses a single-core optical fiber as a transmission medium and performs multichannel bidirectional transmission using different wavelength bands in the down direction and the up direction. The principle configuration of is shown.

That is, for example, the even wavelength λ11 = 1550n transmitted from the transmitter 11 on the sender side.
m, λ12 = 1552nm, λ13 = 1554nm 3
The optical signal of the channel is transmitted to the other party as a down signal by the one-core optical fiber 13 through the comb filter 12, and then is transmitted through the comb filter 14 to the receiving apparatus 1 of the other party.
5 is received.

On the other hand, for example, odd-numbered wavelengths λ21 = 1551, λ22 = 1553, λ23 = 15 transmitted from the transmission device 16 on the other side through the comb filter 17.
The 55 nm 3-channel optical signal is transmitted to the sender side as an upstream signal by the single-core optical fiber 3,
The signal is received by the receiver 19 on the sender side via the comb filter 18.

FIG. 4A is a diagram illustrating the transmission characteristics of the comb filter 12 and the comb filter 14.

In other words, the comb filters 12 and 14 have the even-numbered wavelengths λ11 = 1550 nm and λ12 transmitted from the transmitter 11 on the sender side.
= 1552 nm, λ13 = 1554 nm, three-channel optical signals are allowed to pass, but the receiver side transmitter 1
6, the odd-numbered wavelength λ21 = 1551,
In order to prevent interference between the upstream optical signal and the downstream optical signal on the receiver side by preventing the optical signals of the three channels of λ22 = 1553 and λ23 = 1555 nm from passing through, for example, as shown in the figure, It is a filter having a comb-shaped transmission characteristic.

FIG. 4B is a diagram illustrating the transmission characteristics of the comb filter 17 and the comb filter 18.

That is, in the comb filters 17 and 18, these odd-numbered wavelengths λ21 = 1551 and λ22 = 1 transmitted from the receiver-side transmitter 16 are used.
The optical signals of three channels of 553, λ23 = 1555 nm are allowed to pass, but the even-numbered wavelengths λ11 = 1550 nm and λ12 = 1 transmitted from the transmitter apparatus 11 on the sender side.
In order to prevent the interference between the upstream optical signal and the downstream optical signal on the receiver side by preventing the optical signals of the three channels of 552 nm and λ13 = 1554 nm from passing through, for example, a comb shape as shown in the drawing is used. It is a filter having a transmission characteristic of.

In FIG. 5, as shown in FIG. 1, a single optical fiber is used as a transmission medium, and a single channel bidirectional transmission is performed by using different wavelength bands in the down direction and the up direction. It shows a configuration when the directional optical wavelength division multiplexing transmission system is actually applied to a short-distance bidirectional optical transmission system for connecting a subscriber station and a subscriber's house.

That is, in this system, a plurality of bidirectional transmissions of one channel are performed from the relay station A side through the transmitter T and the receiver R using different wavelength bands in the downlink direction and the uplink direction, respectively. As a transmission medium of n (for example, n = 10) lines, for example, the downlink has a nominal wavelength λ1.
= 1300 nm (actual wavelength λ = 1300 to 1320n
m) optical signal, upstream has a nominal wavelength λ2 = 1550 nm
Optical fibers 11, 12 ... 1n each for transmitting an optical signal (actual wavelength λ = 1540 to 1560 nm)
Are connected to subscriber station B.

Further, from the subscriber station B, transmission of a plurality of m lines for performing bidirectional transmission of one channel using different wavelength bands in the up direction and the down direction via the transmitting device T and the receiving device R, respectively. As a medium, for example, the downstream direction has a nominal wavelength λ1 = 1300 nm (actual wavelength λ = 1300-1
320 nm optical signal, upstream has a nominal wavelength λ2 = 15
Optical fibers 21 and 2 for transmitting optical signals of 50 nm (actual wavelength λ = 1540 to 1560 nm), respectively.
2 ... 2 m is a plurality of subscriber homes C (for example, n = 10)
Are connected to the transmitting device T and the receiving device R.

In FIG. 5, the filter 2, the filter 4, the filter 7, and the filter 8 shown in FIG.
Since they are incorporated in each of the transmitting device T and the receiving device R, their illustration is omitted.

Further, as shown in FIG. 3, a single-core bidirectional optical fiber which uses a single-core optical fiber as a transmission medium and performs multichannel bidirectional transmission by using different wavelengths in the down direction and the up direction. When the wavelength division multiplexing transmission system is actually applied to a short-distance bidirectional optical transmission system for connecting a subscriber's house and a station, the configuration is substantially the same as that of FIG.

By the way, in the short-distance bidirectional optical transmission system as shown in FIG. 5, an optical fiber of the same number as the number of subscribers is required between the side of the relay station A and the subscriber station B.

For this reason, optical wavelength division multiplexing (WDM) using an arrayed-waveguide diffraction grating type multiplexer / demultiplexer (AWG), which has recently been adopted in a long-distance backbone bidirectional optical transmission system.
By applying the communication method to a short-distance bidirectional optical transmission system that connects a subscriber and a station, it is possible to reduce the number of required optical fibers.

Here, the AWG is based on, for example, the document "NTT.
R & D Vol. 49 No. 62000 pp29
As disclosed in U.S. Pat. No. 5,089,078, an input waveguide, an array waveguide, an output waveguide, and a lens waveguide connecting these waveguides are usually integrated together on a substrate. It is a combined demultiplexer.

When the AWG having such a structure is used as a demultiplexer, the optical signal from the input waveguide is spread by the lens waveguide and then branched into the arrayed waveguide.

The branched optical signal has a phase difference due to the difference in the lengths of the respective waveguides, and when they are combined again in the lens waveguide, a specific output corresponding to the phase difference is produced. It is focused on the waveguide.

Since this focusing position differs depending on the wavelength of the optical signal, the optical wavelength division multiplexed signal (WDM optical signal) is output to different output waveguides for each wavelength, and wavelength separation or division is performed by the filter function of the AWG. Be waved.

Further, when the AWG having such a structure is used as a multiplexer, it is sufficient to perform the function reverse to that described above.

FIG. 6 shows a conventional long-distance backbone system bidirectional system realized by adopting an optical wavelength division multiplexing (WDM) communication system using an arrayed-waveguide diffraction grating type multiplexer / demultiplexer (AWG). The connection configuration from the relay station A side to the subscriber station B when the optical transmission system is applied to a short-distance optical transmission system for connecting a subscriber's house and a station is shown.

The configuration shown in FIG. 6 does not utilize the circulation characteristics of the AWG used in the present invention described later.

That is, in the configuration shown in FIG. 6, for example, in the downstream direction, the AWG 41 on the side of the relay station A
Combines four optical signals (λ1, λ2, λ3, λ4) into 1
Wave WDM signal is transmitted to the first optical fiber 42 of the first core, and by the filter function of the AWG 43 of the subscriber station B,
The WDM signal of one wave is demultiplexed, and again four waves (λ1, λ
2, λ3, λ4) optical signals are separated.

In the upstream direction, the AW on the subscriber station B side
By G44, the optical signals of four waves (λ1, λ2, λ3, λ4) are combined and transmitted as a one-wave WDM signal to the second one-core optical fiber 45, and by the filter function of the AWG 46 on the relay station A side. WDM signal of 1 wave is demultiplexed and again 4
The optical signals of waves (λ1, λ2, λ3, λ4) are separated.

A conventional long-distance backbone bidirectional optical transmission system realized by adopting such an optical wavelength division multiplexing (WDM) communication system using an AWG is used to connect a subscriber and a station. Since the bidirectional optical transmission system applied to the optical transmission system does not utilize the circulation characteristic of the AWG used in the present invention described later, the station from the relay station A side to the subscriber station B side is used. Since the connection of the transmission medium to and from is separate in the downstream direction and the upstream direction, a total of two single-core optical fibers are used as the first and second single-core optical fibers 42 and 45.

[0033]

However, as described above, in the conventional technique as shown in FIG.
In order to realize the service for single-fiber subscribers, the same number of optical fibers as the number of subscribers is required between the relay station A side and the subscriber station.

Here, in order to reduce the number of single-core optical fibers that need to be connected between the relay station A side and the subscriber station, the subscriber station is provided with an electric multiplexer which requires maintenance or the like. Therefore, there is a problem that it is inefficient in terms of cost and maintenance at the subscriber station.

On the other hand, a conventional long distance realized by adopting an optical wavelength division multiplexing (WDM) communication system using an arrayed waveguide diffraction grating type multiplexer / demultiplexer (AWG) as shown in FIG. When the backbone bidirectional optical transmission system of 1 is applied to a subscriber transmission system, the circulation characteristics of the AWG as used in the present invention described later are not used, and therefore, between the relay station and the subscriber station. Since two optical fibers of one core are required, there is a problem that cost efficiency is low.

The above-mentioned document "NTT R & D V
ol. 49 No. 6 2000pp 298-308 "
Describes a full mesh network using the wavelength circulation of the AWG, the prior art utilizing the wavelength circulation of the AWG only shows an application example as an optical router by the wavelength routing function of the AWG. Not not.

That is, in the prior art, by utilizing the loop characteristics of the AWG, the wavelength fixing which is applicable to the one-core bidirectional optical wavelength division multiplexing transmission system for subscribers, which is improved in cost and efficiency, is achieved. No disclosure or suggestion is made regarding application to an optical access network using a light source and an arrayed-waveguide diffraction grating type multiplexer / demultiplexer (AWG).

By the way, conventionally, the broadcast communication service implemented by CATV is a complete broadcast communication using one wavelength, and one-to-one communication is multiplexed using a plurality of wavelengths. In the multiplex transmission system, there is a problem that the broadcast communication service is not implemented.

Therefore, the present invention has been made in view of the above circumstances, and connects a subscriber's home and a station in a bidirectional optical wavelength division multiplexing transmission system for bidirectional transmission using an optical fiber as a transmission medium. In the short-distance bidirectional optical transmission system, an array applicable to a single-fiber bidirectional optical wavelength division multiplexing transmission system for subscribers, which is improved in cost and efficiency by utilizing the circulation characteristics of AWG An object of the present invention is to provide an optical transmitter / receiver for a bidirectional optical wavelength division multiplexing transmission system having a broadcast communication function suitable for an optical access network using a waveguide diffraction grating type multiplexer / demultiplexer (AWG) and a star coupler. There is.

[0040]

According to the present invention, in order to solve the above-mentioned problems, (1) a first light source having a predetermined wavelength
An optical receiving device for receiving one of the optical signals for external communication for one-to-one communication by bidirectional optical wavelength division multiplexing transmission, and a predetermined wavelength different from the wavelength of the first optical signal. An optical transmitter for transmitting an optical signal corresponding to the second optical signal to the outside to perform one-to-one communication by bidirectional optical wavelength division multiplexing transmission; and a broadcast communication having a predetermined wavelength. An optical receiving device for broadcast communication for receiving an optical signal with the outside for performing broadcast communication by optical wavelength division multiplexing transmission,
The respective wavelengths of the first and second optical signals are externally multiplexed and demultiplexed with respect to the first and second optical signals for one-to-one communication by bidirectional optical wavelength division multiplexing transmission. At the same time, an arrayed-waveguide diffraction grating type multiplexer / demultiplexer (AWG) having a predetermined wavelength passband circulation characteristic for multiplexing the optical signal for the broadcast communication for the broadcast communication by the optical wavelength division multiplexing transmission. Is set as a set of wavelengths that satisfy the circulation characteristic of the wavelength pass band, and the optical transmitter transmits the second optical signal in order to perform one-to-one communication by bidirectional optical wavelength division multiplexing transmission with the outside. One of the two is transmitted to an external star coupler connected to the AWG, and the optical receiving device is for performing one-to-one communication by bidirectional optical wavelength division multiplexing transmission with the outside. , Of the first optical signal from the external star coupler An optical signal for broadcast communication is provided, which comprises a first extracting means for selectively extracting one optical signal and guiding one optical signal of the extracted first optical signals to the optical receiving device. The receiving device selectively extracts an optical signal for the broadcast communication from the external star coupler in order to perform broadcast communication with the outside by optical wavelength division multiplexing transmission,
An optical transmitter / receiver for a bidirectional optical wavelength division multiplexing transmission system, comprising a second extracting means for guiding the extracted optical signal for the broadcast communication to an optical receiver for the broadcast communication. Provided.

Further, according to the present invention, in order to solve the above-mentioned problems, (2) the optical transmission device emits a broadband optical signal that includes a wavelength in a predetermined range and does not include the circulating wavelength of the AWG. An optical transmitter / receiver for a bidirectional optical wavelength division multiplexing transmission system according to (1) is provided, which is an optical transmitter using a broadband light source.

According to the present invention, in order to solve the above-mentioned problems, (3) the optical transmission device is an optical transmission device using a fixed wavelength light source for separately emitting an optical signal having a predetermined wavelength. An optical transceiver for a bidirectional optical wavelength division multiplexing transmission system according to (1) is provided.

Further, according to the present invention, in order to solve the above problems, (4) the optical transmitter, the optical receiver, and the optical receiver for broadcast communication are each connected via an internal coupler. Connected to an external star coupler,
The optical transmitter includes a broadband light source that emits an optical signal in a predetermined wavelength range, and an optical signal having a predetermined wavelength in the second optical signal from the optical signal in the predetermined wavelength range emitted from the broadband light source. A predetermined one of a first fiber grating that selectively extracts a signal and a second optical signal that is selectively extracted by the first fiber grating for one-to-one communication with the outside. Circulator that passes an optical signal having a wavelength of, a isolator that allows an optical signal of a predetermined wavelength of the second optical signal that has passed through the first circulator to pass in one direction, and a pass through the isolator. An optical modulator for performing a predetermined optical modulation on an optical signal of a predetermined wavelength in the second optical signal, and guiding the optical signal to the external star coupler;
A second fiber grating for selectively extracting an optical signal of a predetermined wavelength from the first optical signal from the external star coupler for performing one-to-one communication with the outside; A second circulator for passing an optical signal of a predetermined wavelength among the first optical signals selectively extracted by the second fiber grating and guiding the optical signal to the optical receiving device. The optical receiver includes a third fiber grating for selectively extracting an optical signal for the broadcast communication from the external star coupler to perform broadcast communication with the outside, and the third fiber. (3) A third circulator for passing the optical signal for the broadcast communication selectively extracted by the grating and guiding the optical signal to the optical receiver for the broadcast communication. Bidirectional optical wavelength division multiplexing transmission system for optical transceiver is provided.

According to the present invention, in order to solve the above-mentioned problems, (5) the optical transmitter, the plurality of optical receivers, and the optical receiver for broadcast communication are respectively connected via internal couplers. And a fixed wavelength light source that emits an optical signal having a predetermined wavelength of the second optical signal in order to perform one-to-one communication with the outside. An isolator for passing in one direction an optical signal having a predetermined wavelength of the second optical signal emitted from the fixed wavelength light source, and a predetermined one of the second optical signals passing through the isolator. An optical modulator that applies predetermined optical modulation to an optical signal having a wavelength of 1 to guide the optical signal to the external star coupler. From the Star Coupler A first fiber grating for selectively extracting an optical signal having a predetermined wavelength of the first optical signal; and a first optical signal selectively extracted by the first fiber grating. A first circulator that passes an optical signal having a predetermined wavelength inside the optical receiver and guides the optical signal to the optical receiver. The optical receiver for broadcast communication is configured to perform external broadcast communication with the outside. The optical signal for the broadcast from the star coupler of
A second fiber grating which is selectively extracted; and an optical signal for the broadcast communication, which is selectively extracted by the second fiber grating, is passed to be guided to the optical receiving device for the broadcast communication. An optical transceiver for a bidirectional optical wavelength division multiplexing transmission system as described in (3), which is provided with two circulators.

Further, according to the present invention, in order to solve the above problems (6), the optical receiving device for broadcast communication can be attached and detached as an option (1).
An optical transceiver for a bidirectional optical wavelength division multiplexing transmission system according to any one of (1) to (5) is provided.

[0046]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 7 shows both short-distance connecting a subscriber's house and a station in a one-fiber bidirectional optical wavelength division multiplexing transmission system applied as a first embodiment of the present invention. An array waveguide diffraction grating applicable to a one-core bidirectional optical wavelength division multiplexing transmission system for subscribers, which is improved in cost and efficiency by utilizing the circulation characteristic of AWG in an optical transmission system. Block diagram shown for explaining a connection configuration of an optical transceiver for a bidirectional optical wavelength division multiplexing transmission system having a broadcast communication function suitable for an optical access network using a type multiplexer / demultiplexer (AWG) and a star coupler Is.

That is, FIG. 7 shows a short-distance bidirectional optical transmission system for connecting a subscriber's home and a station in the one-fiber bidirectional optical wavelength division multiplexing transmission system applied as the first embodiment of the present invention. As shown, an array waveguide diffraction grating type multiplexer / demultiplexer (AWG) 101a is installed in the relay station 101, a star coupler 102b is installed in the subscriber station 102 side, and the relay station 101 and the subscriber station 102 are connected to each other. In the meantime, the one-to-one communication by the bidirectional optical wavelength division multiplexing transmission is performed by using the optical signal of the set of wavelengths satisfying the circulation characteristic of the wavelength pass band of the AWG 101a.

Further, in the first embodiment of the present invention, broadcast communication by optical wavelength division multiplex transmission is performed using an optical signal for broadcast communication having a predetermined wavelength.

Here, the circulation characteristic of the AWG means, as shown in FIG. 8, for example, when an AWG having an input / output terminal of 1 × 4 is used as a demultiplexer, the wavelength λ1 from the input terminal side. , Λ2, λ3, λ4 (where λ1 <λ2 <λ
3 <λ4) optical signals and their wavelengths λ1, λ2, λ
Wavelengths λ11, λ12, λ1 that have the same wavelength intervals as those of the optical signals 3 and λ4, that is, have a circular wavelength relationship.
3, λ14 (however, λ11 <λ12 <λ13 <λ14)
When the optical signal of is input, each output end (port) 1,
Wavelengths λ1, λ2, λ3, λ4 from the 2, 3 and 4 sides, respectively.
In addition to the optical signal of, the same output end (port) 1, 2,
The wavelengths of the optical signals that can pass through wavelengths 3 and 4 are at the same wavelength intervals as those of the optical signals of these wavelengths λ1, λ2, λ3, and λ4, that is, wavelengths λ11, λ12, which are in a circular wavelength relationship. This means a filter function capable of outputting optical signals of λ13 and λ14.

That is, in this case, the output end (port) 1
From the side, the optical signal of wavelength λ1 and the optical signal of wavelength λ11 are output.

From the output terminal (port) 2 side, the optical signal of wavelength λ2 and the optical signal of wavelength λ12 are output.

From the output terminal (port) 3 side, the optical signal of wavelength λ3 and the optical signal of wavelength λ13 are output.

From the output terminal (port) 4 side, an optical signal of wavelength λ4 and an optical signal of wavelength λ14 are output.

In FIG. 7, one optical transmitting device (T11 ... Tn1) and one optical receiving device (R11 ... Rn) are provided on the input side of the AWG 101a on the relay station 101 side, respectively.
n1) and n optical transceivers TR11 ... TRn1
Are connected via n couplers C11 ... Cn1.

Here, n optical transceivers TR11 ... TR
The n optical transmitters T11 ... Tn1 in n1 respectively include a first optical signal of wavelengths λ1 to λn and emit a broadband optical signal that does not include the circulating wavelength of the AWG 101a BPS11 ... BPSn1. And the wavelength λ from the optical signals in the predetermined wavelength range emitted from the n broadband light sources BPS11 ... BPSn1.
The AWG for the first optical signal from 1 to λn
Wavelength λ that forms a set of wavelengths that satisfy the circulation characteristics of the wavelength passband of
Band limitation is performed so that the second optical signals 1 ′ to λn ′ are not allowed to pass, and the first optical signals having wavelengths λ1 to λn are allowed to pass to the external AWG 101a for multiplexing. Leading broadband pass filter and BPF11
.. and BPFn1.

Furthermore, each of the optical transmitters T11 ... Tn1
The n wide band pass filters BPF11 ... BPFn1
In1 for passing the first optical signal that has passed through in one direction in one direction, and the n isolators I
Optical modulators MOD11 ... MODn1 are provided, which perform predetermined optical modulation on the first optical signals that have passed through 11 ... In1 and guide the first optical signals to the couplers C11 ... Cn1.

Then, n optical transmitters T11 ... Tn1
Respectively, the n optical receivers R11 ... Rn1 in the n optical transceivers TR11 ... TRn1 are respectively
The coupler C11 ... The second optical signals of wavelengths λ1 ′ to λn ′ demultiplexed by the AWG 101a.
Received via Cn1.

The output side of the AWG 101a on the side of the relay station 101 is connected to one end of a single single-core optical fiber F100 that performs single-core bidirectional optical multiplex transmission via a bidirectional optical amplifier OA.

Then, this single single-core optical fiber F1
The other end of 00 is the star coupler 10 on the subscriber station 102 side.
It is connected to the input side of 2b.

The star coupler 1 on the subscriber station 102 side
On the output side of 02b, in n subscriber homes 1 ... n,
N optical transceivers TR12 ... TRn2 each having one optical receiver (R12 ... Rn2), one optical transmitter (T12 ... Tn2) and each optical receiver for broadcast communication (R13 ... Rn3) , N couplers C12 ... Cn2
Connected through.

Then, each optical transmitter T12 in the n optical transceivers TR12 ... TRn2 on the subscriber's home 1 ... N side.
Tn2 is a broadband light source BPS that emits an optical signal in a predetermined wavelength range including each wavelength of the second optical signal.
12 ... BPSn2 and the n broadband light sources BPS12
The first fiber grating FG12 that selectively extracts an optical signal of a predetermined wavelength of the second optical signals from the optical signal of the predetermined wavelength range emitted from BPSn2.
FGn2 and the n first fiber gratings FG12 ... FGn2 are passed through an optical signal of a predetermined wavelength of the second optical signals selectively extracted to the AWG 101a on the side of the relay station 101. First circulator C leading to an external star coupler 102b to be connected
C12 ... CCn2.

Further, each of the optical transmitters T12 ... Tn2 respectively has the n first circulators CC12 ... C.
An isolator I12 ... In2 that allows the second optical signal that has passed through Cn2 to pass in one direction, and a predetermined optical modulation is performed on the second optical signal that has passed through the n number of isolator I12 ... In2. Coupler C12 ... Cn2
Optical modulators MOD12 ... MODn2 that lead to the external star coupler 102b via the optical modulators.

Further, the optical receivers R12 ... In the n optical transceivers TR12 ... TRn2 on the subscriber homes 1 ...
Rn2 is the external star coupler 102, respectively.
Second fiber gratings FG13 ... FG for selectively extracting an optical signal of a predetermined wavelength from the first optical signal guided from b through an internal coupler C12 ... Cn2
n3 and the n second fiber gratings FG
13 ... A second circulator CC1 which passes an optical signal of a predetermined wavelength of the second optical signals selectively extracted by FGn3 and guides it to each of the optical receivers R12 ... Rn2.
3 ... CCn3.

Further, the optical receivers (R13 ... Rn3) for each broadcast communication in the n optical transceivers TR12 ... TRn2 on the subscriber homes 1 ... , The third optical fiber FG13 ... FGn3 for selectively extracting the optical signal for the broadcast communication from the external star coupler 102b and the third optical fiber FG14 ... FGn4 are selectively extracted. And a third circulator CC14 ... CCn4 for passing the optical signal for the broadcast communication and guiding it to the optical receiving device for the broadcast communication.

The first to third fiber gratings FG12 ... FGn used in this embodiment.
2, and FG13 ... FGn3 and FG14 ... FGn4
Are elements for selectively extracting an optical signal having a desired wavelength component from an optical signal having a plurality of wavelength components.

Therefore, such a first fiber grating FG12 ... FGn2 is connected to the broadband light source BPS12.
... BPSn2, circulator CC12 ... CCn2
, And the optical modulators MOD12 ... MODn2 together, the respective optical transmitters T12 ... Tn2 are respectively
This makes it possible to function as an optical transmitter having a desired wavelength component.

Similarly, the second fiber grating F
G13 ... FGn3 and circulator CC13 ... CC
By using together with n3, each optical receiving device R12 ... R
Therefore, each of n2 can function as a receiving device that receives an optical signal having only a desired wavelength component from an optical signal having a plurality of wavelength components.

Similarly, the third fiber grating F
G14 ... FGn4 and circulator CC14 ... CC
By using together with n4, each of the optical receivers R13 ... Rn for broadcast communication receives an optical signal of only a desired wavelength component for broadcast communication from an optical signal having a plurality of wavelength components. It can be made to function as a receiving device for communication.

Then, n optical transmitters / receivers T11 in the n optical transmitters / receivers TR11 ... TRn1 on the side of the relay station 101.
The first optical signals of wavelengths λ1 to λn respectively output from Tn1 and n subscriber homes 1 ... n optical transceivers TR12 ... TRn2 on the n side n optical transmitters T12 ... Tn2 The second optical signals of wavelengths λ1 ′ to λn ′ respectively output from the AW are as described above.
It is assumed that it is set so as to satisfy the circulating wavelength relationship of G101a.

That is, wavelengths λ1 and λ1 ', λ2 and λ
2 '... λn and λn' are AWs on the side of the relay station 101, respectively.
It is a circulating wavelength in G101a, and is a wavelength of an optical signal that can pass through the same output port of AWG 101a.

Further, the wide band pass filters BPF11 ... BPFn used in the optical transmitter-receiver according to the present embodiment.
1 is the broadband light source BPS11 ... BPSn as described above.
1 is a passive element that removes the optical signal of the circulating wavelength component of the AWG other than the required wavelength from the predetermined wavelength range that includes the first optical signal of the wavelengths λ1 to λn emitted from the first optical signal. It has a function to prevent interference with the optical signal from the direction.

The AWG 101a on the side of the relay station 101 used in the system according to this embodiment is of the temperature independent type.

In addition, isolators I11 ... In1 and I12 ... In used in the system according to the present embodiment.
2 has a function of blocking an optical signal from the opposite direction.

Then, the AWG 101a on the side of the relay station 101 used in the system according to the present embodiment emits light from the n optical transmitters T11 ... Tn1 of the n optical transceivers TR11 ... TRn1 on the side of the relay station 101. The optical signals of the wavelengths λ1, λ2 ... λn are multiplexed and multiplexed, and the optical wavelength division multiplexed signal (W
(DM signal), while demultiplexing the optical wavelength division multiplexed signal (WDM signal) from the single single-core optical fiber F100, n optical receiving devices R11 ... Rn on the side of the relay station 101.
It is a passive element that directs the optical signals of wavelengths λ1 ′, λ2 ′, ...

Further, the star coupler 102b on the subscriber station 102 side used in the system according to the present embodiment.
Are n subscriber homes 1 ... n optical transceivers TR1 on the n side
2 ... n optical transmitters T12 ... Tn2 in TRn2
The optical signals of wavelengths λ1 ′, λ2 ′, ... λn ′ emitted from the optical fiber F10 are combined and multiplexed to form a single single-core optical fiber F10.
The optical wavelength division multiplex signal (WDM signal) is transmitted to 0, the optical wavelength division multiplex signal (WDM signal) from the single optical fiber F100 is demultiplexed, and n subscriber homes 1 ...
n of n optical transceivers TR12 ... TRn2 on the n side
The optical receivers R12 ... Rn2 have wavelengths λ1, λ2, ... λ.
Optical wavelength division multiplexing signal (WDM signal) including n optical signals
Is a passive element that directs

Next, the relay station 101 and the subscriber station 102
, And a one-to-one communication operation by bidirectional optical wavelength division multiplexing transmission as transmission and reception of an optical signal between n subscriber homes 1 ...

First, n optical transmitters / receivers TR11 ... TRn1 on the side of the relay station 101 have n optical transmitters T11.
Among Tn1, the optical signal emitted from the first optical transmitter T11 passes through the AWG 101a on the side of the relay station 101, and is transmitted through the single optical fiber F100 as an optical signal of wavelength λ1. .

At this time, the first optical transmitter T1 in the n optical transceivers TR11 ... TRn1 on the side of the relay station 101 is used.
The optical signals emitted from the optical transmitters 1 to 1 are wavelengths λ2 to λ emitted from the second to nth optical transmitters T21 to Tn1, respectively.
It is multiplexed with a plurality of optical signals up to n.

As a result, optical wavelength division multiplexed signals (WDM signals) having wavelengths λ1, λ2 ... λn are transmitted through the single optical fiber F100.

This optical wavelength division multiplexed signal (WDM signal)
Are respectively output from the n output ports of the star coupler 102b to the n optical fibers F1 ... Fn.

Here, the optical wavelength division multiplexed signals (WDM signals) output from the output ports of the star coupler 102b to the optical fibers F1 ...
Optical subscribers TR of N subscriber homes 1 ... n through 12
12 ... Each optical receiving device R12 ... Rn2 in TRn2
Then, as described above, the second fiber grating FG
13 ... FGn3 and circulator CC13 ... CCn
3 in combination with each other, the optical signals of desired wavelengths among the first optical signals of wavelengths λ1 to λn are selectively extracted to be received separately.

Similarly, the optical signal of wavelength λ1 'emitted from the first optical transmitter T12 in the first optical transceiver TR12 on the side of the first subscriber's house 1 is as described above.
The signal is transmitted through the same optical fiber F1 via the coupler C12, and the star coupler 102 on the subscriber station 102 side is transmitted.
reach b.

The optical signal of this wavelength λ1 'is sent to the subscriber station 10
By passing through the star coupler 102b on the second side,
It is transmitted through a single optical fiber F100.

At this time, the optical signals of the wavelength λ1 'are transmitted from the optical transmitters T22 to Tn in the second to n-th optical transceivers TR22 ... TRn2 on the second to n-th subscriber homes 2 ...
2 is multiplexed with a plurality of optical signals emitted from

As a result, the wavelengths λ1 ', λ2' ... λn '
The optical wavelength division multiplexed signal (WDM signal) is transmitted through the single optical fiber F100.

This optical wavelength division multiplexed signal (WDM signal)
When passing through the AWG 101a on the relay station 101 side,
The optical signals are demultiplexed by the filter function of the WG characteristic and are output as the second optical signals of wavelengths λ1 ′, λ2 ′ ...
The n optical receivers R11 ... Rn1 in the n optical transceivers TR11 ... TRn1 on the side of the relay station 101 respectively receive from the n output ports of the WG 101a.

Next, the relay station 101 and the subscriber station 102
Then, the operation of the broadcast communication by the optical wavelength division multiplexing transmission as the transmission / reception of the optical signal between the n subscriber homes 1 ...

First, n optical transmitters / receivers T11 ... TRn1 in the n optical transmitters / receivers TR11.
Among Tn1, the optical signal emitted from the first optical transmitter T11 passes through the AWG 101a on the side of the relay station 101, and is transmitted through the single optical fiber F100 as an optical signal of wavelength λ1. .

At this time, the first optical transmitter T1 in the n optical transceivers TR11 ... TRn1 on the side of the relay station 101 is used.
The optical signals emitted from the optical transmitters 1 to 1 are wavelengths λ2 to λ emitted from the second to nth optical transmitters T21 to Tn1, respectively.
It is multiplexed with a plurality of optical signals up to n.

As a result, the optical wavelength division multiplexed signals (WDM signals) of wavelengths λ1, λ2 ... λn are transmitted through the single optical fiber F100.

In this case, for simplification of explanation, it is assumed that the optical signal of wavelength λn is set as the optical signal for broadcast communication.

Therefore, in this case, the above-mentioned single-fiber optical fibers F1 ... Fn are F1 ... Fn-1, and n subscriber homes 1 ... n are n-1 subscriber homes 1 ... N. As -1, it is assumed that the n-th optical fiber Fn and the n-th optical transceiver TRn2 installed in the n-th subscriber home n do not exist.

This optical wavelength division multiplexed signal (WDM signal)
Is an n-1 single optical fiber F1 ... Fn- from each output port of the star coupler 102b on the subscriber station 102 side.
1 is output separately.

Here, the optical signal of wavelength λn included in the optical wavelength division multiplexed signal (WDM signal) output from each output port of the star coupler 102b to the one optical fiber F1 ... The optical signals for the information communication are the optical transceivers TR12 ... of the subscriber homes 1 ... n-1.
Through the second fiber gratings FG13 ... FGn3 in the TRn2-1, the optical receivers R13 ... Rn3-1 for each broadcast communication, as described above, the third fiber gratings FG14 ... FGn4 and the circulators CC14 ... In combination with and, the optical signals of the desired wavelength λn are selectively extracted so that they are simultaneously received.

(Second Embodiment) FIG. 9 shows a short distance connecting a subscriber's home and a station in a one-fiber bidirectional optical wavelength division multiplexing transmission system applied as a second embodiment of the present invention. An array waveguide diffraction grating applicable to a one-core bidirectional optical wavelength division multiplexing transmission system for subscribers, which is improved in cost and efficiency by utilizing the circulation characteristic of AWG in an optical transmission system. Block diagram shown for explaining a connection configuration of an optical transceiver for a bidirectional optical wavelength division multiplexing transmission system having a broadcast communication function suitable for an optical access network using a type multiplexer / demultiplexer (AWG) and a star coupler Is.

That is, FIG. 9 shows a short-distance bidirectional optical transmission system for connecting a subscriber's house and a station in the one-fiber bidirectional optical wavelength division multiplexing transmission system applied as the second embodiment of the present invention. As shown, an array waveguide diffraction grating type multiplexer / demultiplexer (AWG) 101a is installed in the relay station 101, a star coupler 102b is installed in the subscriber station 102 side, and the relay station 101 and the subscriber station 102 are connected to each other. In the meantime, the one-to-one communication by the bidirectional optical wavelength division multiplexing transmission is performed by using the optical signal of the set of wavelengths satisfying the circulation characteristic of the wavelength pass band of the AWG 101a.

Also, in the second embodiment of the present invention, as will be described later, broadcast communication by optical wavelength division multiplex transmission is performed using an optical signal having a predetermined wavelength for broadcast communication. ing.

Then, in the second embodiment of the present invention,
N optical transceivers TR11 ... TRn1 on the side of the relay station 101
, Nn of optical transmitters T11 ... Tn1 in FIG. 1 respectively use fixed wavelength light sources WFS11 ... WFSn1 for individually emitting the first optical signals of wavelengths λ1 to λn, and at the subscriber homes 1 ... n side. n optical transceivers TR12
... n optical transmitters T12 ... Tn2 in TRn2
However, each of the wavelength fixed light sources WFS12 ... WFSn individually emits the second optical signals of wavelengths λ1 ′ to λn ′.
The second embodiment is the same as the above-described first embodiment except that 2 is used.

Therefore, also in the second embodiment, as in the first embodiment, the one-to-one communication by the bidirectional optical wavelength division multiplexing transmission and the optical wavelength division multiplexing transmission are performed. Broadcast communication can be performed.

Further, according to each of the embodiments of the present invention as described above, the number of optical fiber cores required as an optical fiber to be used as a single single-core optical fiber can be reduced, and the efficiency can be reduced. Can be used for various purposes.

Further, according to the first embodiment of the present invention as described above, an inexpensive broadband light source can be used due to the filter function of the AWG.

Further, according to each of the embodiments of the present invention as described above, since the passive element such as the AWG is used, the wavelength stability, the power saving, the increase / decrease wave / acceleration / deceleration of the transmitter / receiver are obtained. It has excellent expandability.

Further, according to each of the embodiments of the present invention as described above, it is possible to realize a leased line service without sharing a band.

[0105]

As described above, according to the present invention, therefore, a subscriber's house and a station are connected to each other in a bidirectional optical wavelength division multiplexing transmission system for bidirectional transmission using an optical fiber as a transmission medium. In a short-distance bidirectional optical transmission system, an array guide applicable to a single-fiber bidirectional optical wavelength division multiplexing transmission system for subscribers, which is improved in cost and efficiency by utilizing the circulation characteristics of AWG It is possible to provide an optical transceiver for a bidirectional optical wavelength division multiplexing transmission system having a broadcast communication function suitable for an optical access network using a waveguide diffraction grating type multiplexer / demultiplexer (AWG) and a star coupler.

[Brief description of drawings]

FIG. 1 is a view showing a single-core optical fiber used as a transmission medium,
In addition, 1 is set by using different wavelength bands in the down direction and the up direction.
FIG. 1 is a diagram showing a principle configuration of a one-core bidirectional optical wavelength division multiplexing transmission system that performs bidirectional transmission of channels.

2A is a diagram illustrating the transmission characteristics of a filter 2 and a filter 4 in FIG. 1, and FIG. 2B is a diagram illustrating the transmission characteristics of a filter 7 and a filter 8 in FIG. It is a figure which illustrates.

FIG. 3 is a diagram showing a case where a single optical fiber is used as a transmission medium,
FIG. 1 is a diagram showing a principle configuration of a one-core bidirectional optical wavelength division multiplexing transmission system that performs multichannel bidirectional transmission using different wavelengths in a downlink direction and an uplink direction.

4 (a) is a comb filter 1 in FIG.
2 and FIG. 4 are diagrams illustrating transmission characteristics of the comb filter 14, and FIG. 4B is a comb filter 17 in FIG.
9 is a diagram illustrating the transmission characteristics of a comb filter 18 and FIG.

FIG. 5 is a diagram illustrating a single-core bidirectional transmission in which a single optical fiber is used as a transmission medium and different wavelength bands are used in a down direction and an up direction as shown in FIG. FIG. 1 is a diagram showing a configuration when a bidirectional optical wavelength division multiplexing transmission system is applied to a short distance bidirectional optical transmission system for actually connecting a subscriber's home and a station.

FIG. 6 is an array waveguide diffraction grating type multiplexer / demultiplexer (A
The conventional long-distance backbone bidirectional optical transmission system, which is realized by adopting the optical wavelength division multiplexing (WDM) communication system using WG), is used as a short-distance optical transmission system for connecting subscriber homes and stations. It is a block diagram which shows the connection structure from the relay station A side to the subscriber station B when applied.

FIG. 7 is an AWG in a short-distance bidirectional optical transmission system for connecting a subscriber's home and a station in a one-fiber bidirectional optical wavelength division multiplexing transmission system applied as a first embodiment of the present invention. Array waveguide diffraction grating multiplexer / demultiplexer (AWG) applicable to a one-core bidirectional optical wavelength division multiplexing transmission system for subscribers, which is improved in cost and efficiency by utilizing the circulation characteristics of 2) and a star coupler are block diagrams shown for explaining a connection configuration of an optical transceiver for a bidirectional optical wavelength division multiplexing transmission system having a broadcast communication function suitable for an optical access network.

FIG. 8 is a diagram shown for explaining a function of a circulation characteristic of the AWG used in FIG.

FIG. 9 is an AWG in a short-distance bidirectional optical transmission system for connecting a subscriber's home and a station in a one-fiber bidirectional optical wavelength division multiplexing transmission system applied as a second embodiment of the present invention. Array waveguide diffraction grating multiplexer / demultiplexer (AWG) applicable to a one-core bidirectional optical wavelength division multiplexing transmission system for subscribers, which is improved in cost and efficiency by utilizing the circulation characteristics of 2) and a star coupler are block diagrams shown for explaining a connection configuration of an optical transceiver for a bidirectional optical wavelength division multiplexing transmission system having a broadcast communication function suitable for an optical access network.

[Explanation of symbols]

101 ... relay station, 102 ... Subscriber station, F100 ... a single optical fiber, 101a ... AWG, TR11 ... TRn1 ... Optical transceiver, T11 ... Tn1 ... n optical transmitters, R11 ... Rn1 ... n optical receiving devices, C11 ... Cn1 ... n couplers, 102b ... Star coupler F1 ... Fn ... n single-core optical fibers, 1 ... n ... n subscriber homes, T12 ... Tn2 ... n optical transmitters, R12 ... Rn2 ... n optical receiving devices, C12 ... Cn2 ... n couplers, TR12 ... TRn2 ... Optical transceiver, BPS12 ... BPSn2 ... Broadband light source, BPF11 ... BPFn1 ... Broadband pass filter, I11 ... In1 ... isolator, MOD11 ... MODn1 ... Optical modulator, OA ... Bidirectional optical amplifier, FG12 ... FGn2 ... first fiber grating, 102b ... an external star coupler, CC12 ... CCn2 ... First circulator, I12 ... In2 ... isolator, MOD12 ... MODn2 ... Optical modulator, FG13 ... FGn3 ... second fiber grating, CC13 ... CCn3 ... second circulator, WFS11 ... WFSn1 ... Fixed wavelength light source, WFS12 ... WFSn2 ... Fixed wavelength light source, FG14 ... FGn4 ... third fiber grating, CC13 ... CCn3 ... Third circulator, R13 ... Rn3 ... Optical receiving device for broadcast communication.

Claims (6)

[Claims] 1. A one-to-one correspondence between one of the first optical signals having a predetermined wavelength and the outside by bidirectional optical wavelength division multiplexing transmission.
And a pair of optical signals corresponding to a second optical signal having a predetermined wavelength different from the wavelength of the first optical signal from the outside and bidirectional optical multiplex transmission. (1) an optical transmitter for transmitting in order to carry out communication, and a broadcast communication for receiving an optical signal having a predetermined wavelength for broadcast communication with the outside in order to carry out broadcast communication by optical wavelength division multiplexing transmission An optical receiver is provided, wherein the first and second optical signals have external wavelengths of 1: 1 by bidirectional optical wavelength division multiplexing transmission of the first and second optical signals. An arrayed-waveguide diffraction grating having a predetermined wavelength passband loop characteristic for multiplexing and demultiplexing for communication and multiplexing the optical signal for the broadcast communication for the broadcast communication by optical wavelength division multiplexing transmission. Type multiplexer / demultiplexer (AW
G) is set as a set of wavelengths satisfying the circulation characteristic of the wavelength passband, and the optical transmission device is configured to perform the one-to-one communication with the outside by bidirectional optical wavelength division multiplexing transmission. One of the optical signals is the AW
The optical receiver is provided with a transmitting means for transmitting to an external star coupler connected to the G, and the optical receiver is connected to the external star coupler in order to perform one-to-one communication by bidirectional optical wavelength division multiplexing transmission. First extracting means for selectively extracting one optical signal of the first optical signals and guiding the one optical signal of the extracted first optical signals to the optical receiving device. The optical receiver for broadcast communication selectively selects an optical signal for broadcast communication from the external star coupler in order to perform broadcast communication with the outside by optical wavelength division multiplexing transmission. For bidirectional optical wavelength division multiplexing transmission system, characterized by comprising: second extracting means for extracting and extracting the extracted optical signal for the broadcast communication to an optical receiving device for the broadcast communication. Optical transceiver. 2. The optical transmission device is an optical transmission device that uses a broadband light source that emits a broadband optical signal that includes a wavelength in a predetermined range and does not include the circulating wavelength of the AWG. An optical transceiver for a bidirectional optical wavelength division multiplexing transmission system according to claim 1. 3. The bidirectional optical wavelength according to claim 1, wherein the optical transmission device is an optical transmission device using a fixed wavelength light source that separately emits an optical signal having a predetermined wavelength. Optical transmitter and receiver for division multiplexing transmission system. 4. The optical transmission device, the optical reception device, and the optical reception device for broadcast communication are respectively connected to the external star coupler via an internal coupler, and the optical transmission device has a predetermined configuration. A broadband light source that emits an optical signal in a wavelength range, and an optical signal having a predetermined wavelength in the second optical signals from the optical signal in the predetermined wavelength range that is emitted from the broadband light source, and the external signal is one-to-one. And a first fiber grating that is selectively extracted, and an optical signal of a predetermined wavelength of the second optical signals that is selectively extracted by the first fiber grating are passed therethrough. A first circulator; an isolator that allows an optical signal of a predetermined wavelength of the second optical signal that has passed through the first circulator to pass in one direction; and an isolator that has passed through the isolator. An optical modulator that applies predetermined optical modulation to an optical signal of a predetermined wavelength of the second optical signal and guides the optical signal to the external star coupler, and the optical receiving device is one-to-one with the external A second fiber grating for selectively extracting an optical signal of a predetermined wavelength from the first optical signal from the external star coupler, and a second fiber grating. A second circulator that selectively passes the optical signal of a predetermined wavelength among the first optical signals and guides the optical signal to the optical receiving device; and the optical receiving device for broadcast communication, A third fiber grating for selectively extracting the optical signal for the broadcast communication from the external star coupler for performing broadcast communication with the outside, and selectively by the third fiber grating Extraction The bidirectional optical wavelength according to claim 2, further comprising: a third circulator that passes the emitted optical signal for the broadcast communication and guides it to the optical receiver for the broadcast communication. Optical transmitter and receiver for division multiplexing transmission system. 5. The optical transmitter, the plurality of optical receivers, and the broadcast optical receiver are respectively connected to the external star coupler via an internal coupler, and the optical transmitter is A fixed wavelength light source that emits an optical signal having a predetermined wavelength of the second optical signal for one-to-one communication with the outside, and the second optical signal that is emitted from the fixed wavelength light source. An isolator for passing an optical signal having a predetermined wavelength in one direction in one direction, and performing a predetermined optical modulation on the optical signal having a predetermined wavelength of the second optical signal passing through the isolator. An optical modulator that leads to the external star coupler, wherein the optical receiving device determines a predetermined one of the first optical signals from the external star coupler in order to perform one-to-one communication with the outside. Optical signal with wavelength A first fiber grating selectively extracted, and an optical signal having a predetermined wavelength among the first optical signals selectively extracted by the first fiber grating are passed to the optical receiving device. A first circulator that guides the optical signal, wherein the optical receiver for broadcast communication selectively transmits the optical signal for broadcast communication from the external star coupler to perform broadcast communication with the outside. And a second fiber grating that is extracted by the second fiber grating, and a second fiber grating that selectively passes the optical signal for the broadcast communication selectively extracted by the second fiber grating and guides the optical signal to the optical receiving device for the broadcast communication. An optical transceiver for a bidirectional optical wavelength division multiplexing transmission system according to claim 3, further comprising a circulator. 6. The optical transmitter / receiver for a bidirectional optical wavelength division multiplexing transmission system according to claim 1, wherein the optical receiver for broadcast communication is removable as an option. apparatus.