KR20010003185A - Tuneable wavelength optical transceiver and its application on the subscriber loop system - Google Patents

Abstract

PURPOSE: A fiber loop carrier system using a wavelength variable optical transceiver is provided to increase the number of subscribers with new wavelength without the necessity of modifying each of the devices in operation and to select a desired service supply source, if necessary, by easily using time and wavelength multiplexing in common. CONSTITUTION: A service supply side section comprises a plurality of wavelength variable optical transceivers(1-5-1-7). A subscriber side section comprises a plurality of wavelength variable optical transceivers(12-1-12-3). The wavelength variable optical transceivers(1-5-1-7) and the wavelength variable optical transceivers(12-1-12-3) communicate through optical power couplers(3-4,3-5). Each wavelength variable optical transceiver is comprised of an optical band pass filter(7), an optical receiving diode(8), an electrical receiving part(10), an electrical transmitting part(11), a broadband light source(9) and an optical power coupler(3-6). The optical band pass filter(7) sets up central wavelength corresponding to a control signal. The optical receiving diode(8) converts an optical signal into an electrical signal. The electrical receiving part(10) receives the electrical signal from the optical receiving diode(8). The electrical transmitting part(11) provides a communication signal and outputs the control signal. The broadband light source(9) converts the communication signal into an optical signal. The optical power coupler(3-6) supplies the optical signal of the broadband light source(9) to the optical band pass filter(7) and provides an optical signal from the optical band pass filter(7) to the optical receiving diode(8).

Description

Optical subscriber transmission system using a variable wavelength optical transmission and reception device {TUNEABLE WAVELENGTH OPTICAL TRANSCEIVER AND ITS APPLICATION ON THE SUBSCRIBER LOOP SYSTEM}

The present invention relates to an optical subscriber transmission system, and more particularly, to an optical subscriber transmission system using a variable wavelength optical transmission and reception device.

In the optical subscriber transmission system, a transmission scheme in which multiple channels are multiplexed in time or multiplexes in a single optical path in order to increase optical transmission efficiency is used.

A method of multiplexing a plurality of channels in time among transmission schemes used in the optical subscriber transmission system is illustrated in FIG. 1A.

As shown, the time multiplexing optical subscriber transmission system of FIG. 1A includes a service supply side optical transmission and reception apparatus 1-1, a subscriber side optical transmission and reception apparatus 2-1, 2-2, 2-3, Optical power combiner (3-1) and optical path (4-1), (4-2), (4-3), (4-4), and the transmission process of the transmission system of this configuration receiving mode, That is, the case where the devices 2-1, 2-2, and 2-3 receive the information transmitted from the device 1-1 will be described.

First, when the receiving loop is formed, the service supply-side optical transmitting / receiving device 1-1 provides information (a, b, c) to be provided to the devices 2-1, 2-2, and 2-3. And sequentially transmit the information (a, b, c) with a time difference as shown. In this case, the transmitted information is wavelength modulated using the same wavelength. In other words, the device 1-1 is time multiplexing the information a, b, c using the same wavelength. The time multiplexed information a, b, c is provided to the optical power combiner 3-1 via the optical path 4-1.

The optical power combiner 3-1 transmits the multiplexed information a, b, and c by the subscriber line through the optical paths 4-2, 4-3, and 4-4. (2-1), (2-2) and (2-3).

Therefore, each subscriber-side optical transmitting / receiving device 2-1, 2-2, or 2-3 is provided with information a, b, and c, respectively, and the device 2-1, 2 -2), (2-3) can communicate by extracting only the information of the time promised from the information (a, b, c).

In the meantime, a case where the devices 2-1, 2-2, and 2-3 transmit information (a, b, c) to the device 1-1 will be described. 2-1, 2-2, and 2-3 transmit information a, b, and c at the time promised with device 1-1, respectively. c) is transmitted to the device 1-1 without colliding with each other.

On the other hand, in order for the information (a, b, c) to be transmitted / received in real time from each subscriber connected to the devices 2-1, 2-2, or 2-3, the devices 2 -1) (2-2), (2-3) should operate at a higher speed than the required speed (time required to transmit only one of the information a, b, c). In addition, in a time multiplexing optical subscriber transmission system, a transmission system is constructed and in operation, and there is a need to increase the number of subscribers, that is, devices 2-1, 2-2, and 2-3. In this case, in order to increase the number of subscribers, all the optical transceivers 2-1, 2-2, and 2-3 should be replaced with higher speed devices. Since it is generally proportional to the transmission speed, there is a problem that the cost of the optical transmission and reception device becomes expensive.

Meanwhile, FIG. 1B illustrates a case in which information (d, e, f) is transmitted in a wavelength multiplexing scheme, and the service supply side optical transmission and reception apparatuses 1-2, 1-3, 1-4, Subscriber side optical transmitter and receiver (2-4), (2-5), (2-6), optical power combiner (3-2), (3-3) and optical paths (4-5) to (4-11) The transmission process of the transmission system having such a configuration, that is, the information transmitted from the devices 1-2, 1-3, and 1-4; 2-5) and (2-6) will be described taking the case of receiving as an example.

First, when the receiving loop is formed, the service supply side optical transmitting / receiving devices 1-2, 1-3, and 1-4 are connected to the devices 2-4, 2-5, and 2-6. Each information (d, e, f) to be provided is generated, and the information (d, e, f) is simultaneously transmitted in correspondence with three wavelengths as shown. That is, the devices 1-2, 1-3, 1-4 and the devices 2-4, 2-5, 2-6 correspond to each other and each information is configured. It is to multiplex the wavelengths (d, e, f) by wavelength. The wavelength-multiplexed information (d, e, f) is provided to the optical power combiner (3-3) via the optical path (4-8).

The optical power combiner 3-3 receives the multiplexed information d, e, f for each wavelength through the optical paths 4-9, 4-10, and 4-11. (2-4), (2-5) and (2-6).

Thus, each subscriber-side optical transmitting and receiving device 2-4, 2-5, 2-6 is provided with information d, e, f, respectively, and the device 2-4, 2 -5) and (2-6) extract only the specified wavelength components and receive them.

On the other hand, devices 2-4, 2-5, and 2-6 provide information d, e, and f to devices 1-2, 1-3, and 1-4. For example, the apparatuses 2-4, 2-5, and 2-6 simultaneously transmit information (d, e, and f) modulated at different wavelengths. The optical power combiner 3-3 transmits this information d, e, f to the devices 1-2, 1-3 and 1-4, and the device 1-2. , (1-3), (1-4) extract and receive only predetermined wavelength components, respectively. Thus, the information (d, e, f) is transmitted to the device (1-2), (1-3), (1-4) without colliding with each other.

In the case of multiplexing by wavelength as described above, the service supply side optical transmission and reception apparatuses 1-2, 1-3, and 1-4 and the subscriber side optical transmission and reception apparatuses 2-4, 2-5, and ( 2-6) should use independent wavelength according to correspondence. Accordingly, the subscriber can transmit various wavelengths in order to communicate with the optical transmission / reception device of the service supply side (1-2), (1-3), (1-4) in which the desired service is provided. (2-4), (2-5), (2-6) are required.

However, in general, since a light source used for optical communication, such as a laser, has only one central wavelength in a narrow band, lasers emitting different wavelengths as necessary for wavelength multiplexing may be used for each optical transmission / reception apparatus 2-4, ( 2-5), (2-6). However, such a tunable laser device is very expensive and cannot be used, and as described above, each of the optical transmission and reception devices 2-4, 2-5, and 2-6 is fixed with one specific service supply side device. It has a structure that communicates (wavelength is fixed).

As described above, since the time multiplexing method uses a single wavelength, in order to increase the number of subscribers while maintaining the original service performance, there is a problem in that the subscriber optical transmission / reception device has to be replaced with a device having a higher transmission speed than before. In the case of the wavelength multiplexing scheme, there is a problem that subscribers cannot access various service providers because only one service provider is connected.

Accordingly, the present invention has been made to solve the above-mentioned problems, and by easily sharing time and wavelength multiplexing, it is possible to increase the number of subscribers by granting a new wavelength without changing each device in operation, as well as the service desired by the subscriber. It is an object of the present invention to provide an optical subscriber transmission system using a tunable transmission and reception device capable of selecting a source as needed.

That is, the present invention provides an optical subscriber transmission system using a wavelength tunable optical transceiver, comprising: a service supply side section including a plurality of wavelength tunable optical transceivers; A subscriber side section including a plurality of variable wavelength optical transmission and reception devices; An optical power combiner for multiplexing an optical signal generated from a wavelength tunable optical transceiver within a service supply side section and a wavelength tunable optical transceiver within a subscriber side section, wherein the wavelength tunable optical transmitter / receiver sets a center wavelength corresponding to a control signal. An optical band pass filter for transmitting and receiving a signal having a set center wavelength; A light receiving diode for converting an applied optical signal into an electrical signal; An electrical receiver for receiving an electrical signal from the photoreceiving diode; An electrical transmitter for providing a predetermined communication signal and outputting a control signal; A broadband light source for converting a communication signal of an electrical transmitter into a broadband optical signal; And an optical power combiner for providing an optical signal of a broadband light source to a central wavelength variable optical band pass filter and providing an optical signal from the central wavelength variable optical band pass filter to an optical receiving diode. to provide.

1A is a block diagram of a conventional optical subscriber transmission system employing a time multiplexing scheme;

1B is a block diagram of a conventional optical subscriber transmission system employing a wavelength multiplexing scheme;

2 is a block diagram of an optical subscriber transmission system using a wavelength tunable optical transmission and reception device according to a preferred embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

1-1 to 1-7: Optical transmitter and receiver on service supply side

2-1 to 2-6: subscriber's optical transceiver

3-1 to 3-6: Optical power combiner

4-1 to 4-18: optical path

5-1 to 5-3: optical waveguide

6-1 to 6-3: electric line

12-1 to 12-3: wavelength variable optical transmission and reception device

7: Center wavelength variable optical band pass filter

8: photoreceive diode

9: broadband light source

10: electrical receiver

11: electrical transmitter

The above and other objects and various advantages of the present invention will become more apparent from the preferred embodiments of the present invention described below with reference to the accompanying drawings by those skilled in the art.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

Prior to the description, the present invention is a technique that can be applied to the subscriber-based optical transmission, and as shown in FIG. 2, each device is installed in the service supply side section, the optical line section, and the subscriber side section. In addition, for convenience of description, it is assumed that the number of optical transmitting and receiving devices and the number of input / output terminals of the optical power combiner are three. First, the optical transmission / reception apparatuses 1-5, 1-6, and 1-7 installed on the service supply side have wavelengths different from each other, that is, (1-5) has wavelengths 1 and (1-6). ) Assumes that wavelength 2 and (1-7) are different from wavelength 3.

Here, the tunable optical transmission / reception apparatus 12-1, 12-2, and 12-3 according to the present embodiment are the center wavelength tunable optical bandpass filter 7, the optical power combiner 3-6, Optical receiving diode 8, electrical receiver 10, broadband light source 9, electrical transmitter 11, optical waveguide 5-1, 5-2, 5-3, electric line 6- 1), (6-2), and (6-3).

The operation process of the optical subscriber transmission system having such a configuration will be described in more detail by classifying it as a transmission / reception process. In this case, the reception means a case where information is transmitted from the devices 1-5, 1-6, and 1-7 to the devices 12-1, 12-2, and 12-3. The term "transmission" refers to a case in which information is transmitted from the devices 12-1, 12-2, and 12-3 to the devices 1-5, 1-6, and 1-7. It is called.

First, the signal processing process at the time of reception is demonstrated.

Signals generated by the service supply-side optical transmitting / receiving devices (1-5), (1-6), and (1-7) pass through optical paths 4-12, (4-13), and (4-14), respectively. Multiplexed at power combiner 3-4 and delivered to optical path 4-15, optical power combiner 3-5, optical path 4-16, 4-17, and 4-18. .

The optical signal input through the optical path 4-17 is filtered only by the wavelength variable optical transmission / reception apparatus, for example, each of the central wavelength variable optical band pass filters 7 in (12-2). The optical wavelength filtered by the central wavelength variable optical band pass filter 7 is set by the control of the electrical transmitter 11 as described later.

Accordingly, the wavelength-variable transceiver 12-1, 12-2, and 12-3 control the filtering wavelength of the central wavelength-variable optical bandpass filter 7 so that the service supply-side optical transmitter / receiver 1-5 is controlled. Signals from (1-6) and (1-7), that is, desired signals may be received among signals transmitted with different wavelengths. In this case, for example, the transceiver 1-5 transmits information as wavelength 1, and the optical band pass filter 7 in the transceivers 12-1, 12-2, and 12-3 is all present. If the wavelength 1 is set to filter, the signal of the transceiver 1-5 is advantageously transmitted to the transceiver 12-1, 12-2, and 2-3, while the transceiver The problem arises when (1-5) only wants to transmit to the device 12-2. This problem can be solved by using a time multiplexing method that has been used in the past. That is, when the transceiver 1-5 wants to transmit respective information to the optical transceiver 12-1, 12-2 using the wavelength 1, it allocates different time to these information, It is easily solved by a time multiplexing method in which the signal of 1 is time-divided and each piece of information is transmitted to the transmission / reception apparatus 12-1 and 12-2.

On the other hand, the optical signal passing through the center wavelength variable optical bandpass filter 7 sequentially performs the optical waveguide 5-1, the optical power combiner 3-6, the optical waveguide 5-2, and the optical receiving diode 8. The electrical signal is converted into an electrical signal, which is transmitted to the electrical receiver 10 through the electric line 6-2 and received as predetermined information.

The remaining wavelength-variable optical transmission / reception apparatus 12-1 and 12-3 also perform the same operation process as described above, and thus description thereof is omitted.

Next, the signal processing process at the time of transmission is demonstrated.

When a communication signal from the electrical transmitter 11 in the tunable optical transmitter / receiver 12-2 is applied to the wide bandwidth light source 9 through the electric line 6-3, the electrical signal is converted into a wide bandwidth optical signal. do. At this time, the bandwidth of the wide bandwidth light source 9 is wider than the sum of the wavelength components required by the transmission system, such a light source 9 can be implemented as a light emitting diode.

The electrical transmitter 11 outputs not only the above-described communication signal but also a control signal necessary for varying the center wavelength of the center wavelength variable optical band pass filter 7, and the control signal is transmitted through the electric line 6-1. The optical band pass filter 7 is passed to.

On the other hand, the wide bandwidth optical signal is transmitted to the center wavelength variable optical band pass filter 7 through the optical waveguide 5-3, the optical power combiner 3-6, and the optical waveguide 5-1 in sequence.

The center wavelength variable optical band pass filter 7 includes the service supply side optical transmission and reception apparatuses 1-5, 1-6, and 1-7 corresponding to the control signals of the electrical transmitter 11 as described above. Only the optical signal in the wavelength band that can communicate is passed through the optical path (4-17).

The optical signal provided through the optical path 4-17 is provided by the optical power combiner 3-5, the optical path 4-15, the optical power combiner 3-4, the optical path 4-12, 4 -13) and (4-14) to the respective optical transmitting and receiving devices 1-5, 1-6, and 1-7.

Therefore, in the service supply side optical transmission / reception apparatuses 1-5, 1-6, and 1-7, only signals of the corresponding light wavelengths (wavelength 1, wavelength 2, wavelength 3) as shown in the graph of Fig. 2 are selected. To receive it.

On the other hand, in the transmission mode, the optical transmission / reception apparatus 12-1, 12-2, and 12-3 can transmit respective pieces of information at the same wavelength using a time multiplexing scheme, and thus the optical transmission / reception apparatuses in time-multiplexing manner. According to the present invention, the information of (12-1), (12-2), and (12-3) can be time-divided and transmitted to the optical transmission / reception apparatuses 1-5, 1-6, and 1-7. Those skilled in the art will readily know.

In addition, the time multiplexing method is an easy matter for a person having ordinary knowledge in the technical field of the present invention, and thus detailed description thereof is omitted.

The remaining wavelength-variable optical transmission / reception apparatus 12-1 and 12-3 also perform the same operation process as described above, and thus description thereof is omitted.

As described above, since the present invention can be used by mixing time and wavelength multiplexing, there is an effect that it is possible to increase the number of subscribers without changing the subscriber device. In addition, the present invention can increase the flexibility in access to the service because the wavelength can be changed in the subscriber device, as well as the effect of overcoming the constraints of the wavelength selection of the optical transmission and reception device when receiving services in other areas by moving the residential area There is.

Claims (1)

In the optical subscriber transmission system using a variable wavelength optical transmission and reception device, I) a service supply side section having a plurality of variable wavelength optical transmission / reception devices 1-5, 1-6, and 1-7; Ii) a subscriber side section including a plurality of variable wavelength optical transmission and reception devices 12-1, 12-2, and 12-3; I) wavelength-tunable optical transmission / reception apparatuses (1-5), (1-6), (1-7) in the service-providing section and the wavelength-variable optical transmission / reception apparatus 12-1, (12-2) in the subscriber-side section; 12-3 communicate via optical power combiners 3-4, 3-5, The wavelength variable type optical transmission and reception device, a) an optical band pass filter 7 for setting a center wavelength corresponding to a control signal and transmitting and receiving a signal having the set center wavelength; b) a light receiving diode 8 for converting an applied optical signal into an electrical signal; c) an electrical receiver (10) for receiving an electrical signal from the photoreceive diode (8); d) an electrical transmitter 11 for providing a predetermined communication signal and outputting the control signal; e) a broadband light source 9 for converting the communication signal of the electrical transmitter 11 into a broadband optical signal; f) providing the optical signal of the broadband light source 9 to the central wavelength variable optical band pass filter 7 and the optical signal from the central wavelength variable optical band pass filter 7 to the optical receiving diode 8 And an optical power combiner (3-6) provided to the optical subscriber transmission system.