JP2003209622A - Hybrid optical transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a configuration capable of providing xDSL (x digital subscriber line) services to the users who receives only conventional telephone services. <P>SOLUTION: In a transmission system for xDSL services, which a telephone signal using a predetermined frequency band and a xDSL signal using a frequency band higher than the predetermined frequency band have to be multiplexed and transmitted, at least a plurality of xDSL signals are converted into a plurality of electric signals of different frequency bands by a frequency converter 207, and a plurality of electric signals of different frequency bands are multiplexed at a synthesizer 208, and then they are converted into optical signals by an electrical-optical converter 209 to be transmitted over an optical fiber transmission path 211, and they are reconverted into xDSL signals by an optical-electrical converter 211, a splitter 216, and a frequency converter 218. <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 hybrid optical transmission system in which xDSL (x Digital Subscriber Line) signals flowing on metallic lines are multiplexed and transmitted on an optical fiber.

[0002]

2. Description of the Related Art In recent years, xDSL (x Digital Subscriber Line) has attracted attention as a means for connecting to a high-speed Internet. xDSL is a high-speed digital communication technology using twisted pairs,
By using a band different from the voice band, this is a technique for transmitting / receiving a signal modulated in a wide band through an existing analog telephone network (metallic cable).

This xDSL technology is classified into several types depending on the signal speed, the difference in modulation method, and the like. For example, SDSL up and down speed of up to about 2Mbps
(Symmetric Digital Subscriber Line) or A with a maximum uplink speed of approximately 1 Mbps and a maximum downlink speed of approximately 8 Mbps
DSL (Asymmetric Digital Subscriber Line), which has an uplink speed of up to 6 Mbps and a downlink speed of up to 55 Mbps
VDSL (Very High-Bit-Rate Digital Subscriber Line)
and so on.

Regarding the details of these xDSL technologies, for example, the publication “xDSL / FTTH textbook”, the first edition in 1999, and the “xDSL access technology”, the Institute of Electronics, Information and Communication Engineers Vol 8
4, No2 (February 2001) p. 84-91.

Next, an example of a general ADSL service configuration will be described with reference to FIG. In the user's house in FIG. 6,
A splitter 104 for demultiplexing the frequency band used by the telephone 103 and the frequency band used by xDSL in the analog electric signal flowing through the existing metallic line, and xDSL for performing modulation / demodulation between the digital electric signal from the PC 102 and the xDSL signal. A modem 101 is provided.

In addition, in the accommodation station, in order to connect the telephone signal from the user's house to the existing telephone network, a splitter 105 for demultiplexing the electric signal in which the telephone signal and the xDSL signal are multiplexed from the user's house. Switch 106 and a DSLAM 107 for terminating xDSL signals from a plurality of user homes.

By using these devices, xDSL can be provided between the user's home and the accommodation station while coexisting with the existing telephone network.
It becomes possible to connect by signal, and it becomes possible to provide a high-speed Internet connection.

On the other hand, as another means for providing a high-speed access line, FTTH (Fiber) using an optical fiber transmission line is used.
To The Home) is entering the practical stage. this is,
Connect the telecommunications carrier's office to the home with an optical fiber,
It provides a high-speed Internet connection environment.

However, the cost of the optical fiber and the construction cost for laying are much higher than those of the existing metallic line. For this reason, a hybrid optical transmission system in which an optical fiber is laid from a telecommunications carrier's office to a point where a cable called a "feeding point" goes up from an underground pipeline to the ground, and then connected by an existing metallic line. Is widespread.

This system is characterized in that it can efficiently accommodate an existing metallic telephone line and can promptly deal with the case where an optical fiber is pulled into a house.

However, since the present hybrid optical transmission system is designed mainly for efficiently accommodating the existing telephone network, the xDSL signal that uses a higher frequency band than the telephone is used. Cannot pass through this hybrid optical transmission system. Therefore, a user (generally called optical accommodation) accommodated in this hybrid optical transmission system is
Cannot receive the service of.

[0012]

As a method of enjoying the xDSL service in such a hybrid optical transmission system, generally, ONU (Opt.
DSL, which was conventionally placed at the station company, on the side of a device called an optical network unit) that converts electrical signals and optical signals.
A method in which an AM is installed and an xDSL signal is terminated and processed can be considered.

However, in this DSLAM, xDSL
It is necessary for each user to perform complicated processing such as signal modulation / demodulation, format conversion, and demultiplexing. For this reason,
From the viewpoint of its size and power consumption, it is very difficult to accommodate it on the side of the ONU where space saving is required.

In addition, since the service specifications of the xDSL service may be changed in the future, workers must go to the ONU device installed in a remote place to repair or replace the infrastructure each time. Is very inefficient. Therefore, it is desired that the DSLAM device be installed at the bureau as much as possible.

In view of the above problems, there has been a demand for a method of realizing an ONU device which is small in size and has low power consumption and which can pass an xDSL signal.

[0016]

In order to solve such a problem, a first electric signal using a predetermined frequency band, such as an xDSL service, and a first electric signal using a frequency band higher than the predetermined frequency band are used. In the transmission system in which two electrical signals are required to be multiplexed and transmitted, the hybrid optical transmission system of the present invention is configured to convert at least a plurality of second electrical signals into a plurality of electrical signals in different frequency bands. A first frequency converter, a combiner for multiplexing a plurality of electric signals of different frequency bands output from the plurality of frequency converters, and each of the above-described multiplexed output from the combiner An electric / optical conversion device for converting a plurality of electric signals in different frequency bands into optical signals, an optical fiber transmission line for transmitting the optical signals, and the optical fiber transmission An optical / electrical converting device for converting the optical signal output from the optical / electrical converting device into a plurality of multiplexed electric signals of different frequency bands, and the multiplexed different frequencies output from the optical / electrical converting device. Distributor for separating a plurality of electric signals of a band into a plurality of electric signals of different frequency bands, and a plurality of electric signals of the different frequency bands output from the distributor to the second electric signals. And a plurality of second frequency converters for converting. Then, the first electric signal described above is also converted into an optical signal by the electric / optical conversion device in the same manner as the second electric signal in the state of being individually or multiplexed with the second electric signal, and then transmitted through the optical fiber. Transmission through the road, then light /
The electric conversion device converts the first electric signal.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) FIG. 1 shows an example of the configuration of an xDSL service in the first embodiment of the present invention. In FIG. 1, as an example, user homes 1, 2, ...
It shows a configuration in which a plurality of N electrical signals are multiplexed by an RO (Remote Office) installed at a feeder and accommodating an ONU, and are connected to an accommodating station.

In the configuration shown in FIG. 1, the optical fiber transmission line 211 extends from the accommodation station to the feeder point (RO in the figure).
Are connected to the user homes 1, 2, ...
· Up to N are connected by conventional metallic wires.

.., N, for example, the user house 1, the frequency band used by the telephone 203 and the xDSL in the analog electric signal flowing through the existing metallic line.
Splitter 204 that demultiplexes the frequency band used in
And an xDSL modem 201 for performing modulation / demodulation between the digital electric signal from the PC 202 and the xDSL signal.

An RO accommodating a plurality of user homes 1, 2, ..., N receives an electrical signal in which a telephone signal from each user home 1, 2, ..., N and an xDSL signal are multiplexed. , A plurality of splitters 20 for separating telephone signals and xDSL signals respectively
5. Telephone line card 206 which is a terminating device for multiplexing a plurality of separated telephone signals by using a technique such as AD conversion and time division multiplexing. E / O converter 210 for converting the information of the multiplexed telephone signal into an optical signal in which it is superimposed, separated xD
A frequency converter 207 for converting an SL signal into a different frequency region for each user signal, a combiner 208 for electrically multiplexing the frequency-converted xDSL signal for each user, and a subcarrier component for the multiplexed xDSL signal. E to convert the multiplexed xDSL signal information into an optical signal superimposed
An optical fiber transmission line 211 for connecting the O / O converter 209 and the RO to the accommodating station is provided.

Then, this RO and the optical fiber transmission line 211
The O / E converter 213 for converting an optical signal in which a telephone signal is multiplexed into an electric signal is connected to the accommodation station connected with the telephone, which is a terminal device for separating the multiplexed telephone signal for each user. Line card 214, exchange 215 for connecting telephone signals to the telephone network, O / E converter 212 for converting optical signals in which xDSL signals are multiplexed into electric signals, multiplexed xD
Distributor 21 that distributes SL signals for each user
6, a frequency filter 217 for extracting only different predetermined frequency components from the multiplexed xDSL signal, and the frequency domain converted by the frequency converter 207 is the original xD.
A frequency converter 218 for converting the SL signal into the frequency domain,
And D for terminating the xDSL signals of multiple users
SLAM 219 is provided.

Next, the operation when the xDSL signal and the telephone signal are sent from the user homes 1, 2, ...

First, in each of the user homes 1, 2, ..., N, the data transmitted from the PC 202 is the xDSL modem 2
At 01, modulation into an xDSL signal is performed and converted into a broadband analog signal. At this time, the frequency band used for the xDSL signal is, for example, 25 in the case of ADSL.
If the band from KHz to 1,100 KHz is VDSL, 138 KH
The z-12 MHz band is used. Meanwhile, the regular phone 203
The frequency band used for the telephone signal is less than 4 KHz. In this way, since the xDSL signal uses a frequency band higher than the frequency band used for the telephone signal, the telephone signal and the xDSL signal are multiplexed by the splitter 204 without interference.

The multiplexed telephone signal and xDSL signal are
Telephone signal and xDSL again at splitter 205 in RO
Separated into signals. This splitter 205 is installed by the number of users that can be accommodated in RO, and is split into a telephone signal and an xDSL signal for each user.

The telephone line card 206 is composed of an AD converter for converting an analog signal into a digital signal, a time division multiplexer for multiplexing a user signal for each time slot, and the like, and a telephone separated by the splitter 205. The signals are multiplexed by this device as telephone signals for multiple users.

The multiplexed telephone signal is converted into an optical signal by the E / O converter 210 for converting an electric signal into an optical signal, and is transmitted to the accommodation station by the optical fiber transmission line 211. As the device for multiplexing / opticalizing the telephone signal, it is possible to use the device used in the conventional optical transmission system that opticalizes up to the feeder.

On the other hand, the plurality of xDSL signals for each user separated by the splitter 205 are converted into frequency regions different from the original xDSL frequency arrangement by the frequency conversion device 207 corresponding to each user.

The details of this conversion are shown in FIG. In FIG. 2, details of the conversion process for multiplexing the ADSL signals of users 1, 2, ..., N are shown. And ADSL
The user use band per person is 1,100 KHz which is the use frequency band of the signal.

From FIG. 2, the frequency conversion device 207 causes the frequency domain of the ADSL signal of the user 2 to 1,100 KHz.
Is converted into the frequency range of 2,200 KHz to 3,300 KHz. The reason why the frequency range after conversion of the user 2 is not set to 1100 KHz to 2200 KHz is that a guard band is provided to prevent mutual interference due to side lobes or the like.

Similarly, the ADSL signal of user N is also E /
Maximum frequency that O converter 209 can oscillate (1GHz in the example)
It can be seen that the frequency domain has been converted. The ADSL signal of the user 1 is not converted from the original frequency domain, so it is not necessary to connect it to the frequency conversion apparatus 207. However, the oscillation characteristic of the E / O conversion apparatus 209 does not have linearity and the frequency domain is unchanged. Then, if the loss becomes large, it is necessary to convert to another frequency domain.

The ADSL signals thus converted into different frequency regions for each user are electrically combined by the combiner 208 without interfering with each other, and the E / O converter 20 is provided.
Converted to an optical signal by 9.

In FIG. 2, the details of the conversion processing are described by taking the ADSL signal as an example as described above, and therefore, 1,100K.
Hz is used as a user use band per person. Therefore, it is necessary to change the user use band per person and the setting of the frequency domain to be converted according to the type of xDSL. For example, when applying this configuration to a VDSL signal,
Since the frequency band used by each user is about 12 MHz, the frequency range of user 2 after frequency conversion is 2
It becomes 4MHz-36MHz.

By the above processing, the telephone signals of a plurality of users and the xDSL signal are multiplexed, respectively, and the optical fiber transmission line 21
It becomes possible to transmit to the accommodation station by using 1.

In FIG. 1, an optical fiber transmission line for transmitting an optical signal obtained by converting a multiplexed telephone signal and an optical fiber transmission line for transmitting an optical signal obtained by converting a multiplexed xDSL signal. Although the paths are expressed as individual configurations, it is possible to use the same optical fiber transmission path by applying WDM technology or the like.

Next, in the accommodation station, the multiplexed telephone signals of a plurality of users converted into optical signals are converted into original electric signals by the O / E converter 213 which converts the optical signals into electric signals. It Then, the multiplexed telephone signals of the plurality of users, which are converted into the electric signals, are transmitted to the telephone line card.
The telephone signal of each user is separated by 214 and connected to the telephone network by exchange 215.

On the other hand, the multiplexed xDSL signals of a plurality of users converted into optical signals are converted into original electric signals by the O / E converter 212. Then, the multiplex DSL signals of the plurality of users converted into the electric signals are distributed by the distributor 216 for the number of users.

In the distributed xDSL signal, the xDSL signals of a plurality of users are electrically multiplexed, so that the frequency filter 217 removes components other than the frequency converted for each user. Then, x converted into a predetermined frequency region that has passed through the frequency filter 217
The frequency converter 218 converts the DSL signal into the original xD signal.
Frequency range of SL signal (ADSL: ~ 1,100KH
z, VDSL is converted to ~ 12MHz).

The xDSL signal converted into the original frequency domain is a DSL for terminating the xDSL signals of a plurality of users.
It is terminated by AM219 and is connected to the Internet as a digital signal. By such an operation, it becomes possible to transmit the xDSL signal even for a user who has made the light up to the feeder line.

As described above, according to this embodiment, in the RO in which the ONU is installed, the xDSL signal is electrically frequency-converted, then multiplexed, and converted into an optical signal. It is possible to provide the xDSL service even to the optical accommodating user who can only provide the telephone service.

Further, when the xDSL signal is multiplexed, frequency conversion and multiplexing are performed electrically as an analog signal as compared with time division multiplexing, which requires A / D conversion.
Hardware downsizing and power saving can be realized.

Further, since it becomes possible to install the DSLAM in the conventional accommodating station instead of the RO, it is necessary to send a worker to the RO to repair or replace the base even when the specifications of the xDSL service are changed. Disappears.

The signal flow described with reference to FIG. 1 describes only the upstream signal from the user's house to the accommodation station. The downlink signal from the accommodating station to the user's house can be bidirectionally executed by providing the same configuration as that shown in FIG.

FIG. 3 shows an example of the configuration of a downlink xDSL service in the first embodiment. In FIG. 3, the same components as those in FIG. 1 are designated by the same reference numerals. Although there is no big difference in the basic configuration, since the signal flow is reversed, the distributor 217 is provided on the RO side, and the predetermined frequency different from each of the xDSL signals multiplexed in the subsequent stage. A frequency filter 217 for extracting only the component is arranged.

More specifically, a telephone line card 206 for multiplexing a plurality of telephone signals, and a first E / O for converting a plurality of multiplexed telephone signals output from the telephone line card 206 into optical signals. Converter 210, optical fiber transmission line 21 for transmitting an optical signal in which a plurality of telephone signals are multiplexed
1, the optical signal output from this optical fiber transmission line 211,
O / E converter for converting multiple telephone signals multiplexed
213, a telephone line card 214 for separating a plurality of multiplexed telephone signals output from the O / E converter 213 into a plurality of telephone signals.

Further, a plurality of frequency converters 207 for converting a plurality of xDSL signals into a plurality of electric signals of different frequency bands, and a plurality of frequency converters 207 output from the plurality of frequency converters 207, respectively, of different frequency bands. A combiner 208 that multiplexes electric signals, and outputs from this combiner 208,
E / O converter 209 for converting a plurality of multiplexed electric signals of different frequency bands into optical signals, optical fiber transmission line 211 for transmitting the optical signals, and optical fiber transmission line 211
The optical signal output from the O / E converter 212 for converting the optical signal output from the above into a plurality of multiplexed electrical signals of different frequency bands, and each of the multiplexed outputs output from the O / E converter 212 A distributor 216 and a frequency filter 217 for separating a plurality of electric signals in different frequency bands into a plurality of electric signals in different frequency bands, and converting the separated plurality of electric signals in different frequency bands into xDSL signals. Multiple frequency converters 218, multiple telephone signals and multiple x
And a plurality of splitters 204 for respectively multiplexing the DSL signals and outputting a plurality of multiplexed electric signals.

(Second Embodiment) FIG. 4 shows an example of the configuration of the xDSL service in the second embodiment of the present invention. The basic configuration is similar to the configuration of FIG. 1 of the first embodiment, and a plurality of electric signals of user homes 1, 2, ..., N are installed at feeder points to accommodate ONUs. RO (Remote Office)
Shows a configuration in which they are multiplexed with each other and connected to the accommodation station. The difference from the first embodiment is that a splitter 415 is provided on the accommodation station side instead of the splitter 205 installed in RO in FIG.

Each user home 1, 2, ..., N has a first
The frequency band used by the telephone 403 and x
A splitter 404 for demultiplexing the frequency band used in DSL and an xDSL modem 401 for performing modulation / demodulation between the digital electric signal from the PC 202 and the xDSL signal are provided.

The RO accommodating a plurality of user homes 1, 2, ..., N receives an electrical signal in which the telephone signal from each user home 1, 2 ,. Frequency converter 405 for converting each user's signal into a different frequency domain, a combiner 406 for electrically multiplexing the frequency-converted user's signal, and converting the multiplexed user's signal into an optical signal. An E / O converter 407 and an optical fiber transmission line 408 connecting the RO and the accommodating station are provided.

Then, this RO and the optical fiber transmission line 408
An O / E converter 409 for converting an optical signal into an electric signal, telephone signals of a plurality of users, and x are connected to the accommodation station connected by.
Distributor 410 for distributing electric signals in which DSL signals are multiplexed only for users, multiplexed multiplexed telephone signals and xDS
A frequency filter 413 for extracting only different predetermined frequency components from the L signal, a frequency conversion device 414 for converting the frequency domain converted by the frequency conversion device 405 into the original telephone signal and the frequency domain of the xDSL signal, the telephone signal and x.
A splitter 415 for separating the DSL signal, a telephone line card 411 which is a terminating device for receiving the telephone signal of each user separated by the splitter 415, an exchange 412 for connecting the telephone signal to a telephone network, and xDSL of a plurality of users. A DSLAM 416 is provided for terminating the signal.

Next, the operation of the configuration shown in FIG. 4 will be described. The basic operation is the same as that of the first embodiment. Further, unlike the first embodiment, since the splitter 415 is installed on the accommodation station side, the RO frequency conversion device 40
In 5, the frequency range of the telephone signal is 0-4KHz and xD
Frequency range of SL signal (~ 1,100 for ADSL signal)
KHz) is treated as an electric signal of each user of 0 to 1,100 KHz without being separated, and conversion to a different frequency domain is performed for each electric signal of each user. After that, as in the first embodiment, the combiner 406 and the E / O converter 407 are used to multiplex the electrical signals of the respective users and convert them into optical signals, and the optical fiber transmission path 408 sends the signals to the accommodation station. Is sent.

Next, in the accommodation station, the optical signal in which the telephone signals of a plurality of users and the xDSL signal are multiplexed is converted into an electric signal by the O / E converter 409, and is distributed to each user by the distributor 410. To be done. Since the distributed electric signals also include the signals of other users whose frequencies have been converted,
The frequency components of other users are removed by the frequency filter 413. The electrical signal from which the signals of other users have been removed is converted by the frequency conversion device 414 into the original telephone signal and x.
Frequency range of DSL signal (0 to 1,1 for ADSL signal)
00KHz, VDSL signal is converted to 0-12MHz).

The electrical signal converted into the original frequency domain is separated by the splitter 415 into a telephone signal and an xDSL signal. The separated xDSL signal is terminated by the DSLAM 416 and connected to the Internet as a digital signal. A telephone line card with similarly isolated telephone signals
It is input to 411 and is connected to the existing telephone network via the exchange 412. By such an operation, similarly to the first embodiment, the xDSL even for the user whose light is illuminated up to the feeder line point.
It becomes possible to transmit a signal.

According to the configuration of the second embodiment, in addition to the effects of the first embodiment, the splitter and telephone line card installed in the RO in the first embodiment are accommodated by the accommodating station. By installing it on the side, it is expected that the hardware configuration of the RO will be smaller and the power consumption will be reduced. Further, in the RO, the telephone signal and the xDSL signal are collectively frequency-converted and multiplexed, so that the optical fiber transmission line connecting the RO and the accommodating station can be shared, and the installation cost of the optical fiber can be reduced. .

Note that the signal flow described in FIG. 4 described above describes only the upstream signal from the user's house to the accommodation station, as in FIG. The downlink signal from the accommodating station to the user's house can be bidirectionally executed by providing the same configuration as that shown in FIG.

FIG. 5 shows an example of the configuration of a downlink xDSL service in the second embodiment. In FIG. 5, the same components as those in FIG. 4 are designated by the same reference numerals. Although there is no big difference in the basic configuration, since the signal flow is reversed, the distributor 410 is provided on the RO side, and the predetermined frequency different from each of the user signals multiplexed in the subsequent stage. A frequency filter 413 for extracting only the component is arranged.

[0056]

According to the hybrid optical transmission system of the present invention, a first electric signal using a predetermined frequency band and a second electric signal using a frequency band higher than the predetermined frequency band, such as an xDSL service. In a transmission system that needs to be multiplexed with a signal to be transmitted, at least a plurality of second electric signals are converted into a plurality of electric signals in different frequency bands by a frequency conversion device, and then multiplexed to perform electric / optical conversion. Since the optical fiber transmission line is transmitted by using the device and the optical / electrical conversion device, it is possible to realize a configuration capable of providing the xDSL service even to the optical accommodating user who can only perform the telephone service in the related art. It will be possible.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration example of an xDSL service in a first embodiment of the present invention.

FIG. 2 is a diagram showing details of frequency conversion in the first embodiment.

FIG. 3 is a configuration diagram showing a configuration example of a downlink xDSL service in the first embodiment.

FIG. 4 is a configuration diagram showing a configuration example of an xDSL service in the second exemplary embodiment of the present invention.

FIG. 5 is a configuration diagram showing a configuration example of a downlink xDSL service in a second embodiment.

FIG. 6 is a configuration diagram showing an example of a general ADSL service configuration.

[Explanation of symbols]

201, 401 xDSL modem 202,402 PC 203,403 telephone 204, 205, 404, 415 splitter 206, 214, 411 Telephone line card 207, 218, 405, 414 Frequency converter 208,406 synthesizer 209, 210, 407 E / O converter 211,408 Optical fiber transmission line 212,213,403 O / E converter 215, 412 switch 216,410 distributor 217, 413 frequency filter 219,416 DSLAM

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5K002 AA01 AA03 AA06 BA04 BA05                       DA02 DA08 FA01                 5K022 AA03 AA12 AA22                 5K051 AA05 AA09 BB02 CC00 DD07                       DD12 DD14 FF07 JJ01 JJ02                       JJ03 JJ12 KK01

Claims (5)

[Claims] 1. A plurality of transmissions, each transmitting a multiplexed electric signal in which a first electric signal using a predetermined frequency band and a second electric signal using a frequency band higher than the predetermined frequency band are multiplexed. Path, a plurality of splitters that respectively input a plurality of the multiplexed electrical signals and separate into the first electrical signal and the second electrical signal, and a plurality of the first plurality of splitters output from the plurality of splitters. A first terminating device that multiplexes an electric signal, and a first electric / optical device that converts the plurality of multiplexed first electric signals output from the first terminating device into a first optical signal. A converter, a first optical fiber transmission line for transmitting the first optical signal, and a plurality of first multiplexed optical signals output from the first optical fiber transmission line First optical / electrical conversion device for converting into an electric signal of A second terminating device that separates the plurality of multiplexed first electrical signals output from the first optical / electrical conversion device into the plurality of first electrical signals; A plurality of first frequency conversion devices that convert the plurality of second electric signals that are output to a plurality of electric signals that have different frequency bands; and the different frequency bands that are output from the plurality of frequency conversion devices And a second electric / optical converter for converting the plurality of multiplexed electric signals of different frequency bands output from the combiner into a second optical signal. A device, a second optical fiber transmission line for transmitting the second optical signal, and a second optical signal output from the second optical fiber transmission line in the multiplexed different frequency bands For multiple electrical signals A second optical / electrical conversion device for converting the plurality of electric signals of the different frequency bands, which are multiplexed, and output from the second optical / electrical conversion device. And a plurality of second frequency converters for respectively converting the plurality of electric signals of the different frequency bands output from the distributor into the second electric signals. Hybrid optical transmission system. 2. A first transmission line for transmitting a plurality of first electric signals using a predetermined frequency band, a first terminating device for multiplexing the plurality of first electric signals, and the first A first electric / optical conversion device for converting the plurality of multiplexed first electric signals output from the terminating device into a first optical signal; and a first electric / optical conversion device for transmitting the first optical signal. An optical fiber transmission line; a first optical / electrical conversion device for converting the first optical signal output from the first optical fiber transmission line into the plurality of multiplexed first electric signals; A second terminating device that separates the plurality of multiplexed first electric signals output from the first optical / electrical conversion device into the plurality of first electric signals; and the predetermined frequency band. A second transmission path for transmitting a plurality of second electric signals using a high frequency band, A plurality of first frequency conversion devices for converting the plurality of second electric signals into a plurality of electric signals in different frequency bands, and a plurality of the different frequency bands output from the plurality of frequency conversion devices. A combiner that multiplexes electric signals; a second electric / optical conversion device that converts the plurality of multiplexed electric signals of different frequency bands output from the combiner into second optical signals; A second optical fiber transmission line for transmitting the second optical signal; and a plurality of electric signals of different frequency bands in which the second optical signal output from the second optical fiber transmission line is multiplexed. A second optical / electrical conversion device for converting into a signal; and a plurality of the multiplexed multiple electric signals of different frequency bands output from the second optical / electrical conversion device. To an electrical signal A divider that is separated from each other; a plurality of second frequency conversion devices that respectively convert the plurality of electric signals of the different frequency bands output from the distributor to the second electric signals; and the plurality of first frequency converters. A hybrid optical transmission system comprising: an electric signal; and a plurality of splitters for respectively multiplexing the plurality of second electric signals and outputting a plurality of multiplexed electric signals. 3. The hybrid optical transmission system according to claim 1, wherein the first optical fiber transmission line and the second optical fiber transmission line are the same optical fiber transmission line. Optical transmission system. 4. A plurality of transmissions each transmitting a multiplexed electric signal in which a first electric signal using a predetermined frequency band and a second electric signal using a frequency band higher than the predetermined frequency band are multiplexed. Path, a plurality of first frequency conversion devices for converting the plurality of multiplexed electric signals into a plurality of electric signals in different frequency bands, respectively, and the different first frequency conversion devices output from the plurality of first frequency conversion devices. A combiner for multiplexing a plurality of electric signals in a frequency band, and an electric / electrical converter for converting the plurality of multiplexed electric signals in different frequency bands outputted from the combiner into an optical signal
An optical converter, an optical fiber transmission line for transmitting the optical signal, and an optical / electrical device for converting the optical signal output from the optical fiber transmission line into a plurality of multiplexed electric signals of different frequency bands. A converter for separating the plurality of multiplexed electric signals of different frequency bands output from the optical / electrical converter into a plurality of electric signals of different frequency bands; A plurality of second frequency converters for respectively converting the plurality of output electric signals of different frequency bands into the multiplexed electric signals; and inputting the plurality of multiplexed electric signals, respectively. A hybrid optical transmission system, comprising: a plurality of splitters for separating a signal and the second electric signal. 5. The hybrid optical transmission system according to claim 1, wherein the first electric signal is an analog electric signal used in a telephone, and the second electric signal is a digital subscriber line. A hybrid optical transmission system characterized by being a digital electric signal used in.