JPH0354930A - Optical branching device and optical transmission path network - Google Patents

Abstract

PURPOSE:To obtain an economical and highly reliable equipment by using an optical signal as it is for switching processing. CONSTITUTION:An optical signal inputted from an input terminal 11 is divided into two directions by an optical divider 21, one is outputted to an output terminal 13 through an exciting light multiplexer 22, an eluvium doping fiber 29, etc., and the other is outputted to an output terminal 15 through exciting light multiplexers 28, 30, an eluvium doping fiber 29, and so on. The fiber 29 amplifies the optical signal and control light by the incidence of exciting light, but optical signal transmitting optial fibers 330, 331 are disconnected by the control light. When the control light from a control light transmitting optical fiber 36 is stopped, the saturated light of the fiber 29 is reset, the optical signal made incident through the multiplexer 28 is amplified and projected, the fibers 330, 331 are connected, and a short-circuiting route is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical branching device and an optical transmission line network that are used in an optical transmission line network using optical fiber cables and switch transmission lines.

? 2. Description of the Related Art In order to configure a bus-type optical transmission line network, an optical branching device including an optical repeater for amplifying attenuated optical signals and a switch for switching optical signal transmission lines is required.

FIG. 6 is a bronc diagram showing an example of the configuration of a conventional optical branching device.

In the figure, an optical cable 61 serving as a trunk line. ,6l3 is
Optical fiber 521.524 and power supply line 59■? It is composed of 9■. The optical cable 61 serving as a branch line is composed of optical fibers 522 and 523.

The optical branching device 60 includes optical fibers 52+. A photoelectric conversion circuit 53 that converts the optical signal input from 52a into an electrical signal.
．． 55, electro-optical conversion circuits 54 and 56 that convert electrical signals output to optical fibers 52χ and 524 into optical signals, and optical fibers 52. , 524 are connected to optical fibers 52■.
52, or a short-circuit path connecting the optical fibers 52 and 524, and an electric processing circuit 58 that performs amplification and other processing, and the power supplied from the feeder line 59, respectively. A power supply circuit 57 that supplies power to the circuit is provided.

Note that the optical branching device 60 is normally used as an optical signal branching means of an optical transmission line network in which a branch line is connected to a trunk line to form a bus-type optical transmission line.

Here, if a break or other failure occurs in the branch optical cable 61■, the electrical processing circuit 58 connects the optical fiber 521 to the optical fiber. The transmission path is switched to a short-circuit path connecting the optical cable 524, and the transmission path is switched to disconnect the optical cable 61■.

(Problem to be Solved by the Invention) By the way, for example, in a submarine relay transmission network using submarine optical cables, the optical branching equipment required when establishing a bus-type or star-type optical transmission network is not suitable for a long period of time. High reliability is required because it must operate without maintenance.However, in conventional optical branching equipment, each circuit uses many parts including semiconductor elements, and the required In order to ensure reliability, it is necessary to make the reliability of a large number of parts h extremely high, which makes the optical branching device expensive.

Furthermore, since the transmission line is normally monitored at the landing station, it is necessary to separately secure a transmission line for sending control information for switching the transmission line.

The present invention solves these conventional problems, and aims to provide an optical branching device that uses light to control switching of optical signal transmission paths, and an optical transmission line network that uses this optical branching device. The purpose is

[Means to solve the problem]

FIG. 1 is a principle block diagram of an optical branching device according to claim 1.

In the figure, the main optical signal input/output section is connected to the main line and inputs and outputs the optical signal of the first wavelength, and the branch line is connected to the branch line and inputs and outputs the optical signal to be added and dropped from the main line. An optical signal input/output section, a branching means for switching between a branch path connecting the main optical signal input/output section and the branch optical signal input/output section, and a short circuit path connecting the main optical signal input/output sections. The optical branching device includes a control light input section into which a control light of a second wavelength different from the first wavelength is manually input via a branch line, and the branching means receives the optical signal from the main optical signal input/output section. An optical branching element that branches into a branch path and a short-circuit path and sends an optical signal from the branch path or short-circuit path to the main optical signal input/output section, and an excitation light of a predetermined wavelength that is driven by power supplied from the main line. It is inserted into a short-circuit path with a light source for excitation light that generates a
and an optical amplification element that performs amplification control of an optical signal in accordance with the incidence of control light.

FIG. 2 is a principle block diagram of the optical transmission network according to claim 2.

In the figure, a bus-shaped main line including an optical fiber that transmits an optical signal of a first wavelength and a feeder line that supplies power;
There are main line end local parts installed at both ends of the main line that transmit and receive transmission information and supply power, and branch lines that are branched from the bus-like main line and include optical fibers that return and transmit optical signals that are added and dropped to the main line. In an optical transmission network that includes a branch line end local section that extracts and inserts transmission information at the end of the branch line, and an optical signal branching means that branches and short-circuits the optical signal at the connection between the main line and the branch line, the optical signal The branching means is constituted by the optical branching device according to claim 1, and a control light light source that generates control light of the second wavelength is installed at a local end of the branch line, and the branch line transmits the optical signal and the control light. We plan to do so.

Further, the optical branching device according to claim 3 includes a main optical signal input/output unit connected to the main line and into which the optical signal of the first wavelength is input/output, and a branch line connected to the main line and added/dropped between the main line and the main line. A branch optical signal input/output section to which optical signals to be transmitted are input/output, a branch path connecting between the main optical signal input/output section and the branch optical signal input/output section, and a branch path connecting the main optical signal input/output sections. An optical branching device comprising a branching means for switching between a short-circuit path and a short-circuit path, including a control light input section into which control light of a second wavelength different from the first wavelength is manually input via a branch line, and the branching means an optical branching element that branches an optical signal from an optical signal input/output section into a branch path and a short circuit path, and sends an optical signal from the branch path or short circuit path to a main optical signal input/output section; A first optical amplification element that is excited by the pumping light incident from the branch optical signal input/output section and amplifies the optical signal, and a first optical amplification element that is inserted into the short circuit path and excited by the pumping light incident from the main optical signal input/output section. state, and is equipped with a second optical amplification element that performs amplification control 1111 of the optical signal in response to the incidence of the control light.

Further, the optical transmission line network according to claim 4 includes a bus-like main line including an optical fiber that transmits an optical signal of a first wavelength, and main line ends that are provided at both ends of the main line and that transmit and receive transmission information. A branch line including an optical fiber that is branched from a bus-like main line and returns and transmits optical signals that are added and dropped to and from the main line, and a branch line end local part that extracts and inserts transmission information at the end of this branch line. , an optical transmission line network comprising optical signal branching means for branching and short-circuiting optical signals at a connection between a main line and a branch line,
The optical signal branching means is constituted by the optical branching device according to claim 3, in which a pumping light light source for generating pumping light is installed in the main line end local part, and a second wavelength control device is installed in the branch line end local part. A light source for control light that generates light and a light source for excitation light that generates excitation light are installed, and the trunk line is configured to transmit optical signals and excitation light, and the branch lines transmit optical signals, excitation light, and control light. The pumping light to be input to the first optical amplification element of the optical branching device is made to enter the branch optical signal input/output section of the optical branching device via the branch line from the pumping light light source at the local end of the branch line. The excitation light incident on the second optical amplification element is transmitted from the excitation light source at the local end of the main line through the main line, and from the excitation light source at the local end of the adjacent branch line through the branch line, the optical branching device, and the main line. The configuration is such that the main optical signal is input to the main optical signal input/output section.

(Function) In the optical branching device according to claim 1, a branching path and a short-circuiting path are formed through the optical branching element and the optical amplifying element, in which the optical signal is processed as it is.

Here, the optical amplifying element inserted into the short-circuit path is excited by the pumping light and amplifies the input optical signal.
Its gain is controlled by control light (OPC '89
POSTDEADLINE PAPER↑HURSD
AY, FEBRUARY 9, 1989. PD1
5” A 212km NON-REPETEDEr
+3 DOPE DFIBER AMPLIFIER
SIN AN IM/DIRECT-DET
ECTION REPETEI? SYSTEM'
K. IIAGIMOTO et al.).

In other words, when the branch line is connected normally and the control light is being input, the optical amplification element becomes saturated with its output due to this control light, and there is almost no gain for the optical signal, and a transmission path using a branch path is established. . Furthermore, when the branch line is cut and the control light is cut off, the optical amplification element amplifies the optical signal, forming a transmission line with a shortened path.

In this way, the optical branching device according to the first aspect can directly perform automatic switching and amplification of transmission lines as optical signals.

The optical transmission network according to claim 2 uses the optical branching device according to claim 1 as an optical signal branching means of a bus-type optical transmission network, and the optical branching device has a control provided at a branch line end local part. By taking in the control light from the light source through the optical fiber of the branch line, it becomes possible to automatically switch to a short circuit path when the branch line is cut, for example. Furthermore, switching and amplification of optical signals on the transmission path can all be processed as they are as optical signals.

In the optical branching device according to claim 3, whereas the optical branching device according to claim 1 includes a light source for excitation light inside thereof,
A system is adopted in which excitation light is supplied from the outside (main line and branch line) together with the optical signal, and a first optical amplification element and a second optical amplification element that amplify the optical signal with excitation light are installed in the branch path and short-circuit path, respectively. Therefore, when the branch line is connected normally, the pump light is supplied from the branch line to the first optical amplification element, and the control light is supplied from the main line to the first optical amplification element. While the excitation light is supplied to the second optical amplification element,
Since the control light that creates the output saturation state is supplied from the branch line, a transmission line using a branch path is formed in the same way.

On the other hand, if the branch line is cut, the first optical amplifying element is no longer supplied with pumping light and stops functioning as an optical amplifying element, and the second optical amplifying element, which is supplied with pumping light from the main line, is Since the control light is no longer incident on the amplification element, a transmission path with a short circuit path is formed in the same way.

In other words, the optical branching device according to the third aspect of the present invention can directly perform automatic switching and amplification of transmission lines as they are optical signals.

The optical transmission network according to claim 4 uses the optical branching device according to claim 3 as an optical signal branching means of a bus-type optical transmission line, and the optical branching device has a main line end local part and a branch line end local part. By adopting a configuration in which excitation light is taken in from the provided excitation light light source via the main line and branch line, and control light is taken in from the control light light source provided at the local end of the branch line via the branch line, the branch line can be It becomes possible to automatically switch to a short circuit path upon disconnection. Furthermore, switching and amplification of optical signals on the transmission path can all be processed as they are as optical signals.

[Example] Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 3 is a block diagram showing the configuration of an embodiment of the optical branching device according to claim 1.

In the figure, the optical branching device of this embodiment has an optical fiber 33 for optical signal transmission serving as a trunk line. , 331, an optical signal input terminal 11, an optical signal output terminal 15, and an optical signal transmission optical fiber 35 serving as a branch line. , 351 respectively connected to the optical signal output terminal 13 and the optical signal input terminal l4.
The optical signal transmission path is switched between a branch path and a short-circuit path.

Wavelength 1.55 Cμ input manually from optical signal input terminal 11
m] is output in two directions via the optical divider 21.

This one optical signal passes through the excitation light multiplexer 22, and is output to the optical signal output terminal l3 via the erbium-doped fiber 23 and the 1.55 μm wavelength light passing filter 24.

Further, the optical signal manually inputted from the optical signal input terminal l4 is transmitted through a light passing filter 24 with a wavelength of 1.55 μm. , through the erbium-doped fiber 25, further passes through the pump light multiplexer 26, is input to the optical coupler 27, and is output to the optical signal output terminal l5.

The other optical signal output from the optical divider 2l has a wavelength of 1.
．． The light passes through a 55 μm light passing filter 243 and further passes through a control light multiplexer 28 and enters an erbium-doped fiber 29 . The optical signal emitted from the erbium-doped fiber 29 passes through the pump light multiplexer 30 and has a wavelength of 1.5.
The signal is inputted to the optical coupler 27 via the 5 μm light passing filter 31 and outputted to the optical signal output terminal 15.

Mains power supply! tfA34. The semiconductor laser 37 to which power is supplied from the power supply terminal 12 connected to the power supply terminal l2 connected to the power supply line 34 and the power supply terminal 16 connected to the power supply line 34 has a wavelength of 1.48 [μm
] outputs excitation light. This excitation light is transmitted through the optical divider 38
The light beams are incident on the pumping light multiplexers 22, 26, and 30 via the optical fibers, reflected by each, and incident on the corresponding erbium-doped fibers 23, 25, and 29.

In addition, the wavelength 1 that is transmitted from the control light input terminal l7 connected to the control light transmission optical fiber 36 installed alongside the branch line
．． 53 C μm] is reflected by the control light multiplexer 28 and enters the erbium-doped fiber 29.

Here, the principle block diagram of the present invention shown in FIG.
The correspondence relationship with the example configuration diagram shown in the figure is shown.

The light source for excitation light is the semiconductor laser 37, the optical branching element is the optical divider 21 and the optical coupler 27, the optical amplification element is the erbium dove fiber 29, and the main optical signal input/output section is the optical signal input terminal 11 and the optical coupler 27. Signal output terminal 1
5, the branch optical signal input/output section is the optical signal output terminal 13 and the optical signal input terminal l4, and the control light input section is the control light input terminal 17. In this embodiment, the erbium-doped fibers 23 and 25 are inserted into the branch path, but this is for optically amplifying the branch optical signal depending on the length of the branch line and other conditions. , is not necessarily required as an optical branching device.

In addition, an optical divider 38, excitation light multiplexers 22, 26, 30
The control optical multiplexer 28 efficiently transfers the optical signal and the excitation light or control light to the erbium-doped fibers 23, 25,
This is a configuration for injecting the light into No. 29. Furthermore, the wavelength is 1.55
μm light passing filter 24. 243 blocks the excitation light emitted from the erbium-doped fiber 29, and the 1.55 μm wavelength light passing filter 3l blocks the control light emitted from the erbium-doped fiber 29.

The erbium-doped fiber 29 emits excitation light (wavelength 1.4
8 Cμm)) enters an excited state, and light fS (wavelength 1.55 (μm)) and control light (wavelength 1.5
3 (μm)), but the output becomes saturated due to the control light, and there is almost no gain with respect to the optical signal. That is, apparently, the optical fiber 3 for optical signal transmission
3. and an optical fiber for optical signal transmission 33. becomes disconnected.

On the other hand, since the erbium-doped fibers 23 and 25, which are excited by the incidence of the pumping light (wavelength 1.48 (μm)), amplify the optical signal, the optical fiber 33. , 33+, an optical fiber 35 for optical signal transmission serving as a branch line. , 35. It is possible to form a bus-type transmission path to which the

When the control light from the control light transmission optical fiber 36 is stopped, the erbium-doped fiber 29 is no longer saturated, so the optical signal that is input through the control light multiplexer 28 is amplified and output. The emitted optical signal is outputted to the optical fiber 33 for optical signal transmission via the excitation light multiplexer 30, the wavelength 1.55 μm light passing filter 31, the optical coupler 27, and the optical signal output terminal 15, and is output to the optical fiber 33 for optical signal transmission, and is output to the optical fiber 33 for optical signal transmission. Optical fiber 33 for signal transmission. A short circuit path to which the optical fiber 33I for optical signal transmission is connected can be defined.

FIG. 4 is a block diagram showing the configuration of an embodiment of the optical branching device according to claim 3.

Components similar to the optical branching device shown in FIG. 3 are designated by the same reference numerals, and their description will be omitted.

The feature of this embodiment is that the optical signal transmission optical fiber 33 serves as the trunk line for pumping light (wavelength 1.48 Cμml) supplied to each erbium-doped fiber 23, 25, 29 in the optical branching device. , 33, and an optical signal transmission optical fiber 35 serving as a branch line. , 35, wavelength-multiplexed into optical signals (wavelength: 1.55 Ctt m)), and has no excitation light source (semiconductor laser 37) inside. That is, the light source for excitation light is the optical fiber 33 for optical signal transmission which becomes the main line. , 331, the optical fiber 3 for optical signal transmission serves as a main line end local part and a branch line.
Provided at the local end of the branch line connected to 5.351.

In addition, in this embodiment, control light (wavelength 1.53 Cμm) for controlling the erbium-doped fiber 29 in the short-circuit path is used.
It is also assumed that the optical signal and the excitation light are wavelength-multiplexed and input from the optical signal transmission optical fiber 35, which is a branch line. Therefore, in this embodiment, the control light input section and the branch optical signal input/output section are the same, and the optical filter 70 separates only the control light and makes it enter the control light multiplexer 2.
However, the optical signal input terminal 14 and the erbium-doped fiber 2
The structure is inserted between 5 and 5.

With such precautions, under normal conditions (when no fault has occurred in the branch line), the erbium-doped fibers 23 and 25 inserted into the branch path become the optical signal transmission optical fiber 35 that becomes the branch line. , 351 (wavelength 1)
．． 48 Cμm)), the optical signal (wavelength 1
．． 55 Cμm]).

In addition, the erbium-doped fiber 29 inserted into the short-circuit path receives the residual part of the pumping light supplied to the erbium-doped fiber of another adjacent optical branching device, and the pumping light emitted from the local end of the main line, which becomes the main line. Optical fiber for signal transmission 33. , 33, and performs an amplification operation on the short-circuited optical signal (wavelength 1.55 (μm)), but at the same time, the control light (wavelength 1.53 Cμm)) is passed through the optical filter 70 and the control light combiner. The light is input to the erbium-doped fiber 29 via the waveguide 28, and similarly operates to block the optical signal.

On the other hand, the optical fiber 35o35 for optical signal transmission which becomes a branch line
, when a disconnection failure or the like occurs and the optical signal, control light, and pumping light supplied from the local end of the branch line to the optical branching device are cut off, the pumping light is no longer supplied to the erbium-doped fibers 23 and 25, and the optical The signal is almost blocked. Further, although control light is no longer supplied to the erbium-doped fiber 29, the optical signal transmission optical fiber 33 serves as a trunk line.

Since pumping light is supplied from 331, it functions as an optical amplification element for optical signals, forming a short circuit path.

? FIG. 5 is a block diagram showing the configuration of an embodiment of the optical transmission network according to claim 2.

Note that this example shows a bus-type submarine optical transmission network in which optical signals with a wavelength of 1.55 Cμm are transmitted, and the optical branching device used has the configuration of the optical branching device shown in Fig. 3. but,
The same applies to the case where the optical branching device shown in FIG. 4 is used.

In FIG. 5, the landing station 40 and the landing station 40■
is an optical fiber 33 for optical signal transmission, which serves as a trunk line. ~33■
and a power supply line 34. ~34■ and optical branching device 44,,4
Connected via 4■.

The optical branching devices 44I and 44■ have optical fibers 35 for optical signal transmission serving as branch lines. 35, and landing stations 403, 40. through control light transmission optical fibers 36l, 362. is connected. Note that here, for ease of explanation, it is assumed that the optical signal is transmitted in the direction from the landing station 40 to the landing station 402.

The landing station 40 is a transmission terminal device 41 that outputs an electrical signal obtained by converting the information to be transmitted into a transmission path code. , this electrical signal is converted into an optical signal with a wavelength of 1.55 Cμm] and an optical fiber 33 for transmitting the optical signal. an electro-optical conversion circuit 42 and a power supply line 34. The power supply circuit 43 is connected to the power supply circuit 43.

The landing station 40■ has a photoelectric conversion circuit 49 that converts an optical signal with a wavelength of 1.55 Cμm input from the optical fiber 33■ for optical signal transmission into an electrical signal, and extracts transmitted information from this electrical signal. The transmission terminal device 50 and the feeder line 3
4. The power supply circuit 51 is connected to the power supply circuit 4.

The landing stations 403 and 404 have optical fibers 3 for transmitting optical signals.
5. , 35 ■ A photoelectric conversion circuit 46, 4 that converts a manually generated optical signal with a wavelength of 1.55 (μm) into an electrical signal.
6■, and an information extraction/insertion unit 47, , 47■ that extracts the information transmitted from this electrical signal and inserts the information to be transmitted.
Then, the electrical signal into which information is extracted and inserted is transmitted at a wavelength of 1.55 C.
An optical fiber 35 for converting into an optical signal of [μm] and transmitting an optical signal,
, 35, an electro-optical conversion circuit 48, , 4B2
Equipped with.

Furthermore, the feature of the present invention according to claim 2? Landing station 40. , 40. has a wavelength of 1.53 (μ
m] control light is generated, and the control light transmission optical fiber 36
Control light beams tA 451, 45 are provided to be sent to the respective optical branching devices 44+, 44■ via 1, 362.

Here, the correspondence between FIG. 2 and FIG. 5 will be shown. The main line end local areas are landing stations 40l, 40■, and the branch line end local areas are landing stations 403, 40. The optical signal branching means are optical branching devices 44, 44■, and the control light light source is the control light light source 4.
5. , 45■.

The control light with a wavelength of 1.53 (μm) is transmitted to the optical branching device 44I,
44■, the optical fiber 33 for optical signal transmission. , an optical fiber for optical signal transmission 33 , an optical fiber for optical signal transmission 331 , and an optical fiber for optical signal transmission 33 . is apparently cut off, creating a branching route.

From the landing station 40 on the transmitting side to the optical fiber 3 for optical signal transmission
3. The optical signal sent to is sent to the optical fiber 35 for optical signal transmission via the optical branching device 441. is output to the landing station 4.
03. Landing? At 403, a photoelectric conversion circuit 46. and information extraction insertion section 47. The information to be transmitted is extracted and inserted via the electro-optical conversion circuit 4, and an optical signal with a wavelength of 1.55 Cμm is sent again from the electro-optical conversion circuit to the optical branching device 441 via the optical fiber 35 for optical signal transmission. Transmit.

This optical signal is transmitted to the optical branching device 44. The signal is output from the optical fiber 33 for optical signal transmission.

Similarly, the optical signal transmitted to the optical branching device 44■ is sent to the landing station 444 and the optical fiber 33 for optical signal transmission.
It is transmitted to the landing station 40 (2) on the receiving side via (2).

Here, for example, the optical fiber 35 for optical signal transmission between the optical branching device 441 and the landing station 403. , 351 and the submarine optical cable including the control light transmission optical fiber 361 is cut, the supply of control light to the optical branching device 44 is stopped. As a result, the optical branching device 44. Now, the optical fiber 33 for optical signal transmission as described above. , 33, can be formed to disconnect the landing station 40.

In this way, even if the branch submarine cable is cut, the transmission path can be automatically switched.

In addition, in the optical transmission line network according to claim 4, the landing station 40
The landing stations 40z, 404 are equipped with excitation light sources that generate excitation light with a wavelength of 1.48 (μm), and the landing stations 40z, 40
4 is equipped with a control light light source that generates control light with a wavelength of 1.53 (μm), and is connected to a predetermined optical fiber (in the above embodiment, an optical fiber for optical signal transmission in order to wavelength-multiplex the optical signal). The other configurations and operations will be explained in the same manner.

Further, in this embodiment, a bus-type optical transmission network has been described, but a similar optical branching device and optical transmission network can also be configured in a star-type optical transmission network.

〔Effect of the invention〕

As described above, the optical branching device according to claim 1 is capable of automatically switching the branching route or the short-circuiting route of the transmission line, and also performs all the switching processing and amplification processing using optical signals as they are. Therefore, it is possible to provide an economical and highly reliable optical branching device, which has excellent stability and can significantly reduce the number of electrical circuit components.

Further, in the optical transmission network according to claim 2, the optical branching device of the present invention is used in a bus-type optical transmission line, and the control light is transmitted to the optical branching device using an optical fiber attached to an optical fiber for optical signal transmission serving as a branch line. By transmitting the information to the branch line, it can be easily disconnected in the event of a branch line disconnection or other failure.

Further, in the optical branching device according to claim 3 and the optical transmission line network according to claim 4, a light source for excitation light of the optical branching device is further unnecessary, and reliability can be improved due to a reduction in the number of parts. .

In this way, a highly reliable optical transmission line network can be constructed, making it possible to keep the downtime rate of the entire transmission line network low. Furthermore, when applied to a submarine optical transmission line network, the installation work can be simplified by downsizing the optical branching device.

Further, such optical branching devices and optical transmission line networks are considered to be effective in application to coastal routes or large-scale optical LANs on the ocean floor and on land.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the principle of the invention according to claim 1. FIG. 2 is a block diagram of the principle of the invention according to claim 2. FIG. 3 is a block diagram showing an embodiment of the optical branching device according to claim 1. FIG. 4 is a block diagram showing an embodiment of the optical branching device according to claim 3. FIG. 5 is a block diagram showing an embodiment of the optical transmission network according to claim 2. FIG. 6 is a diagram showing an example of the configuration of a conventional optical branching device. 11, 14... Optical signal input terminal, 12, l6... Power supply terminal, 13, l5... Optical signal output terminal, l7...
Control light input terminal, 21, 38... optical divider, 22,
26, 30...pumping light multiplexer, 23, 25, 29...
・Erbium dove fiber, 24, 31...wavelength 1
．． 55 μm light passing filter, 27... optical coupler,
28... Control light multiplexer, 33, 35... Optical fiber for optical signal transmission, 34... Power supply line, 36... Optical fiber for control light transmission, 37... Semiconductor laser, 40...・
Landing station, 41, 50... Transmission terminal equipment, 42, 48
...Electro-optical conversion circuit, 43, 51, 57... Power supply circuit, 44, 60... Optical branching device, 45... Light source for control light, 46, 53, 55... Photo-electrical conversion circuit , 47・
...Information extraction insertion section, 54, 56...Electro-optical conversion circuit, 58...Electrical processing circuit, 61...Optical cable, 7
0... Optical filter. Branch line Figure 1 Main line Figure 2 Figure 6

Claims (4)

[Claims] (1) A trunk optical signal input/output section that is connected to the trunk line and inputs and outputs the optical signal of the first wavelength, and a branch line that is connected to the branch line and inputs and outputs the optical signals that are added/dropped to and from the trunk line. Branching means for switching between an optical signal input/output section, a branch path connecting between the trunk optical signal input/output section and the branch optical signal input/output section, and a short circuit path connecting between the trunk optical signal input/output sections. an optical branching device comprising: a control light input section into which control light of a second wavelength different from the first wavelength is input via the branch line; an optical branching element that branches the optical signal from the output section to the branch path and the short circuit path, and sends the optical signal from the branch path or the short circuit path to the main optical signal input/output section; and electric power supplied from the main line. a pumping light light source that is driven by a pump and generates pumping light of a predetermined wavelength; and a pumping light light source that is inserted into the short-circuit path, is brought into an excited state by the incidence of the pumping light, and amplifies the optical signal in response to the incidence of the control light. An optical branching device characterized by comprising an optical amplifying element that performs control. (2) A bus-shaped main line that includes an optical fiber that transmits an optical signal of the first wavelength and a feeder line that supplies power, and a main line terminal section that is installed at both ends of this main line and that sends and receives transmitted information and supplies power. a branch line branching from the bus-like main line and including an optical fiber for returning and transmitting optical signals that are added and dropped to and from the main line; and a branch line end local part that extracts and inserts transmission information at the end of the branch line. , an optical transmission line network comprising an optical signal branching means for branching and short-circuiting an optical signal at a connection part between the main line and the branch line, wherein the optical signal branching means is constituted by the optical branching device according to claim 1. An optical transmission line network, characterized in that a control light light source that generates control light of a second wavelength is installed at a local end of the branch line, and the branch line is configured to transmit an optical signal and control light. (3) A trunk optical signal input/output section that is connected to the trunk line and inputs and outputs the optical signal of the first wavelength, and a branch line that is connected to the branch line and inputs and outputs the optical signal that is added/dropped to and from the trunk line. Branching means for switching between an optical signal input/output section, a branch path connecting between the trunk optical signal input/output section and the branch optical signal input/output section, and a short circuit path connecting between the trunk optical signal input/output sections. an optical branching device comprising: a control light input section into which control light of a second wavelength different from the first wavelength is input via the branch line; an optical branching element that branches an optical signal from the output section to the branch path and the short circuit path, and sends an optical signal from the branch path or the short circuit path to the main optical signal input/output section; , a first optical amplification element that is excited by the excitation light incident from the branch optical signal input/output section and amplifies the optical signal; and a first optical amplification element that is inserted into the short circuit path;
and a second optical amplification element that is brought into an excited state by the excitation light incident from the main optical signal input/output section and performs amplification control of the optical signal in response to the input of the control light. Optical branching device. (4) a bus-like main line including an optical fiber that transmits an optical signal of a first wavelength; a main line end local section provided at both ends of this main line for transmitting and receiving transmission information; and a main line branched from the bus-like main line. , a branch line including an optical fiber that returns and transmits optical signals that are added/dropped to and from the main line, a branch line end local section that extracts and inserts transmission information at the end of the branch line, and a connecting part between the main line and the branch line. In an optical transmission line network comprising an optical signal branching means for branching and short-circuiting an optical signal, the optical signal branching means is constituted by the optical branching device according to claim 3, and the main line end local part is provided with pumping light. A light source for excitation light that generates excitation light is installed at a local end of the branch line, and a light source for control light that generates control light of a second wavelength and a light source for excitation light that generates excitation light are installed at the local end of the branch line, The branch line is configured to transmit an optical signal and excitation light, and the branch line is configured to transmit an optical signal, excitation light, and control light, and the excitation light incident on the first optical amplification element of the optical branching device is Pumping light that is made to enter the branch line optical signal input/output section of the optical branching device from the light source for pumping light in the local part of the branch line end via the branch line, and is made to enter the second optical amplification element, is for pumping light in the local part of the main line end. Light is made to enter the trunk optical signal input/output section from the light source through the trunk line, and from the excitation light light source at the local end of the adjacent branch line, through the branch line, the optical branching device, and the trunk line. Transmission network.