JPH1126848A - High-reliability optical amplifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-reliability optical amplifier the circuit scale of which can be reduced by providing an optical switch which is connected to two independently excited pumping light sources and can selectively output the light from one of the light sources. SOLUTION: Optical signals transmitted through a signal light transmitting optical path fiber 10A are outputted to another signal light transmitting optical path fiber 10B after the signals are coupled with each other by means of 1,480 nm/1,550 nm WDM optical coupler 4A and amplified by excited light. The excited light is excited by means of exciting diodes 7A and 7B and inputted to an optical fiber mounting substrate 1A. The excited light rays inputted to the substrate 1A are respectively made incident to the different incident ports of an optical switch 5A. The switch 5A selects either one of the excited light rays by means of a switch switching circuit 6A and outputs the selected excited light to the coupler 4A. When abnormality occurs in the selected one of the exciting diodes 7A and 7B of pumping light source mounting substrates 1B and 1C, only the abnormal substrate is exchanged by switching the switch 5A without interrupting the operation of the system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in reliability of optical amplification used in an optical transmission system such as a large-capacity long-distance trunk system in the field of optical communication.

[0002]

2. Description of the Related Art In the field of optical communication, especially in backbone transmission systems, many systems have been proposed in which amplifier systems are duplicated to improve reliability. FIG. 9 and FIG. 10 show a well-known conventional repeater fiber amplifier redundant system in long-distance relay optical transmission. A first conventional example will be described with reference to FIG. In FIG. 9, 1U, 1
U2 is an optical fiber amplifier mounting substrate, 1V is an optical coupler mounting substrate for distributing an optical signal transmitted by one optical fiber to 1U, 1U2, 1W is an optical fiber amplifier 1U, 1U
Optical switch mounting board 2A, 2A2, 2 for selecting and outputting one of the optical signals amplified by 2 by an optical switch.
B and 2B2 are optical isolators for preventing an incident optical signal from going backward by reflection, and 3A and 3A2 have wavelengths of 1550n.
An erbium-doped fiber containing erbium ions, which is a medium for amplifying an m-band optical signal, includes an excitation light of 1480 nm for exciting the erbium ions and a light source of 15 m.
A multiplexing coupler for multiplexing a 50 nm band optical signal, 5A is an optical switch for selecting and outputting only one of the optical signals incident on the optical fiber amplifier mounting board 1W, and 6A is a control for controlling switching of the optical switch 5A. A circuit, 7A, 7A2, an excitation laser diode for exciting the erbium ion,
8A, 8A2 are pump laser diode control circuits for controlling the outputs of the pump laser diodes 7A, 7A2, 9A, 9
A2, 9B, 9B2, 9K, 9L, 9M, 9N, 9P,
9P is an optical connector for connecting each substrate with an optical fiber, 10
A, 10A2, 10B, 10B2, 10I, and 10J are transmission line optical fibers for transmitting signal light, and 11K is an optical fiber amplifier mounting substrate 1U that transmits an optical signal transmitted by one optical fiber and incident on the optical coupler mounting substrate 1V. , An optical coupler distributed to 1U2.

Next, the operation will be described. In FIG. 9, light transmitted through the optical fiber 10I enters the optical coupler mounting board 1V from the optical connector 9K, is split into two waves by the optical coupler 11K, and is output from the optical connectors 9L and 9M, respectively. Of the two branched signals, the signal output from the optical connector 9L is transmitted through the optical fiber 10A, enters the optical connector 1U from the optical connector 9A, and is transmitted to the isolator 2A.
Laser diode 7 through the optical fiber 3A
A is amplified by the excitation light that has passed through the WDM optical coupler 4A from A, and then passes through the optical isolator 2B to pass through the optical connector 9
Output from B. The optical signal output from the optical connector 9B is transmitted through the transmission line optical fiber 10B and transmitted to the optical connector 9N.
The light then enters the optical switch mounting substrate 1W. On the other hand, the signal output from the optical connector 9M is also transmitted through the optical fiber 10A2 of the signal light transmission line, enters the erbium-doped fiber mounting substrate 1U2 from the optical connector 9A2, is amplified, and is output from the optical connector 9B2. The signal light is transmitted through the optical fiber 10B2 to the optical switch mounting board 1W from the optical connector 9P. Light incident from the optical connectors 9N and 9P is incident on separate incident ports of the optical switch 5A, and the optical switch 5A is switched by the control signal of the optical switch control circuit 6A so as to select either one of the optical signals and output. I do. The selected optical signal is output from the optical connector 9Q to the transmission line optical fiber 10J. If an abnormality occurs in one of the erbium-doped fiber mounting substrates 1U and 1U2, the optical switch control circuit 6A switches the optical switch 5A to the other, thereby constructing a highly reliable system.

A second conventional example will be described with reference to FIG.
In this example, one excitation (pump) light source is shared by two systems. In FIG. 10, 4B, 4B2
Is a multiplexing coupler that multiplexes a 1480 nm band optical signal with a 1480 nm band optical signal that excites the erbium ion.
A and 7B are pump laser diodes for pumping the above-mentioned erbium ions, 10C and 10C2 are transmission line optical fibers for transmitting pump light, and 11G is an optical coupler for multiplexing two-input pump light and distributing it again to two outputs. . The other elements are equivalent to the correspondingly numbered elements in FIG.

[0005] The operation of the apparatus having the above configuration will be described. FIG.
, The optical signals transmitted through the signal light transmission line optical fibers 10A and 10B are 1480 nm / 1550n, respectively.
The pumping lights are multiplexed by mWDM optical couplers (mixers) 4B and 4B2, amplified through erbium-doped optical fibers 3A and 3A2, and amplified by signal light transmission line optical fibers 10B and 10B.
Output to B2. On the other hand, the pumping light is output from one of the pump laser diode (pumping light source) 7A and the pump laser diode (pumping light source) 7B, is split into two by the optical coupler 11G, passes through the optical couplers 10C and 10C2, and is 1480 nm / 1550 nm WDM. Optical coupler 4
B and 4B2 combine with the optical signal. When an abnormality occurs in the active system of the pump laser diodes (excitation light sources) 7A and 7B, the pump laser diode is switched to the standby system pump laser diode by the electric control signal 14D. By doing so, a highly reliable system can be constructed. In this case, since two amplifiers are excited by one pump (pump) light, a pump light source having a high output is required. Alternatively, a predetermined output cannot be obtained with one amplifier pump light.

[0006]

In the conventional redundant configuration of the optical fiber amplifier as shown in FIG. 9, the cost is high due to the redundancy including the expensive optical passive components.
In the case of a submarine repeater, the cost of lifting the repeater in the event of a failure is enormous, so make the parts themselves highly expensive parts with high reliability, or if a single system fails even after duplexing, the failure location Exchange alone is not possible. On the other hand, in the case of a land repeater, if the system is duplicated, it is possible to replace only the failed part when one system fails. However, when the circuit is completely duplicated, the circuit scale is doubled, and the cost is more than doubled. In particular, optical parts such as an optical fiber amplifier are expensive, and the required cost is extremely large in consideration of replacement. .

[0007]

SUMMARY OF THE INVENTION A highly reliable optical amplifier according to the present invention has two pump light sources that are independently pumped in a configuration in which a pump light source amplifies an input signal in an optical fiber, and the two light sources are separately pumped. An optical switch is provided for selecting light from the connected and excited light source and supplying it to the optical fiber.

Alternatively, in a configuration in which an input signal in an optical fiber is amplified by a pump light source, optical mixers provided on an input side and an output side of the optical fiber for amplifying the input signal are connected to the two optical mixers. Two pump light sources that are excited by only one of them are provided, and a pump power control circuit that controls which of the two pump light sources is excited is provided.

Alternatively, in a configuration in which an input signal in an optical fiber is amplified by a pump light source, optical mixers provided on an input side and an output side of the optical fiber for amplifying the input signal are connected to the two optical mixers. And two pump light sources that only one of them is excited, and an optical switch that is provided between the two pump light sources and the two optical mixers and connects only the exciting pump light source to the optical mixer. Equipped.

Alternatively, in a configuration in which an input signal in an optical fiber is amplified by a pump light source, a plurality of optical amplification units each including an optical fiber and an optical mixer provided for optical amplification in the optical fiber are provided. An output side is connected to the plurality of optical amplification units, and an optical coupler having the same number or more of inputs as the number of outputs on the output side is connected to the input side of the optical coupler. A plurality of pump light source units each having a number equal to or greater than the number of outputs of the optical coupler are provided with a pump light source unit in which an optical switch for turning on / off light is combined.

Alternatively, in a configuration in which an input signal in an optical fiber is amplified by a pump light source, a plurality of optical amplification units each including an optical fiber and an optical mixer provided for optical amplification in the optical fiber are provided. The output side is connected to the plurality of optical amplifying units, and an optical coupler provided with the same number or more of inputs as the number of outputs on the output side, and the pump light source connected to the input side of the optical coupler is connected to the number of outputs of the optical coupler. And a pump power control circuit that monitors light in the optical amplification unit or the optical coupler and excites and controls a predetermined number of the pump light sources.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1 FIG. 1 shows a configuration of a highly reliable optical amplifier according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 1A denotes an optical fiber amplifier mounting substrate, 1B and 1C denote excitation light source mounting substrates on which a 1480 nm excitation laser diode and its control circuit are mounted, and 2A and 2B denote optical isolators for preventing an incident optical signal from going backward by reflection. 3A has a wavelength of 1550
An erbium-doped fiber containing erbium ions, which is a medium for amplifying an optical signal in the nm band, 4A has a pump light of 1480 nm for exciting the erbium ions and 1550n.
Mixer (WDM optical coupler) for multiplexing m-band optical signals, 5A
Is an optical switch for selecting and outputting one of the excitation lights incident from the excitation light source mounting boards 1B and 1C, and 6A is an optical switch 5
A control circuit for controlling the switching of the switch A, 7A and 7B are excitation laser diodes (excitation light sources) for exciting the erbium ions, and 8A and 8B are pump laser diodes 7
A pump laser diode control circuit for controlling the outputs of A and 7B, 9A, 9B, 9C, 9D, 9E and 9F are optical connectors for connecting each substrate with optical fibers, 10A and 10B are transmission line optical fibers for transmitting signal light. , 10C and 10D are transmission line optical fibers for transmitting the pump light.

Next, the operation of the above-described apparatus will be described. In FIG. 1, an optical signal to be transmitted through the optical fiber 10A of the signal light transmission line is incident on the erbium-doped fiber mounting substrate 1A, and 1480 in the erbium-doped optical fiber 3A.
nm / 1550 nm WDM optical coupler (mixer) After being amplified by the pumping light generated by being coupled and incident by the optical coupler (mixer) 4A, it passes through the optical isolator 2B and passes through the signal optical transmission line optical fiber 1
0B is output. The pumping light is pumped by the pumping laser diodes 7A and 7B in the pumping light source mounting boards 1B and 1C on which the pumping laser diode is mounted, and is transmitted through the pumping light transmission line optical fibers 10C and 10D, respectively, and is input to the erbium-doped fiber mounting board 1A. You. The input pump lights are respectively incident on different incident ports of the optical switch 5A.
The optical switch 5A selects one of the pump lights by the switch switching circuit 6A, and selects 1480 nm / 1550 nmW.
Output to the DM optical coupler (mixer) 4A. These active components are normally only active and the standby system is not. If an abnormality occurs in a selected one of the pump laser diodes 7A and 7B of the pump light source mounting boards 1B and 1C on which the pump laser diode is mounted, the switch 5A is switched to the other while the system is in the operating state, and at the same time, the pump laser diode therefor Is excited to replace only the abnormal substrate.

According to the present embodiment, only the most reliable optical passive components are mounted on the erbium-doped fiber mounting substrate 1A, and only the electrically active components are configured in a redundant configuration. Mounting board 1
B, 1C, and when an abnormality occurs in the active system of the redundant unit, the system can be switched to the standby system while the system is in operation and only the abnormal board can be replaced, so that the reliability and the operability are high.
In addition, a system with a minimum circuit scale can be constructed.
Also, since only the optical switch is inserted in the path of the pumping light, the power of the pumping light input to the 1480 nm / 1550 nm WDM optical coupler (mixer) 4A is at a level comparable to that in the case of full redundancy. Therefore, a desired amplified optical signal can be obtained without the drawbacks of the second conventional example.

A case in which the optical reliability optical amplifier of the present invention is applied to a system in which one amplifier amplifies two amplifiers will be described. FIG. 2 is a diagram showing the configuration, in which 1A2 is an optical fiber amplifier mounting board, and 1E is 148.
A substrate on which a 0-nm pump laser diode, its control circuit, and an optical coupler are mounted, and 11A and 11B are optical couplers. 2A2, 2B2 optical isolator, 3A2 optical fiber, 4A2 optical mixer, 5A2
A2 optical switch, 6A2 optical switch control circuit, 7
The C and 7D laser diodes and the 8C and 8D diode control circuits are equivalent to the components mounted on the allied board of FIG. Also, 9A2, 9B2, 9C2, 9D
2, 9G and 9H are optical connectors, 10C2 and 10D2 are optical fibers for transmitting pumping light.

The operation of the apparatus having the above configuration can be easily assumed from the configuration diagram of FIG. 2, but only the outline will be described. Erbium-doped fiber mounting substrates 1A and 1A having the same function
2 are mounted in the same device, and the respective excitation lights from the excitation light source mounting boards 1D and 1E mounted with the pump laser diode are input from the optical connectors 9C2 and 9D2, respectively. The pumping light is the pumping light source mounting board 1 on which the pump laser diode is mounted.
In D, the laser beams are always output from the excitation laser diodes 7A and 7C, both of which are excited, and are multiplexed once by the coupler 11A. The multiplexed pump light is split into two again, output to the optical connectors 9E and 9G, respectively, and input to the erbium-doped fiber mounting substrates 1A and 1A2. The pump laser diode-mounted pumping light source mounting board 1E has exactly the same configuration as the pump laser diode-mounted pumping light source mounting board 1D, and pump light is similarly input to 1A and 1A2. The active pump and the standby pump are selected by the optical switches 5A and 5A2. Pump laser diodes 7A and 7 in pump light source mounting board 1D mounted with pump laser diodes
If an abnormality occurs in one of C, the pump laser diode control circuits 8A and 8C increase, for example, one of the optical couplers 11A so that the combined output does not fluctuate and adjust the output so as to compensate for the decrease in the other. . 1E performs the same control. If an abnormality occurs in one of the pump light source mounting boards 1D and 1E, which is in the operating state, and the pump laser diode becomes uncontrollable, the optical switch control circuit 6 in the erbium-doped fiber mounting board 1A, 1A2
The optical switches 5A and 5A2 are switched by A and 6A2. Of the boards 1D and 1E, the board in which an abnormality has occurred is switched to the normal board while the system is in the operating state, and only the abnormal board is replaced.

As described above, when two optical fiber amplifiers are mounted in the same device, the output power and the reliability of each optical fiber amplifier are kept high, and the number is smaller than that of the configuration shown in FIG. Since the scale can be increased, a system with high reliability and further reduced circuit scale can be constructed. Although an optical coupler and an optical switch are inserted in the path of the pumping light, the power of the pumping light input to the 1480 nm / 1550 nm WDM optical coupler (mixer) 4A is completely redundant by increasing the number of pump laser diodes. Since input can be performed at a level comparable to that in the case, a desired amplified optical signal can be obtained.

Embodiment 2 FIG. A description will be given of an optical amplifier in which only a passive element without a movable element such as an optical switch is mounted on an amplifier unit and the reliability is further improved. FIG. 3 is a configuration diagram of a highly reliable optical amplifier according to the present embodiment. In the figure, 1F is an optical fiber amplifier mounting board,
G and 1H are boards on which a 1480 nm pump laser diode, its control circuit, an optical switch and its control circuit are mounted, 4B is a multiplexing coupler for multiplexing 1480 nm pump light and 1550 nm band optical signal, and 5B is an optical switch. , 6B
Is a control circuit for controlling switch switching, and the other elements are the same as the elements of the same number in the first embodiment.

The operation of the apparatus having the above configuration can be easily understood from the configuration diagram of FIG. 3, but only the outline will be described below. In the configuration of FIG. 3, the optical switch 5 in 1A in the configuration of FIG.
A and its control circuit 6A are replaced by an optical coupler 11A, so that the two-output pump light of the optical coupler 11A is 1480 nm / 15 from both sides of the erbium-doped optical fiber 3A.
The configuration is such that light is incident through 50 nm WDM optical couplers (mixers) 4A and 4B. The switching of the excitation light is performed by connecting the optical switches 5A and 5B to the outputs of the pump laser diodes (excitation light sources) 7A and 7B of the excitation light source mounting boards 1G and 1H on which the pump laser diode is mounted. 6A and 6B. When an abnormality occurs in one of the pump laser diodes 7A and 7B of the optical couplers 1G and 1H that is in the operating state, the optical switches 5A and 5B are simultaneously switched by the optical switch control circuits 6A and 6B while the system is in the operating state, and only the abnormal substrate is changed. Exchange. According to the apparatus of the present embodiment, all of the non-redundant components 1F can be composed only of passive optical components, so that a more reliable system can be constructed as compared with the configuration of FIG. Moreover, the effect that the total pumping light power input to the erbium-doped fiber mounting substrate 3A can be input at a level comparable to that in the case of complete redundancy is the same.

A case in which the optical amplifier having the configuration shown in FIG. 3 is applied to the system shown in FIG. 2 will be described. FIG. 4 shows the configuration,
In the figure, 1F2 is an optical fiber amplifier mounting substrate, 1
Reference numerals I and 1J denote boards on which a 1480 nm pump laser diode, its control circuit, an optical coupler, an optical switch, and its control circuit are mounted. 4B2 is a multiplexing coupler, 5C,
5D is an optical switch 6C, 6D is a switch control circuit, 1
1A2 and 11C are two-input and two-output optical couplers. The other elements are equivalent to the same numbered elements shown in FIGS.

An outline of the operation of the apparatus having the above configuration will be described. In the figure, erbium-doped fiber mounting boards IF and IF2 having the same function are mounted in the same device, and pump light from pump laser diode mounted pump light source mounting boards 1I and 1J is input from optical fibers 10C and 10D, respectively. The pumping light is supplied from the optical couplers 11B and 11C of the boards having the same functions as the pumping light source mounting boards 1D and 1E of FIG.
Via the optical switches 5A and 5C, 5B and 5D controlled by the erbium-doped fiber mounting substrate 1F,
It is supplied to F2. When an abnormality occurs in one of the pump light source mounting boards 1I and 1J in the operating state, the optical switch 5 remains in the system operating state.
A, 5B, 5C, and 5D are simultaneously switched to replace only the abnormal board.

Switching of the optical switch in the configuration of FIG.
Even if the pump power is controlled so as to switch which one is excited, the operation and the effect are similar. FIG. 5 is a configuration diagram of an optical reliability optical amplifier using the above-described pump power control circuit. In the figure, 1K denotes an optical fiber amplifier mounting substrate, 1L and 1M denote substrates on which an excitation laser diode and its control circuit are mounted, and 1N controls the output power of the excitation laser diode in order to keep the output of the optical fiber amplifier constant. This is the board on which the control circuit is mounted. Also one
1D is an optical coupler for branching and outputting a part of the amplified optical signal, 12A is a photodiode for monitoring the optical signal branched for 11D, and 13A is an output of the pump laser diode based on the optical power monitored by the above-described photodiode. A control circuit for controlling power; 14A is an electric signal obtained by electrically converting the optical power monitored by the photodiode;
B and 14C are control signals for controlling the output power of the pump laser diode. The other elements are the same as those of the same numbers in FIGS.

An outline of the operation of the apparatus having the above configuration will be described. In the figure, an optical coupler having the same function as 1F in FIG.
Are connected, and a part of the branched optical signal is photoelectrically converted by the photodiode 12A. The electrical converted signal 14A is controlled by a pump power control circuit 13A in the control circuit mounting board 1N to control the output of the excitation laser so that the electrical signal 14A becomes constant.
To the pump laser diode control circuit 8 in the pump light source mounting boards 1L and 1M respectively mounted with the pump laser diode.
A, 8B. Thus, the outputs of the pump laser diodes (excitation light sources) 7A and 7B are controlled. When an abnormality occurs in one of the pump light source mounting boards 1L and 1M on which the pump laser diode is mounted, the pump power control circuit 13A sets the erbium-doped fiber mounting board 1K.
The output of the pump laser diode in which the abnormality has occurred is gradually turned off while the output light signal of the other is kept constant, and the output of the other pump laser diode is increased. If only the substrate having the pump laser diode turned off in this way is replaced in the system operation state, the pump power control circuit 13A
After the replacement, control is performed again so that the pumping high output of the pumping light source mounting boards 1L and 1M mounted with the pump laser diode becomes the same level.

Embodiment 3 FIG. In the above embodiment, the circuit that switches the pumping light using the optical switch or the optical coupler is described while saying that the loss is small. In this embodiment, a highly reliable optical amplifier which does not require these elements and has extremely high pump light use efficiency will be described. FIG. 6 is a configuration diagram of a highly reliable optical amplifier according to the present embodiment. In the figure, 1P is an optical fiber amplifier mounting board. The other elements of the numbers are the same as those of the same numbers already shown in FIGS.

An outline of the operation of the apparatus having the above configuration will be described. FIG.
5 is a configuration in which the optical coupler 11A in FIG. 5 is omitted and the respective pumping lights are directly connected to the mixers 4A and 4B. The pumping lights 7A and 7B are not combined and the respective mixers 4A and 7B are not combined.
B and 4A are input to the optical fiber 3A to perform optical amplification. For example, the laser diode 7A is excited as the active system, but when an abnormality is detected, the laser diode 7A is switched to the other laser diode 7B and excited. According to the configuration of FIG. 6, since there is no optical coupler in the transmission path of the pump light as compared with the configuration of FIG. 5, insertion loss and cost can be suppressed. Also, as in the other embodiments, the total pumping light power input to the optical fiber 3A from the mixer 4A or 4B can be increased.

An arrangement using an optical switch may be used instead of the arrangement for switching and controlling the pump power. FIG. 7 is a configuration diagram of the high reliability optical amplifier having the above configuration.
Denotes an optical fiber amplifier mounting substrate. The other elements are equivalent to the already described elements of the same number. In the apparatus having this configuration, the abnormality of the excitation light is detected, the active excitation light source and the optical switch in which the abnormality has occurred are turned off, and the excitation light source of the standby system is excited to turn on the optical switch.

Embodiment 4 A high-reliability optical amplifier in which the specific gravity of the standby system is reduced or optical amplification is performed with a low excitation light source will be described. FIG. 8 is a configuration diagram of a highly reliable optical amplifier according to the present embodiment. In the figure, 1G2 is a substrate on which a pump laser diode is mounted, 1R and 1S are substrates on which an optical fiber amplifier is mounted, and 1T is a substrate on which an optical coupler is mounted. 5A2 is an optical switch, 6A2 is an optical switch control circuit,
7A2 is a pump laser diode, and 8A2 is a pump laser diode control circuit. 9I, 9J, 9I2, 9
E2 is an optical connector, 10E, 10F, 10G, 10G
2, 10H are transmission line optical fibers, and 11E is an optical coupler. The other elements are indicated by the same numbers as the elements in FIGS.

An outline of the operation of the apparatus having the above configuration will be described. In the connection of the optical switch shown in FIG. 8, the laser diode mounting boards 1G and 1H are excited for use, and the laser diode mounting board 1G2 is a standby system. In FIG. 8, excitation light is input to the erbium-doped fiber mounting substrates 1R and 1S from the optical connectors 9D and 9D2, respectively. As the pumping light, two systems out of the three redundant configurations of the pumping light source mounting boards 1G, 1H, and 1G2 mounted with the pump laser diode are selected and output by the optical switches 5A, 5B, and 5A2. In this case, the pump laser diode is mounted. Of the excitation light source mounting boards 1G and 1G2 are selected. Excitation light source mounting substrate 1G, 1H, 1G2 mounted with pump laser diode
Is input to the optical coupler mounting board 1T, is connected to the three input ports of the optical coupler 11E, and
The light is branched to an output port and supplied to the erbium-doped fiber mounting substrates 1R and 1S. Excitation light source mounting board 1 mounted with two pump laser diodes in operation
If an abnormality occurs in one of the G and 1H pump laser diodes 7A and 7B, the optical switch 5 is controlled by the optical switch control circuits 6A, 6B and 6A2 while the system is operating.
A, 5B, and 5A2 are simultaneously switched, and only the board in the abnormal state is switched to the excitation light source mounting board 1G2, which is a spare board, and only the abnormal board is replaced.

In the present embodiment, the case of two optical fiber amplifier mounting boards and three redundant excitation laser diode mounting boards is described. However, the optical coupler of the optical coupler mounting board is an M to N coupler (M> N). By setting N), a system can be constructed with M redundant excitation laser diode mounting substrates for N optical fiber amplifier mounting substrates. FIG.
As shown in the example, one standby system may be used for two active systems. According to the above-described configuration, since the erbium-doped fiber mounting substrates 1R and 1S do not include active components and movable components, the feature of high reliability is the same as in the other embodiments. If the number of combined inputs of the combining / branching optical coupler 11E is increased and the number of pump laser diodes of the pumping light source is correspondingly increased, the optical fiber to be amplified including these increased pumping light sources is also included. More than three excitation light sources such as 3A can be used, and each excitation light source can be configured with a relatively low power excitation light source.

Although not shown in the figure, instead of using the optical switches 5A, 5B and 5A2 in the configuration of FIG.
The switching control of the pump radar diode control circuits 8A, 8B, 8A2 may be performed using the pump power control circuit shown in FIG. The operation of the apparatus having the above-described configuration is clear from the operation description of the apparatus in each of the embodiments described above, and thus the description is omitted. This configuration also has the same features of the devices in the above-described embodiments.

[0031]

As described above, according to the present invention, a plurality of pumping systems are switched and connected to a single optical amplification object, and only active components operating in an unreliable electric circuit have a redundant configuration. Therefore, there is an effect that the circuit scale can be reduced while having high reliability. In addition, since the parts of the passive components that operate only with highly reliable optical signals are not switched, there is an effect that the level change of the optical signals due to the redundancy can be reduced.

Further, since the present invention is configured to switch between the working mode and the standby mode without using an optical coupler, there is an effect that optical loss can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a highly reliable optical amplifier according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of another highly reliable optical amplifier according to the first embodiment.

FIG. 3 is a configuration diagram of a highly reliable optical amplifier according to a second embodiment of the present invention.

FIG. 4 is a configuration diagram of another highly reliable optical amplifier according to the second embodiment.

FIG. 5 is a configuration diagram of another highly reliable optical amplifier according to the second embodiment.

FIG. 6 is a configuration diagram of a highly reliable optical amplifier according to a third embodiment of the present invention.

FIG. 7 is a configuration diagram of another high reliability optical amplifier according to the third embodiment.

FIG. 8 is a configuration diagram of a highly reliable optical amplifier according to a fourth embodiment of the present invention.

FIG. 9 is a configuration diagram of an optical fiber amplifier having a redundant configuration as a first conventional example.

FIG. 10 is a configuration diagram of an optical fiber amplifier having a redundant configuration as a second conventional example.

[Explanation of symbols]

1A, 1A2, 1F, 1F2, 1K, 1P, 1Q, 1
R, 1S1U, 1U2 Erbium-doped fiber mounting substrate, 1B, 1C, 1D, 1E, 1G, 1G2, 1H, 1
I, 1J, 1L, 1M Pump laser diode mounting pump light source mounting board, 1N pump power control circuit mounting board, 1T, 1V optical coupler mounting board, 1W optical switch mounting board, 2A, 2B, 2A2, 2B2 optical isolator, 3A , 3A2 Erbium-doped optical fiber, 4
A, 4B, 4A2, 4B2 1480nm / 1550n
mWDM optical coupler (mixer), 5A, 5A2, 5B, 5
C, 5D, 5A2 optical switch, 6A, 6A2, 6B,
6C, 6D, 6A2 Optical switch control circuit, 7A, 7A
2, 7B, 7C, 7D, 7A2 Pump laser diode (excitation light source), 8A, 8A2, 8B, 8C, 8D, 8
A2 pump laser diode control circuit, 9A, 9B,
9C, 9D, 9E, 9E2, 9F, 9G, 9H, 9I,
9I2, 9J, 9K, 9L, 9M, 9N, 9P, 9Q,
9A2, 9B2 optical connectors, 10A, 10B, 10I,
10J, 10A2, 10B2 Signal optical transmission line optical fiber, 10C, 10D, 10E, 10F, 10G, 10G
2, 10H, 10C2, 10D2 Pump optical transmission line optical fiber, 11A, 11B, 11C, 11D, 11E, 1
1K, 11A2 coupler, 12A photodiode,
13A pump power control circuit, 14A, 14B, 14
C, 14D electrical signal.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04B 10/06 10/04

Claims (5)

[Claims] 1. A configuration in which a pump light source amplifies an input signal in an optical fiber, comprising: two pump light sources that are independently excited; and a light source that is connected to the two light sources and that selects light from the excited light source. A high-reliability optical amplifier comprising an optical switch for supplying the optical fiber to the optical fiber. 2. A configuration in which an input signal in an optical fiber is amplified by a pump light source, wherein the optical mixer is provided on an input side and an output side of the optical fiber for amplifying the input signal, and is connected to the two optical mixers. And a pump power control circuit for controlling which one of the two pump light sources is excited, and a pump power control circuit for controlling which of the two pump light sources is excited. 3. A configuration in which a pump light source amplifies an input signal in an optical fiber, wherein the optical mixer provided on the input side and the output side of the optical fiber for amplifying the input signal is connected to the two optical mixers. And two pump light sources that only one of them is excited, and an optical switch that is provided between the two pump light sources and the two optical mixers and connects only the excited pump light source to the optical mixer. A highly reliable optical amplifier, comprising: 4. In a configuration in which an input signal in an optical fiber is amplified by a pump light source, an optical amplifier unit comprising the optical fiber and an optical mixer provided for optical amplification in the optical fiber is provided. A plurality of units, an optical coupler having an output side connected to the plurality of optical amplification units, and an optical coupler provided with the same number or more of inputs as the number of outputs on the output side; a pump light source connected to the input side of the optical coupler; A high-reliability optical amplifier comprising: a plurality of pump light source units each having a number equal to or greater than the number of outputs of the optical coupler; . 5. A configuration in which a pump light source amplifies an input signal in an optical fiber, wherein an optical amplifier unit comprising the optical fiber and an optical mixer provided for optical amplification in the optical fiber is provided. A plurality of units, an optical coupler having an output side connected to the plurality of optical amplifying units, and an input side having the same number or more as the number of outputs on the output side; and a pump light source connected to the input side of the optical coupler. ,
A plurality of outputs equal to or more than the number of outputs of the optical coupler, and a pump power control circuit that monitors light in the optical amplification unit or the optical coupler and excites and controls a predetermined number of the pump light sources. A highly reliable optical amplifier characterized by the following.