JP5735392B2 - Optical amplification repeater, optical amplification repeater transmission system, and optical amplification method - Google Patents

Description

  The present invention relates to an optical amplifying repeater, an optical amplifying repeater transmission system, and an optical amplifying method that enable battery-driven communication even when a relay station fails, and ensure signal quality even when the battery is dead.

  In order to increase the distance of an optical transmission system, it is indispensable to insert an optical amplification repeater for compensating for propagation loss in the optical fiber in the middle of the transmission path. In a backbone optical transmission system, optical amplification repeaters are generally inserted at intervals of several tens of kilometers, and an erbium-doped fiber amplifier (EDFA) is used as an optical amplifier used in the optical amplification repeater. In the EDFA, an optical signal is amplified by exciting an erbium-doped fiber (EDF) with light different from the signal wavelength band.

  Patent Documents 1 and 2 disclose an optical amplification repeater transmission system that appropriately sets and controls the optical output level of an optical amplification repeater from a terminal station even when the number of optical wavelength multiplexing is changed or the route is changed. Patent Document 3 discloses a configuration in which an optical amplification repeater is bypassed by an optical switch using degradation information of an optical amplifier as a trigger.

JP-A-6-21897 JP-A-6-69890 JP 7-264126 A

  However, when the relay station where the existing optical amplifying repeater is installed fails, the light source for exciting the EDF cannot be operated. Therefore, in an existing system, in the case of a power failure, an unexcited EDF becomes a loss medium having a large loss, so that the optical signal passes through the optical amplifier and is affected by the large loss of the EDF, thereby ensuring signal quality. In this case, a sufficient signal power level cannot be secured, and signal transmission with secured signal quality becomes impossible.

  Furthermore, even when it is assumed that an optical amplifier capable of battery drive is installed in the relay station, a normal inexpensive UPS (uninterruptible power supply) has a backup time of several minutes to several tens depending on the charging capacity of the secondary battery. Only about a minute can be supplied. For this reason, it cannot cope with a large-scale power outage for a long time. In addition, when the battery runs out, the loss of EDF at the time of non-excitation is very large. Therefore, if even one station loses power, signal transmission that ensures signal quality becomes impossible.

  The above-mentioned patent document describes the quality degradation of the optical wavelength multiplexed signal due to a power failure, and means for solving the quality degradation of the optical wavelength multiplexed signal when power supply to the battery-driven optical amplifier is completely stopped (battery is exhausted). Nothing is stated.

  Accordingly, the present invention provides an optical amplification repeater, an optical amplification repeater transmission system, and an optical amplification method that enable long-term communication with a battery drive even in the event of a power outage at a relay station and ensure signal quality even when the battery is dead. For the purpose.

  In order to achieve the above object, an optical amplification repeater of an optical transmission system according to the present invention includes a pumping light source that generates pumping light that amplifies signal light, a pumping light source control mechanism that controls output power of the pumping light source, and a power failure An optical amplifier including a battery for supplying electric power to the pumping light source, and the pumping light source control mechanism reduces a driving current supplied to the pumping light source from a normal time when a power failure occurs, and outputs the pumping light source. Reduce power.

  The excitation light source control mechanism preferably reduces the output power of the excitation light source to a light output level that matches a minimum necessary transmission capacity or a minimum transmission capacity that can be transmitted when a power failure occurs.

  The optical amplifier further includes an input light power monitor or an output light power monitor, and the pumping light source control mechanism is stepwise until a predetermined minimum quality is reached based on a monitor value of the input light or the output light. It is also preferable to reduce the output power of the excitation light source.

  The optical switch further includes an optical switch having a function of switching a path at an input / output end of the optical amplifier, and the optical switch preferably switches to a path that does not include the optical amplifier when the battery cannot supply power. .

  In order to achieve the above object, an optical amplification repeater transmission system according to the present invention is an optical amplification repeater transmission system comprising an optical transmitter, an optical receiver, an optical amplification repeater, and a management system. An excitation light source that generates excitation light that amplifies the excitation light source, an excitation light source control mechanism that controls output power of the excitation light source, and a battery that supplies power to the excitation light source in the event of a power failure. Based on a control message from the management system, the control mechanism lowers the drive current supplied to the excitation light source when the power failure occurs, and reduces the output power of the excitation light source.

  The optical receiver includes means for monitoring the quality of the received optical signal and notifying the management system, the management system stepwise until a predetermined minimum quality is reached based on the notification. It is also preferable to notify the optical amplification repeater of a control message for reducing the output power of the pumping light source.

  In order to achieve the above object, an optical amplification method according to the present invention includes an excitation light source that generates excitation light for amplifying signal light, an excitation light source control mechanism that controls output power of the excitation light source, An optical amplification method in an optical amplifier comprising a battery for supplying power, wherein the pumping light source control mechanism detects a power failure, and the driving current supplied to the pumping light source by the pumping light source control mechanism is higher than normal. Reducing the output power of the excitation light source.

  In the present invention, by intentionally reducing the output power of the excitation light source of the optical amplifier, the power consumption (battery consumption) by the excitation light source is suppressed, the battery-driven optical amplifier is operated longer, and communication is further improved. It can be maintained for a long time.

  Furthermore, when the optical amplifier cannot be driven by the battery, the path in the optical amplifying repeater is switched, so that loss due to the optical amplifier is eliminated, and signal transmission with a high signal quality becomes possible.

1 shows a configuration of an optical amplification repeater transmission system according to the present invention. 1 shows a configuration of a battery-driven optical amplifier according to the present invention. 1 shows a configuration of an optical amplification repeater with a built-in optical switch according to the present invention. The flow of the control signal of the whole optical amplification repeater transmission system is shown. Three examples of the present invention are shown. The change in signal power when two consecutive relay stations fail. The change in signal power when one relay station fails is shown.

  EMBODIMENT OF THE INVENTION The form for implementing this invention is demonstrated in detail below using drawing. FIG. 1 shows the configuration of an optical amplification repeater transmission system according to the present invention. This system includes an optical transmitter 1, an optical amplification repeater 2, and an optical receiver 3, and an optical signal output from the optical transmitter 1 is amplified and relayed by the optical amplification repeater 2 to be a long-distance optical fiber. Is received and received by the optical receiver 3.

  FIG. 2 shows the configuration of the battery-driven optical amplifier of the present invention. The battery-driven optical amplifier 4 is used in the optical amplification repeater 2 and includes a pumping light source 41, a pumping light source control mechanism 42, a battery 43, and an EDF 44.

  The excitation light source 41 generates excitation light for exciting the EDF, and is configured by a laser diode or the like. The battery 43 is a commonly used secondary battery such as a UPS. In the present invention, power can be supplied for several minutes to several tens of minutes in normal use. The EDF 44 amplifies the optical signal with the excitation light.

  The excitation light source control mechanism 42 operates by reducing the drive current supplied to the excitation light source 41 to be lower than normal in order to maintain the drive time of the optical amplifier 4 by the battery 43 as long as possible when a power failure occurs. Reduce power consumption (battery consumption). For example, the transmission capacity is reduced to the minimum necessary transmission capacity or the minimum transmission capacity that can be transmitted, and the optical amplifier 4 outputs the output power of the pumping light source (effectively necessary profit) according to the transmission capacity. Reduce supply). In addition, the pumping light source control mechanism 42 cooperates with the transmission quality monitor to reduce the output power of the pumping light source 41 of the optical amplifier 4 to such an extent that a minimum quality (for example, 10-12 dB or less after FEC (forward error correction)) can be ensured. To reduce.

  Further, the optical amplifier 4 has a function of transmitting and receiving a control signal, and it is also possible to control the drive current supplied to the pumping light source 41 based on this control signal.

  FIG. 3 shows the configuration of the optical amplification repeater with a built-in optical switch of the present invention. The optical switch built-in optical amplification repeater 2 includes a battery-driven optical amplifier 4 and an optical switch 5.

  The battery-driven optical amplifier 4 is the above-described optical amplifier, and the optical switch 5 has a function of switching the path at the input / output end of the optical amplifier 4 and is not powered (when the battery 43 can no longer supply power). Therefore, by switching to a path that does not include the optical amplifier 4, the optical amplifier 4 can be bypassed and can be prevented from being affected by a large loss due to the non-excited EDF.

  FIG. 4 shows the overall control signal flow of the optical amplification repeater transmission system. The management system 6 is connected to the optical transmitter 1 and the optical receiver 3 via a control network. The management system 6 transmits capacity (number of wavelengths) information or pumping light source setting information to the optical transmitter 1 based on power failure occurrence information, quality information from the optical receiver 3, and the like. The optical transmitter 1 puts this information on the control signal, notifies the optical amplification repeater 2, and controls the drive current supplied to the pumping light source 41 by the pumping light source control mechanism 42 based on this control signal. Note that this control signal is transmitted over an optical fiber or by a dedicated management network.

  FIG. 5 shows three embodiments of the present invention. FIG. 5a shows an example in which the transmission capacity of the optical fiber is minimized and the output power of the pumping light source is lowered accordingly.

1) When the management system 6 detects a power failure, the management system 6 sends a control message to the optical transmitter 1 to lower the transmission capacity (number of wavelengths, etc.) to the minimum capacity required in an emergency or the minimum capacity that can be transmitted. Send.
2) The optical transmitter 1 transmits a control signal to the optical amplification repeater 2 so that the optical output level matches the transmission capacity. For example, when the transmission capacity is reduced from a 100-wavelength system to a 10-wavelength operating system, a control signal is transmitted so that the optical output level is reduced by 10 dBm.
3) Upon receiving the control signal, the pumping light source control mechanism 42 of the optical amplifying repeater 2 controls the light output level of the pumping light source 41 so as to obtain a desired output level.

  In this embodiment, the light output level of the excitation light source 41 is reduced as compared with the case of normal battery driving. For this reason, the driving time of the battery is significantly increased as compared with the conventional case, and it is possible to cope with a power failure for a long time. For example, if the transmission capacity is reduced from a 100-wavelength system to a 10-wavelength operating system, the power consumption will be about one-tenth, and even a UPS with a battery of only a few minutes to tens of minutes will be about 10 times It is possible to have a battery for several tens of minutes to several hours.

  FIG. 5b shows an example in which the optical receiver 3 decreases the pumping light power to the minimum quality while monitoring the quality.

1) When the management system 6 detects a power failure, the management system 6 transmits the pumping light source setting request and the pumping light source setting parameters to the optical transmitter 1 step by step. The optical transmitter 1 transmits the information to the corresponding optical amplifying repeater 2. The optical amplification repeater 2 that has received the control signal controls the optical output level of the pumping light source.
2) The optical receiver 3 monitors the light quality in the state of 1) and notifies the management system 6 of it. The management system 6 repeats 1) and 2) until it reaches a predetermined minimum quality (eg, 10-12 dB after FEC (forward error correction)).

  The present embodiment is applicable when the management system 6 does not hold the transmission capacity at the minimum capacity required in an emergency and the minimum capacity that can be transmitted, and the optical receiver 3 monitors the optical quality. Control the light output level of the excitation light source until the minimum quality is achieved. For this reason, the optical output level of the pumping light source is not lowered below the minimum quality, and the optical amplification repeater 2 can maintain the minimum transmission quality. Further, as in the example of FIG. 5a, the transmission capacity does not decrease to the minimum necessary capacity immediately after the power failure, so that if the power failure is short, there is no influence on the user.

  FIG. 5c shows an example in which the optical amplifying repeater 2 alone is driven to a predetermined gain instead of being controlled from the outside such as the management system 6 or the like.

1) The excitation light source control function 42 holds in advance the excitation light source setting parameters at the time of a power failure (the minimum capacity necessary in an emergency or the transmission capacity at the minimum capacity that can be transmitted).
2) The excitation light source control function 42 detects that a power failure has occurred.
3) The excitation light source control function 42 reduces the output power of the excitation light source based on the excitation light source setting parameter at the time of a power failure.

  Further, the optical amplifier 4 includes an input optical power monitor and an output optical power monitor, and it is possible to control the optical output level of the pumping light source step by step using the monitor values as in the embodiment of FIG. 5b. is there.

  In this embodiment, it is possible to autonomously control the light output level of the excitation light source without using the management system 6.

  5A, 5B, and 5C can be optical amplification repeaters with built-in optical switches. In this case, it is possible to avoid the influence of a large loss due to the non-excited EDF even when no power is supplied.

  The effects of the present invention are shown below. FIG. 6 shows the change in signal power when two consecutive relay stations fail. The relay station includes a battery-driven optical amplifier. In the method of the present invention, since the output power of the excitation light source is reduced at the time of a power failure, the signal light level is lower than that at the normal time, but is kept higher than when there is no battery.

  FIG. 7 shows the change in signal power when one relay station fails. The relay station is an optical amplification repeater with a built-in optical switch, and shows a change in signal power in the optical amplification repeater transmission system when one of the relay stations fails and the battery runs out. In the method of the present invention, since there is no loss due to non-excited EDF, the signal light level is kept higher than in the conventional method.

  As described above, the function of controlling the excitation light power of the optical amplifier at the time of a power failure of the optical repeater station makes it possible to operate the battery-driven optical amplifier for a longer time and maintain the communication for a longer time. In addition, the function of bypassing the optical amplifier by the optical switch eliminates the loss due to the optical amplifier, and enables signal transmission with ensured signal quality.

  Moreover, all the embodiments described above are illustrative of the present invention and are not intended to limit the present invention, and the present invention can be implemented in other various modifications and changes. Therefore, the scope of the present invention is defined only by the claims and their equivalents.

DESCRIPTION OF SYMBOLS 1 Optical transmitter 2 Optical amplification repeater 3 Optical receiver 4 Battery drive type optical amplifier 5 Optical switch 6 Management system 41 Excitation light source 42 Excitation light source control mechanism 43 Battery 44 EDF

Claims (7)

An excitation light source that generates excitation light for amplifying signal light;
An excitation light source control mechanism for controlling the output power of the excitation light source;
A battery for supplying power to the excitation light source during a power failure;
Comprising an optical amplifier comprising
An optical amplification repeater for an optical transmission system, wherein the pumping light source control mechanism reduces the output power of the pumping light source by lowering the drive current supplied to the pumping light source than in normal times when a power failure occurs.   The pumping light source control mechanism reduces the output power of the pumping light source to a light output level that matches a minimum necessary transmission capacity or a minimum transmission capacity that can be transmitted when a power failure occurs. The optical amplification repeater described in 1. The optical amplifier further comprises an input optical power monitor or an output optical power monitor,
2. The light according to claim 1, wherein the excitation light source control mechanism reduces the output power of the excitation light source in stages until a predetermined minimum quality is reached based on a monitor value of input light or output light. Amplifying repeater. An optical switch having a function of switching a path at an input / output end of the optical amplifier;
4. The optical amplification repeater according to claim 1, wherein the optical switch switches to a path that does not include the optical amplifier when the battery cannot supply power. 5. In an optical amplification repeater transmission system including an optical transmitter, an optical receiver, an optical amplification repeater, and a management system,
The optical amplification repeater is:
An excitation light source that generates excitation light for amplifying signal light;
An excitation light source control mechanism for controlling the output power of the excitation light source;
A battery for supplying power to the excitation light source during a power failure;
Comprising an optical amplifier comprising
The excitation light source control mechanism reduces the output power of the excitation light source by reducing the drive current supplied to the excitation light source from the normal time when a power failure occurs based on a control message from the management system. An optical amplification repeater transmission system. The optical receiver comprises means for monitoring the quality of the received optical signal and notifying the management system;
6. The management system according to claim 5, wherein, based on the notification, the optical amplification repeater is notified of a control message for gradually decreasing the output power of the pumping light source until a predetermined minimum quality is reached. The optical amplification repeater transmission system described. An excitation light source that generates excitation light for amplifying signal light;
An excitation light source control mechanism for controlling the output power of the excitation light source;
A battery for supplying power to the excitation light source during a power failure;
An optical amplification method in an optical amplifier comprising:
The excitation light source control mechanism detecting a power failure;
Reducing the drive current supplied to the excitation light source by the excitation light source control mechanism from the normal time, and reducing the output power of the excitation light source;
An optical amplification method comprising:

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