JPS62216537A - Line supervisory method - Google Patents

Abstract

PURPOSE:To reduce the cost of a measuring instrument by receiving light from a light emitting element section connected to one terminal of an optical submarine cable laid already by a photodetection element section connected to the other terminal to supervise the said optical submarine cable in laying the optical submarine cables twice or over separately. CONSTITUTION:A light emitting diode or a laser diode 81 is connected between a watertight case 5 of a laid optical submarine cable 2 and a feeder line 21 and a prescribed DC voltage is applied via the feeder line 21 to the diode 81, which is emitted. The light is always received by the photodetection section (e.g., photodiode) 9 provided to a land station (not shown) through an optical fiber 21 and its level is supervised, then whether or not the optical submarine cable is subjected to disconnection or damage is detected easily. That is, since the light sent from one terminal of the optical submarine cable is utilized directly, range possible for supervision is extended up to nearly 55km of one relay section.

Description

[Detailed Description of the Invention] [1 Already Required] In the optical submarine cable system, when the optical submarine cable is laid in two or more parts, the installed optical submarine cable is installed before the start of the next installation. The cable can be monitored using an inexpensive measuring device, and the monitoring distance can be extended.

[Industrial application field]

The present invention relates to a track monitoring method, and particularly to an improvement in a track monitoring method for monitoring the presence or absence of damage to an optical submarine cable during installation.

In general, as a transmission line, optical fiber cables have superior characteristics compared to coaxial cables, such as: 1) being smaller and lighter; 2) having less propagation loss and being able to transmit large-capacity signals.

For example, 36 MIIz analog signal (telephone line 270
In the case of a submarine coaxial cable that transmits 0ch (equivalent to 0ch), repeaters must be installed at approximately 6kTr1 intervals, but 1
．． In the case of an optical submarine cable that transmits a 280M)lz digital signal (equivalent to 3840 channels of telephone line) using light with a wavelength of 3 μm, repeaters may be installed at intervals of about 55 km. For this reason, there is a tendency to shift from submarine coaxial cable systems to optical submarine cable systems in the future.

Next, when two types of vessels are used to lay an optical submarine cable: a shallow-water laying ship and a deep-water laying ship, for example, when the former is used for laying the cable, as shown in the track laying diagram in Figure 3. The other end of the laid optical submarine cable 2 is led into the land station 1, but one end is terminal-treated and a buoy 3 is attached until the latter starts laying the optical submarine cable (for example, from 1 to 2). (Rikizuki) Cables are left on the seabed, but the cables laid during this period may be cut or damaged by fishing boat anchors or nets, so the presence or absence of such damage must be constantly monitored using a measuring device. It is necessary.

[Conventional technology]

FIG. 4 shows a block diagram of a conventional example. As shown in the figure, 1
One end of the optical submarine cable 2 without a repeater, which was laid in the first test, is housed in a watertight case 5 made of conductive material such as aluminum, waterproofed with taping 6, etc., and left on the seabed. Ru. Therefore, in order to monitor the cable for breakage or damage, the land station connects, for example, a general-purpose optical pulse echo measuring device 7 to the other end.

This measuring device has a transmitting section 71. Receiving section 72. Consisting of a recording section 73, the pulse sent out from the transmitting section 71 and the receiving section 7
A recording unit 73 records the distance to the reflection point based on the time difference between the reflected pulses received in step 2, and if the distance to the reflection point has a predetermined length, it is determined that there is no blemish.

[Problem that the invention seeks to solve]

However, this measuring device measures distance by receiving attenuated light reflected at one end of the optical submarine cable, so for example 2
The problem is that it can only measure up to about 0 km (about 40 km round trip) and is expensive.

[Means for solving problems]

As shown in Fig. 1, the above problem arises when the optical submarine cable is laid in two or more parts, and when the optical submarine cable is laid in two or more stages, the light emitting element part 8 connected to one end of the optical submarine cable 2 that has already been laid is emitted. This can be solved by the line monitoring method of the present invention, in which the optical submarine cable is monitored by receiving light at the light receiving element section 9 connected to the other end.

[Effect]

In the present invention, a light emitting element section 8 is connected to one end of a laid optical submarine cable 2, power is supplied to it via a power supply line 21, and light is transmitted from there. At the land station, the light-receiving level of this light is constantly monitored by the light-receiving element section 9 to monitor whether the installed optical cable is disconnected or damaged.

At this time, since direct light is used instead of reflected light as in the past, it is possible to monitor optical submarine cables up to 55 m long, which is approximately the same as the relay interval, and the monitoring distance becomes longer.
The price is reduced because the measuring device only needs to detect the level of received light.

〔Example〕

FIG. 2 shows a block diagram of an embodiment of the invention.

The same symbols refer to the same objects throughout the design, and the light emitting device section 8 in FIG. 1 is the light emitting diode or laser diode 81 in FIG. 2.

In the figure, a light emitting diode or laser diode 81 is connected between the watertight case 5 of the installed optical submarine cable 2 and the power supply line 21, and a predetermined DC voltage is applied via the power supply line 21 to cause it to emit light.

This light passes through an optical fiber 21 to a land station (not shown).
Since the light-receiving element section (for example, photodiode) 9 provided in the optical submarine cable constantly receives light and monitors its level, it is possible to easily detect whether or not the optical submarine cable is disconnected or damaged.

In other words, since the light sent out from one end of the optical submarine cable is directly used, the monitoring distance is extended to about 55 km in the relay section, and a special measuring device such as a hourglass can be used instead of a general-purpose and expensive measuring device. The cost of the measuring device is reduced because a measuring device is used.

[Effects of the Invention] As described in detail above, according to the present invention, there is an effect that the monitorable distance is increased to about 55 km, and the price is reduced because the measuring device is a dedicated measuring device.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the principle of the present invention, FIG. 2 is a block diagram of an embodiment of the present invention, FIG. 3 is a line layout diagram, and FIG. 4 is a block diagram of a conventional example. In the figure, 2 is an optical submarine cable, 8 is a light emitting element section, and 9 is a light receiving element section. !

Claims (1)

[Claims] When installing an optical submarine cable in two or more parts, the light from the light emitting element part (8) connected to one end of the already laid optical submarine cable (2) is transferred to the light receiving unit connected to the other end. A track monitoring method characterized in that the optical submarine cable is monitored by constantly receiving light in an element section (9).