Submarine Cable Line Monitoring System

The SLM 1630 provides the line monitoring function for the submarine communication system.

The submarine communication system is characterized by the stable and reliable communication quality, good privacy and inconspicuousness, and strong anti-interference ability. As a means of transoceanic communication, this system surpasses any other communication means. As the large-capacity submarine system is widely used, the submarine cable faults have increasing effect on the society. Therefore, the faults of submarine cable lines must be located in a fast and accurate manner.

Networking

As the submarine cable line monitoring equipment, the SLM 1630 is used to monitor the working status and locate faults of the submarine system. In the case of a system that has repeaters (RPTs), the SLM equipment can monitor the current fiber status and repeater status. By analyzing the backscatter detection light, the equipment can also locate faults of a line and monitor the transmission performance of the submarine system. On the U2000 Web LCT, you can query the fault location information and performance events reported by the SLM equipment.

The SLM 1630 is used together with the SLTE equipment in landing stations of the submarine system.

Figure 1 Usage of the SLM 1630 in the submarine system

OTDR Technology

The SLM 1630 uses the optical time domain reflectometry (OTDR) technology to locate faults of a line. Based on the OTDR technology, detection optical pulses are transmitted into the fiber and then are scattered by scatter particles. If the detection optical pulses reach the fiber crack area, Fresnel reflection occurs. The Fresnel reflection light and Rayleigh backscatter light are transmitted into the receiver by using the beam splitter, and then become electrical signals that change with the time. By using the OTDR technology, you can determine the distance between the fault point and measurement point correctly. The SLM 1630 transmits services at C band and uses different wavelengths for detection light and service light.

See Figure 2. In the transmit direction, the optical multiplexer multiplexes the service optical signals and detection optical signals from the SLTE equipment into the submarine cable. In the receive direction, the optical signals from the submarine cable are split into backscatter detection light and service light by the filter. The service light is transmitted into the SLTE equipment, and the backscatter detection light is transmitted into the line monitoring board to perform detection and analysis and to report the line information to the U2000 Web LCT.

Figure 2 OTDR technology in the submarine communication system