An RFTS is a test system designed to improve the efficiency of operation and maintenance management of optical fibre lines which are installed at a fibre-optic cable termination station. The system works by constantly monitoring individual fibres in the cable using the OTDR technology for continuous measurements and is able to indicate a failure location on an electronic map. Having done so it then notifies maintenance staff.
The test system is intended to speed up the identification and location of failures (such as increased loss, fibre breaks and water ingress) and it also enables a maintenance centre to test the installed equipment as a remote manual test during cable installation.
The ability to perform automatic testing of multiple fibres at once saves installation labour time and costs and reduces the overall work period required.
“In today’s competitive environment detecting fibre degradation before failure while reducing mean time to repair is key”, says Terry Marrinan, Vice-President, Test & Measurement, Europe & South East Asia, for Yokogawa Test & Measurement Europe. “The time saved by using an RFTS to locate and isolate the first fibre break can pay for itself by yielding a full return on investment and achieving a higher level of customer satisfaction through improved quality of service.”
The hardware of the AQ7277B OTDR module is based on Yokogawa’s AQ7280 OTDR, using its optical performance in terms of short dead zone (0.6 m typical) and high dynamic range (up to 50 dB). Moreover, its size is reduced by 60% compared to its predecessor, which improves its integration into the RFTS. Its dimensions are now 230 mm (W) × 50 mm (H) × 140 mm (D), and weight is approximately 1 kg.
There are two models in the AQ7277B family, both equipped with an Ethernet (10BASE-T/100BASE-TX) interface as standard. The AQ7277B-B01 takes measurements at 1650 nm, a wavelength which does not affect the communication wavelengths of 1310/1490/1550 nm. It is equipped with a built-in cutoff filter to isolate it from wavelengths lower than 1650 nm, and so can perform accurate measurements on “live” lines (where active communication signals are travelling). This model is also optimised for testing passive optical networks (PON), and can measure through the high-port-count splitters used in modern PON systems.
The AQ7277B-B02 is designed for monitoring long-distance optical fibres – greater than 200 km in real-life environmental conditions - -being capable of a 50 dB dynamic range. It operates at a wavelength of 1550 nm.