Optical Time-domain Reflectometer (OTDR)

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Incorporation of Micro-OTDR (uOTDR™) for Fibre Fault Detection and Localisation

Uniquely, Metrodata's EDD family supports fibre fault detection and localisation capabilities, expanding the range of tools available to the Carrier for the provisioning and trouble-shooting of fibre-based Ethernet networks.

Metrodata's FCM9002, FCM9003, FCM9004 and FCM9005 EDDs now include software drivers to support the iSFC® Fast Fiber Fault Finder transceivers manufactured by Optical Zonu Corp. of California. Installed just like other plug-in fibre interfaces, to either LAN or WAN SFP ports of the EDD, these single-fibre, full duplex transceivers have built-in 'Optical Time-domain Reflectometer' (OTDR) functionality.

iSFC ®Fast Fiber Fault Finder transceivers transmit and receive at the same wavelength and are therefore generally to be used in pairs. Within the family are variants both with and without the OTDR functionality, so it is possible to pair these devices such that the OTDR variant is at just one end of a fibre link, or both, as required.

When deploying the iSFC ® Fast Fiber Fault Finder with uOTDR ™, when the link is broken or disconnected, the optical fibre fault-detection mechanism calculates the distance to the fault along the fibre path. In combination with the EDD, this can trigger an alarm to a Service Provider's Network Operations Centre and report both the loss of communications and the distance to the problem, allowing fast remedial action to be undertaken, as illustrated below.

iSFC Fibre Fault Detection

The OTDR functionality underpinning this capability is based on the principle of measuring the time delay between transmission of a pulse of light from the optical transceiver and reception back at the transceiver of a corresponding pulse 'reflected' back from the discontinuity (i.e. the breakage or disconnection point). This is represented graphically in the diagram below.

iSFC Fibre Break

Metrodata Ltd. is the strong first EDD vendor to incorporate full commercial support for automated OTDR-based fault detection in this manner, and is pleased to be working in co-operation with Optical Zonu Corp. to bring not only comprehensive Ethernet service monitoring in terms of throughput, packet-loss, latency and jitter, but now also physical layer fibre fault detection and localisation, to its Telecoms Carrier and Ethernet Service Provider customers.