Reflection Immune Operation
RIO® (Reflection Immune Operation) Incorporates Two (2) Elements:
1) Checks the optical power source to ensure that there is no “self -lock” (i.e. will never allow the SFP to link with its own reflected signal).
2) Uses the DPS™ feature to overcome the operational issue of opening an active link (a more difficult problem to handle).
Reflection Immune Operation – RIO® Eliminates Reflection Problems which Plague Legacy SFSW SFPs. Single Fiber Single Wavelength (SFSW) Transceivers transmit and receive at the same wavelength, on single fiber, doubling the optical fiber plant capacity. SFSW transceivers offer many potential benefits to the Network Operator – e.g. seamless CWDM integration, half the fiber, half the CWDM passives and easier fiber management.
Open connectors, fiber faults and intermittent connections, which commonly occur in field deployments, create optical reflections of varying intensities. SFSW transceivers can be susceptible to signals generated by these reflections in the optical fiber cable plant. For example, the reflection from an open non-angle polished (PC or UPC – Blue) optical connector is about 15 dB. The reflected signal may return to the receiver section of the originating transceiver at power levels well within the operating sensitivity range of the receiver. This may cause the originating transceiver to detect this false signal, appearing to the network switch (or any host equipment) as though it was receiving a proper signal. But, in fact, an optical loopback condition is created in the network, wreaking havoc with network operations.
Since SFSW transceivers suffer such drawbacks in the presence of optical reflections, their application under real-world conditions has been limited compared to that of their two-wavelength single fiber, or, two-fiber cousins. Because SFSW transceivers offer many potential benefits to the Network Operator, a comprehensive solution to the reflection sensitivity problems would provide significant benefits.
RIO® technology solves the SFSW reflection problems. Optical Zonu’s SFC™ and iSFC® Transceivers incorporate Reflection Immune Operation, or RIO® for short. This feature means that our transceivers can recognize reflected signals and will never report a link based upon a false reflected signal… ever.
Integrated into the SFC™ and iSFC® Transceiver hardware and firmware, RIO® is totally automatic in operation and transparent to the host network gear and optical fiber network (PC and UPC Blue or APC Green optical connector types).
Now, for the first time, SFC™ and iSFC® SFSW transceivers may be substituted anywhere a standard two-fiber SFP Optical Link exists.
In Summary – The network operator and network users may now enjoy the benefits of SFSW operation, without any of the drawbacks associated with legacy systems. Reflection Immune Operation – RIO® resolves self-reflection from an open connector and/or other reflectors in the optical fiber network. Only the legitimate remote data is ever transferred to the host equipment.