Fiber Optical Line Protection Switches


Photonwares produces net-ready Optical Line protection (OLP) switches featuring ultra-fast switch (<100ns) so that minimum data will be lost in the event of a fiber link failure. OLP enhances and secures the reliability of an optical network by using two routes in which one is active and another a redundant standby fiber line. OLP is used in pairs, one at each end of the optical network transmission line. It has optical tap detectors constantly monitoring optical power of the active optical fiber as well as the standby optical fiber. A build-in testing laser is launched into the standby fiber to make sure its integrity. In case the optical power inside the active fiber gets lower than a user-defined threshold, the OLP automatically switches the link to go through the standby fiber, restoring the communication and services.
Photonwares provides 2 types of line protection: 1:1 line protection and 1+1 line protection. Wavelengths and connectors can be customized to meet special control and applications. The device is available with standard 1U rackmount and Pluggable Module.

OLP 1:1
The most commonly used OLP is OLP 1:1, as shown in the diagram below, consisting of the main fiber route and a standby fiber route between the two sites and associated fiber optical switches. In normal operation, the data are transmitted and received through the main route. Inside ILP, detectors are incorporated at Rx ports to detect the decreasing of the optical power. When a fault is detected on the main route, the system will switch both the transmitting and receiving from the main route to the standby route. The advantages of 1:1 OLP system are low optical insertion loss, and the optical fiber for the backup path can also be used for other business.
OLP 1+1
OLP 1+1 is shown in the following diagram, in which the optical power from Tx is split into two with a ratio of 50:50 and transmits through both main and standby routes. While for Rx, the optical signal with better quality will be selected when a fault is detected. The advantage of OLP 1+1 system is less optical switching. However, there will be larger insertion loss compared with the OLP 1:1 system.