A loopback test can be a hardware or software method which feeds a received signal or data to the sender. It is actually used being an aid in debugging physical connection problems.
Fiber optic transceiver is definitely the fundamental part in almost any fiber optic communication network equipment. Its function is identical to your computer’s Ethernet Card. (although virtually all modern computers integrate it on the motherboard, less a separate PCI card anymore)
Fiber optic transceiver has two ports, a transmitter port and a receiver port. The direct attach cable port sends out laser signal to a linked transceiver and the receiver port receives laser signal from the other transceiver.
On fiber optic transceiver manufacturing floors and in R&D labs, we usually work with a fiber optic loopback module to verify the transceiver is working perfectly as designed as opposed to using another transceiver as its partner.
Basically exactly what the loopback module does is directly routing the laser signal from your transmitter port to the receiver port. We can compare the transmitted pattern with the received pattern to make certain they are identical and get no error.
The most common types of fiber optic transceiver are SC, LC and MTRJ connector types. But each connector type is split again by fiber type, connector polish type and attenuation.
Each connector type is accessible for 3 fiber types. These are 50/125um multimode, 62.5/125um multimode and 9/125um single mode.
Only PC polish is offered for multimode type fibers. But also for single mode fiber, two connector polish types are available: UPC polish and APC polish.
In addition to fiber type, working wavelength is definitely the other essential aspect for selecting the appropriate fiber optic loopback module to your specific application. Available wavelengths are 850nm, 1310nm dexhpky91 1550nm. 850nm and 1310nm are for multimode applications and 1550nm is perfect for single mode applications.
You may specify exactly how the signal power level needs to be reduced in the loopback path. Simply because the receiver port cannot handle quite high power. And in person fiber optic cable, there are always attenuations introduced by fibers, equipment and physical environment. So the transmitter power is attenuated into a safe level throughout the network before reaching another receiver.