What are fiber optic loopback modules

Fiber Optic Loopback modules are also called optical loopback adapters. There are LC loopback modules, SC loopback modules and other types. They are designed for testing, engineering and the burn-in stage of boards or other equipment. Optical loopback adapters provide system test engineers a simple but effective way of testing the transmission capability and the receiver sensitivity of network equipment. Fiber Optic Loopback Modules are designed for testing and engineering purposes. Fiber Optic Loopback Modules provide system test engineers with a simple but effective way of testing the transmission capability and receiver sensitivity of fiber optic network equipment. Fiber Optic Loopback Modules may also be used for the burn-in stage of boards and other equipment. Fiber Optic Loopback Modules incorprate two fiber optic connectors. One fiber optic connector is plugged into the output port, while the other fiber optic connector is plugged into the input port of the equipment. :: How to use: One connector is plugged into the output port, while the other is plugged into the input port of the equipment. :: Other Information Fiber Optic Loopbacks are designed to provide return patch for a fiber optic signal. They are used for fiber optic testing applications or network restorations. When used in testing applications, loopback signals are used for diagnosing problems. The best practice is to send a loopback test to network equipment, one at a time for isolating the problem. Fiber optic loopback modules are made with a variety of fiber cable jacket types and cable diameters. We provide fiber optic loopbacks according to industry standard, all products are fully tested before shipping. Fiber optic loopbacks are designed in a compact footprint. They are compliant with fast Ethernet, fiber channel, ATM and Gigabit Ethernet. Common fiber optic loopbacks types are: SC fiber optic loopback, FC fiber optic loopback, LC fiber optic loopback, MT-RJ fiber optic loopback. Fiber Optic Loopback Specifications: Insertion loss: Less than 0.2dB Exchangeability = 0.2 (500 cycle passed) Operating temperature range: Less than 0.2 dB ( -40 to +80°C) What types of Fiber loopback modules are available? The most popular types of fiber optic loopback modules are SC, LC, FC and MTRJ connector types. But each connector type is divided again by fiber type, connector polish type and attenuation. >>Fiber Types Each connector type is available for three fiber types. They are 10G OM3 50/125um multimode, OM2 50/125um multimode, OM1 62.5/125um multimode and 9/125um single mode. >>Connector Polish Types Only PC polish is available for multimode type fibers. But for single mode fiber, two connector polish types are available: UPC polish and APC polish. >>Working Wavelength In addition to fiber type, working wavelength is the other important factor for choosing the correct fiber optic loopback module for your specific application. Available wavelengths are 850nm, 1310nm and 1550nm. 850nm and 1310nm are for multimode applications and 1550nm is for single mode applications.

Fiber optic transceiver loopback test

Fiber optic transceiver is the fundamental part in any fiber optic communication network equipment. Its function is exactly the same as your computer’s Ethernet Card. (although almost all modern computers integrate it on the motherboard, not as a separate PCI card anymore)

Fiber optic transceiver has two ports, a transmitter port and a receiver port. The transmitter 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 use a fiber optic loopback module to verify the transceiver is working perfectly as designed instead of using another transceiver as its partner.

Basically what the loopback module does is directly routing the laser signal from the transmitter port back to the receiver port. Then we can compare the transmitted pattern with the received pattern to make sure they are identical and have no error.

What is a loopback test?

A Fiber optic loopback test is a hardware or software method which feeds a received signal or data back to the sender. It is used as an aid in debugging physical connection problems.

What types of Fiber loopback modules are available?

The most popular types of fiber optic loopback modules are SC, LC and MTRJ connector types. But each connector type is divided again by fiber type, connector polish type and attenuation.

    

Fiber Types

Each connector type is available for three fiber types. They are OM2 50/125um multimode, OM1 62.5/125um multimode and 9/125um single mode.

Connector Polish Types

Only PC polish is available for multimode type fibers. But for single mode fiber, two connector polish types are available: UPC polish and APC polish.

Working Wavelength

In addition to fiber type, working wavelength is the other important factor for choosing the correct fiber optic loopback module for your specific application. Available wavelengths are 850nm, 1310nm and 1550nm. 850nm and 1310nm are for multimode applications and 1550nm is for single mode applications.

Fiber optic Attenuation

You can specify how the signal power level should be reduced in the loopback path. This is because the receiver port cannot handle very high power. And in real life fiber optic network, there are always attenuations introduced by fibers, equipment and physical environment. So the transmitter power is attenuated to a safe level through the network before reaching the other receiver.

However since you are routing the transmitter directly back to the receiver, attenuation usually must be added to protect the receiver.

How much fiber optic attenuation should be added depends on your transceiver type and you must decide it by yourself. Fortunately, there are a wide range of attenuation options available from 0dB, 1dB, 2dB to 24dB or even more.

Fiberstore offer fiber lookback module，fiber optic transceiver and other fiber optic products