Different measurement devices are used to test optical fibres. In addition to analyzers and power measurement devices, optical sources that can be readout with the help of monitors are also used.
Convenient measurement of optical power.
The optical power inside fibres can easily be measured with the in-line monitors of the 500 series. They make it possible to digitally display the optical power currently being transmitted. The display can be switched between absolute and relative power.
The 500 series is available for SM, MM, and PM fibres.
With the in-line power meter "Series 100" by Eigenlight one can easily determine the power of light that goes through a fibre. The monitor is connected to the fibre and diverts a small portion of the beam onto an photodiode, which creates a photo current proportional to the optical power.
The device uses epoxy-free optical paths; however, it does not use massive optics and does not employ scatter field coupling.
The optical components are packed into a hermetically sealed, inexpensive miniature housing. They can also be equipped with a standard single mode fibre (SMF28) or a special polarization maintaining Panda fibre. Applications can be found wherever optical power has to be measured inside fibres, e.g. fibre amplifiers (EDFA), Raman amplifiers, optical switches, DWDM mux/demux systems, etc.
With the in-line power meters Series 500 by Eigenlight one can easily determine the power of light that passes through a fibre, absolute or relative.
As a specialty these devices offer a directivity. Even though light can pass in both directions equally well, only the optical signal of one direction is detected. In this way it is easy to measure the back reflection of an optical component, for example. First, the unit is connected between source and test sample. Then, a 100% reference reflector (optional accessory) is connected and its reflection is measured. Finally, the test sample is measured. The light travels from the source through the monitor (where it is undetected) to the test sample. The signal that is reflected back is measured by the monitor and given a value for its reflection.
The power monitor is also suitable for online measurements of optical amplifiers. Power monitors without housings (Series 100) are available for OEM applications.
Measuring the amplification of optical amplifiers during operation is also easy. One monitor is connected to the input fibre, another to the output fibre. In bidirectional transmission systems two reversely inserted monitors can measure the powers in both directions independently and simultaneously. Further uses include power monitoring in fibre optical systems, test of alarm thresholds, system tests, and many more.