Fiber-Optical Measurement Devices

In optical measurement technology, different measurement devices are used to test optical fibers. In addition to analyzers and power measurement devices, optical sources that can be readout with the help of monitors are also used.

In-Line Monitors

Convenient measurement of optical power.

Fiber-Optical Measurement Devices

Description

The optical power inside fibers can easily be measured with the in-line monitors of the 300 and 400 series. The devices have LCD displays on opposing sides for better readability. Depending on the type of monitor, the insertion loss is between 0.3 and 2.0 dB. Versions for single mode, multi-mode, and polarization-maintaining fibers are available.

Series 100: Measuring Power Inside the Fiber

With the in-line power meter "Series 100" by Eigenlight one can easily determine the power of light that goes through a fiber. The monitor is connected to the fiber and diverts a small portion of the beam onto an InGaAs 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 insertion loss of 0.05 dB is very low. The reflection is below –70 dB and the polarization dependent loss is below 0.01 dB. The directivity is better than 30 dB and the power limit is +32 dBm.

The optical components are packed into a hermetically sealed, inexpensive miniature housing. They can also be equipped with a standard single mode fiber (SMF28) or a special polarization maintaining Panda fiber. Other single mode fibers and special specifications are available upon request. Applications can be found wherever optical power has to be measured inside fibers, e.g. fiber amplifiers (EDFA), Raman amplifiers, optical switches, DWDM mux/demux systems, etc.

Optical Power Meters with Directivity

With the in-line power meters "Series 300" and "Series 400" by Eigenlight one can easily determine the power of light that passes through a fiber, absolute or relative. The dimensions of the monitors are only 9.7 x 3.7 x 3.6 cm.

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 are available for OEM applications.

Measuring the amplification of optical amplifiers during operation is also easy. One monitor is connected to the input fiber, another to the output fiber. In bidirectional transmission systems two reversely inserted monitors can measure the powers in both directions independently and simultaneously. Further uses include power monitoring in fiber optical systems, test of alarm thresholds, system tests, and many more.

The devices have LCD displays on opposing sides for better readability. Depending on the type of monitor, the insertion loss is between 0.3 and 2.0 dB. They are automatically switched on and off, controlled by light.