SOLIHULL, U.K. -- Arden Photonics has launched a new product, the MPX-1, for measuring the Mode Power Distribution (MPD) of multimode optical fibres. MPD is an important factor in accurate measurements of both bandwidth and loss.

The MPX-1 provides a comprehensive measurement capability, which enables users to measure MPD directly as well as to calculate international standard parameters such as Coupled Power Ratio (CPR) and Encircled Flux.

The results of both bandwidth and loss measurements in multimode fibres are strongly dependent on the distribution of modes in the fibre. With the advent of 1Gb and 10Gb multimode systems, there is an increased awareness that bandwidth as well as loss can limit the ability of a system to carry the traffic for which it was designed. The widespread use of VCSEL laser sources as transmitters also confuses the situation because the modal properties of VCSELs are very different to the measurement equipment used to characterise the installed system. Discrepancies between OTDR and Insertion Loss measurements can also be attributed to the modal launch conditions of the light source. So it is vital to know not only which modes are being launched into the fibre under test but also whether they propagate down the fibre. The MPX-1 will measure in real time the mode profile of the fibre under test. Test fibres can be connected to the MPX-1 using a range of industry standard connectors.

Using the MPX's control software, operators can quickly achieve a direct measurement of the distribution of power among the various modes in a multimode fiber. The measurement technique, which is based on established standards, consists of analyzing the near-field distribution at the end of a fiber patchcord using high speed video and image processing techniques. Real-time visualization of the modal distribution enables the effects of mode-filters and fiber handling to be studied and optimized.

The MPX-1 has already found applications in qualifying multimode fiber couplers, LED LAN test sources, OTDR test equipment, VCSEL laser sources for Gigabit Ethernet and the development of mode-filters and mode-scramblers. Measurements are performed at 850nm.

Arden Photonics Ltd.