As the optical communications industry continues to evolve, industry standards are being established to characterize the performance of optical components. One of these emerging standards is FOTP-203, which characterizes multimode fibers by encircled energy analysis. Encircled energy, as the name implies, describes the energy encircled within a circular radius inside the fiber. It is usually quantified as the radius from the center of the fiber required to encircle 75 percent of the light energy through the fiber. The power distribution of a fiber described by the encircled energy value is a crucial factor in ensuring the required data transmission in Gigabit Ethernet systems. The encircled energy measurement, as specified in FOTP Standard 203, is performed in the following manner. The near field of the fiber is imaged with a microscope objective lens and a CCD camera. The reference center of the fiber is determined from the near-field for a fully launched LED source. Then the telecomm laser source, typically a VCSEL, is installed with an offset launch condition to only excite higher order modes. The encircled energy analysis is then performed for this source using the LED centroid reference. The Photon FO 8350 Encircled Energy Fiber Analyzer is an instrument and software package dedicated to encircled energy measurement of single-mode fiber, as specified in FOTP-203. For more information, visit our web site or contact Photon sales: PH: 408-226-1000; Web site:www.photon-inc.com; Email: email@example.com.