The basic process is straightforward: turn the meter on, set it to the correct wavelength, clean your connectors, plug in, and read the display. But getting accurate, meaningful results depends on understanding a few key details about wavelength settings, reference levels . How to Test a Pigtail with Multimeter? A Step-by-Step Guide Disclosure: As an Amazon Associate, I earn from qualifying purchases. This post may contain affiliate links, which means I may receive a small commission at no extra cost to you. As the components like fiber, connectors, splices, LED or laser sources, detectors and receivers are being developed, testing confirms their performance specifications and helps. An optical power meter measures the strength of light traveling through a fiber optic cable, giving you a reading in dBm (decibels relative to one milliwatt). The conventional method, known as the cutback method, involves coupling fiber to the source and measuring the power out. When a fiber optic system is successfully tested and determined to meet the customer's specific requirements and relevant industry standards, the system performance and individual links can be said to be “certified” to that relevant specification or standard. You measure optical power in dBm or insertion loss in dB. Consistent procedures ensure accuracy. Verify light travels from transmitter to receiver.