Since optical power is a zero bounded positive quantity, signals from a detector observing such modulated light will similarly be zero bounded positive signals. To make a peak-to-peak measurement, the power meter captures both the maximum and minimum values of the. An optical power meter (OPM) is a device used to measure the power in an optical signal. It's very useful in many jobs, especially in communications, fiber optics, andelectronics. They are designed to measure the power of optical signals, which is essential for ensuring the proper functioning of optical systems. In this article, we will explore the definition.