What Is an Optical Power Meter?
An optical power meter measures the intensity or power of light, particularly in fiber-optic communications. It may also be referred to by other names, such as a laser power meter, irradiance meter, photometer, or illuminance meter, based on the light type and measurement units involved. Despite the varied terminology, all these devices serve the fundamental purpose of quantifying light’s physical intensity.
Uses of Optical Power Meters
Optical power meters precisely measure the absolute light intensity from various sources, including optical fiber communication wavelengths, lasers, and LEDs. They are essential for ensuring the safe and efficient use of light sources, especially in preventing harm from overexposure to intense light, which can be hazardous to living organisms, including eye damage.
Principle of Optical Power Meters
Optical power meters utilize sensors such as photodiodes and biosensors that employ the photoelectric effect to translate light intensity into measurable physical values like current or temperature changes. These devices typically feature a semiconductor sensor to detect light intensity and an indicator for result display. Calibration at specific wavelengths is crucial for accurate measurements due to the sensors’ varying efficiency in converting light intensity based on the wavelength of received light.
Other Information About Optical Power Meters
1. About the Optical Wavelengths Handled by Optical Power Meters
While optical power meters measure light intensity, they do not measure wavelengths directly. Users must set the measurement wavelength, and the device uses a corresponding calibration. Meters often support selectable wavelengths, catering to applications from Blu-ray and DVD production to optical fiber communications, with popular ranges including 400 nm to 700 nm for visible light and 1,300 nm to 1,550 nm for fiber optics.
2. Points to Keep in Mind When Measuring Optical Power
Choosing the appropriate optical power meter for the wavelength of interest is crucial for accurate measurements. Photodiodes, based on the photoelectric effect, vary in their wavelength handling capabilities; for instance, InGaAs photodiodes cover 800 nm to 1,700 nm, suitable for near-infrared through certain fiber optic communication bands, whereas Si-based photodiodes are better for visible light. Consistency in measured wavelengths, stable temperature, and a vibration-free environment are vital for reliable evaluations, especially in optical fiber communications where wavelengths can vary with temperature and mechanical stress.