People are usually familiar with electronic multimeters which can measure voltage, current and resistance. An optical power meter looks and works just like a multimeter. It consists of a display unit and a calibrated sensor to measure the light power transmitted in optical fibers.

Where is it used?

Optical power meters are broadly used in the fiber optic communication industry. It usually comes in two types: desktop type and handheld type.

The desktop type has much higher resolution and is usually used in R&D applications in the lab, fiber optic components and systems manufacturing floors.

The Handheld type has lower resolution and comes in a handy handheld footprint for easy field use. So it is regularly used by fiber optic cabling technicians in datacom, telecom and CATV network maintenance.

Working wavelength of the power meter

In the handheld optical power market, the most popular wavelengths are 850nm, 1300nm, 1310nm and 1550nm. 850nm and 1300nm are for multimode applications. 1310nm and 1550nm are for single mode applications.

It is best to choose an optical power meter which is calibrated for all four wavelengths to get the most out from your money. So you can cover both multimode and single mode network applications.

Traceable calibration of fiber optic power meters

Power meters are calibrated using a traceable calibration standard such as an NIST standard. NIST laboratories provide measurements and standards for U.S. industry.

Detector types

The optical detector in a handheld optical power meter is responsible for converting light energy into electronic volt so the circuit board in the instrument can measure it accordingly. The type of detector determines wavelength range and its dynamic range.

Silicon type detectors can sense 350nm to 1100nm wavelength light. Germanium detectors can sense 750nm to 1800nm. The most popular InGaAs detectors can measure 850nm to 1650 nm.

What is dynamic range?

An optical power meter's dynamic range spec tells you what light power range it can effectively and correctly measure.

When we talk about light power, we usually use the unit dBm. As a reference, 1mW light energy is defined as 0 dBm. So a 2mW light energy can be defined in dBm as 10*log10(2mW/1mW) = 3.0 dBm. And 0.5mW is defined in dBm as 10*log10(0.5mW/1mW) = -3.0 dBm.

So a handheld optical power meter with -50~+3dBm dynamic range actually can measure light energy from 0.0001mW to 2mW.

Manufactures of optical power meters

The handheld power meter market is crowded with Agilent, Anritsu, EXFO, Noyes and some other less known brand names. But this type of product is pretty mature and usually you can safely shop around.

Agilent demonstrated a new optical power meter with four or eight power-sensor channels that provides manufacturing users with increased throughput and operational efficiency. Designed for characterizing optical multi-port components, these optical power meters provide device connectivity, high-speed measurement data acquisition, and fast data transfer for post-processing.

There are many more important factors to consider when choosing your ideal optical power meter. Such as adapter types, relative accuracy, absolute accuracy, display precision and more. We have a more detailed coverage on these on our web site.