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What is an optical power meter?
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.
There are even more important factors to consider such as adapter types, relative accuracy, absolute accuracy, display precision and more! We cover these fiber optic power meters, handheld optical power meter and laser power meters in much more details on our web site.
Is there any way to watch dog or horse racing live on my iPhone?
Some tracks can be viewed on a computer but
that does not mean it will work on a iPhone or
other handheld device. Help me out you hardcore
gamblers. Thanks for your help.
The links below should help you in some way or some how..good luck, and enjoy. 
http://www.trackcast.net/index.php
http://horseracing.cbssports.com/cbs/liveracing/
December 22nd, 2009 at 4:18 pm
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