When testing the loss in conjunction with glass fiber, certain principles must be taken into account all the time.
1 wavelength test must always be the same as the wavelength of the work. Since the loss of glass fiber light varies with the wavelength, you get the wrong result, if your measuring the wavelength is different than the wavelength of the work. For example, if a system is designed to 1550nm, but test with 1310nm light source and measuring device, the result is not correct.
2.The tests light source must be equal to that the work equipment lightwave light source. If the system is an LED, you need to the test with an LED source. If the system is designed for multi-mode laser light, you must have a multi-mode laser light source for the examination. This also applies to the single laser light source
Glass fiber in a test
In a test of the loss of basic configuration, four types of testing are needed. They are the source of light, the meter is the reference to patch cables and adapters (drehsteifer clutch).
Here are some considerations when choosing your equipment.
The light source must be the same wavelength, the functioning material, a good mode (multi-mode and single mode, the same as the hardware operating system) type (LED or laser, as well as the operation of the vehicles) and the wrong connection.
The counter must have the possibility of the same wavelength as the light source, easy access and calibrated.
The reference patch cables are of high quality, at a loss to know, good connections and are the same type as vegetable fibers on the sample.
The adapter (drehsteifer clutch) are high-quality ceramic sleeves and his good guy (FC, SC, LC, etc.).
Understanding dB (decibels) in glass-fibre-test loss
As in any situation, energy, fiber light unit for energy in milliwatts (mW), but a practical unit is dB (decibels).
Decibels (dB) is most common in the electronics test. It is the relationship between two levels. A level is the entrance and the other is the issue. The ratio is calculated by logarithmic, as described below.
By measuring the energy, dB is defined as follows: dB = 10 x log (energy output / input energy)
For example, after a combination of fiber, light on the issue of energy is 50% of its contribution, the loss of connection is 10log (0.5) = -3 dB.
Since dB is actually a report that it is not absolute. So, on the sample of the situation, we have no idea about the actual power in May, from 0.1 mW and 1 mW.
That is why we have a different unit dBm. It is the relationship between the performance measured by the power of 1mW. It is defined as: = 10xlog dBm (measured power/1mW)
For example, a light 0.1mW power expressed in dBm is 10xlog (0.1mW/1mW) =- 10 dBm.
From above, we know that dBm is an absolute unity, we know exactly how it is mW.
For the fiber loss attempts decibels is often used unit, because it is much easier to work. Why? DB, because two values can be easily added or withdrawn. For example, a combination of fiber May, a total of three sections, each with the loss of 0.5dB, 5dB and 0.5dB. The total loss can be easy to conclude that 0.5dB + 5dB + 6 = 0.5dB dB. You can try to convert milliwatts and you will see that I have quite!
Tags: fiber optic, LED, loss testing
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