How to choose an optical power meter and related precautions

How to choose an optical power meter and related precautions

How to choose optical power meter
Optical instrument optical power meters are divided into different models, precision, interface and other parameters. When using, choose the appropriate optical power meter according to the different needs of users, and mainly refer to:

1. Make sure these models are consistent with your measurement range and display resolution.

2. With the dB function of direct insertion loss measurement.

3. Choose the best probe type and interface type

4. Evaluate the calibration accuracy and manufacturing calibration procedures to match your optical fiber and connector requirements.

When choosing meters, temperature is perhaps the most stringent criterion. On-site portable equipment should be at -18°C (no humidity control) to 50°C (95% humidity)

What is Optical multimeter:

Used to measure the optical power loss of the optical fiber link.

There are the following two optical multimeters:

1.      It consists of an independent optical power meter and a stable light source.

2.      Integrated test system combining optical power meter and stable light source

In a short-distance local area network (LAN), where the endpoints are within walking or talking, technicians can successfully use an economical combination optical multimeter at either end, a stable light source at one end and an optical power meter at the other end. For long-distance network systems, technicians should equip a complete combination or integrated optical multimeter at each end.

Precautions
Some manuals will only have two parameters: luminous power and transmission distance. Sometimes it will explain the transmission distance calculated by the fiber attenuation per kilometer, mostly 0.5db/km. Divide the minimum transmission distance by 0.5, which is the maximum light that can be received. Power, if the received optical power is higher than this value, the optical transceiver may be burned out. Divide the maximum transmission distance by 0.5, which is the sensitivity. If the received optical power is lower than this value, the link may not work.
The unit of the optical power of the light source is dbm. It has its luminous and received optical power in the manual of the fiber optic transceiver or switch. Generally, the luminescence is less than 0dbm. The minimum optical power that the receiving end can receive is called sensitivity, and the maximum optical power that can be received is reduced. The unit of the desensitivity value is db (dbm-dbm=db), which is called the dynamic range. The luminous power minus the receiving sensitivity is the allowable fiber attenuation value. The actual luminous power during the test minus the actual received optical power， the value is the fiber attenuation (db). The best value of the optical power received by the receiving end is the maximum optical power that can be received-(dynamic range/2), but it is generally not so good. Because of the characteristics of each optical transceiver and optical module, the dynamic range is different, so the specific allowable attenuation of the fiber depends on the actual situation. Generally speaking, the allowable attenuation is about 15-30db.