Understanding optical power meter

Used to measure absolute optical power or relative loss of optical power through a length of fiber. In fiber optic systems, measuring optical power is the most basic, much like a multimeter in electronics. In fiber optic measurement, the optical power meter is a heavy duty common meter. By measuring the absolute power of the transmitter or optical network, an optical power meter can evaluate the performance of the optical equipment. Using an optical power meter in combination with a stable source, it is possible to measure connection loss, verify continuity, and help evaluate fiber link transmission quality.

Optical power meter operation method and precautions

An optical power meter is an instrument used to measure absolute optical power or relative loss of optical power through a length of optical fiber. In fiber optic systems, measuring optical power is the most basic, much like a multimeter in electronics; in fiber optic measurements, optical power meters are heavy-duty common meters. By measuring the absolute power of the transmitter or optical network, an optical power meter can evaluate the performance of the optical equipment. Using an optical power meter in combination with a stable source, it is possible to measure connection loss, verify continuity, and help evaluate fiber link transmission quality.
The use of the source optical power meter should choose different types of optical power meters according to different usage conditions:

1. dB function with direct insertion loss measurement.

2. Make sure these models match your measurement range and display resolution.

3. Evaluate calibration accuracy and manufacturing calibration procedures to match your fiber and connector requirements.

4. Choose the optimal probe type and interface type

Light source optical power meter considerations

Some specifications will only have two parameters of luminous power and transmission distance. Sometimes, the transmission distance calculated by the attenuation per kilometer of fiber is mostly 0.5db/km. The minimum transmission distance is divided 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. The maximum transmission distance divided by 0.5 is the sensitivity. If the received optical power is lower than this value, the link may not work.

The unit of light source optical power is dbm. In the specification of the fiber transceiver or switch, there is its illuminating and receiving optical power. Generally, the illuminating light is less than 0 dbm. 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 value of the de-sensitivity 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 at the time of testing minus the actual received optical power. The value is the fiber loss (db). The best value of the optical power received at the receiving end is the maximum optical power that can be received - (dynamic range / 2), but generally not so good. Because of each optical transceiver and optical module The dynamic range is different, so the specific amount of fiber can allow the attenuation depends on the actual situation. Generally, the allowable attenuation is about 15-30db.

The fiber test TX and RX must be tested separately. In the case of single fiber, only one fiber is used, so only one test is required. The realization principle of single fiber is WDM according to the production company, but I think the possibility of using fiber coupler Higher sex.

There are two ways to connect the optical fiber. One is a fixed connection, the other is a movable connection, and the fixed connection is a fusion connection. The special device is used to discharge, and the optical fiber is melted to connect the two optical fibers together. The advantage is that the attenuation is small, and the disadvantage is that The operation is complicated and the flexibility is poor. The active connection is through the connector, usually connecting the pigtail on the ODF. The advantage is that * for simple flexibility, the disadvantage is that the attenuation is large. Generally speaking, the attenuation of an active connection is equivalent to one kilometer of fiber. The attenuation can be estimated as follows: including fixed and active connections, the fiber attenuation is 0.5db per kilometer. If the active connection is quite small, the value can be 0.4db. The simple fiber does not include the active connection, which can be reduced to 0.3db. The theoretical value is pure. The fiber is 0.2db/km; for insurance, 0.5 is better in most cases.

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