How to choose the optical receiver
Due to the long transmission distance and fast transmission speed of
optical fiber, it can carry a variety of information at the same time.
Therefore, in CATV, more and more people begin to use optical fiber communication
system. In this system, the optical receiver is responsible for receiving the
transmitted light waves, and with minimal additional noise and distortion,
recovering the information carried by the optical carrier after fiber
transmission, completing the conversion from light to electricity. Therefore,
the output characteristics of optical receiver reflect the performance of the
whole optical fiber communication system.
In CATV, optical receivers can be divided into optical receivers without
filters and optical receivers with filters according to its structure and use.
The optical receiver with filter can be divided into whether it has WDM or not.
Therefore, it is best to choose a suitable optical receiver according to your
needs.
Why do optical receivers
need filters
In today’s optical fiber communication system,
because the optical transmitter and OLT work together, they will output light
waves of many different wavelengths, such as: 1310nm; 1490nm; 1550nm. The
wavelength of light waves that are really useful for CATV is 1550nm, and the
optical receiver with filter can shield the light waves of 1310nm and 1490nm,
leaving only the light waves of 1550nm to be transmitted into CATV.
And the optical receiver without filter will
transmit the light waves of 1310nm, 1490nm, 1550nm into the CATV, which may
have a certain impact on the TV signal, such as noise.
Why do optical receivers
need WDM
First of all, all optical receivers with WDM are
equipped with filters. Whether WDM is needed depends on whether you need
1310nm, 1490nm light waves. For example, if your optical receiver needs to be
connected to an ONU, then you need WDM. WDM can distinguish the 1310nm and
1490nm light waves in the optical receiver and transmit it to the lower-level
ONU. The optical receiver without WDM will only simply shield the 1310nm,
1490nm light wave, and only retain the 1550nm light wave.
Conclusion
Choose the optical receiver according to your
actual usage. For CATV alone, it is best to choose an optical receiver with a
filter, which can only retain the light waves you need and shield other light
waves. If you still need to connect the ONU, it is best to choose an optical
receiver with WDM, which can help you distinguish the light waves required by
the ONU and transmit the corresponding light waves into the CATV and ONU
respectively.
