There are three test challenges for 5G / data center optical module:
1.The higher data rate of optical module from 10g to 25G, the change of optical module electric chip. The increase of high frequency signal, especially for long distance, needs to increase CDR chip processing. In order to deal with signal jitter, signal attenuation, jitter tolerance measurement, pressure eye test is done at the receiving end, and reception equalizer is introduced for 25G optical module.
2. New modulation mode, more complex need to be tested.
3. Balance of fiber resources, distance, performance and cost: many kinds of multiplexing technologies in 5G network. Including the use of optical fiber white tape, PON, in order to save as much as possible on the front transmission fiber, the use of wavelength division technology.
The WDM technology applied in 5G optical carrier can be divided into coarse wavelength division multiplexing, medium wavelength division multiplexing, fine wavelength division multiplexing and dense wavelength division multiplexing.
There are six wavelengths in the coarse wavelength division, and the number of wavelengths in the middle wavelength division and dense wavelength division will double. The maximum wavelength of DWDM is 40, and the wavelength interval is from 20nm to 0.4nm.
The application of WDM in 5G carrier network needs to test CWDM / DWDM in the optical module. There are two ways. The first is wavelength scanning test, which will use broadband light source and spectrometer, and the other way will use adjustable laser source and optical micro mirror or combine with polarization synthesizer to test. The difference between the two methods is that the spectrometer covers a wide range of wavelengths. But the shortcomings are obvious, the test speed is slow, the efficiency is not high, and the test completeness is insufficient. So many of them will use adjustable laser source and optical micro mirror scanning test.
