Amplification of 120 GBaud (240 Gbps) PAM4 signals with a SHF M827 B amplifier is shown to be possible using equalization techniques of a software-based multi-tap FFE filter.

As the R&D activity for >100 Gbaud PAM4 and coherent technology intensifies, many of our customers are turning to SHF’s family of driver amplifiers in the >60 GHz regime for these demanding applications.

Traditionally, a high-speed sampling oscilloscope has been the standard method characterizing the time domain performance.  However, in the >100 GBaud regime, the limited bandwidth of oscilloscopes has proved to be increasingly inadequate.  To support these techniques and also to provide further evidence to support the potential time domain response of SHF amplifiers in the >100 GBaud regime, SHF has implemented an in-house software-based multi-tap FFE equalizer to illustrate the potential performance of our high bandwidth amplifiers in the regime >100 GBaud.

Example measurements with the SHF M827 B amplifier are shown below. Further measurements of other SHF amplifiers and SHF modules can be requested.

100 GBaud (200 Gbps)

directly sampled
from SHF M827 B amplifier

after
equalization

 

120 GBaud (240 Gbps)

directly sampled
from SHF M827 B amplifier

after
equalization

 

For above measurements the SHF 616 C data source was used to generate a 350 to 450 mVpp signal, whilst the amplifiers are driven within the linear region (below P1dB).  With the equalizer software, a 6-tap configuration was applied to predict the potential output waveform.  This could be a useful base for module developers in pursue of a practical equalizer technology for real system applications.