We confirmed the change in noise suppression effectiveness with and without insertion of ferrite beads.
We also checked to determine if there were any effects on voltage or current waveforms, aside from noise suppression effectiveness.
We checked for changes in ripple noise to confirm effectiveness in reducing noise flowing to the power supply side on transmitter power line ① in the figure below, and we checked for changes in transient response to confirm absence of harmful effects on the voltage waveform at VCSEL power input ②.
We also checked for changes in the current waveform flowing to the VCSEL.
Method of confirming noise suppression effectiveness
Voltage① → Confirmation based on ripple noise
Voltage② → Confirmation based on transient response
Current → Confirmation based on current wave form