Dear Arjina,
Please refer to the different examples in the Example Library of OptiSystem on these topics. There are examples on RoF and active mode-locked lasers. Please note that the signals either electrical or optical are sampled signal and the signal generated by Mode-locked laser is noise signal which you can be converted to sampled signal using the components in Default/Signal Processing Library/Tools/Optical or Default/Signal Processing Library/Tools/Electrical.
Regards,
Ahmad