Return-to-Zero Modulator using a Single NRZ Drive Signal and an Optical Delay Line Interferometer

We propose and demonstrate a new technique for variable duty cycle return-to-zero (RZ) modulation, employing a phase modulator driven by a single electrical non-return-to-zero (NRZ) signal and an optical delay-line interferometer. Unlike other methods for generating RZ, no synchronisation between two electrical driving signals is needed.