Implementation of a Reconfigurable Optical Logic Gate Using a Single I/Q Modulator With Direct Detection

We propose and investigate a new scheme to realize all-optical logic gates using a single I/Q modulator with direct detection. Both intensity and phase of the optical signal are utilized to represent the four different states of two binary inputs, whereas direct detection is used to map the four states to the corresponding binary output. This structure is very simple and has the potential to reach high speed. All of the basic logic gates can be implemented by adjusting the bias voltages of the two arms, peak-peak voltages of the driving signals, and the phase shift. Experiments are successfully carried out to realize all six basic logic gates at the data rate up to 10 Gb/s with eye diagrams clearly observed. Extinction ratios (ERs) of the output signals are increased for all these logic gates, compared with the original input signals. ER decreases when increasing the data rate from 1 to 10 Gb/s. Up to 24 logic gates can be implemented by using a single I/Q modulator.