Fig. 2
From: High-dimensional optical quantum logic in large operational spaces
a Experimental setup of the state preparation, the X gate, and the state measurement. IM intensity modulator, PM phase modulator, MZM Mach–Zehnder modulator, PZT piezo-electric-phase shifter, SPD single-photon detector. The circle-shaped fibers indicate the delay; each circle is equivalent to one time-bin delay (6 ns). b The transformation matrix. c Counts measured after overlapping all three output time bins, for a time-bin superposition state input into the X gate. The blue errorbars are obtained from five measurements for each phase. The subtracted background was about 200 per 2 s
