Fig. 3: Experimental platform.
From: Experimental adaptive Bayesian estimation of multiple phases with limited data
A type-II parametric down conversion source (PDC) generates photon pairs, which are spectrally selected via interference filters (IF) and coupled to single-mode fibers (SMF). One of the photons is directly measured by detector DT acting as trigger for the experiment. The other photon, after polarization compensation (PC), can be injected in any of the three input ports of the interferometer via a single-mode fiber array (SMFA). After evolution, photons are collected via a multimode fiber array (MMFA) and measured through detectors Di, with i = 1, 2, 3. Coincidences between DT and any of Di are recorded via a time-to-digital converter. The results of the measurement are processed and employed to apply the adaptive protocols. The layout of the integrated circuit (shown in the bottom panel) includes eight resistors to modulate the input transformation (RA), the output one (RB), and the internal phases (Ri, with i = 1, …, 6) as described in the main text.
