Fig. 4: Schematic of the experimental setup.
From: Theoretical and experimental characterization of non-Markovian anti-parity-time systems
Two nominally identical semiconductor lasers SCL1 and SCL2 are controlled by pump currents J1 and J2 respectively, and independent temperature controllers. The glass slide GS1 (GS2) reflects a small amount (8%) of light to the photodiode PD1 (PD2) to measure steady-state laser intensities I1,2. Mirrors M1 and M2, along with the variable neutral density (VND) filter provide bidirectional, time-delayed feedback. The transmission through the VND, and therefore the coupling κ, is determined by using another laser SLC3 along with a photodiode PD3.
