Figure 1
From: Collapse on the line – how synthetic dimensions influence nonlinear effects
Experimental realization of light propagation on a 2D mesh lattice. (a) Experimental set-up consisting of two pairs of fibers connected via 50/50 couplers. In front of each loop, consisting of about 30 km of optical fiber, there is an erbium-doped fiber amplifier (EDFA) for loss compensation. Acoustic optical modulators (AOMs) in the inner and Mach-Zehnder modulators (MZMs) in the outer pair allow for amplitude modulation. Additionally, phase modulators (PMs) are placed in the inner and outer right loop. (b) and (c) Equivalent 2D lattice and measured time trace at the photodetector (PD) of the inner loop: A pulse is created and injected into the outer left loop. During each round trip, it splits in the fiber couplers and generates four smaller pulses with different arrival times according to the fiber pieces they have passed. The power of the pulses is measured in each round trip m (blue line), sampled electronically (black dashed line) by a computer software and mapped onto a 2D lattice according to the arrival times (here displayed for m = 2) Thus pulses effectively propagate on a 2D synthetic lattice where a step in +/− x direction corresponds to a passage through the longer/shorter inner loop and transport in +/− y – direction is realized by transits through the long/short outer loop.
