Fig. 4.

Coherent diffusive equalisation in a dissipatively coupled waveguide array. a–c Experimentally measured intensity distributions for three different values of γt ↔ κ ₁ z. Here, the maximum propagation distance of the device is z = 30 mm, κ ₁ is tuned by varying the wavelength (λ) of incident light, as in Fig. 3. The central waveguide of the chain, indicated by the white circle, was excited at the input for all measurements. In this device, the waveguides in the chain are coupled via identical reservoirs, each containing twenty coupled waveguides. d–f Numerically calculated intensity distributions corresponding to a–c respectively