Figure 2.

On-chip unscrambling of optical modes. (a) Mixed modes are reconstructed at the output port of the 4 × 4 silicon photonic mesh by sequentially tuning the MZI beam splitters. To reconstruct the first mode (m=1, Mode D) at port Out₁, the first row of the mesh (M₁) is configured by progressively nulling the light intensity at the lower output arms of MZI S₁₁, S₁₂ and S₁₃, where a CLIPP detector is integrated (b). (c) Normalized power of Mode D measured by CLIPP1 integrated after S₁₁. Depending on the initial MZI biasing (Sⁱ₁₁), convergence to different equivalent solutions S^f₁₁ (local minima of the map) may be achieved.