Figure 3. Multimode entanglement via emulated linear optics networks.

Squeezed light and vacua are mixed together using unitary operations in order to produce entangled mode states. Unless otherwise stated beamsplitters are 50% reflective. Other reflectivities are denoted by splitting ratios; 2:1 denotes a 33% reflectivity, and 3:1 denotes a 25% reflectivity. Superscripts denote mode basis and subscripts denote mode number; there is a one-to-one correspondence between spatial mode bases shown here and those shown in Fig. 2 . (a) The emulated linear optics network used to measure 2-mode EPR entanglement . (b) 8-mode entanglement via a calculated concatenation of beamsplitter and π phase shift operations . The dots between a and b imply virtual networks for N=3...7, again not shown for brevity.