A circulating fluidized bed boiler includes a rectangular furnace having multiple particle separators connected to an upper portion of each of a front wall and a back wall of the furnace. An example of a beam coupler and splitter includes a first waveguide having a first waveguide bevel and a bend, the first waveguide bevel to totally internally reflect at least some light incident thereon. The system further includes a rating module configured to provide a rating to the data item based on the one or more metrics associated with the at least one of the agent or the data item.