A prosthesis is provided for implantation into a knee joint compartment between a femoral condyle and its corresponding tibial plateau. An input is received corresponding to a user-selected point near a boundary of a nodule. Thus, since the shutter contacts only the non-information area of the disk, the information area of the disk is protected during an operation of the shutter to open and shut the opening hole. Typically, the PLC waveguide wafer includes a waveguide core region bound by upper and lower cladding layers.