A system for establishing a session between two entities in a telecommunications network. A source-mount in the first region rotates about the axis, and an X-ray source on the source-mount directs first and second incident beams of X-rays to impinge on the sample at first and second angles along beam axes that are orthogonal to the axis. Also provided is a photonic integrated circuit, PIC, for use in a WDM optical communication system, the PIC including the integrated photonic component.