We derive generic phase and amplitude coupling relations for beam splitters–combiners that couple a single port with three output ports or input ports, respectively. We apply the coupling relations to a reflection grating that serves as a coupler to a single-ended Fabry–Perot ring cavity. In the impedance-matched case such an interferometer can act as an all-reflective ring mode cleaner. It is further shown that in the highly undercoupled case almost complete separation of carrier power and phase signal from a cavity strain can be achieved.
© 2006 Optical Society of America
Diffraction and Gratings
Original Manuscript: September 19, 2005
Manuscript Accepted: November 3, 2005
R. Schnabel, A. Bunkowski, O. Burmeister, and K. Danzmann, "Three-port beam splitters-combiners for interferometer applications," Opt. Lett. 31, 658-660 (2006)