title: Universally balanced photonic interferometers.
abstract: A new general class of optical interferometers is proposed, and the physical principle of their operation is explained. They split the spectrum entering one input port among the interferometer arms in an arbitrarily chosen wavelength- and/or time-dependent manner but guarantee broadband constructive interference into a single output port by symmetry. The design relies only on time reversibility of Maxwell's equations and a phase condition that holds for lossless, reflectionless four-ports. As an application, a new Vernier scheme is proposed to multiply the tuning and free spectral range of microphotonic add-drop filters. It provides effective suppression of both the amplitude and the phase response of unwanted resonant passbands.
authors.affiliation: Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. milos@mit.edu
authors.forename: Milos A
authors.initials: MA
authors.lastname: Popović
authors.forename: Erich P
authors.initials: EP
authors.lastname: Ippen
authors.forename: Franz X
authors.initials: FX
authors.lastname: Kärtner