TRACK CHANGING BY USE OF THE PHASE RESPONSE OF MICROSPHERES AND RESONATORS

A microsphere or resonator that is side coupled to an incident optical beam induces a phase response in the beam. In the so-called overcoupl ed regime, the amplitude of the incident beam remains unmodulated, whe reas the phase goes through a shift of pi at resonance. This shift is insensitive to the details of the coupling geometry or the resonant mo de. In conjunction with an interferometer, the phase response can be u sed to switch the beam between two well-defined outputs, thus offering a robust means of deploying microspheres and other microresonators in practical photonic devices. (C) 1998 Optical Society of America.