Multifunction optical filter with a Michelson-Gires-Tournois interferometer for wavelength-division-multiplexed network system applications.

We propose using a novel multifunction optical filter with a Michelson-Gires-Tournois interferometer (MGTI) for future smart wavelength-division-multiplexed network system applications. The MGTI filter is a typical Michelson interferometer in which one of its reflecting mirrors is replaced with a Gires-Tournois resonator. One unique feature of this device is that it can function as a channel-passing (CP), a channel-dropping (CD), or a wide-bandpass (BP) filter, depending on the interferometer arm-length difference. Other interesting features are that (1) the linewidths of both the CP and the CD filter are twice as narrow as that of a typical Fabry-Perot filter with similar parameters, (2) theoretical visibility is always unity regardless of the mirror reflectance value, and (3) the BP filter has an excellent boxlike response function. Numerical results showing these characteristics are presented.

Optical wave-front transformer using the multiple-reflection interference effect inside a resonator.

We propose a new class of optical wave-front transformer based on a different mechanism that uses the multiple-reflection interference effect in a Gires-Tournois resonator (GTR) as the physical mechanism for phase modification. By coating the front surface of a GTR with a predefined graded reflectivity profile, one can synthesize various optical elements. We present the basic concept of our proposal by synthesizing a lenslike element as a proof-of-principle example. One unique feature of this element is that it can function as a reflecting mirror, a converging lens, or a diverging lens, depending on the resonator length. Other applications are briefly discussed.