Tunable Fano resonance with an ultra-wide free spectral range from a photonic integrated circuit.

In this paper, a reconfigurable photonic integrated circuit that can produce various resonances is proposed and demonstrated. Particularly, it can generate a high performance Fano resonance with an ultra-wide free-spectral range. Moreover, the extinction ratio, slope rate, and center wavelength of the Fano resonance are tunable using integrated phase shifters. This work paves the way towards a variety of new applications, including low threshold lasers, low power consumption modulators, and high sensitivity sensors.