Reconfigurable silicon filter with continuous bandwidth tunability

Abstract

We present the design and the fabrication of compact tunable silicon-on-insulator bandpass filters based on the integration of a Mach-Zehnder interferometer with ring resonators and activated via thermo-optic phase shifters. The proposed architecture provides wide filter bandwidth tunability from 10% to 90% of the free spectral range preserving the filter off-band rejection. Possible applications are channel subset selection in wavelength division multiplexing optical systems, adaptive filtering to signal bandwidth, and reconfigurable filters for gridless networking.

Compact and low-loss liquid crystal loaded Mach-Zehnder optical switch based on Si wire waveguide

“…In Si PICs, phase control is a key function for the realization of various important devices such as optical switches, modulators, variable wavelength filters, and coherent receivers [1,2,3,4,5]. It would also be a practical solution for compensating the parasitic phase-shifts stemming from structural size errors in fabricated Si photonic devices [6,7].…”

“…The integration of heaters on Si waveguides is one of the major phase control techniques owing to the relatively large thermo-optic (TO) effect of silicon [2,5].…”

“…The fabricated optical switch with 100-µm-long phase shifter had a small footprint, within 300 Â 80 µm 2 , and showed quite low device losses and relatively smooth spectra with a voltage-length product of ∼0.4 V·mm. Moreover, the thermal characteristics of the device were also evaluated.…”

Tunable silicon photonics directional coupler driven by a transverse temperature gradient

“…Reconfigurable photonic integrated circuits (PICs) capable of dynamically adapting their characteristics to the requirements of time-varying optical systems are attracting increasing interest in a variety of application fields, including on-chip networking [1], optical communication systems [2], microwave photonics [3] and general purpose optical processing devices [4]. Depending on the specific architecture and technological platform, reconfigurable PICs require a number of tunable elements, such as variable phase shifters [1][2][3][4][5], active gain/loss waveguide sections [4] and controllable power-splitting devices [3,5], to either modify the frequency domain response or optimize the circuit performance by counteracting fabrication tolerances [5].…”

“…Depending on the specific architecture and technological platform, reconfigurable PICs require a number of tunable elements, such as variable phase shifters [1][2][3][4][5], active gain/loss waveguide sections [4] and controllable power-splitting devices [3,5], to either modify the frequency domain response or optimize the circuit performance by counteracting fabrication tolerances [5].…”