GHz-bandwidth optical filters based on high-order silicon ring resonators

Abstract

Previously demonstrated high-order silicon ring filters typically have bandwidths larger than 100 GHz. Here we demonstrate 1-2 GHz-bandwidth filters with very high extinction ratios (~50 dB). The silicon waveguides employed to construct these filters have propagation losses of ~0.5 dB/cm. Each ring of a filter is thermally controlled by metal heaters situated on the top of the ring. With a power dissipation of ~72 mW, the ring resonance can be tuned by one free spectral range, resulting in wavelength-tunable optical filters. Both second-order and fifth-order ring resonators are presented, which can find ready application in microwave/radio frequency signal processing.

Low-power, chip-based stimulated Brillouin scattering microwave photonic filter with ultrahigh selectivity

“…While this is difficult to achieve with all-electronic filters [3][4][5][6][7], integrated microwave photonic (IMWP) filters [8] can readily achieve multi-gigahertz tuning range without significant degradation in their frequency response. However, these filters typically exhibit limited resolution (GHz instead of MHz linewidths) and are plagued by trade-offs between key parameters, such as between the frequency tuning range and the resolution for multi-tap filters [9][10][11][12][13]; or between the peak rejection and the resolution for resonator-based filters [14][15][16][17][18].Stimulated Brillouin scattering (SBS) [19][20][21][22] offers a route to MHz-resolution IMWP filters. Although SBS has been widely studied in optical fibers, recently there has been a growing interest in harnessing SBS in nanophotonic waveguides [22][23][24][25][26][27].…”

Integrable microwave filter based on a photonic crystal delay line

“…Preliminary efforts towards integration have relied on resonant delay lines provided by ring cavities and coupled resonant optical waveguides [17][18][19][20] . These approaches suffer from an intrinsic trade-off between dispersion and bandwidth, preventing broadband operation.…”

Programmable optical processor chips: toward photonic RF filters with DSP-level flexibility and MHz-band selectivity

“…The processor chips feature a waveguide propagation loss of 0.25 dB/cm and a filter bandwidth smaller than 1 GHz for an FSR of 13.5 GHz. In Dong et al [99], demonstrated silicon processor chips comprising coupled RRs up to fifth order as shown in Figure 22, which feature a propagation loss of 0.5 dB/m and provide bandpass filters with GHz-level bandwidths. Also in silicon waveguides, Orlandi et al…”