W-Band High-Q Microwave Photonic Filter With the Third-Order Dispersion Precompensation

A scheme to perform high-quality (high-Q) W-band (75-110 GHz) microwave photonic filters (MPFs) with tunability and reconfigurability is proposed and experimentally demonstrated. The analysis reveals an inverse proportional relationship between the operating frequency of the MPF and the compensatory ability of the optical spectrum processor (OSP) when mitigating the third-order dispersion (TOD). To extend the operating frequency of the MPF to W-band, we present a TOD precompensation technology implemented by a quadratic phase provider (QPP) device. Providing the OSP with an additional quadratic phase shift, the QPP can shift and extend the systematic TOD compensation range, thus resolving the operating frequency limit imposed by the conventional OSP-based technique. Combined with an automatic in-line TOD compensation procedure, the systematic TOD can be precisely compensated. With an almost complete cancelation of TOD in the filter, a tunable and reconfigurable single-passband W-band filter with a 3-dB bandwidth of around 15.5 MHz and a record-setting Q-factor of 6459 is obtained.