Design of continuously-tunable photonic fractional Hilbert transformer based on a high birefringent planar Bragg grating

A wideband and continuously tunable integrated fractional order photonic Hilbert transformer is proposed and demonstrated. The device is realized by a simple apodised Bragg grating within a germano-borosilicate high birefringent planar substrate, achieving a 120GHz operating bandwidth and fractional order tuning capability. The order of photonic Hilbert transform can be constantly controlled by changing the polarization state of input light. Schematic design and properties of the device are presented and discussed Keywords-component; Integrated Optics; Optical Signal Processing; Microwave Photonics.