Terahertz-bandwidth photonic fractional Hilbert transformer based on a phase-shifted waveguide Bragg grating on silicon

Abstract

We propose and experimentally demonstrate the first THz bandwidth on-chip photonic fractional Hilbert transformer. The reported design uses a novel approach, based on a uniform and nonapodized single phase-shifted integrated waveguide Bragg grating on silicon, where the fractional order P can be engineered by simply varying the effective index modulation δn. Experimental results for P=1.5 show very low processing error for a broad range of pulse bandwidths between 77 GHz and 2.07 THz, corresponding to a time-bandwidth product as high as 27.

Wideband dynamic microwave frequency identification system using a low-power ultracompact silicon photonic chip

“…1c and connected as in Fig. 1a, is integrated on-chip to access both the transmission and reflection responses of the PS-WBG, avoiding the need for an off-chip optical circulator1718. To the best or our knowledge, a WBG filter is here employed in an entirely different configuration, simultaneously using the device in transmission and in reflection, an approach that enables critical improvements in the accuracy and robustness of the measurement system.…”

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

“…Some salient works demonstrated remarkable filter features that outrun state-of-the-art allelectronics implementations, such as terahertz bandwidth [40], multi-octave tuning [41], nanosecond switching speed [42], microwatt control [43], and power extinction exceeding 60 dB [44]. Recent work of ours proposed and experimentally demonstrated a full-integration-ready approach of such filters with DSP-like flexibility by means of introducing software-defined circuit programmability into the processing core chips [45].…”

On-Chip Instantaneous Microwave Frequency Measurement System based on a Waveguide Bragg Grating on Silicon

“…The filter is implemented using a phase-shifted waveguide Bragg grating (PS-WBG) fabricated at IMEC on a silicon-on-insulator (SOI) nanowire 220 nm (thick) × 500 nm (wide), using CMOS-compatible equipment. The layout and fabrication details are reported in [11]. A Y-branch is integrated on the chip to access both the transmission and reflection responses at the same time, without the need for an off-chip circulator.…”