Efficient generation of ultra-broadband parametric fluorescence using chirped quasi-phase-matched waveguide devices

We present a highly efficient photon pair source using chirped quasi-phase-matched (QPM) devices with a ridge waveguide structure. We developed QPM waveguide devices with chirp rates of 3% and 6.7%. Spectrum measurements reveal that the generated photons have bandwidths of 229 nm and 325 nm in full width at half maximum (FWHM), alternatively, 418 nm and 428 nm in base-to-base width for the 3% and 6.7% chirped devices, respectively, which are much broader than the bandwidth of 16 nm in FWHM observed with a non-chirp device. We also evaluate the generation efficiency of photon pairs from coincidence measurements using two superconducting single photon detectors (SSPDs). The estimated generation efficiencies of photon pairs were 2.7 x 10(6) pairs/s.mu W and 1.2 x 10(6) pairs/s.mu W for the 3% and 6.7% chirped devices, respectively, which are comparable to the generation efficiency for the non-chirp device of 2.7 x 10(6) pairs/s.mu W. We also measured the frequency correlation of the photon pairs generated from the 6.7% chirped device. The experimental results clearly show the frequency correlation of the generated broadband photon pairs. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement