Generation of near-infrared correlated photon pairs in a long optical nano-fibers

Observation of photon-pair generation in the normal group-velocity-dispersion regime with slight detuning from the pump wavelength

“…In addition, the fiber based photon-pair sources are able to be directly coupled to fiber systems with negligible coupling loss, but waveguide-to-fiber coupling efficiency of a periodically poled SPDC crystal is reported about 50% [8]. The SFWM process has been studied intensively for the fiber-based photon generation [6,[9][10][11][12][13][14][15][16][17][18][19][20] for quantum information applications including quantum key distribution.Photon-pair generation via SFWM is active near the zero group-velocity-dispersion (GVD) wavelength, λ ZGVD , in the anomalous GVD regime [6,[9][10][11][12][13][14][15] or normal GVD regime [16][17][18][19][20]. In the normal GVD regime, the wavelength of the generated photon pairs is significantly detuned from the pump wavelength.…”

“…Therefore, the precise measurement of the GVD spectrum is required, but it is often tricky with short length optical fibers. One way to overcome this problem is engineering the dispersion of a commercial fiber by heating and pulling the fiber, but this method is an ambitious research field [19,20,23]. On the other hand, if a slightly detuned pair can be generated in the normal GVD regime, the constraint for the λ ZGVD of medium can be weakened, but it has not been reported to the best of our knowledge because phases are mis-matched in this regime due to the Kerr effects of the media.…”

“…In addition, the fiber based photon-pair sources are able to be directly coupled to fiber systems with negligible coupling loss, but waveguide-to-fiber coupling efficiency of a periodically poled SPDC crystal is reported about 50% [8]. The SFWM process has been studied intensively for the fiber-based photon generation [6,[9][10][11][12][13][14][15][16][17][18][19][20] for quantum information applications including quantum key distribution.…”

“…Photon-pair generation via SFWM is active near the zero group-velocity-dispersion (GVD) wavelength, λ ZGVD , in the anomalous GVD regime [6,[9][10][11][12][13][14][15] or normal GVD regime [16][17][18][19][20]. In the normal GVD regime, the wavelength of the generated photon pairs is significantly detuned from the pump wavelength.…”

“…Solution I and II are the fundamental solutions with k p =k s =k i , and solution III in the normal GVD regime is for signal/idler photons far from the pump wavelength (k p ≠ k s ≠ k i but 2k p =k s + k i + 2γP p ). With a non-zero pump power, the photon pairs can be generated for the regime II and III (red curves in figure 1(a)) [6,[9][10][11][12][13][14][15][16][17][18][19][20], but the nonlinear Kerr effects, 2γP p , in equation (2) cause difficulties in the generation of solution I for the normal GVD regime. Figure 1(b) shows the normalized probability density spectrum of photon pair emission against the pump wavelength.…”