Parasitic Photon-Pair Suppression via Photonic Stop-Band Engineering

We calculate that an appropriate modification of the field associated with only one of the photons of a photon pair can suppress generation of the pair entirely. From this general result, we develop a method for suppressing the generation of undesired photon pairs utilizing photonic stop bands. For a third-order nonlinear optical source of frequency-degenerate photons, we calculate the modified frequency spectrum (joint spectral intensity) and show a significant increase in a standard metric, the coincidence to accidental ratio. These results open a new avenue for photon-pair frequency correlation engineering.

Figure 1

Various SFWM processes with down and up arrows representing pump and generated frequencies, respectively: (a) single-pump, (b) idealized dual-pump, and (c) dual-pump with undesired noise from parasitic single-pump processes.

Figure 2

Sketch of the class of structure with a periodic index modulation that we consider for photon-pair generation.

Figure 3

Joint spectral intensities for our example system both (a) without and (b) with a moiré Bragg grating introduced. Desired degenerate photons are marked with a square and desired stop bands with circles. The dual-pump process corresponds to the center diagonal bands, while parasitic single-pump $x$-polarized and $y$-polarized processes correspond to upper and lower diagonal bands, respectively.

Figure 4

Coincidence to accidental ratios for our example system both with and without the introduction of a moiré Bragg grating. The dashed line corresponds to the idealized maximum value of $1/{|\zeta |}^2$.