  The effects arising from the inherent continuous-mode nature of photonic
pulses were poorly understood but significantly influence the performance of
quantum devices employing photonic pulse interaction in nonlinear media. Such
effects include the entanglement between the continuous wave-vector modes due
to pulse interaction as well as the consequence of a finite system bandwidth.
We present the first analysis on these effects for interactions between
single-photon pulses, demonstrating their impact on the performance of quantum
phase gates based on such process. Our study clarifies a realistic picture of
this type of quantum devices.
