Deterministic reshaping of single photon spectra using cross phase modulation
With an ultrafast refractive index change in an optical fiber, frequency entanglement of twin photons is modulated on the fly. The frequency conversion of light has proved to be a crucial technology for communication, spectroscopy, imaging, and signal processing. In the quantum regime, it also offers great potential for realizing quantum networks incorporating disparate physical systems and quantum enhanced information processing over a large computational space. The frequency conversion of quantum light, such as single photons, has been extensively investigated for the last two decades using all optical frequency mixing, with the ultimate goal of realizing lossless and noiseless conversion. I demonstrate another route to this target using frequency conversion induced by cross phase modulation in a dispersion managed photonic crystal fiber. Owing to the deterministic and all optical nature of the process, the lossless and low noise spectral reshaping of a single photon wave packet in the telecommunication band has been readily achieved with a modulation bandwidth as large as 0.4 THz. I further demonstrate that the scheme is applicable to manipulations of a nonclassical frequency correlation, wave packet interference, and entanglement between two photons. This approach presents a new coherent frequency interface for photons for quantum information processing.
Science Advances