Zhenda Xie

Near-infrared Hong-Ou-Mandel interference on a silicon quantum photonic chip

Near-infrared Hong-Ou-Mandel quantum interference is observed in silicon nanophotonic directional couplers with raw visibilities on-chip at 90.5%. Spectrally-bright 1557-nm two-photon states are generated in a periodically-poled KTiOPO₄ waveguide chip, serving as the entangled photon source and pumped with a self-injection locked laser, for the photon statistical measurements. Efficient four-port coupling in the communications C-band and in the high-index-contrast silicon photonics platform is demonstrated, with matching theoretical predictions of the quantum interference visibility. Constituents for the residual quantum visibility imperfection are examined, supported with theoretical analysis of the sequentially-triggered multipair biphoton, towards scalable high-bitrate quantum information processing and communications. The on-chip HOM interference is useful towards scalable high-bitrate quantum information processing and communications.

Extended ultrahigh-Q-cavity diode laser

We report on a study of a 698 nm extended cavity semiconductor laser with intracavity narrowband optical feedback from a whispering gallery mode resonator. This laser comprises an ultrahigh-Q (>10(10)) resonator supporting stimulated Rayleigh scattering, a diffraction grating wavelength preselector, and a reflective semiconductor amplifier. Single longitudinal mode lasing is characterized with sub-kilohertz linewidth and a 9 nm coarse tuning range. The laser has a potential application for integration with the 1S0-3P0 strontium transition to create compact precision atomic clocks.

Strongly Nondegenerate Resonant Optical Parametric Oscillator

We demonstrate a low-threshold, visible light, resonant OPO with widely separated harmonics. Pumping a MgF2 resonator at 780nm we observe generation of harmonics at 50 and 100THz from the carrier. The process is phase matched due to interaction of different mode families of the resonator.

Temporal magnification with large observation duty ratio using synchronized optical buffer

We demonstrate a method to substantially increase the observation duty ratio in temporal-magnification system without sacrificing the temporal resolution. 30% or even 100% observation duty ratio can be achieved on a 10-ns or longer waveform.

Low noise single photon frequency upconversion using Ti-indiffused periodically-poled lithium niobate waveguides with efficient narrowband filtering

We demonstrate single-photon frequency-upconversion using a titanium-infused periodically-poled lithium niobate waveguide by L-band erbium-doped fiber amplifier pump. Internal efficiencies up to 84.4% and dark-count rate of 44kHz are achieved with narrowband filtering down to 3.5GHz.