Biomedical subjects

Xiuping Xie

Publications and source records attributed to Xiuping Xie.

3 recordsLinked to original sources

PubMed2006

Narrow-linewidth near-degenerate optical parametric generation achieved with quasi-group-velocity-matching in lithium niobate waveguides.

We demonstrate narrow-linewidth near-degenerate optical parametric generation in reverse-proton-exchange lithium niobate waveguides with quasi-group-velocity-matching, which is realized by using wavelength-selective directional couplers and tight-radius bends. With appropriate designs for 1.6 ps long pump pulses at 785.1 nm we obtained near-degenerate signal (idler) pulses with a time-bandwidth product as low as 1.1, compared with 10.5 for conventional devices without quasi-group-velocity-matching. This improvement in the temporal property is a result of both a pulse compression effect and a filter effect coming from our scheme of quasi-group-velocity-matching.

Journal Article↗

PubMed2006

Two-spatial-mode parametric amplifier in lithium niobate waveguides with asymmetric Y junctions.

For optical parametric amplifiers in proton-exchange waveguide devices reported to date, both the signal and the idler photons are in the TM00 mode, causing difficulty in distinguishing signal from idler. We report a two-mode optical parametric amplifier. The key components, asymmetric Y junctions, successfully launch the pump wave in a pure TM10 mode and separate the signal and the idler in the TM10 and TM00 modes with a power ratio of as much as 27.5 dB. With high parametric gain, optical parametric generation with a threshold of 300 pJ/pulse was demonstrated for 1.8 ps long pump pulses near 780 nm. These periodically poled lithium niobate waveguides are efficient integrable photon sources.

Journal Article↗

PubMed2004

Mode multiplexing in optical frequency mixers.

Asymmetric Y junctions allow the development of a new class of optical frequency mixers that utilize higher-order waveguide modes for signal processing. We measure high-contrast (>30 dB) mode sorting in asymmetric Y junctions by use of a novel technique: efficient TM00, TM10, and TM20 mode mixing in a periodically poled lithium niobate waveguide. We also demonstrate an odd-to-even mode wavelength converter capable of spectral inversion without offset or bidirectional wavelength conversion.

Journal Article↗