Entangled Photon Pair Sources based on Periodically Poled Silica Fiber
Changjia Chen
Entangled photons are a fundamental resource in quantum applications. Broadband entangled photon sources have been used in applications such as high-resolution quantum sensing and wavelength-multiplexed quantum communication. In particular, in fiber-based quantum applications such as long-distance quantum clock synchronization and quantum key distribution in deployed fiber networks, a practical entangled source that is robust and compatible with silica fiber is highly sought after. Periodically poled silica fiber (PPSF) has been demonstrated to be a promising resource of entangled photon-pairs. PPSF uses the induced second-order nonlinearity in poled fiber to generate polarization-entangled photon pairs based on type-II spontaneous parametric down-conversion. The negligible group birefringence of the PPSF ensures high-quality and broadband polarization entanglement without compensation, making it particularly suitable for these quantum applications. The PPSF-based source has a lot of potentials to be tapped because of its high entanglement quality, broadband emission bandwidth, simple structure, and its compatibility with the existing fiber infrastructure. In this thesis, I focus on the development of the PPSF-based entangled photon sources. I first investigate the design and the manufacturing process of the PPSF where I try to produce PPSF with improved performance and innovative properties. Next, I study the compensation-free nature of the PPSF-based polarization entanglement source and discuss the interplay between dispersion, birefringence, emission bandwidth, and polarization entanglement. Based on the theory, a commercial PPSF-based photon-pair source prototype is developed and patented. It has to my knowledge the simplest design of all polarization-entangled sources reported so far in the literature. Furthermore, I broaden the biphoton bandwidth by building a PPSF photon-pair source that emits biphotons at telecom O-band. With more than 24THz bandwidth, the biphotons generated in this source are the broadest of all O-band polarization-entangled photon sources reported to my knowledge. I also propose and experimentally demonstrate a polarization-frequency hyperentangled photon source using PPSF, which provides higher dimensionality by making use of entanglement in multiple degrees of freedom. Overall, this thesis contributes to the development of PPSF technology for practical quantum applications. I anticipate that the PPSF-based photon-pair source will play an important role in the era of quantum technology.
•Jun 1, 2022•0 citations