Nonlinear Interferometers for Quantum Information Processing and Metrology

The ability to generate biphoton state with tunable properties in various degrees of freedom (DoFs) is always a challenging task in the field of quantum information processing. This arises from the fact that generating such biphoton state puts many constrains on the design and fabrication of the biphoton sources. In this thesis, I propose a novel common-path nonlinear interferometer (NLI) to generate biphoton states with tunable properties without the need for any modification to the biphoton source itself. I further utilize our NLI scheme to perform a precision dispersion measurement as well. First, I developed a comprehensive model, which accounts for the effects of the pump temporal coherence, as well as the chromatic dispersion and the birefringence of the linear medium inside the NLI. I have shown that through manipulating the dispersion and birefringence of the linear medium inside the NLI, biphoton properties in both frequency and polarization DoFs can be tuned (simultaneously or separately). Variants of all-fiber NLIs, consisting of periodically-poled silica fibers as the nonlinear media, which generate biphotons, and a single-mode fiber with an inline polarization controller as the linear section, are constructed for proof-of-principle demonstrations. Biphoton states with comb-like spectra are obtained from the NLI, without requiring any modification to the nonlinear media. Furthermore, biphoton states with tunable degree of polarization entanglement (in the range of 0 to 1) are predicted and experimentally generated with our interferometer. More significantly, through the simultaneous manipulation of the chromatic dispersion and birefringence of the linear medium, a novel class of biphoton states with coupled frequency and polarization DoFs is also obtained. The frequency-dependent polarization entanglement feature, which is the signature of such states, is experimentally verified. The abovementioned NLIs are also utilized to demonstrate precision dispersion measurement on a 5-m-long single-mode fiber sample, with a sensitivity of ~0.009 ps/nm. Our sensitivity is comparable to that of the existing state-of-the-art dispersion measurement techniques, but unlike the latter, ours eliminates the need for interferometer balancing, beam alignment, and phase stabilization. The simplicity, robustness and versatility of our demonstrated NLI technique illustrates its important role in quantum state engineering and quantum metrology.

Department dc:contributor.department

Electrical and Computer Engineering

Year dc:date.issued

2021

Author dc:creator

• Riazi, Arash

Advisor dc:contributor.advisor

• Qian, Li

• Biphoton shaping
• biphoton spectral engineering
• Dispersion measurement
• Entanglement tuning
• Nonlinear interferometer

Statement dc:rights

• Attribution-NoDerivatives 4.0 International

Licence dc:rights.uri

• http://creativecommons.org/licenses/by-nd/4.0/

Handle dc:identifier.uri

http://hdl.handle.net/1807/108907

OAI identifier oai:identifier

oai:utoronto.scholaris.ca:1807/108907