RT Dissertation/Thesis
T1 Spatial Propagation and Characterization of Quantum States of Light in Integrated Photonic Devices
A1 Barral Raña, David
A2 Universidade de Santiago de Compostela. Facultade de Física. Facultade de Óptica e Optiometría. Departamento de Física Aplicada. Programa de Doutoramento: Láser, Fotónica e Visión
K1 Spatial Propagation
K1 Estados cuánticos de luz
K1 Dispositivos fotónicos
AB In this dissertation we introduce a quantum theory of propagation oflight in integrated photonic devices. The necessity of this theory is justi eddue to the conceptual and formal inconsistencies the Hamiltonian theorypresents when dealing with propagation problems. Taking into account theorthonormalization property and the modal norms, we carry out a canonicalquantization of the ux of Momentum and derive Heisenberg equations. Weapply it to coupling devices with di erent features of the refractive index:inhomogeneities, nonlinear response and losses; like N  N linear and nonli-near directional couplers and spontaneous parametric down conversion andspontaneous four wave mixing-based nonlinear inhomogeneous waveguides.Likewise, we introduce the optical  eld-strength space and the amplitudeprobability distributions in this representation, and by means of a spatial-type Lagrangian theory we derive by path integration propagators in thisspace for di erent-media based devices. In this way we solve the propagationfor discrete and continuous variables.Next, we present a new method of characterization of quantum statesintroducing a generalized quantum polarization, based on the con nement inparticular regions of the optical  eld space of the probability distributionsof quantum states. Likewise, we propose a consistent polarization degree,a  gure which measures how di erent a state is from a full unpolarizedone, showing its application to the characterization of various examples ofstationary and dynamic quantum states.The last aim of this dissertation is to measure quantum states of lightpropagating in integrated photonic devices. We designe a versatile and relia-ble electro-optic integrated device to accomplish this goal. This device allowscarrying out any SU(2) unitary transformation and is able to be nested aswell, allowing its extension to SU(N) transformations. Likewise, it outper-forms other current schemes based on pasive directional couplers due to itsability to reduce the e ect produced by fabrication errors, a very importantfact when complex circuits are involved. We perform simulations and showpossible applications.In summary, in this thesis we develop tools to design and simulate theperformance of photonic devices, as well as propose a characterization me-thod for quantum states propagating within, with interest in the conti-nuously growing  eld of integrated quantum photonics.
YR 2015
FD 2015-11-23
LK http://hdl.handle.net/10347/13702
UL http://hdl.handle.net/10347/13702
LA eng
DS Minerva
RD 23 abr 2026