Uniform TitleQuantum stochastic communication with photon-number squeezed light
NameParamanandam, Joshua (author), Parker, Michael (chair), Cheung, Kin (internal member), Gajic, Zoran (internal member), Rutgers University, Graduate School - New Brunswick,
SubjectElectrical and Computer Engineering,
DescriptionSqueezed states of light have found importance in quantum cryptography due to the no-cloning theorem which prevents two states from being identical to each other. The quantum state with quadrature operators X1 and X2 can be visualized as a point in phase space with the center being l angle X1 r angle, l angle X2 r angle surrounded by an error region which satisfies the minimum uncertainty product l angle Delta X [1 over 2] r angle l angle Delta X [2 over2] r angle=1/16. These states are intrinsically secure since one needs to know which quadrature the measurement is to be made and any attempt to measure the wrong quadratures with arbitrary accuracy would disturb the message. Of course, the eavesdropper cannot simultaneously measure both quadratures with infinite precision for each. This thesis describes a method that not only encodes information in the amplitudes of the quadratures alone but also in the uncertainty of those states. One example of squeezed light is the number-phase squeezed state which satisfying the uncertainity relation l angle Delta n [superscript] 2 r angle l angle Delta phi [superscript] 2 r angle=1/4. An implementation is demonstrated where the information is encoded only in the photon number uncertainity and the phase variable is ignored.
The barrier regulation mechanisms such as macroscopic coulomb blockade in semiconductor junction diodes are responsible for generating photon fluxes with penetration below the standard quantum limit(shot noise level). The thesis describes a comprehensive quantum mechanical Langevin model which details the various mechanisms responsible for producing photon number squeezing from the thermionic emission to the diffusion current limits. Quantities such as the pump fluctuations and cross correlation spectral densities are studied under constant current and constant voltage conditions. The research investigates the generation of photon number squeezed light from high efficiency light emitting diodes. A measurement setup for subshot noise is constructed and each stage is properly calibrated. Experiments were performed to determine the squeezing spectra and Fanofactors for the L2656 and the L9337 high efficiency LEDs. The L9337 produces a squeezing of 1.5dB below the shot noise level over a bandwidth of 25Mhz, the largest known penetration at room temperature. The quantum stochastic communicator is also demonstrated. The research shows that the switching elements used in the modulation of the electrical bias which in turn affect the regulation mechanisms do not affect the statistics of the emitted light under certain conditions. The decoding of the time varying variances is achieved by using time frequency analysis with the aid of the spectrum analyzer.
NoteIncludes bibliographical references (p. 259-263).
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.