Research On Entangled Photon Pair Source Based On Spontaneous Four Wave Mixing Process

Light makes all the lives on the earth alive as the carrier of energy and makes the whole earth to be a village as the carrier of information.Optics has been widely studied always.Human beings' scientific cognition to light can trace back to the age of Newton.Newton believed that light was like some kind of particle and this could explain reflection and refraction phenomena very well.At the same time,Huygens thought that light had properties of Mechanic Waves and later people use this to explain interference and diffraction phenomena which particle of light could not make it clear.In 1905,Albert Einstein solved this problem by describing light as composed of discrete quanta.People become to realize that light has wave-particle duality.In the 1960s,with the birth of laser and fiber,people's cognition to light become wider and deeper.As an important project of nonlinear optics,the four wave mixing process which is a third order parameter process originates from the bound electron's nonlinear response in material.In this process,two or three light waves' interactions produce two or one new wavelengths.Nowadays,four wave mixing finds applications in optical phase conjugation,parametric amplification,supercontinuum generation and micro-resonator based frequency comb generation.Along with the development of quantum mechanics and quantum communication technology,entangled photon source has been studied widely and deeply as the key part of quantum entanglement.In spontaneous four wave mixing process,two identical pump photons annihilate and give birth to a pair of correlate photons at signal wavelength and idler wavelength.Thus this process has been studied as an effective method to generate correlated photon pairs.This dissertation focuses on the spontaneous four wave mixing process in dispersion shifted fiber and silicon on insulator waveguide and produces different kinds entangled photon pair sources by using the correlate photons.These all-fiber,mini,integrate entangled photon pair sources are of great potential in future quantum networks.The main contents are as follows:1.The dual-pump four wave mixing process has been studied in dispersion shifted fiber and high nonlinear fiber.The influence of the pump's polarization state to four wave mixing efficiency is verified.Moreover,we have tried to verify the spontaneous four wave mixing process in fibers.2.We prepare multiplexed polarization entangled and time-bin entangled photon pair sources based on Dense Wavelength Division Multiplexing system and correlate photons generated by spontaneous four wave mixing process in dispersion shifted fiber in room temperature.Without subtraction of the accidental coincidence,the visibility can reach nearly 90%.3.The Hong-Ou-Mandel experiment for two independent nearly same all-fiber correlate photon pair sources generated in two 300 meters long dispersion shifted fibers has been realized.A general theoretical description of the single photon spectral purity of the photon source generation in dispersion shifted fiber is given,the influences of the pulse width and filtering bandwidth to the purity are simulated and the optimized condition for purity single photon generation is obtained.4.By using the multiplexed correlate photon pair source generated by the spontaneous four wave mixing process in silicon on insulator waveguide assisted by Dense Wavelength Division Multiplexing system,the energy-time correlation properties are verified and polarization entangled photon source and time-bin entangled photon source are produced.Without subtraction of the accidental coincidence,the visibilities can reach more than 95%.The innovations in this dissertation are as follows:1.We produce the all-fiber multiplexed entangled photon pair sources based on the theory of spontaneous four wave mixing process in fiber and the Dense Wavelength Division Multiplexing system.At the same time,the theory has been verified.2.In the Hong-Ou-Mandel experiment,a general theoretical description of the single photon spectral purity of the photon source generation in dispersion shifted fiber is given,the influences of the pulse width and filtering bandwidth to the purity are simulated and the optimized condition for purity single photon generation is obtained.3.By using the silicon on insulator waveguide and Dense Wavelength Division Multiplexing system,a mini,integrate,multiplexed correlate photon pair source which covers more than 14 channel pairs in other words 24nm is produced.Further on,a polarization entangled and a time-bin entangled multiplexed photon source is obtained.