Theoretical And Experimental Investigation For The Generation Of Non-classical Light At 1.5μm With Continuous Variables

In the past fifty years,one of the remarkable evolvement for the research of quantum optics fields is the generation of non-classical light and application in quantum information.Quantum information was originally investigated with the discrete variables(DV) and was recently extended to the continuous variables(CV) system in the infinite dimension Hilbert space. The CV quantum communication has attracted wide interest due to the potential advantages such as high bit transmission rate.Recently,the experimental investigation of quantum teleportation,quantum dense coding, entanglement swapping have been already realized.with CV non-classical light.The wavelength in those experiments is at 1.06μm or 1.08μm.However, the non-classical light needs to be transmitted in fiber to realize the practical quantum information system.There is a higher negative dissipation for above-mentioned wavelength in the fiber transmission.Especially the quantum characters of the non-classical light will reduce exponentially.If a non-classical light at 1.5μm can be employed,there will be a lowest dissipation because of transparent windows for fiber at the wavelength.So during my PhD study,our group investigates the generation of CV non-classical light at 1.5μm in theoretical and experimental aspect.Following four parts will be presented in this thesis:1) A high power continuous wave(CW) single frequency 1560 nm laser was experimentally generated based on a seeded fiber amplifier.A weak feedback technique with confocal FP cavity was utilized to improve the quantity of the laser source.The maximum output power of laser is 2W with the seeded power of 1mW.There were excess amplitude noise and phase noise for laser because of seeded source intrinsic noise and amplifier's ASE (Amplifier Spontaneous Eradiation) noise.So the weak feedback technique with confocal FP cavity was utilized to restrain the laser frequency fluctuation and excess noise. 2) A high power CW single frequency 780 nm laser was obtained by qusi-phase-matched crystal second harmonic generation(SHG).Fisrtly,we analyzed the SHG principle and tolerance of experimental parameters for the optimal efficiency.The above-mentioned laser was employed as pump source, A 700mW 780nm laser source was obtained with pump power of 960mW, the SHG conversion efficiency is 73%.The SHG cavity was locked in the frequency of pump laser for a steady-going 780nm output power employing the lock-in amplifier technique and electronic servo-system.3) A 2.4dB CV squeezed vacuum at 1.5μm was experimentally generated by means of optical parametric process.There is a standing-wave cavity and Periodically Poled Lithium Niobite(PPLN) crystal for optical parametric oscillator(OPO).Above-mentioned laser source at 1560nm and 780nm were used for pump light and signal light with OPO process. Furthermore,we experimentally analyzed influence of fluctuation with pump light and signal light on generated squeeze.4) A description for the generation of CV quantum entanglement at 1.5μm through coupling two single-mode squeeze on 50/50 beam splitter. And we analyzed influence of fluctuation with pump light and mode mismatch on the quantum entanglement.In conclusion,we introduce the research,development and application of CV non-classical light in this thesis,especially for experimentally investigation for CV squeeze state,entangled state and its application in quantum information:Those investigation is a basis for our research.In this thesis,a CV squeezed vacuum at 1.5μm was generated,and two high power CW single frequency laser sources were obtained at 1560nm&780nm. Meanwhile some theoretical research were developed for instructional effect for experiment.