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The Design Of NPRO Laser For 1.55μm Wavelength And The Suppression Of Its Intensity Noise

Posted on:2015-11-01Degree:MasterType:Thesis
Country:ChinaCandidate:W J YueFull Text:PDF
GTID:2308330473952629Subject:Electronic and communication engineering
Abstract/Summary:PDF Full Text Request
1.55μm laser is applied widely in the field of coherent optical communication and interferometric gravity-wave detectors, due to that its wavelength is in the third communication window. Applications such as optical phase locking, coherent laser communication and detection can both benefit from the development of high efficiency, narrow line-width, low noise and single frequency laser sources at this wavelength. Non-planar ring oscillator(NPRO) has been widespread concern due to its high stability, narrow line-width, single-longitudinal-mode output and high frequency tunability. In this paper, as far as we know, we are the first one to adopt Er: glass or Cr4+: YAG as the gain medium of monolithic non-planar ring oscillator in order to obtain low noise, norrow line-width and unidirectional traveling laser with wavelength at 1.55μm. This paper consists of four aspects as follwing:(1). The research on intensity noise of three-level energy system solid-state laser based on full quantum theory: firstly, we analyse the energy level structure of Er doped glass and Cr doped YAG; secondly, the quantum dynamic model of the interaction between the light and atoms and the quantum Langevin equation which contains the pump source, activate the atom and the cavity mode are established; in succession, we can get the equations of motion by solving the Langevin equation; Then, it is possible to simplify the equations of laser motion by means of the method of first-order approximation; next, we derive the noise transfer function and noise spectrum by using the Fourlier transform to the equations of motion, combined with the boundary conditions.(2) The design theory of monolithic non-planar ring oscillator: firstly, we analyse the geometry and working principle of monolithic non-planar ring oscillator; secondly, the round trip transmission matrix of the NPRO can be obtained by means of the theory of Jones matrix and the optical equivalence principle; then the eigenvalues are obtained by solving the transfer matrix. Next, the round trip loss and loss difference between the clockwise and counterclockwise is calculated. The NPRO can be process out, once the design parameters are obtained by optimizing the loss and loss difference. Finally, we make use of the optical path tracking software to verify the reliability of the resonator design parameters.(3) Suppressing the intensity noise with negative feedback circuit: Based on the research on intensity noise of three-level energy system solid-state laser based on full quantum theory, we derive the noise transfer function of the output laser with the additional negative feedback circuit.(4) Simulation analysis of laser noise property: Firstly, we analyse the relationship between the noise spectrum and all kinds of noise sources by simulation. Then, we study how the intensity noise varys with the pump power. Next, the influence of the noise of pump source on the intensity noise is researched. Finally, we analyse the noise suppression effect of the negative feedback loop.
Keywords/Search Tags:non-planar ring oscillator(NPRO), Jones matrix, noise transfer function, negative feedback
PDF Full Text Request
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