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Research And Application Of Novel All-Fiber Filter And Semiconductor Ring Laser

Posted on:2016-05-14Degree:DoctorType:Dissertation
Country:ChinaCandidate:Z X KangFull Text:PDF
GTID:1228330470455960Subject:Communication and Information System
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The fiber filter with lots of advantages are key devices in multiwavelength fiber laser and fiber sensor system. Under the supports of National Nature Science Foundation of China and the Major State Basic Research Development Program of China, theis thesis is devoted to investigate the all-fiber sensor and multiwavelength fiber laser based on several novel fiber filters. The semiconductor ring lasers (SRLs) exhibit outstanding optical bi-stability. And considering its intrinsic monolithic integration and low-power consumption, the SRL is considered as one of the most promising photonic functional devices in all-optical networks. Focusing on the RTN properties、feedback characterics of the SRLs and their applications in chaos communication, this thesis makes lots of research and discussion in-depth. The main achievements are listed as follows:1. Two novel all-fiber sensing configurations for discrimination measurement of temperature and strain are proposed and experimentally demonstrated, which all solve effectively the problem of temperature cross-sensitivity. The TCF with embedded FBG based sensor can achieve resolutions of4.3048με and0.4562℃for strain and temperature, respectively; While the strain and temperature resolutions are10.07με and0.311℃for the up-taper Mach-Zehnder interferometer (MZI) with an in-line FBG based sensor. A novel all-fiber laser sensor based on an in-line FBG cascaded with a segment of TCF for simultaneous measurements of temperature and strain is reported and demonstrated. The center wavelength sensitivities to strain and temperature are1.48pm/με and9.2pm/℃. The laser peak power sensitivities to strain and temperature are7.52×10-4mW/με and-4.45×10-3mW/℃, respectively.2. A spacing-tunable dual-wavelength erbium-doped fiber laser based on twin core fiber comb-filter is proposed and demonstrated. Single-polarization dual-wavelength laser output with extinction ratio of45dB and output power of-10dBm is achieved at room temperature. The dual-wavelength spacing can be tuned continuously from0nm to2.4nm by adjusting the PC states. Both the wavelengths are linearly polarized light and mutually orthogonal, the DOP are99.8%and99.7%, respectively. A novel fiber filter with polarization dependent property based on the core-cladding modes interference of the taper-pair is proposed and fabricated. A multiwavelength erbium-doped fiber laser is proposed and demonstrated. In the situation of0.8nm spacing,7lasing wavelength with the OSNR of more than35dB is achieved. The power fluctuations of all lasing wavelengths are less than0.6dB during the30minutes of measuring time. The number of oscillation wavelength can be switched by tuning the PC states.3. A comprehensive frequency-domain multimode model is built and implemented to investigate the dynamics and the RIN properties of SRLs. Remarkable and unusual low frequency noise enhancement in the form of a broad low frequency tail extending all the way to the relaxation oscillation peak is observed. The low-frequency RIN level runs up to10-13or10"14Hz-1,1-2orders of magnitude more than conventional semiconductor lasers.4. A novel frequency-domain multimode theoretical model to analyze the dynamical performances of the SRLs subjected to OFB is derivated and established by taking into account the Langevin noise sources. This model is applicable for arbitrary amount of OFB ranging from very weak to very strong. For the bidirectional external feedback, as the strength of OFB increasing, the SRLs experience the bidirectional stable operation、periodic pulsation、period doubling pulsation and chaos.When the SRLs operate in the chaos region, the total RIN rise to a higher level,2-3orders of magnitude more than the case of free-running. A novel all-optical square wave generator with duty cycle of50%and repetition frequency of several GHz is proposed. The repetition frequency or duty cycle can be tuned conveniently by the change of the external time-delay.5. A novel multimode SRLs based chaotic synchronization system is proposed and its potential in chaos-based secure communication is demonstrated. The message encoding and decoding using CSK and CM technique have been analyzed from the point of view of the total lasing output and partial output, respectively. And as the transmission rate increases, the recovered message quality is gradually degraded. The demodulation Q factor is reduced from9.86of250Mb/s to5.497of5Gb/s. The importance of the in-line amplification for improvement of the system performance induced by the loss in the long-haul fiber link is discussed. The influence of dispersion and nonlinearity of the transmission link on the synchronization performance and communication quality are investigated.
Keywords/Search Tags:fiber filter, multi-wavelength fiber laser, fiber sensor, decouplingmeasurement, semiconductor ring laser, relative intensity noise, external opticalfeedback, chaotic optical communication
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