基于射频驱动单边带调制器的循环扫频光源研究

发布时间：2018-01-04 03:19

本文关键词：基于射频驱动单边带调制器的循环扫频光源研究　出处：《天津大学》2015年硕士论文　论文类型：学位论文

【摘要】：扫频光源输出的激光频率以特定的步长随时间快速变化,能够实现一定光谱范围内激光波长的扫描输出,在光纤传感、激光测量以及光学相干层析等领域中有着重要的应用。本文研究了利用射频电信号控制单边带(SSB)调制器实现激光光源腔外循环扫频输出。该方法在激光器腔外独立进行波长扫频,不影响激光腔的固有结构,便于激光器自身参数的升级和优化;波长扫频由射频电信号控制,可以有效避免机械扫频的限制,实现扫频步长和稳定性的提高;同时,采用光谱分段扫描法,能够同时获得高精度和高速率的扫频输出。本文的主要内容如下:一、光源的腔外移频研究理论分析了SSB调制器对输入光信号的光谱调制过程,移频步长精确等于射频信号频率。实验分别获得了单波长信号10MHz~20GHz的移频结果和多波长信号20MHz~18GHz的整体移频结果。二、单波长光源腔外循环扫频研究理论研究了基于SSB调制器的循环扫频过程,设计了单波长光源腔外循环扫频装置。分别对内调制和外调制两种脉冲光源进行了腔外循环扫频实验和数据分析。扫频步长为0.04nm时,实现了5.8nm范围内光谱平坦度为?1.5dB,扫频频率18.5kHz的扫频输出。分析了噪声对循环扫频输出的影响,提出并初步实验验证了利用未泵浦掺铒光纤作跟随式滤波器抑制自发辐射噪声的方法。三、多波长光源腔外循环扫频研究设计构建了双波长光源腔外循环扫频实验装置。获得了1.6nm范围内0.08nm扫频步长时214kHz的双波长扫频输出,以及0.04nm扫频步长时122kHz的双波长扫频输出。设计了基于多波长光源的腔外循环扫频实验装置。初步将连续多波长光进行循环扫频,获得了23nm范围内57个波长的扫频输出,光谱平坦度小于?5dB。
[Abstract]:The laser frequency of the sweep light source changes rapidly with the specific step length, which can realize the scanning output of the laser wavelength in a certain spectral range, and it can be sensed in the optical fiber. Laser measurement and optical coherence tomography have important applications. In this paper, the control of SSBs with single sideband by radio frequency (RF) signal is studied. The modulator realizes the frequency sweep output of laser source outside the cavity, and the wavelength sweep is carried out independently outside the laser cavity. It does not affect the inherent structure of the laser cavity and is convenient to upgrade and optimize the laser parameters. Wavelength sweep is controlled by radio frequency signal, which can effectively avoid the limitation of mechanical frequency sweep and improve the sweep step and stability. At the same time, the spectral piecewise scanning method can be used to obtain high precision and high speed sweep output. The main contents of this paper are as follows: 1. The spectral modulation process of input light signal by SSB modulator is analyzed theoretically. The accuracy of the frequency shift step is equal to the frequency of the radio frequency signal. The frequency shift results of the single-wavelength signal 10MHz ~ 20GHz and the multi-wavelength signal of 20MHz ~ 18GHz are obtained respectively. 2. The theory of frequency sweep outside the cavity of single wavelength light source is studied. The cyclic frequency sweep process based on SSB modulator is studied. In this paper, a single wavelength light source extracavity frequency sweep device is designed. The experiment and data analysis of the two pulse light sources are carried out. The sweep step is 0.04nm. The spectral flatness in the range of 5.8 nm has been achieved. 1.5 dB, the frequency sweep output of 18.5 kHz. The effect of noise on the frequency sweep output is analyzed. The method of using unpumped erbium-doped fiber as a follower filter to suppress spontaneous emission noise is proposed and preliminarily verified by experiments. 3. Study and Design of Multi-wavelength Light Source Extracavity Cycling Frequency sweep experiment device with double wavelength Light Source external Circulation Frequency sweep is designed and constructed, and the double-wavelength sweep frequency output of 214kHz with 0.08nm sweep step is obtained in the range of 1.6nm. . And the double wavelength sweep output of 122 kHz at 0.04nm sweep step. The experiment device of frequency scanning outside cavity based on multi-wavelength light source is designed. The continuous multi-wavelength light is preliminarily used to sweep the frequency. The sweep frequency output of 57 wavelengths in the range of 23 nm is obtained, and the spectral flatness is less than? 5dB.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN761;TN24

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