可调谐窄带宽的负系数微波光子滤波器

针对负系数微波光子滤波器很难用正系数的光学抽头来实现,提出了一款基于色散器件级联的可调谐、窄带宽、负系数微波光子滤波器。利用整形后的多波长光纤激光器的输出信号作为滤波器的抽头光源,将单模光纤与F-P光纤环级联作为延迟单元,实现滤波器的频率选择性。利用相位调制器和级联的色散器件共同作用,实现负系数的微波光子滤波器。实验得到了波长间隔为0.34 nm的多达37个激光信号的稳定输出,进而基于此实验结果仿真研究了F-P光纤环中C2、C3的耦合系数r、不同长度的可调谐光纤延迟线（TODL）和延迟单元中不同长度的单模光纤等参数对微波光子滤波器性能的影响。     

基于多波长光纤激光器和色散器件级联的微波光子带通滤波器

提出了一种基于多波长光纤激光器和色散器件级联的微波光子带通滤波器。该滤波器利用双折射光纤环镜对多波长激光器的输出信号进行整形,整形后的信号作为滤波器的抽头,实现滤波器的可重构性。将标准单模光纤(SSMF)和光纤延迟环级联作为延迟单元,实现滤波器的频率选择性。通过改变波长间隔或标准单模光纤的长度,实现滤波器的可调谐性。研究结果表明与只用SSMF作延迟单元相比,该微波光子滤波器的品质因数Q提高了182.26,3dB带宽减小了670MHz。     

基于色散光纤环级联结构的可调谐带通微波光子滤波器

提出并验证了一种宽调谐带宽的带通微波光子滤波器设计方案。该滤波器借助可调谐光纤光栅Sagnac环对宽带光源进行均匀切割,产生波长间隔可调的连续光载波作为滤波器的抽头,结合色散光纤环级联结构,实现滤波器的可重构性。研究结果表明,在光电调制器和光电探测器的频率带宽足够大的情况下,当光纤光栅Sagnac环的臂长差在0.50~8.28mm内变化、可调谐光纤延迟线的最小变化步长为0.01mm时,该方案能够实现滤波器中心频率在8.0506~1333.2000GHz内调谐,调谐步长为161.01MHz,边瓣抑制比达到27dB。     

一种新型可调谐多波长光纤激光器的研究与设计

研究基于非线性偏振旋转实现多波长光纤激光器的机理和方法,利用等效Lyot双折射光纤滤波器作为波长选择器件,设计了一种室温条件下可调谐多波长光纤激光器简化结构,使激光器更易于全光纤集成.该设计实现了输出波长在一定范围内连续可调谐,具有稳定多波长输出的优点,是未来密集波分复用通信系统的理想光源.     

基于重构等效啁啾超结构光纤光栅的可调谐微波光子滤波器的仿真研究

提出了一种新型的基于重构等效啁啾(REC)超结构光纤光栅的可调谐微波光子滤波器的结构。根据REC技术, 利用同一块均匀相位掩模板可以灵活地设计制作出具有不同斜率的线性群时延的光纤光栅。作为有限冲击响应(FIR)滤波器的抽头延时单元, 不同光纤光栅之间群时延的差值决定了滤波器的自由频程(FSR)。通过改变可调谐激光器的输出波长来选择不同的抽头间时延差从而达到调谐FSR目的。仿真结果表明, 该滤波器可以实现中心频率从21 GHz到33 GHz的连续可调。事实上, 由于REC技术的灵活性, 在理论上对于任意给定的频段和调谐范围, 这种新型的滤波器结构都能够实现。     

波长间隔可调谐多波长光纤光学参量振荡器

提出并实现了一种以高非线性色散位移光纤为增益介质,以光栅对形成谐振腔,简单线形结构的连续光抽运的波长间隔可调谐多波长光纤光学参量振荡器(MW-FOPO)。采用波长可调谐的窄线宽激光器作为抽运种子光源,以伪随机相位调制抽运光来抑制高非线性光纤中的受激布里渊(SBS)散射效应,结合高功率掺铒光纤放大器构成光纤光学参量振荡器的大功率抽运,通过四波混频(FWM)效应获得了室温下稳定的多波长激光输出。MW-FOPO的波长间隔可以通过调节抽运波长进行调谐。在1505~1615 nm光谱范围内,获得了17条消光比大于10 dB的多波长谱线。实验证明了MW-FOPO实现多波长激光光源的优异特性。     

基于DMD滤波器的波长间隔可调谐的双波长单纵模光纤环形激光器

提出一种稳定的波长间隔可调谐的双波长单纵模环形光纤激光器。在复合环形谐振腔中,采用由数字微镜装置（DMD）滤波器和两个不同长度的次级环形谐振腔组成的多重滤波的方式来选择激光器的工作模式。其中,DMD滤波器可以从掺铒光纤的自发增益谱中任意选择两个波长并将它们耦合进光路中;次级环形谐振腔作为模式滤波器,可以保证激光器输出单纵模激射;利用非线性光子晶体光纤（HN-PCF）的四波混频（FWM）效应,使激光器输出均衡平稳的双波长激射。在室温条件下,不用移动实验装置中的任何器件,通过将位置不同的光栅映射在DMD滤波器上来实现双波长间隔可调谐,调谐范围为0.165nm到1.08nm,调谐步长为0.055nm。     

基于Mach-Zehnder滤波的可调谐光纤激光器

() ()基金项目: 。摘要:为了实现高稳定性的可调谐激光输出,提出并设计了一种基于Mach-Zehnder(M-Z)滤波结构,结合Fabry-Perot(F-P)滤波器的可调谐掺铒光纤激光器,并对激光器的原理及实现方案进行理论分析和实验验证。所设计激光器系统的泵浦源工作波长为976 nm;长度5 m的掺铒光纤作为增益介质;采用全光纤M-Z结构进行滤波,并结合F-P滤波器实现单波长激光可调谐输出。实验中,通过调节F-P滤波器,在泵浦功率为60 mW时,实现了1547～1568 nm范围内单波长激光的稳定可调谐输出,波长调谐间隔小于1.7 nm,每个输出波长的边模抑制比均大于55 dB,线宽均小于0.1 nm。     

基于DMD滤波器的波长间隔可调谐的双波长单纵模光纤环形激光器（英文）

提出一种稳定的波长间隔可调谐的双波长单纵模环形光纤激光器.在复合环形谐振腔中,采用由数字微镜装置(DMD)滤波器和两个不同长度的次级环形谐振腔组成的多重滤波的方式来选择激光器的工作模式.其中,DMD滤波器可以从掺铒光纤的自发增益谱中任意选择两个波长并将它们耦合进光路中;次级环形谐振腔作为模式滤波器,可以保证激光器输出单纵模激射;利用非线性光子晶体光纤(HN-PCF)的四波混频(FWM)效应,使激光器输出均衡平稳的双波长激射.在室温条件下,不用移动实验装置中的任何器件,通过将位置不同的光栅映射在DMD滤波器上来实现双波长间隔可调谐,调谐范围为0.165 nm到1.08 nm,调谐步长为0.055 nm.     

基于SBS的通带可变微波光子滤波器

提出并分析了一种大范围可调谐的通带可变微波光子滤波器。它基于受激布里渊散射(SBS)效应并使用2个调制器与1个光纤布喇格光栅生成泵浦信号。通过分别调节这2个调制器的调制频率,可得双通带滤波器和通带间隔可变的四通带滤波器,并实现滤波器中心频率的大范围连续可调谐,而在整个调谐过程中,滤波器的3dB带宽保持不变。仿真分析了不同调制信号对滤波器通带及中心频率的影响,以及滤波器的带宽与泵浦的功率和SBS增益介质长度的关系。     

A tunable microwave photonic filter with complex coefficient based on slicing spectrum and stimulated Brillouin scattering

In this paper,we propose a method to realize microwave photonic filter(MPF) with complex coefficient,whose central frequency f 0 and 3 dB bandwidth are tunable.The complex coefficient is realized by multi-wavelength optical source and stimulated Brillouin scattering(SBS).The central frequency of the filter is tuned by adjusting the phase shift caused by SBS without changing its frequency response.The frequency selectivity of filter can be improved through increasing the bandwidth of broadband optical source(BOS) or decreasing wavelength separation to increase the taps of MPF.The mainlobeto-sidelobe suppression ratio(MSSR) of the filter is affected by the weight of each tap.When the length of fiber is 0.5544 m in birefringence fiber loop mirror(FLM),the MSSR is improved by 18.55 dB compared with that without the weight controlling.     

Tunable and narrow linewidth multi-wavelength Brill- ouin-erbium fiber laser using dual-wavelength pumping

We demonstrate a multi-wavelength Brillouin-erbium fiber laser (BEFL) with narrow linewidth and tunable wavelength interval using dual-wavelength Brillouin pumping. The generation of multi-wavelength output in BEFL is based on the combination of stimulated Brillouin scattering (SBS) and four-wave mixing (FWM) effect in a fiber cavity. The tunable wavelength interval is determined by the artificially controlled wavelength interval of the pumping lasers. The BEFL could compress a 1 MHz pump laser to a 340 Hz Brillouin Stokes laser, which proves the BEFL has excellent capability of linewidth compression. An erbium-doped fiber pumped by 980 nm laser is inserted into the cavity to further amplify the Brillouin laser. The wideband multi-wavelength BEFL covering over 50 nm is successfully generated when the 980 nm pump power is 400 mW. These features of multi-wavelength BEFL provide an effective method for optical communication systems and optical fiber sensing.     

Tunable self-seeded multi-wavelength Brillouin-erbium fiber laser based on few-mode fiber filter

A tunable self-seeded multi-wavelength Brillouin-erbium fiber laser (BEFL) is proposed and demonstrated based on a few-mode fiber filter (FMFF) with varying temperature. The FMFF configuration is a section of uncoated few-mode fiber (FMF) sandwiched between two up-tapers. As the temperature varies from 25 °C to 125 °C, the transmission spectrum of FMFF moves towards the longer wavelength. The self-excited Brillouin pump is internally achieved by cascaded stimulated Brillouin scattering (SBS) in the single mode fiber (SMF). Then employing the FMFF temperature variation characteristics in the ring cavity fiber laser, the multi-wavelength of the output laser can be tuned, and the tunable range is about 8.0 nm. The generation of up to 15 Brillouin Stokes wavelengths with 16 dB optical signal-to-noise ratio (OSNR) is realized.     

A variable coefficient microwave photonic filter based on multi-wavelength fiber laser and Mach-Zehnder interferometer

A microwave photonic filter（MPF） with variable coefficient is proposed and demonstrated, which is constructed by a multi-wavelength fiber laser and Mach-Zehnder interferometer（MZI）. Through changing the slope characteristics of Mach-Zehnder interference spectrum adjusted by optical variable delay line（OVDL）, the conversion from phase modulation（PM） to intensity modulation（IM） is realized. The multi-wavelength fiber laser with Lyot-Sagnac optical filter has variable wavelength spacing. So the designed filter has a variable number of taps and tap weights. As a result, the tunable range of passband center frequency is 2.6 GHz. The reconfigurability of MPF can be also realized by adjusting the output of fiber laser.     

A widely tunable microwave photonic notch filter with adjustable bandwidth based on multi-wavelength fiber laser

A widely tunable microwave photonic notch filter with adjustable bandwidth based on multi-wavelength fiber laser is proposed and demonstrated. The multi-wavelength fiber laser generates the multi-taps of the microwave photonic filter (MPF). In order to obtain notch frequency response, a Fourier-domain optical processor (FD-OP) is introduced to control the amplitude and phase of the optical carrier and phase modulation sidebands. By adjusting the polarization controller (PC), different numbers of taps are got, such as 6, 8, 10 and 12. And the wavelength spacing of the multi-wavelength laser is 0.4 nm. The bandwidth of the notch filter is changed by adjusting the number of taps and the corresponding bandwidths are 4.41 GHz, 3.30 GHz, 2.64 GHz and 2.19 GHz, respectively. With the additional phase shift introduced by FD-OP, the notch position is continuously tuned in the whole free spectral range (FSR) of 27.94 GHz. The center frequency of the notch filter can be continuously tuned from 13.97 GHz to 41.91 GHz. This work has been supported by the National Natural Science Foundation of China (No.11444001), and the Municipal Natural Science Foundation of Tianjin in China (No.14JCYBJC16500). E-mail:cynever@163.com      

一种新颖的基于AFMLF的双倍布里渊频移间隔的MWBEL

提出了一种基于非线性放大光纤环形镜(AFMLF)滤波器的双倍布里渊频移间隔的多波长掺铒光纤激光器(MWBEL)环形腔结构,其中非线性放大光纤环形镜被用作滤波器。当980nm泵浦功率为10.29dBm、可调激光源(TLS)的中心波长为1 563nm、功率为-3dBm时,得到了波长间隔为0.16nm的12阶偶数阶多波长激光输出。同时,还研究了980nm抽运功率、偏振控制器(PC)以及可调激光源的中心波长对输出斯托克斯光波数的影响。     

采用双Sagnac环滤波器的可切换多波长光纤激光器

提出了一种基于双Sagnac环滤波器的可切换多波长掺铒光纤激光器,该滤波器由基于保偏光纤和少模光纤的Sagnac环并联构成,结构简单,利用其梳状滤波特性,实现了掺铒光纤激光器的多波长输出。采用传输矩阵法详细分析了双Sagnac环的传输特性,进一步搭建了线性腔掺铒光纤激光器,实验中通过调节偏振控制器,改变腔内偏振态,在室温下得到稳定可切换的单、双、三波长激光输出,且激光器输出波长的位置可调。研究结果表明,输出激光波长的边模抑制比大于34 dB,稳定性测量中波长漂移量小于0.05 nm,具有良好的稳定性,可应用于波分复用及全光通信系统等领域。     

基于受激布里渊散射放大效应的可调谐多波长激光器的研究

为了获得高质量的可调谐多波长激光器,提出并 验证了一种结构简单的基于受激布里 渊散射(SBS)放大效应的多波长激光器。首先设计了单频布里渊环形腔激光器,将单频 激光信号 作为信号光,通过SBS放大效应实现了超过12个波长的激光输出,且 产生的波长数可以 进一步增加。该激光器的波长间隔为0.087nm,通过调节泵浦波长和 功率实现了可调谐的多 波长输出。在20 min的时间间隔内,测量了信号的稳定性, 实验结 果表明, 本文的多波长激光器展现了较高的稳 定性。     

Continuous True-Time-Delay System Employing a Novel Tunable Chirped Fiber Grating Delay Line and a Sampled Grating Based Multiwavelength Fiber Laser

A photonics true-time-delay system for phased array antenna beam steering employing a novel tunable chirped fiber grating delay line and a multi-wavelength erbium-doped fiber ring laser source based on a sampled grating filter is proposed. The tunable chirped fiber grating, which act as a continuous time-delay element, is achieved by bending a uniform fiber Bragg grating bonded at a slant onto the lateral surface of a simply supported beam. This technique allows the dynamic control of the chirp rate and spectral width of the grating without center wavelength shift. By adjusting the chirp rate of the fiber grating via bend strain, this kind of tunable chirped fiber grating could achieve very low and adjustable delay times, therefore provides higher angle resolution for scanning microwave beam, even the wavelengths of laser source are fixed and un-tunable. The true-time-delay system using proposed tunable chirped fiber grating delay element and sampled grating based laser source is constructed and demonstrated experimentally.