共查询到20条相似文献,搜索用时 31 毫秒
1.
《Fiber and Integrated Optics》2007,26(4):201-215
An integrated photonic architecture is introduced and used to realize an optical filter with direct form I realization. The architecture offers gain from semiconductor optical amplifiers, and this gain results in an active optical filter whose filter response depends on the individual gains. The presence of gain provides advantages in filter performance, and tunable and adaptive functionality. The optical filter is modeled as a discrete time system and the z-transform is used in its analysis and design. A low-pass filter design example is presented and the filter coefficients are derived in terms of gains and coupler splitting ratios. The region of stable operations is derived by applying the Schur-Cohn stability test. 相似文献
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Jian Tong Duncan L. MacFarlane Issa Panahi L. Roberts Hunt Govind Kannan Gary A. Evans 《Fiber and Integrated Optics》2013,32(4):201-215
Abstract An integrated photonic architecture is introduced and used to realize an optical filter with direct form I realization. The architecture offers gain from semiconductor optical amplifiers, and this gain results in an active optical filter whose filter response depends on the individual gains. The presence of gain provides advantages in filter performance, and tunable and adaptive functionality. The optical filter is modeled as a discrete time system and the z-transform is used in its analysis and design. A low-pass filter design example is presented and the filter coefficients are derived in terms of gains and coupler splitting ratios. The region of stable operations is derived by applying the Schur-Cohn stability test. 相似文献
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We demonstrate a multi-wavelength semiconductor optical amplifier (SOA) fiber ring laser with a dual-pass Mach-Zehnder interferometer (MZI) filter. Two SOAs with different gain spectra provide sufficient gain and a wider gain spectrum to facilitate multi-wavelength lasing. The dual-pass MZI, configured by adding an optical isolator to the two outputs of the conventional MZI, serves as comb filter for multi-wavelength operation, and its extinction ratio can be enhanced to twofold as that of the conventional MZI in the same parameters. To investigate the influences of a dual-pass MZI filter and a conventional MZI filter on multi-wavelength operation, two different cavity configurations are presented and compared, including a single-SOA ring cavity and a double-SOA ring cavity. Stable simultaneous operation at 82 wavelengths, with a wavelength spacing of 40 GHz and a power deviation of 5 dB, and with a minimum optical signal-to-noise ratio (OSNR) of 28 dB, is observed from the double-SOA ring cavity using a dual-pass MZI filter. 相似文献
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A novel shape-adjustable narrowband optical filter utilizing stimulated Brillouin scattering in an optical fiber is proposed and demonstrated. In this scheme, binary-phase-shift-keying modulation is applied to the pump wave to broaden and shape the Brillouin gain spectrum. By choosing an appropriate modulation data pattern, we realized a flat-top steep-cutoff optical bandpass filter with a 3-dB bandwidth of 1.5 GHz and a 10-dB bandwidth of 2 GHz is realized. In addition, a tunable optical notch filter is also realized by deamplification of the anti-Stokes wave. 相似文献
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N. Md. Yusoff M. H. Abu Bakar S. J. Sheih F. R. Mahamd Adikan M. A. Mahdi 《Laser Physics》2010,20(8):1747-1751
Erbium-doped fiber amplifier with flat gain over 30 nm bandwidth is demonstrated using flexible selective band methods. The
band optical amplifier was designed to cater 44 wavelength division multiplexing channels which were separated into bands
of 4 nm. Without using any gain flattening filter, the gain of optical amplifier was maintained at 19 dB with a maximum gain
variation of less than 1.6 dB even though the input signal power was varied from −19 to −6 dBm. The amplifier was able to
maintain 1 dB gain flatness with 83% chance for any selective bands of 4 nm within the wavelength range from 1530 to 1565
nm. This feature is very attractive to support band optical networks. 相似文献
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We report a widely tunable ring-cavity tellurite fiber Raman laser covering the S+C+L+U band. A tunable range (1495-1600 nm, limited by the tunable optical bandpass filter) over 100 nm is obtained by using a single-mode tellurite fiber with high Raman gain coefficients (55 W(-1)km(-1)) and large Raman shift (~22.3 THz) as the gain medium. Furthermore, the free-running 1665 nm Raman fiber laser is achieved from the ring cavity by removing the tunable optical bandpass filter, which shows that such a tellurite fiber has potential for constructing a widely tunable fiber Raman laser covering the S+C+L+U band. A high optical signal-to-noise ratio of over 60 dB for almost all of the tunable range is also demonstrated. 相似文献
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A tunable all-optical microwave notch filter with a negative tap based on a semiconductor optical amplifier and a dispersive medium is demonstrated. A negative tap is realized through the cross gain modulation in the semiconductor optical amplifier. The free spectrum range of the notch filter can be tuned by tuning the wavelength of one of the two laser sources. The influence of the amplitude mismatch of the two lasers on the performance of the filter is analyzed. The present notch filter is easy to implement and cost-effective. 相似文献
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The filter mechanism of a tunable filter with narrow-band in bulk semiconductor laser amplifier (SLA) is analyzed, which is suitable for dense wavelength division multiplexed (DWDM) optical fiber networks. The wavelength selectivity of the filter is derived from nondegenerate four-wave mixing (NDFWM) in semiconductor gain medium. It uses the direction of propagation to separate the desired wave-mixing product from the other light beams. The filters are shown to have very narrow passbands (subangstrom bandwidth) tunable over the entire semiconductor gain bandwidth. We gave the theoretical analysis of NDFWM effect in semiconductor gain medium is given and a set of nonlinear coupled wave equations is deduced, which are processed efficiently by Runge-Kutta method in numerical simulation. The influences of various structural parameters of the filter on the output bandwidth and efficiency were also discussed. 相似文献
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Inhomogeneous loss generated by multimode laser linewidth broadening in an optical fiber is experimentally studied. With this mechanism, multiwavelength lasing is achieved by use of either fiber Raman gain or erbium-doped fiber gain. Through various pump powers and optical filter bandwidths, the relationship between inhomogeneous loss and the performance of a multiwavelength fiber laser is studied, and a physical explanation is provided. 相似文献
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JIANG Yan CUI YipingTo whom correspondence should be addressed. PANG Shuming 《Chinese Journal of Lasers》1999,8(6):489-496
1 Introduction Today,withthequickdevelopmentofthehighdensewavelengthdivisionmultiplexing,thelinkcapacitywillbegreatlyenhanced.Alternatively,theenhancementofthelinkcapacitydependsontherelativelyhighwavelengthresolutionofthewavelengthfiltersintherecei… 相似文献
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A variable transmission spectrum single-passband narrowband optical filter is proposed and experimentally demonstrated. It is based on forward stimulated interpolarization scattering (SIPS) in a photonic crystal fiber by applying a differential quadrature phase-shift keying modulation to the pump wave to broaden and shape the SIPS gain spectrum. By choosing the bit rate of the modulation data pattern, a flat-top steep-cutoff optical bandpass filter with a 3?dB bandwidth of 70?MHz and a 10?dB bandwidth of 90?MHz is realized. In addition, a variable narrowband optical notch filter is also realized by attenuation of the pump wave. 相似文献
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By using Faraday optical filter combined with four-wave mixing (FWM) amplifier, a narrow bandwidth optical amplifying atomic filter with switchable dual-passband is demonstrated experimentally. The two transmission peaks of the filter correspond to the Stokes and anti-Stokes frequencies, exhibiting a Raman gain in 13- and 17-fold, respectively, with bandwidth of ~120 MHz. By properly setting pump laser detuning, switching between filter passbands is realized. We also investigate the dependence of peak transmission on both pump laser intensity and Rb cell temperature. This atomic filter can find practical applications in long-distance laser communications and laser remote-sensing systems. 相似文献
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高功率激光多程放大系统光束传输的计算分析 总被引:6,自引:6,他引:0
报道了高功率激光多程放大系统光束传输的模拟程序, 该程序考虑了放大介质的增益分布、增益饱和、增益恢复系数、介质吸收损耗、B积分以及光阑和空间滤波器等光学元件对激光传输和放大的影响, 并给出了典型的计算实例。 相似文献
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ExperimentalandTheoreticalResearchorDFWMTunableNarowOpticalBandpasFilterZHANGXuemingYEJiaxiong(DepartmentofOptoelectronicEngi... 相似文献
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报道了高功率激光多程放大系统光束传输的模拟程序, 该程序考虑了放大介质的增益分布、增益饱和、增益恢复系数、介质吸收损耗、B积分以及光阑和空间滤波器等光学元件对激光传输和放大的影响, 并给出了典型的计算实例。 相似文献
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有源循环式光脉冲复制系统的输出特性研究 总被引:1,自引:0,他引:1
改进并验证了一种基于有源循环光纤延迟线的模拟光脉冲信号复制技术.实验系统采用低增益掺铒光纤放大器补偿循环损耗.进行了光脉冲信号复制的仿真和实验,在掺铒光纤放大器增益为6.774 dB,光滤波器-3 dB,带宽为0.8 nm时,测得第500个复制光脉冲的信噪比为31 dB.仿真和实验结果表明,选用小增益掺铒光纤放大器可以实现低于3 dB的噪音系数,降低掺铒光纤放大器的放大自发辐射噪音并提高输出脉冲序列的信噪比,有望成为提高光脉冲复制器性能的一种新方法.在系统中插入窄带光滤波器等手段也是改善信噪比的有效措施. 相似文献