基于分布反馈注入锁定的连续可调光子微波倍频实验研究

提出了一种基于注入锁定分布反馈式(DFB)激光器的双波长差频微波/毫米波信号产生方案。方案利用正弦波光信号通过半导体光放大器(SOA)进行非线性展宽,产生高阶分量,然后注入到两个DFB激光器后进行锁定放大,产生频率连续可调的倍频信号。在实验中,注入的正弦波光信号频率为1.25GHz,得到20～40GHz频率范围内1.25GHz的任意自然数倍的连续可调微波信号,其最高倍频数为32。     

基于注入锁定和时域综合的倍频三角波产生技术

提出并验证了一种利用载波抑制调制和半导体激光器注入锁定相结合的倍频三角波产生方案。方案中激光器发出的连续光经正弦信号驱动的马赫-曾德尔调制器进行抑制载波调制后分为两路,一路保持不变,另一路注入分布反馈激光器锁定放大调制光的高阶谐波分量,获得六倍频信号。两路信号经相位和功率比控制,合路后在光电探测器中叠加产生二倍频的三角波信号。实验利用频率为3GHz和4GHz的正弦调制信号产生了6GHz和8GHz的二倍频全占空三角波信号。理论分析和实验结果均证明了此方案的可行性,避免了复杂的谱线操作,所提方案更加简单高效,在高重复频率三角波产生方面有显著优势。     

基于8字型结构布里渊多波长光纤激光器的可调谐高频微波产生

提出基于8字型结构布里渊多波长光纤激光器的可调谐高频微波的产生方法,该结构耦合输出奇次阶斯托克斯光,从而实现间隔约为20GHz或0.16nm的双波长激光信号输出,第一阶斯托克斯光和第三阶斯托克斯光功率变化在±0.35dB以内。双波长激光信号通过外差的方式进入高速光电探测器产生21.39GHz的微波信号,所得到微波信号的信噪比约为20dB,通过拟合得到3dB线宽约为2MHz,微波信号功率变化在±0.75dB以内。并对比抽运光和第二阶斯托克斯光拍频的微波信号线宽,线宽约为2 MHz。通过调节抽运光的波长实现了微波信号可调谐,范围为±0.28GHz。实验结果说明,所提结构可实现近20GHz的可调谐微波信号,对进一步提高微波信号的质量进行了分析。     

基于波长计实现多路激光的长稳锁定

介绍了一种简单的激光器频率锁定方法,该方法直接将多路激光器频率锁定到波长计。为了测量激光频率的锁定效果,当频率锁定时,利用参考于氢钟的飞秒光梳测量其频率。研究结果表明:锁定到波长计的548 nm光纤激光器的频率抖动在1 MHz以内,阿仑方差在20 s时可达到5×10~(-11);397 nm和866 nm可调谐半导体激光器的频率抖动在±5 MHz以内,长期漂移速度小于2 MHz/h。     

基于前馈调制的光载毫米波发生器的设计与实现

提出了一种新型的基于16倍频前馈调制(FFM)技术的160GHz光生毫米波方法。以两个频率相互锁定、间隔为100GHz的激光器为光源,通过两级前馈调制和三级光学交织选择,产生160GHz间隔的二相相关光学边。通过高速光电探测,实现低相位噪声的毫米波信号产生。建立了相应的理论模型,并进行了仿真分析。理论结果表明,该方法可以有效降低系统误码率,提高系统效率。同时,由于该方法结构简单、成本较低,对光载射频通信系统具有重要应用价值。     

取样光栅分布反馈激光器阵列器件研究

采用了一种基于取样光栅原理制作多通道增益-折射率耦合型光栅的方法,成功制作了8波长分布反馈(DFB)激光器阵列,阵列中各激光器的阈值电流为30～40 mA,注入电流为100 mA时的平均输出光功率为10mW,阵列器件实现了波长的可选择性激射,相邻激光器间的频率间距为200 GHz,验证了用取样光栅方法制作DFB激光器阵列的可行性。     

光子学技术生成微波信号

文章对现有通过光子学技术生成微波信号的方法作了简要的综述,并介绍了我们提出的一种利用激光拍频产生可调谐微波信号的新方法.这种方法基于光纤光栅法珀滤波器与光纤环形腔激光器技术,产生波长间隔可调谐的双波长单纵模激光,使用高速光电探测器对双波长激光进行拍频,生成频率可调的微波信号.实验上获得了频率为9.4885～10.0712GHz的微波信号.文中所提出的方法在无线接入网,无线传感网,射频信号光纤传输,软件无线电等方面有应用前景.     

基于直流光注入直调DFB-LD的可调光毫米波信号产生技术

提出了一种基于直流光注入直接调制分布反馈式半导体激光器(DFB-LD)的载波可调的光毫米波生成方案,利用直接调制DFB-LD的输出瞬态波长随驱动电流增大而蓝移的特点,将直流光注入至直调DFB-LD的0码波长附近注入锁定。锁定的直调激光器在1码时输出的蓝移波长与原注入波长相位相干,再通过光电探测器将拍频信号转换为调制的光毫米波信号。实验重点讨论了40GHz光毫米波的产生,同时完成了30、40、50和60GHz光毫米波的可调谐性实验。本文的方案结构简单,无需外调制器和微波本振,载波可调并可产生高至60GHz光毫米波信号,可作为光/无线混合接入中成本节省的光上变频方案。     

DFB激光器的高稳定宽带锁频方案设计和实现

提出了一种可用于两台半导体分布反馈(DFB)激光器的高稳定宽带锁频方案,高稳定光频锁定范围可覆盖50MHz至11GHz.通过测量和计算得出两台DFB激光器的光频差与目标频率之间的误差,然后基于比例-积分-微分(PID)控制算法反馈控制其中一台DFB激光器的温度和电流,分别粗调和微调其输出光频率,最终实现两台激光器的光频差锁定.实验结果表明,在连续工作2小时内宽带锁频稳定度的均方根误差优于5MHz,接近理论极限.     

基于光相位锁定的载波可变光的毫米波产生技术

提出和实现了一种新型适用于光/无线混合接入的光子载微波产生方案.该方案利用直接调制分布反馈式半导体激光器可以产生宽谱信号的特点,将较低频率正弦信号直接调制半导体激光器,在半导体激光器中进行频谱展宽,然后把宽谱信号注入到多个半导体激光器中进行相位锁定从而作为相干锁定光源.用上述光源在不同波长加载不同信号进行传输,在接收端使用不同通带特性的光学滤波器对信号进行处理,可以选择接收基带信号、光子微波时钟信号、上行光源或不同载波频率的光子微波调制信号.作为验证,分别完成了2.5 Gbps基带信号、20 GHz和40 GHz光副载波调制信号的产生与接收.因为受限于试验条件,只进行了原理验证,但该系统理论上可集成波导设计,无需高频调制器件,并可生成更高载频光子微波信号,有利于未来的光/无线混合接入和超密集波分复用系统.     

Four-Wave Mixing Crosstalk Measurement in a Highly Doped L-Band Erbium-Doped Fiber Amplifier by Using Half of the Signal Channels

We propose a four-wave mixing (FWM) crosstalk measurement method for a signal with 50 GHz spaced wavelength channels in a highly doped L-band erbium-doped fiber amplifier (EDFA). The method uses the crosstalk measured by using a signal with 100 GHz spaced wavelength channels. This approach is based on analyses of the channel spacing dependence of FWM signal generation and the effect of the gain evolution of each signal channel along the EDF during FWM signal generation at a specific frequency. It is shown that reducing the channel spacing from 100 to 50 GHz has little impact on the efficiency of FWM generation if the gain evolution is the dominant term in FWM generation. It is also shown that the contributing ratio of the gain evolution of each channel is almost the same for the two signals. These results enable us to develop a measurement method for estimating the FWM crosstalk in an L-band EDFA applied to a wavelength-division multiplexing system with a 50 GHz spaced signal by using a 100 GHz spaced signal and a compensation factor. The validity of the measurement method is successfully demonstrated experimentally.      

An integrated coupled-cavity 16-wavelength digitally tunable laser

We present a digitally tunable laser that was realized by coupling two wavelength periodical four-channel lasers. The lasers were coupled with a multimode interference coupler, in such a way that the device has a common intracavity output waveguide containing the full multiplexed signal. In the two laser cavities, 1 /spl times/ 4 PHASARs were used with a channel spacing of 100 and 400 GHz, respectively. By coupling each PHASAR to four semiconductor optical amplifiers, 4 /spl times/ 4 channels were generated. The measured SMSR for each of the 16 wavelengths is better than 40 dB.     

可调谐激光器波长控制

文章介绍了可调谐激光器的波长调节及稳定控制的设计方法,并通过试验验证了其可行性.该设计由温度控制、偏置电流控制及锁波电路3部分组成,温度控制粗调波长,偏置电流控制微调波长,而锁波电路主要是针对外界温度发生变化时提供反馈.它适用于温度控制型分布反馈式 (DFB)可调谐激光器的外围电路设计.     

Thermally controlled wavelength locker integrated in widely tunable SGDBR-LD module

A sampled-grating distributed Bragg reflector laser module having an integrated multiwavelength locker has been developed and evaluated. The uniquely designed wavelength locker made of thermally controlled etalon has provided uniform wavelength monitoring and very stable wavelength locking in the 188-ITU grid channels (37 nm) with 25-GHz spacing. Over the case temperature from -5/spl deg/C to 65/spl deg/C, the laser wavelength was locked within /spl plusmn/0.5 GHz, and the total power consumption of the module was less than 4 W.     

InP‐Based Polarization‐Insensitive Planar Waveguide Concave Grating Demultiplexer with Flattened Spectral Response

InP‐based planar waveguide 48‐channel concave grating demultiplexers with a channel spacing of 0.8 nm (100 GHz) are described and demonstrated. Polarization insensitivity and flattened spectral response are successfully achieved by the introduction of a polarization compensator and a two‐focus grating, respectively. The fabricated device shows a polarization‐dependent wavelength shift of less than 20 pm and a ?3 dB spectral width of about 0.55 nm (68.75 GHz) over all channels.     

Monolithic DWDM source with precise channel spacing

We report a low-cost manufacturing approach for fabricating monolithic multi-wavelength sources for dense wavelength division multiplexing(DWDM)systems that offers high yield and eliminates crystal regrowth and selective area epitaxy steps that are essential in traditional fabrication methods.The source integrates an array of distributed feedback(DFB)lasers with a passive coupler and semiconductor optical amplifier(SOA).Ridge waveguide lasers with sampled Bragg side wall gratings have been integrated using quantum well intermixing to achieve a fully functional four-channel DWDM source with 0.8 nm wavelength spacing and residual errors<0.13 nm.The output power from the SOA is>10 mW per channel making the source suitable for use in passive optical networks(PONs).We have also investigated using multisection phase-shifted sampled gratings to both increase the effective grating coupling coefficient and precisely control the channel lasing wavelength spacing.An 8-channel DFB laser array with 100 GHz channel spacing was demonstrated using a sampled grating with twoπ-phase-shifted sections in each sampling period.The entire array was fabricated by only a single step of electron beam lithography.     

光纤激光传感技术及其应用

超高灵敏度的信号探测在石油勘探、地震预报和安全监测等领域都具有重要的应用价值.近年来出现了一种以分布反馈(DFB)光纤激光器为传感元件的新一代光纤传感器,它具有尺寸小、输出激光信号极窄的光谱线宽和极低的噪声等优势,与高分辨率波长解调技术结合可以达到极高的探测灵敏度.介绍了在光纤激光传感技术及其应用技术方面的研究进展,包括线宽仅为3 kHz、尺寸仅为3.6 cm的窄线宽低噪声DFB光纤激光器的研制及其测试,波长分辨率达3.5×10~(-7) pm/Hz~(1/2)的超高分辨率波长解调系统,基于密集波分复用的光纤激光传感网络,以及相关技术在水声和地震波探测中的应用研究.     

Influence of adjacent channel interference on thefrequency-modulated WDM optical communication system

The effect of adjacent channel interference on the frequency modulated wavelength division multiplexing (FM-WDM) optical communication system is analyzed in this paper. This system uses injection-locked optical discriminator at the output for the demodulation of FM channels. Adjacent channel interference results in crosstalk in the FM-WDM communication system which has been calculated. Dependence of crosstalk on the channel spacing, received signal power in a particular channel, and linewidth enhancement factor of the slave laser incorporated in the optical discriminator has been numerically investigated. The injection-locked discriminator has a typical output crosstalk level of -50 dB for a channel spacing of 100 GHz with optical injection level of -30 dB into the slave laser and is a suitable subsystem to be used in FM-WDM communication system     

Module-packaged tunable laser and wavelength locker delivering 40mW of fibre-coupled power on 34 channels

A continuously tunable laser monolithically integrated with a semiconductor optical amplifier is reported. The chip is co-packaged with a frequency locker in a 26 pin butterfly module, and features over 40 mW of fibre-coupled power with an SMSR >37 dB on 34 ITU channels (50 GHz spacing)