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相比于使用DFB边发射激光器,采用VCSEL激光器作为检测光源的TDLAS激光气体检测系统,具有功耗低的优点。针对低功率下的TDLAS气体检测信号特点,结合VCSEL激光光源调制特性,自主开发了VCSEL激光器驱动模块、信号采集及处理模块,采用波长调制光谱(WMS)技术研制出了一套低功率甲烷(CH4)气体检测系统。选择了1653.7 nm附近CH4分子的吸收峰作为吸收谱线,采用锁相放大器提取二次谐波(2f)信号。实验研究了不同浓度的CH4检测的响应情况,记录2f信号的峰峰值并进行线性拟合,线性度为0.999 8。该检测系统在50~500 ppmv范围内,检测精度优于10%,检测下限为10 ppmv。对250 ppmv的CH4持续检测10 h,数值波动小于±2.4%。引入Allan偏差分析,初始积分时间为1 s时,Allan偏差为9.9 ppmv;积分时间达到359 s时,Allan偏差为0.06 ppmv,表征了系统良好的稳定度。 相似文献
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G. M. Isoe S. Wassin R. R. G. Gamatham A. W. R. Leitch T. B. Gibbon 《Journal of Modern Optics》2017,64(21):2336-2344
Optical fibre communication technologies are playing important roles in data centre networks (DCNs). Techniques for increasing capacity and flexibility for the inter-rack/pod communications in data centres have drawn remarkable attention in recent years. In this work, we propose a low complexity, reliable, alternative technique for increasing DCN capacity and flexibility through multi-signal modulation onto a single mode VCSEL carrier. A 20 Gbps 4-PAM data signal is directly modulated on a single mode 10 GHz bandwidth VCSEL carrier at 1310 nm, therefore, doubling the network bit rate. Carrier spectral efficiency is further maximized by modulating its phase attribute with a 2 GHz reference frequency (RF) clock signal. We, therefore, simultaneously transmit a 20 Gbps 4-PAM data signal and a phase modulated 2 GHz RF signal using a single mode 10 GHz bandwidth VCSEL carrier. It is the first time a single mode 10 GHz bandwidth VCSEL carrier is reported to simultaneously transmit a directly modulated 4-PAM data signal and a phase modulated RF clock signal. A receiver sensitivity of ?10. 52 dBm was attained for a 20 Gbps 4-PAM VCSEL transmission. The 2 GHz phase modulated RF clock signal introduced a power budget penalty of 0.21 dB. Simultaneous distribution of both data and timing signals over shared infrastructure significantly increases the aggregated data rate at different optical network units within the DCN, without expensive optics investment. We further demonstrate on the design of a software-defined digital signal processing assisted receiver to efficiently recover the transmitted signal without employing costly receiver hardware. 相似文献
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This work experimentally demonstrates the potential of multi-level pulse amplitude modulation with direct detection to maximize carrier spectral efficiency and double the Gigabit passive optical networks (G-PON) network data rate. Three scenarios have experimentally been exploited. First, a 1310?nm vertical surface-emitting laser (VCSEL) has directly been modulated with a 10?Gbps OOK data. A receiver sensitivity of ?19.11?dBm is attained, and a successful error free transmission over 22?km SMF fibre achieved, with a transmission penalty of 0.46?dB. To maximize carrier spectral efficiency, 2/4 PAM modulation formats are adopted respectively. A receiver sensitivity of ?14.64 and ?11.63?dBm is attained for 2-PAM and 4-PAM formats respectively. However, a 3.21?km fibre transmission introduces a penalty of 0.64 and 3.30?dB for 2-PAM and 4-PAM formarts respectively. 2/4-PAM modulation formats significantly increase the aggregated data rate at different ONUs within the G-PON without expensive optics investment, though at the cost of reduced transmission reach due to the high bitrate attained. We further demonstrate the design of a software defined digital signal processing assisted receiver to recover the 2/4 PAM transmitted signal without employing costly receiver hardware. 相似文献
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针对铷原予能级跃迁对光谱的特殊需求,设计并制备了795 nm单模垂直腔面发射激光器(VCSEL).根据对VCSEL的光场和模式的分析和计算结果,设计了单模VCSEL芯片结构.采用MOCVD技术生长了外延结构,制备了不同有源区直径的氧化限制型VCSEL芯片并进行了测试.当有源区直径从6 μm减小到3μm时,VCSEL芯片的边模抑制比(SMSR)由8.76 dB增加到34.05 dB,阈值电流由0.77 mA减小到0.35 mA.有源区直径为6,5,4和3μm的VCSEL芯片的输出功率分别为0.37,0.46,0.58和0.44 mW,有源区直径为4μm的VCSEL芯片的远场为圆形光束,发散角为15°.85℃时3.5 μm有源区直径的VCSEL芯片输出功率为0.125 mW,激射波长为795.3 nm.室温3 dB带宽大于8 GHz,满足了铷原子传感器对VCSEL单模光谱、输出功率及调制速率的要求. 相似文献
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Demonstration of Time‐ and Wavelength‐Division Multiplexed Passive Optical Network Based on VCSEL Array 下载免费PDF全文
Sil‐Gu Mun Eun‐Gu Lee Jie Hyun Lee Heuk Park Sae‐Kyoung Kang Han Hyub Lee Kwangok Kim Kyeong‐Hwan Doo Hyunjae Lee Hwan Seok Chung Jong Hyun Lee Sangsoo Lee Jyung Chan Lee 《ETRI Journal》2016,38(1):9-17
We demonstrate a time‐ and wavelength‐division multiplexed passive optical network system employing a vertical‐cavity surface‐emitting laser array–based optical line terminal transceiver and a tunable bidirectional optical subassembly–based optical network terminal transceiver. A packet error–free operation is achieved after a 40 km single‐mode fiber bidirectional transmission. We also discuss an arrayed waveguide grating, a photo detector array based on complementary metal–oxide–semiconductor photonics technologies, and low‐cost key devices for deployment in access networks. 相似文献
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相位共轭反馈对外腔VCSEL非线性的控制 总被引:1,自引:1,他引:0
提出了相位共轭镜(PCM)与外腔垂直腔面发射激光器(VCSEL)相结合的双耦合腔结构,利用相位共轭反馈(PCF)来控制外腔VCSEL的非线性特性,并与用普通光反馈控制非线性特性的情形进行了比较。结果表明:与普通平面镜相比,PCM对放置位置的变化(波长量级)不敏感且PCM反馈可使外腔VCSEL的稳定范围增大;以外腔反射率在5~7ns^-1间变化的功率分岔图为例发现,PCF可抑制多周期和混沌等不稳定状态,控制VCSEI。输出在单周期或倍周期状态;通过PCF和外腔反馈的共同作用。可得到更高频率的单周期或倍周期输出,实现对VCSEL动态特性控制更加容易。 相似文献
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