The Experimental Study on Acousto-optic Modulation Based on Single-mode Fiber Fused Coupler

In-line acoustic-optic (AO) modulation experiments were demonstrated based on the acoustic-optic effect in optical fiber fused taper couplers.About 73%,64%,and 61% modulation have been achieved at frequencies of 0.169 MHz,0.367 MHz and 0.521 MHz with an electrical driving power less than 10 mW,respectively.     

光纤熔锥耦合器的声光调制特性

对光纤熔锥方向耦合器的声光强度调特性进行了实验研究,得到了工作波长为1310nm、声波频率为20.19kHz,电驱动功率为2.6mW,插入损耗为0.5dB,调制深度为64％的声光强度调制特性。     

Power Analysis and Experimental Study of the Fiber Null Coupler with an Acousto-optic Device

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｈｉｇｈ ｐｅｒｆｏｒｍａｎｃｅ ｏｐｔｉｃａｌｓｗｉｔｃｈｉｎｇｔｅｃｈｎｏｌｏｇｉｅｓａｒｅｃｕｒｒｅｎｔｌｙｏｆｅｎｏｒｍｏｕｓｉｎｔｅｒｅｓｔｆｏｒｔｈｅｃｏｍｍｕｎｉｃａｔｉｏｎｓｉｎｄｕｓｔｒｙ .Ｔｏｄａｔｅｍａｎｙｔｅｃｈｎｏｌｏｇｉｅｓｈａｖｅ ｐｒｏｄｕｃｅｄｈｉｇｈ ｐｅｒｆｏｒｍａｎｃｅｃｈａｒａｃｔｅｒｉｓｔｉｃｓ[1,2 ] .Ｔｈｅｒｅｑｕｉｒｅｍｅｎｔｆｏｒｔｈｅｓｕｃｃｅｓｓｆｕｌｔｅｃｈｎｏｌｏｇｉｅｓｗｉｌｌｂｅｌｏｗｉｎｓｅｒｔｉｏｎｌｏ…     

The Experimental Study on Wide band Tunable All-fiber Acousto-optic Filter Based on Null Coupler

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　ＩｎＷＤＭｏｐｔｉｃａｌｆｉｂｅｒｃｏｍｍｕｎｉｃａｔｉｏｎａｎｄｎｅｔｗｏｒｋａｐｐｌｉｃａｔｉｏｎｓ,ｍａｎｙｏｐｔｉｃａｌｃｏｎｔｒｏｌｌａｂｌｅｄｅｖｉｃｅｓａｒｅｄｅｍａｎｄｅｄ ,ｓｕｃｈａｓｃｈａｎｎｅｌｇａｉｎ/ ｐｏｗｅｒｅｑｕａｌｉｚｅｒ,ｃｈａｎｎｅｌｓｅｌｅｃｔｏｒ,ｏｐｔｉｃａｌｓｗｉｔｃｈｉｎｇ ,ａｎｄａｄｄ/ｄｒｏｐｍｕｌｔｉｐｌｅｘｅｒ,ｅｔｃ .Ｉｎｍａｎｙｃａｓｅｓ,ｗａｖｅｌｅｎｇｔｈｔｕｎａｂｉｌｉｔｙｉｓｎｅｅｄｅｄ .Ｔｈｅｂｕｌｋｗ…     

Experimental Measurement of Fused Fiber Coupler and M-Z Interferometer Performance as WDM Devices

Abstract

An experimental study of the WDM response of fused fiber couplers and an M-Z interferometer is presented. The WDM practical implementation limits of single fused fiber couplers, along with fiber tapering measurements, were obtained. Mach-Zehnder interferometric devices based on fused fiber couplers were included in this work in order to surpass the single coupler's WDM limitations and widen the operation range of the analyzed fused fiber devices.     

Experimental Measurement of Fused Fiber Coupler and M-Z Interferometer Performance as WDM Devices

An experimental study of the WDM response of fused fiber couplers and an M-Z interferometer is presented. The WDM practical implementation limits of single fused fiber couplers, along with fiber tapering measurements, were obtained. Mach-Zehnder interferometric devices based on fused fiber couplers were included in this work in order to surpass the single coupler's WDM limitations and widen the operation range of the analyzed fused fiber devices.     

Power Analysis and Experimental Study of the Fiber Null Coupler with an Acousto-optic Device

A single-mode fiber acousto-optic (AO) switch based on a null coupler at wavelength of 1.55 μm is reported.According to the coupled mode theory,power distribution of the null coupler with the acoustic-wave is formulated for general case.Excess loss of 0.1 dB and the schematic graph of throughput and coupled power are obtained experimentally.     

单模光纤耦合器的偏振温度特性研究

理论分析并研究了温度变化对单模光纤耦合器的偏振特性的影响.推导了单模光纤耦合器输出消光比与输入消光比、模式耦合率的关系表达式.利用多个偏振特性不同的光源,进行了在快速温度变化条件下单模耦合器输出消光比随温度变化的测试实验,证明了采用低偏振的光源有利于降低单模耦合器中因温度变化引起的模式耦合效应.最后仿真计算了在光源输出消光比不同的情况下模式耦合引起的光纤陀螺输出误差的大小,为不同环境应用的光纤陀螺选取合适的光源提供了参考.     

单模与多模光纤耦合器的光束合波

现有的光纤耦合器在作为分波器使用时具有较低的插入损耗,在作为合波器时插入损耗较大,为实现低损耗合波目的,提出一种由单模与多模光纤共同构成的混合型光纤耦合器。利用耦合波方程理论分析其工作原理,计算机模拟其耦合过程。采用熔锥法制作工艺,完成单模与多模光纤耦合器的制作,实验结果与理论模拟相吻合;该器件单模到多模光纤的耦合效率、多模到多模光纤的耦合效率均在90％以上,实现了两路光束的功率合波。作为低插入损耗合波器件可广泛应用于光通信以及双包层光纤激光器抽运光的注入。     

A Novel Acoustic Emission Fiber Optic Sensor Based on a Single Mode Optical Fiber Coupler

Ａｓｗｅｋｎｏｗ ,ａｓｉｎｇｌｅｍｏｄｅｆｉｂｅｒｃｏｕｐｌｅｒｉｓａｓｉｍｐｌｅｂｕｔｖｅｒｙｉｍｐｏｒｔａｎｔｆｉｂｅｒｏｐｔｉｃｄｅｖｉｃｅ ,ｗｈｉｃｈｃａｎｂｅｕｓｅｄｉｎｃｏｍｍｕｎｉｃａｔｉｏｎａｎｄｓｅｎｓｏｒｓ.Ｕｓｉｎｇｓｉｎｇｌｅｍｏｄｅｏｐｔｉｃａｌｆｉｂｅｒｄｅｖｉｃｅｓ,ｗｅｃａｎｆａｂｒｉｃａｔｅｓｅｖｅｒａｌａｃｏｕｓｔｉｃ ｏｐｔｉｃｄｅｖｉｃｅｓ ,ｓｕｃｈａｓｆｒｅｑｕｅｎｃｙｓｈｉｆｔｅｒｓ ,ｍｏｄｕｌａｔｏｒｓａｎｄｔｕｎａｂｌｅｆｉｌｔｅｒｓ .Ｓｅｖｅｒａｌ…     

光纤熔锥耦合器的声光强度调制特性

对光纤熔锥方向耦合器的声光强度调制特性进行了实验研究。得到了工作波长为1310nm,声波频率为20.19kHz,电驱动功率为2.6mW,插入损耗为0.5dB,调制深度为64％的声光强度调制特性。     

用于光纤光栅解调的波长敏感光纤耦合器

为了拓宽光纤耦合器的使用范围,开发光纤耦合器的新功能,采用熔锥技术制作波长敏感耦合器,该耦合器在分光的同时对波长敏感。通过耦合理论验证实验结果,实验数据与理论值相符合。实验中得到波长灵敏度最大值为17.86%/nm的耦合器。采用拉锥工艺制作波长敏感耦合器工艺简单,耦合比峰值对应波长控制易于实现。该耦合器可用于光纤光栅布拉格波长漂移解调。令待解调光纤光栅布拉格波长与耦合器波长灵敏度最大值对应的波长一致,当波长发生漂移时,耦合器输出耦合比发生变化。自制的波长敏感耦合器实现了对布拉格波长为1566.71 nm光纤光栅波长漂移的解调,波长漂移1.80 nm,耦合比变化20.34%。此种解调方式具有光路简单,易于与光纤匹配的优点,可以应用在大型建筑中光纤光栅的健康监测。     

熔锥型熊猫光纤耦合器的传输特性分析

熔锥型保偏耦合器的传输特性决定了其光学原理与功能的实现。为了从理论上分析各参量对保偏耦合器传输特性的影响,基于热-结构-电磁多物理场耦合理论,建立了熔锥型熊猫光纤耦合器双锥模型,应用有限元法,分析了各参量对熊猫光纤耦合器传输特性的影响。结果表明应力区与包层折射率差影响耦合区纵向电磁场的分布,折射率差越大,纵向电磁场分布的变形也越大;HE1x1模和HEy11模的传播常量对偏振主轴角度差不敏感,偏振主轴角度差是通过耦合系数进而影响保偏光纤耦合器的消光比的;HE1x1模的传播常量对熔锥的熔锥区横截面椭圆率比较敏感,横截面椭圆率变化6.67%时Δβx11变化0.14%,计算结果表明当熔锥区横截面椭圆率为0.56时可获得较高性能的耦合器。     

熔锥型侧面泵浦耦合器的研究

 现在高功率光纤激光器和光纤放大器采用的双包层掺杂光纤,相对于从半导体泵浦激光器发射出的多模泵浦光束的大发散角,其内包层的直径很小,因此把泵浦光有效地耦合到双包层掺杂光纤的内包层是一个急需解决的难题。研制一种熔锥型侧面泵浦耦合器,可以大幅度提高泵浦光功率,实现增益光纤的多点泵浦,在双包层光纤放大器中使用良好,安全稳定,实现了较高的耦合效率,达到了70%,信号光通过率98%,信号输入与泵浦输入的隔离度大于50 dB,泵浦输入对输出端反向传输光的隔离度27 dB。通过对比结构紧凑性、耦合效率、系统稳定性等相关指标发现,熔锥型侧面泵浦耦合器完全可以满足高功率光纤激光器和光纤放大器的使用要求。     

新型1×4塑料光纤功率耦合器的研制

提出了一种新型的塑料光纤功率耦合器 ,该耦合器与传统的拉锥型和混合棒塑料光纤耦合器不同。理论分析了它的损耗特性。该耦合器基于塑料光纤本身的热特性 ,分别将塑料光纤进行拉锥和热缩构成耦合器的两端 ,结构简单 ,制作容易 ,实验结果表明其性能也可满足塑料光纤短距离通信网的要求     

Null Fiber Coupler with Ultra-high Splitting Ratio of 100000:1 for All-fiber Acousto-optic Switch

A fiber null coupler with very high splitting ratio of 100000: 1 and low excess loss of 0.1 dB is reported. The control of the maximum splitting ratio and loss of the null coupler is studied. Its switching function is experimentally demonstrated by acousto-optic modulation.     

The Experimental Study on Wide-band Tunable All-fiber Acousto-optic Filter Based on Null Coupler

The fiber acousto-optic filter is fabricated successfully for the first time in China. The mode conversion is realized by the acoustic-wave induced perturbation. Excess loss of 0.1 dB and continuous tuning range between 1470 nm and 1580 nm are obtained. The polarization dependence of the filter is studied experimentally.     

熔锥型光纤耦合器拉制过程的仿真和实验研究

基于熔锥型光纤耦合器在拉锥过程中光纤锥形的渐变特性和光纤之间熔融度的变化特点,构建了光纤耦合器在拉制过程中波导结构的变化模型.利用光束传播法对耦合器的拉制过程进行数值模拟,得到耦合器输出光功率随拉伸长度的变化规律以及耦合器的能量分布图.理论模拟和实验结果表明,光纤间熔融度与制作耦合器时的氢气流量及拉伸速度有关,氢气流量大,拉伸速度小,熔融度就大;光纤之间的耦合作用与拉伸长度及熔融度有关,拉伸长度增加或熔融度增大,都会使光纤间的耦合更加显著;拉伸长度不大时,锥形区的耦合可以忽略;随着拉伸长度的增加,光纤变细,耦合作用逐渐增强,锥形区的耦合现象越明显,同时光场也逐渐由纤芯向外发散,产生附加损耗.     

关于氦氖激光器声光调制锁模的实验研究

本实验中,将声光调制锁模器放置在氦氖激光器中的谐振腔里,控制谐振腔中的增益,使声波的频率调制与激光器固有频率间隔一致,从而达既可以到锁模的效果,又可以增加增益,减少能量损耗。通过功率计与示波器检测出激光脉宽、脉冲周、纵模间隔等物理量,与理论值进行比较,判断激光锁模实验的效果。本实验使用的氦氖激光器腔长大于1.55m,是双面全反射腔,可以利用激光锁模技术得到纵模进行比较,从而获得单色性好的超短脉冲激光。