单纵模波长可开关的环形腔光纤激光器

提出并实现了一种单纵模窄线宽输出、波长可开关的光纤激光器.该激光器采用环形腔结构,利用一段未抽运的掺铒光纤(EDF)的饱和吸收效应来实现光纤激光器的单纵模运转与窄线宽输出;同时利用1×2光开关和2个并联的不同中心波长的光纤光栅(FBG)的选波作用,通过控制光开关的电压信号,实现2个输出波长的可开关功能.在17.5 dBm的掺铒光纤放大器(EDFA)输出功率下,获得了2.5 dBm峰值功率,3 kHz线宽的单纵模激光输出;并且输出光的波长在控制电压的作用下可在1545.2 nm和1556.4 nm两个波长之间任意选择.     

基于光子晶体平板传导共振模的低功率光开关

利用严格耦合波算法计算了二维光子晶体平板结构随角度变化透过谱和波长变化透过谱,研究了透过谱上传导共振峰与二维光子晶体平板能带结构的关系。利用共振传导模的低透过和高Q值的特点,设计了基于磷化铟材料的工作在1550nm波长附近的角度分辨和波长分辨的光子晶体光开关。理论模拟结果表明,该结构透过谱上传导共振峰品质因子可达105,非线性折射率变化为10-4即可实现开关对比度接近100%。当信号光或泵浦光分别与光子晶体平板传导共振模耦合时,由于共振耦合使得泵浦光场增强,需要泵浦能量仅为184fJ,为目前所知能量最低的光开关。     

单纵模、波长可开关的线性腔光纤激光器

提出并实现了一种单纵模输出、波长可开关的光纤激光器.该激光器采用线性法布里-珀罗(F-P)腔结构,利用980 nm抽运的掺铒光纤(EDF)作为增益介质,并且通过腔内另一段未抽运的掺铒光纤的饱和吸收效应来实现光纤激光器的单纵模运转;同时利用1×N光开关和N个并联的不同中心波长的光纤光栅(FBG)的选波作用,通过控制光开关的电压信号,实现N个输出波长的可开关功能.在90 mw的抽运功率下,获得了-0.5 dBm峰值功率,3.6 kHz线宽的单纵模激光输出;输出光的波长在控制电压的作用下可在1574.6 nm,1579.7 nm,1584.8 nm和1589.9 nm四个波长之间任意选择.     

基于Fabry-Perot结构的可调波长选择光开关

本文提出波长选择光开关的概念,首次研制出一个基于Fabry-Perot结构的可调波长选择光开关,该开关为2×2光纤端口,每个端口携带N个波长,工作时可以选1个或多个波长,插入损耗小于3dB,波长调谐范围10nm,调谐机构为一对多层三明治结构的压电陶瓷,具有驱动电压低,小于5V的驱动电压可以达到3.3nm的调谐,最大开关时间为1毫秒,开关比优于30dB.最后还分析了其基本透射与反射光谱性能,并讨论其对光通信、光交换网络产生的重要应用价值.     

可调谐双波长低抖动增益开关光脉冲的产生

提出了一种产生可调谐双波长低抖动超短光脉冲的新方法。采用外光注入法来降低增益开关F-P激光脉冲的时间抖动,实现了脉冲光谱的双波长可调谐输出。实验中利用两个多量子阱DFB激光器作为外部种子光源,通过温度控制和偏振态调节使外部种子光有效地耦合到增益开关F-P激光器中,输出的光脉冲时间抖动(均方根)从2.57ps降低至1.06ps,双波长的边模抑制比可达25dB。通过改变DFB激光器和F-P激光器的工作温度,可实现波长从1540nm到1560nm的可调谐输出。     

光通信波段亚波长光栅偏振器的设计与分析

亚波长周期结构光栅具有传统光栅所不具有的特殊特性。基于矢量衍射理论-耦合波分析法对矩形亚波长光栅的衍射效率进行了理论计算,针对光通信中的1 550nm波长设计了一种基于SOI衬底的亚波长偏振光栅,分析了光栅周期、光栅深度、占空比和光栅结构的变化对其偏振特性的影响。仿真结果表明,当光栅的周期为960nm,槽深为230nm,占空比为24%时,可使TM模式的透射率大于95%,TE模式的透射率小于5%,且矩形的光栅结构相对于三角形和圆形的光栅结构具有更好的偏振性能,可有效用于光开关、光隔离器、激光器、光探测器等半导体光电子器件。     

非对称Y分叉全内反射型全光开关

基于全内反射原理和光生载流子注入效应,研究了一种Y分叉全内反射型全光开关.当控制光(波长为805nm)的强度达到150W/mm2时,对于1310nm波长,其开关的消光比可以达到18dB,并对光注入开关机理做了简单的探讨.     

MEMS光开关

采用 MEMS体硅工艺 ,制作了三种结构的微机械光开关 :水平驱动 2 D(二维 )光开关、垂直驱动 2 D光开关和扭摆驱动 2 D、3D(三维 )光开关 .水平驱动光开关采用单层体硅结构 ,另外两种光开关都采用了硅 -玻璃的键合结构 .它们的工作原理都基于硅数字微镜技术 .这三种光开关均采用了静电力驱动 ,具有较低的驱动电压 ,其中扭摆式光开关的驱动电压小于 15 V.对于 2 D开关阵列 ,在硅基上制作了光纤自对准耦合槽 .对后两种光开关的开关特性进行了计算机模拟与分析 ,结果表明这两种光开关具有小于 1ms的开关时间     

850/1550nm智能集成分波光开关的理论设计

理论分析和设计了一种用于850和1550nm两个光通信窗口的、集波长信号分离和光开关功能于一体的智能集成分波光开关,并将弧形结构全内反射面用于该集成结构中.基于Si基半导体SiGe合金材料的等离子体色散效应,对该结构智能集成分波光开关的串音、损耗、消光比等特性进行了分析和模拟计算.计算得到,作为光开关时器件的平均串音、插入损耗和消光比分别为-19,1.3和21dB,作为分波器时平均串音和插入损耗分别为-11和1.1dB.设计结果表明,该集成器件不仅能够实现850和1550nm两种波长光信号的开关,而且还能对这两种波长的光信号进行分离,是一种有前途的智能化集成分波光开关.     

850/1550nm智能集成分波光开关的理论设计

理论分析和设计了一种用于850和1550nm两个光通信窗口的、集波长信号分离和光开关功能于一体的智能集成分波光开关,并将弧形结构全内反射面用于该集成结构中.基于Si基半导体SiGe合金材料的等离子体色散效应,对该结构智能集成分波光开关的串音、损耗、消光比等特性进行了分析和模拟计算.计算得到,作为光开关时器件的平均串音、插入损耗和消光比分别为-19,1.3和21dB,作为分波器时平均串音和插入损耗分别为-11和1.1dB.设计结果表明,该集成器件不仅能够实现850和1550nm两种波长光信号的开关,而且还能对这两种波长的光信号进行分离,是一种有前途的智能化集成分波光开关.     

一种新型基于光子晶体异质结耦合波导的全光开关的设计

基于电磁波在耦合波导中的传输特性,建立了一个光开关模型,利用耦合模理论、平面波展开法以及有限时域差分法进行设计和分析。分别分析改变介质柱的折射率和异质结位置变化对开关功能的影响。结果表明改变介电柱的折射率能影响开关的功能,而异质结耦合波导中介电柱的位置分布对光开关功能影响很小。利用这个特性可以在光开关的设计中有更多的灵活性。     

InGaAsP/InP MQW directional coupler switch with small and low-lossbends for fiber-array coupling

We report on a compact InGaAsP/InP MQW directional coupler switch with spacing between the waveguides at the input and the output facets larger than 125 μm, required for the fiber-array coupling, by employing small low-loss bends. The total device length, including both the coupling and the bending regions, with the different optical confinements in the lateral direction is 2 mm. The coupling region of the switch is 420 μm, and the voltage-length product at switching is around 6 Vmm     

Fused coupler switch using a thermo-optic cladding

An optical switch based on a single-mode fused coupler has been fabricated. The switching is achieved by a thermal refractive index change of a silicone resin cladding material in the coupling region. Fabrication details and device characteristics are described     

Monolithic array of optoelectronic broad-band switches

The response of monolithic arrays of GaAs photoconductors to optical intensity modulation signals and their feasibility of operating as crosspoint arrays in integrated broadband switch matrices are investigated. It is found that individual photoconductors can switch signals at frequencies of up to 1.3 GHz with isolation better than 70 dB and switching time less than 10 ns. In a 2/spl times/2 monolithic array, 65-dB switch isolation and 80-dB crosstalk isolation between channels are achieved in the frequency range 0-130 MHz. The responsivity is essentially uniform within this frequency range and has a value of 0.84 A/W at 820 nm. At higher frequencies electromagnetic coupling between output lines limits the performance with the layout used. This monolithic array thus demonstrates compact broadband matrix switching of signals in the frequency range up to 100 MHz using the optoelectronic switching principle.     

Tunable light propagation in photonic Crystal coupler filled with liquid Crystal

We propose a new photonic crystal coupler-type optical switch which consists of a triangular lattice of air holes filled with liquid crystal (LC). This switch utilizes the decoupling nature. In order to utilize a large refractive index change of LC, /spl pi/ phase-shifted larger air holes are introduced into the core region, compared to the cladding region. In our structure, all air holes are filled with LC and selective injection of LC is not required. By changing the orientation of the applied field, the coupling state changes decoupling from perfect coupling, and switching operation is realized. Switching operation of the present switch is confirmed by the two-dimensional finite-element method (FEM), and also preliminary three-dimensional calculations confirm the two-dimensional FEM results.     

Silica-based 8×8 optical matrix switch integrating newswitching units with large fabrication tolerance

An 8×8 optical matrix switch consisting of asymmetric Mach-Zehnder (MZ) interferometer switching units with a waveguide intersection was fabricated using silica-based planar lightwave circuits (PLC's) on a silicon substrate. This switching unit can realize a high extinction ratio and a wide operation wavelength range even if the coupling ratios of the directional couplers (DC's) consisting the switching unit, deviate greatly from the ideal value of 50%. A matrix switch with a DC-coupling ratio of 30% was fabricated to test the validity of the proposed geometry. The average insertion loss was 7.3 dB in the transverse electric (TE) mode and 7.5 dB in the transverse magnetic (TM) mode. The average extinction ratio was 31.2 dB in the TE mode and 31.3 dB in the TM mode. The wavelength range with an extinction ratio greater than 20 dB was over 100 nm     

Fabrication of semiconductor optical switch module using laser welding technique

The 4/spl times/4, 1/spl times/2, and 1/spl times/4 semiconductor optic-switch modules for 1550 nm optical communication systems were fabricated by using the laser welding technique based on the 30-pin butterfly package. For better coupling efficiency between a switch chip and an optical fiber, tapered fibers of 10-15 /spl mu/m lens radius were used to provide the coupling efficiency up to 60%. The lens to lens distance of the assembled tapered fiber array was controlled within /spl plusmn/1.0 /spl mu/m. A laser hammering technique was introduced to adjust the radial shift, which was critical to obtain comparable optical coupling efficiencies from all the channels at the same time. The fabricated optical switch modules showed good thermal stability, with less than 5% degradation after a 200 thermal cycling. The transmission characteristics of the 4/spl times/4 switch module showed good sensitivities, providing error free transmissions below -30 dBm for all the switching paths. The dynamic ranges for the 4/spl times/4 and 1/spl times/2 switch modules were about 8 dB for a 3 dB penalty and about 17 dB for a 2 dB penalty, respectively.     

High-speed InGaAlAs-InAlAs MQW directional coupler waveguide switchmodules integrated with a spotsize converter having a lateral taper,thin-film core, and ridge

Fully packaged 2×2 and 4×4 semiconductor optical switch modules are successfully developed by integrating spotsize converters (SSCs) consisting of lateral tapers, thin-film cores, and ridges in InGaAlAs-InAlAs multiple quantum-well (MQW) directional coupler waveguide switches in the 1.55-μm wavelength region. Good reproducibility is obtained for the perfect coupling length of the directional coupler by appropriately designing the ridge width and gap of strip-loaded optical waveguides and by making use of the Cl₂ reactive-ion-beam-etching and successive wet-etching. Since the switching time is sufficiently short (<70 ps, which is limited by the driver speed) for the 4×4 switch module, no bits are lost during a 10-Gb/s switching experiment at a wavelength of 1.55 μm     

Two-mode interference photonic waveguide switch

Based on the two-mode interference principle and the free-carrier plasma dispersion effect, a two-mode interference (TMI) photonic waveguide switch with double carrier injection has been designed and fabricated for application in fiber-optic communications. It consists of an input Y-branch with single-mode ridge waveguides, a TMI waveguide coupling section, and an output Y-branch with single-mode ridge waveguides. The single-mode waveguides and the two-mode waveguide are composed of a SiGe waveguide layer on a Si substrate. The width of the TMI region of the switch is two times that of the single-mode waveguide. On the top of the TMI region and one side of the TMI region, two abrupt p-n junctions are made to inject the carriers into the optical modulation region; on the other side of the TMI region, an abrupt carrier collection region is made to collect the carriers when they are forward biased, so that the double carrier injection photonic waveguide switch has the lowest injection current density. The waveguide layers are made of SiGe/Si material, and the rib waveguides are realized by reactive ion etching. The carrier injection regions and the carrier collection region are formed by ion implantation. The input and output facets of the waveguides were ground and polished by a mechanical method. The switch was characterized by using a 1310-nm InGaAsP/InP heterostructure laser diode. Its insertion loss and ON-state crosstalk were measured to be 2.74 and -15.5 dB, respectively, at a total switching current of 110 mA. The switching time is 180 ns, and the fastest switching time is up to 30 ns.