1.3μm偏振无关半导体光放大器单片集成模斑变换器

用金属有机化学气相外延生长并制作了 1.3μm脊型波导偏振无关半导体光放大器集成模斑变换器 ,器件有源区为同时采用压应变量子阱和张应变量子阱的混合应变量子阱结构以获得TE和TM偏振模式的增益平衡 ,模斑变换器采用一种新型脊型侧向锥形波导结构 ;集成模斑变换器的半导体光放大器远场发散角为 12°× 15° ,接近圆形光斑 ,与平头标准单模光纤耦合损耗为 - 2 .6dB ,在水平和垂直方向上的 - 1dB耦合对准容差分别为± 2 .3μm和± 1.6 μm ;在 2 0 0mA偏置电流下 ,半导体光放大器小信号增益近 2 4dB ,在 12 80～ 1340nm波长范围内偏振灵敏度小于 0 .6dB。     

光耦合理论及其在通信元器件中的应用

运用矩阵光学中变换矩阵的理论,并以重叠面积积分的方法为基础,推导出了普遍适用于计算光在光通信元器件中光耦合效率的理论公式,可通过设置边界条件计算单模光纤、扩束光纤、半导体激光二极管以及光波导等不同光学元器件之间的耦合效率。导出了计算单模光纤之间和单模光纤与扩束光纤之间存在横向偏移、轴向偏移时的耦合效率理论通用公式。阐述了扩束光纤的制作方法及光在扩束光纤中的传播,并根据所推导耦合效率理论公式计算结果与单模光纤间和单模光纤与扩束光纤间的耦合实验数据进行了比较。     

铌酸锂薄膜器件脊形波导和光纤耦合特性研究

铌酸锂薄膜因其优异光学性能及容易与结构紧凑的光波导等器件相集成等诸多优势,目前已经成为可调谐Fabry-Perot滤波器、电光调制器等器件领域向集成化和微小型化趋势发展的首选光学材料。由于光波导和光纤的尺寸差异而引起了严重的模场失配使得光纤与光波导耦合时存在着较大的插入损耗问题。仿真分析了超高数值孔径光纤和脊形波导直接耦合时,其光场模式分布、折射率、耦合效率和耦合损耗等关键性能的相互影响。结果表明当刻蚀深度和宽度分别为300 nm和0.8μm时,铌酸锂脊型波导与单模光纤（UHNA7）的耦合效率可达33.8%,而耦合损耗为4.71 dB。仿真比较了上包层材料替换为二氧化硅和氮化硅材料时,脊型波导和单模光纤的耦合效率显著增加到63.4%而耦合损耗被降低到1.98 dB。     

行波半导体激光放大器耦合技术研究

本文从理论上分析了单模光纤与行波半导体激光放大器之间的耦合特性,导出一套简捷的设计光纤耦合头公式,比较不同的结构参数对光纤头耦合性能的影响,选出一种最佳设计方案.经实验验证.采用本文提出的光纤头微透镜处理技术,可使光纤-光放大器耦合损耗降至-3dB.     

三维脊型光波导模斑转换器的设计和优化

在三维有限差分束传播法对脊形光波导的结构参数分析和优化的基础上,对单模光纤和脊形光波导连接耦合用模斑转换器进行了深入的研究,重点分析了影响模斑转换器性能的各种因素,如侧面边界、长度、大端宽度和厚度,以及连接光纤和模斑转换器的过渡波导的有关参数.仿真结果表明,三维锥形光波导模斑转换器大端宽度和厚度在11.5~13.5μm和4.5~6.5μm之间,且长度为200~500μm时插入损耗可低达2dB,比二维锥形光波导模斑转换器的插入损耗约减小2dB,其对横向偏移的容差也远远高于二维锥形光波导模斑转换器,合理的使用非线性边界的模斑转换器可以获得比线性边界的模斑转换器更小的插入损耗;过渡波导的宽度、芯层厚度应和三维锥形光波导模斑转换器的大端宽度和厚度一致,且其长度为150μm左右时损耗较小;另外,此类模斑转换器在减小耦合损耗的同时,还可以有效的进行光波模式的转换.     

锥形透镜光纤与平面光波光路芯片的耦合实验

对锥形透镜光纤（TLF）与半导体多量子阱（MQW）平面光波光路（PLC）芯片的耦合特性进行了实验研究.数值模拟了TLF、普通单模光纤（SMF）分别和PLC芯片脊波导的耦合情形，发现TLF-PLC耦合损耗比SMF-PLC耦合损耗小3.01 dB.测得了TLF的出射光场光斑，分析了出射光场发散范围.建立光纤-PLC芯片耦合实验系统，用放大自发辐射（ASE）宽带光源在1550 nm波长处对比分析了PLC芯片与不同光纤的耦合连接损耗，从而确证最佳方案为TLF-PLC-SMF：即TLF作为入纤，SMF作为出纤时，耦合对准容易实现，损耗为10.798 dB，比TLF-PLC-TLF耦合损耗小4.458 dB.     

硅衬底上锗硅合金光波导的研制

报道锗硅合金在λ＝１．３μｍ的脊形单模光波导的设计，工艺及测量结果。这种光波导的传播损耗已达０．７ｄＢ／ｃｍ。脊形的高４－８μｍ，宽８－１２μｍ，均和单模光纤芯径相当，此外，其数值孔径在光波导的输入，输出端均能和单模光纤匹配，它已满足硅光集成对光波导的要求。文中最后报道了用这种锗硅合金光波导试制Ｙ分支器，并观察到二支分路输出的单模光斑。     

有源弯曲波导反馈特性的三维时域有限差分法仿真

半导体光放大器的耦合光纤形成的外腔反馈通过引入弯曲损耗得以抑制.通过对半导体光放大器有源波导引入对前、后向光场非对称散射损耗,以前向光场部分损耗为代价,反馈光场能量被分布式地较强辐射.时域有限差分法仿真研究表明,通过优化弯曲有源波导的结构,相对于通常的有源直波导,在相同的材料增益和输入、输出条件下,反馈可以下降10 dB以上.由此可以简化高增益半导体光放大器的器件结构.     

电光聚合物波导中的锥形结构

提出并设计了一种基于电光聚合物的锥形波导,可用于单模光纤与电光聚合物波导器件之间的连接.锥形波导中采用了宽度锥形和折射率锥形结构.宽度锥形采用劈形形状,通过宽度和折射率的缓慢变化实现模场转换.劈形形状的宽度锥形具有较小的损耗且易于制作,折射率锥形可采用灰度掩膜光刻技术制作.研究了锥形波导的传输损耗与锥形波导的长度、波导宽度和厚度、材料吸收损耗等参数的关系及其优化,分析了锥形波导中的功率传输、模场分布与模式转换效率.结果显示锥形波导的传输损耗小于0.37 dB,光纤-波导-光纤的连接损耗优于1.62 dB,对插入损耗的改善达到8.78 dB,模场转换效率达到了83.7%.     

集成光学条波导阵列与单模光纤阵列的联接

本文报告了一种新的集成光学条波导阵列与镶嵌在硅V槽中的单模光纤阵列耦合联接方法的设计考虑,导出了确定光纤正确位置及V型槽的几何尺寸的若干计算公式.并讨论了光纤与波导几何尺寸与耦合效率的关系.指出了这是实现单模光纤阵列与条波导阵列的固定联接的有效方法,它简化了波导与光纤的对准程序,即由五维调整简化为平面的一维调整.可实现多个波导和多个光纤的同时对准与固定.最大限度地利用了有效重叠面积,从而提高了光纤与条波导的耦合效率.一组典型的数据是单模光纤(芯径10μm)对单模波导(10μm×5μm)的耦合效率可达55%,而同样尺寸的波导对光纤的最大耦会效率可达86%.     

Efficiency and optical feedback of traveling-wave semiconductor laser amplifier to single-mode fiber coupling: Theory and experiment

This paper analyzes the coupling efficiency and optical feedback of the tapered fiber end with a high-index hemiellipsoidal microlens. Such a device has been used as a coupler of traveling-wave semiconductor laser amplifier (TW-SLA) to single mode fiber (SMF).

A theory of the calculation of coupling efficiency and optical feedback is presented including the effects of spherical aberration and Fresnel reflection of thick lens. In consideration of the large beam divergency of the TW-SLA chip, the finite transmission aperture is introduced.

The calculations are in agreement with experiment results and a group of optimum structure parameters of the coupler are given.     

Analysis of Semi-conductor Laser Diode with Two-dimension Nonlinearly Tapered Waveguide

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｈｉｇｈｅｆｆｉｃｉｅｎｔｃｏｕｐｌｉｎｇｂｅｔｗｅｅｎｃｈｉｐ(ｓｅｍｉｃｏｎｄｕｃｔｏｒｌａｓｅｒｄｉｏｄｅ)ａｎｄｓｉｎｇｌｅｍｏｄｅｆｉｂｅｒｉｓｔｈｅｋｅｙｔｅｃｈｎｏｌｏｇｙｆｏｒｏｐｔｏ ｅｌｅｃｔｒｏｎｉｃｓｉｎｔｅｇｒａｔｉｏｎｉｎｔｈｅｆｕｔｕｒｅｃｏｍｍｕｎｉｃａｔｉｏｎ[1 ] .Ｂｕｔｔ ｃｏｕｐｌｉｎｇｏｆｓｅｍｉｃｏｎｄｕｃｔｏｒｌａｓｅｒｄｉｏｄｅｗｉｔｈｓｉｎｇｌｅｍｏｄｅｆｉｂｅｒｌｅａｄｓｔｏｌａｒｇｅｃｏｕｐｌｉｎｇｌｏｓｓａｎｄｓｅ…     

Analysis of Semi-conductor Laser Diode with Two-dimension Nonlinearly Tapered Waveguide

A novel semiconductor laser diode with a two-dimension nonlinearly tapered waveguide is proposed and its property is studied by Fourier expanding method. It is shown that coupling loss between the semiconductor laser diode and a single mode fiber is reduced effectively, the reduction role of the nonlinearly tapered waveguide is more apparent than that of a linearly tapered waveguide , the minimum coupling loss is 0.36 dB, and the far field divergence is decreased. The reduction mechanism is discussed.     

Numerical model of the polymer electro-optic waveguide

A numerical design model is presented for the polymer waveguide in an electro-optic modulator. The effective index method is used to analyze the height of the core waveguide and rib waveguide, an improved Marcatili method is presented to design the rib waveguide width in order to keep the strong single mode operation and have a good match with the standard fiber. Also, the thickness of the upper cladding layer is discussed through calculating the effective index of the multilayer planar waveguide structure has been obtained by setting the optical loss due to the metallic absorption to an acceptable value (<0.1 dB/cm). As a consequence, we take the EO polymer waveguide structure of UV15:CLD/APC:UFC170 as an example, an optimized design is reported.     

半导体微结构物理效应及其应用讲座第1讲布拉格衍射效应在半导体光电子器件中的应用与发展

文章对布拉格衍射效应在半导体光电子材料和光电子器件，特别是在光纤通信中的光电子器件的应用和发展进行了详细的介绍．文中以布拉格光栅衍射效应的光反馈和选模功能为主线，逐一介绍了X射线双晶布拉格衍射技术在半导体材料、特别是在量子阱和应变量子阱超薄层晶体生长和质量控制方面的作用，介绍了内建布拉格光栅对光通信用光信号源的发展所起的重要作用，波导光栅在复用和解复用过程中的作用，以及光纤布拉格光栅在全光纤通信系统中的应用及发展等．     

Efficient coupling of a laser to a waveguide using a taper designed by conformal mapping

Maximising the optical power collected in a waveguide from the diffracting field of a semiconductor laser is desirable in optical fibre communication systems. However, the spot size and phase front curvature of the laser field usually makes a poor overlap with the mode of the receiving waveguide. Various proposals have been made to improve this coupling. This paper presents the design of a tapered waveguide section, having the correct geometry and refractive index profile, to efficiently capture and transform the rapidly diffracting light from a semiconductor laser to a planar wavefront in a straight waveguide. Experimentally, such an approach requires the refining of available techniques (UV exposure, ion implantation or diffusion) to obtain the required grading of the refractive index profile within the tapered input section of the receiving waveguide.     

Experimental Study of Four Wave Mixing in Semiconductor Laser Amplifier and its Application to Dispersion Compensation in Mid Span Spectral Inversion System

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｔｈｅｍｉｄｓｐａｎｓｐｅｃｔｒａｌｉｎｖｅｒｓｉｏｎｅｍｐｌｏｙｉｎｇｆｏｕｒｗａｖｅｍｉｘｉｎｇｉｎａｓｅｍｉｃｏｎｄｕｃｔｏｒｌａｓｅｒａｍｐｌｉｆｉｅｒ（ＳＬＡ）ｉｓｏｎｅｏｆｔｈｅｐｏｔｅｎｔｉａｌｃｈｒｏｍ?..     

Novel effects in extremely broadband semiconductor optical amplifiers with non-identical quantum wells

An extremely broad emission spectrum is obtained for semiconductor optical amplifiers with multiple quantum wells fabricated on the substrate. The spectral width is nearly 400 nm (1200–1600 nm), which covers the entire usable bandwidth of an optical fiber. Broadband characteristics allow observing three novel effects: (i) the bi-directional guided effect of lasing mode in a bent waveguide of semiconductor optical amplifiers, (ii) the optical switching effect in one semiconductor optical amplifier for optical communication band, and (iii) the effect of separate confinement heterostructure layer thickness.     

Experimental Study of Four-Wave Mixing in Semiconductor Laser Amplifier and its Application to Dispersion Compensation in Mid-Span Spectral Inversion System

Properties of four-wave mixing (FWM) in the semiconductor laser amplifier are studied experimentally in this paper. The optical phase conjugation of the mixing wave is applied to compensate the chromatic dispersion of transmission fiber. It is presented experimental results of the transmission of short optical pulses with 12-ps width over 204 km standard single mode fiber. The results confirm that mid-span spectral inversion (MSSI) employing FWM in a semiconductor laser amplifier is one of potential dispersion compensation techniques for optical transmission over standard single mode fiber with bit rate beyond 40Gb/s.