脊双模波导滤波器的分析及设计

介绍了一种能实现脊双模波导滤波器的新型结构,分析了其腔内模式的耦合极性,利用不同的耦合极性对频率响应的影响可实现具有一对传输零点的双模滤波器,也可实现无传输零点的双模滤波器.以相同脊谐振单元不同的放置方向组成的两种带通滤波器为例,利用AnsoftHFSS仿真得到了两种不同的频率响应,结果与理论分析一致.最后设计出了一个六阶三传输零点的双通带滤波器,带内插损均小于0.6 dB,回波损耗小于-15 dB.     

脊的变化对双脊波导场图的影响分析

对称双脊波导脊的大小变化改变其传输特性参数,采用亥姆霍兹方程有限元方法计算出双脊波导主模截止波长数值,结果与文献结果对比说明计算方法精确有效,求对应的特征向量,就可得到脊波导横截面上的电场分布,从而分析脊大小变化对场结构图的影响。     

脊双模波导滤波器的研究

介绍了一种利用脊谐振器产生的正交准TEM简并模实现脊双模波导滤波器的新方法。通过分析脊谐振器放置在主模传输波导中不同位置的特性,建立了耦合拓扑结构图,实现了三种不同类型的频率响应。利用全波仿真软件AnsoftHFSS,分别以方形和十字交叉这两种脊谐振器作为基本单元,设计出了两腔四阶的脊双模波导滤波器,两个滤波器的插损均小于0.2 dB,回波损耗小于–23 dB,仿真结果与预期吻合。     

Wide-band waveguide and ridge waveguide T-junctions for diplexerapplications

Scattering parameters of E- and H-plane stepped waveguide and E-plane ridge waveguide stepped T-junctions are obtained using an extension of the three-plane mode matching method. An optimization process is applied to find the T-junctions and step dimensions that yield a low reflection coefficient in one of the T-junctions arms over a wide frequency band. An example of the design of a wideband T-junction diplexer is presented. The diplexer filters are inductive window waveguide filters, and are rigorously modeled using mode matching and a novel two-dimensional curve fitting method, which greatly reduces the CPU time for optimization. The diplexer optimization procedure, as well as the filter modeling method, are described. Experimental results on the optimized T-junction and the diplexer are presented; both show excellent agreement with their computed optimum results, without any adjustments or tuning     

高速脊波导激光器寄生电容的分析

高速调制半导体激光器光源是光纤通信系统、相控阵雷达等的关键器件。高速激光器的寄生电容是影响其调制带宽的因素之一。为了减小寄生电容,针对脊波导结构激光器的电容,采用计算机模拟与实际测试相结合的方法,进行了理论分析和实验验证。结果表明,其寄生电容大小不仅与电极金属化面积有关,还与隔离沟的腐蚀深度有关。当腐蚀至波导层时,寄生电容减小到10pF以下。这一结论对实现激光器的高速调制是非常有意义的。     

Asymmetric ridge waveguide radiating element for a scanned planararray

A novel linear array radiating element for use in a large low-sidelobe, planar slot array electronically scanned in azimuth is described. The planar array consists of many vertical resonant linear array elements; i.e. single ridge waveguides with broadwall shunt slots, closely spaced to avoid array grating lobes when the array is scanned in azimuth. Traditional linear broadwall slot arrays require alternating slot displacement from the waveguide centerline, which generates undesirable secondary beams in skewed directions during electronic scan. To eliminate the secondary beams, a design has been devised in which all slots are exactly collinear and lie on the waveguide centerline. The methods considered to achieve the required waveguide asymmetry, the design procedure used in the successful approach, and the experimental results obtained with a demonstration model are presented     

Analysis of the thermo-optic effect in lateral-carrier-injection SOI ridge waveguide devices

The thermo-optic effect in the lateral-carrier-injection pin junction SOI ridge waveguide is analyzed according to the thermal field equation.Numerical analysis and experimental results show that the thermo-optic effect caused by carrier injection is significant in such devices,especially for small structure ones.For a device with a 1000 μm modulation length,the refractive index rise introduced by heat accounts for 1/8 of the total effect under normal working conditions.A proposal of adjusting the electrode position to cool the devices to diminish the thermal-optic effect is put forward.     

侧向注入的载流子注入型SOI光开关中的热效应分析V

根据热场方程,分析了侧向载流子注入pin结SOI脊波导器件中的热光效应影响,数值分析和实验现象表明,在该类电光子器件中,载流子注入产生的热光效应影响明显,尤其对于SOI材料的小截面脊波导结构。如1000微米调制长度的器件,在正常工作时,温升引起的折射率上升已占总的效应的1/8;同时提出了通过调整电极位置来进行散热的减小热光效应影响的方案。     

High-efficiency native-oxide-passivated high-index-contrast ridge waveguide lasers

A GaAs-based high-index-contrast ridge waveguide laser is fabricated using a self-aligned process of deep dry etching plus oxygen-enhanced wet thermal oxidation of low Al-content AlGaAs. Lasers operating at /spl lambda/=813 nm (CW, 300 K) with external differential quantum efficiencies as high as 78% are demonstrated, indicating effective passivation of the directly-oxidised etched active region sidewall surface.     

一种新颖的脊波导功分器

针对通常波导传输的功率分配器中T形接头体积大的不足,基于脊波导和阶梯阻抗变换对导波系统中电磁波传播性能的影响,提出了一种新颖的脊波导H面T形分支结构,利用高频仿真软件HFSS进行仿真优化,结果显示该结构在全X波段内匹配。以此结构为基础,设计加工一个一分六的脊波导功分器,得到较好的实测结果。实际内部尺寸比普通波导功分器减小46%,回波损耗小于20 dB,单路信号波动在±0.35 dB内。这种脊波导H面T形分支结构简单,适合于实际的工程应用。     

Airbridged high-speed AlGaAs-GaAs ridge waveguide lasers

The design of a high modulation response multiple-quantum-well ridge waveguide laser in AlGaAs-GaAs, with low parasitics is discussed. The device was fabricated on a semi-insulating substrate with a wide top contact, and airbridges have been used to connect the ridge top contact to the bonding pads on the semi-insulating substrate. The 3-dB frequency response of the laser has been measured to be 21 GHz, which is a record for unstrained quantum-well AlGaAs-GaAs lasers.     

Low-divergence single-mode ridge waveguide diode lasers

Ridge waveguide laser diodes of a GaAs-AlGaAs separate-confinement graded-index monolithically stacked triple-quantum-well structure have been fabricated. Chemically assisted ion beam etching (CAIBE) was used to etch a 4- mu m-wide mesa which serves as the waveguide for the device. Results for 4- mu m-wide by 600- mu m-long optically coated devices are presented. Single-longitudinal mode, CW output power in excess of 90 mW and a far-field divergence of 21 degrees *3.5 degrees are demonstrated.<>     

基片集成脊波导传输特性的研究

将构成基片集成脊波导脊的一排金属针等效成实金属脊。基于基片集成波导等效宽度计算公式推导了基片集成脊波导等效脊宽的计算公式。运用横向谐振法推导了TE_m0模基片集成脊波导截止频率的计算公式,同时运用这些公式分别计算了TE₁₀模、TE₂₀模和TE₃₀模基片集成脊波导的截止频率,并与仿真软件计算的结果和参考文献所给结果进行了比较。结果显示:利用所给公式计算的结果具有较高的精度,且使用方便。此外,还研究了截止频率与脊宽和脊隙之间的关系,对一种适合宽带应用的宽脊结构进行了讨论。     

Design of ridge waveguide couplers with carrier injection using discrete spectral index method

It is shown that the design of ridge waveguide couplers with a uniformly layered refractive index profile can be extended to include the nonuniformity arising within an active layer as a result of carrier injection. This is analysed using the spectral index method combined with a degenerate perturbation approach. The simplicity of this approach makes it possible to solve design problems in which the correct mixing of the fields beneath the ridges is an essential feature of the modelling, and necessary for accuracy of design.<>     

Compact ridge waveguide slot antenna array fed by convex waveguide divider

A ridge waveguide longitudinal-slot antenna array with a compact transverse dimension is introduced. To broaden the bandwidth of the array, it is divided into two sub-arrays fed by a novel compact convex waveguide divider. A 16-element uniform linear array at X-band was fabricated and measured to verify the validity of the design. The measured bandwidth of S/sub 11//spl les/-15 dB reaches 14.9% while the measured cross-polarisation level is less than -36 dB over the entire bandwidth.     

565 Mbaud 100 km optical system trial using a ridge waveguide DFB laser at 1.478 ?m

565 Mbaud transmission over 100 km of step-index mono-mode fibre using a new ridge waveguide distributed feedback (DFB) laser structure operating at 1.478 ?m and a Ge APD receiver has been demonstrated. No residual dispersion penalty was observed.     

One dimensional scaling of 100 ridge waveguide amplifiers

We have demonstrated the concept of scaling large numbers of laser diodes to achieve high power with good beam quality. We have achieved a system based on scaling 100 ridge waveguide amplifiers with a coherent optical signal distribution network and phase modulators on a 12.2 mm×4.4 mm chip called a unit cell. The unit cell delivers 1.63 W of CW power in the central lobe with diffraction-limited performance. A high performance cooler allows high power CW performance. A custom lens array and computer-controlled phase modulators allow the beam to be collimated with flat phase front     

High-performance 980-nm ridge waveguide lasers with a nearly circular beam

We report high-performance 980-nm ridge waveguide quantum-well lasers with extremely low vertical beam divergence of 13/spl deg/. A very small aspect ratio of 1.6 is obtained at high operating power of 900 mW. In addition to the more circular beam, low threshold, high efficiency, high characteristic temperature, and high output power of over 1.18 W are achieved. The fiber coupled output power can be as high as 680 mW with fiber Bragg grating stabilization. Excellent wavelength and power stability are also demonstrated.     

基于脊波导结构的太赫兹超宽带双工器设计

在射电天文领域,为了实现更宽频带内多谱线同时观测任务,要求太赫兹超导相干接收机向更宽带方向发展。针对下一代太赫兹超宽带接收机的应用需求,提出了一种频段覆盖180~ 420 GHz(相对带宽达87%)的超宽带脊波导双工器设计,主要包括：180~300 GHz频段和320~420 GHz频段宽带脊波导滤波器设计与变换;超宽带太赫兹多级耦合型脊波导双工器优化设计。仿真结果表明该结构能够在180~300 GHz和320~420 GHz频段双工工作,回波损耗整体优于15 dB,通道间隔离度达20 dB以上。     

Multi-λ ridge waveguide gain-coupled DFB laser array

Multi-wavelength gain-coupled quantum well DFB laser array has been fabricated on an InP substrate by simply varying the ridge waveguide width of the element lasers. Owing to the gain-coupling effect, seven singlemode lasing wavelengths around 1.55 μm with ~2 nm spacing were obtained simultaneously. The lasers had low threshold currents and small beam divergence