High-speed and broad optical bandwidth silicon modulator

A high-speed silicon modulator with broad optical bandwidth is proposed based on a symmetrically configured Mach–Zehnder interferometer.Careful phase bias control and traveling-wave design are used to improve the high-speed performance.Over a broadband wavelength range,high-speed operation up to 30 Gbit/s with a 4.5 dB–5.5 dB extinction ratio is experimentally demonstrated with a low driving voltage of 3 V.     

Refined modeling of traveling-wave Ti:LiNbO3 channel waveguide modulator

A refined computation model for traveling-wave operation of external electro-optical phase modulators made of a single titanium in-diffused lithium niobate channel waveguide (Ti:LiNbO₃WG) is described. The modulator circuit model outlined as two traveling-wave coupled microstrips includes microwave losses and dispersion. In the optimization procedure, we consider different circuit load conditions. The influence of a dielectric overlay covering the electrodes is examined. The consolidated techniques of conformal mapping, multiple image, and finite element are used to investigate the microwave characteristics of the structure, and the refractive effective index method is used in calculating the characteristics of the diffused anisotropic optical channel. The performances of Y-cut and Z-cut substrate configurations are compared. We have verified that the Y-cut substrate modulator gives the best overall performance, and that the overlay presence causes significant improvements in the evaluated modulation efficiency and in the bandwidth. A model of the modulator that takes electrode thickness into account permits one to obtain a wider bandwidth.     

Broadband 10 Gb/s operation of graphene electro‐absorption modulator on silicon

High performance integrated optical modulators are highly desired for future optical interconnects. The ultra‐high bandwidth and broadband operation potentially offered by graphene based electro‐absorption modulators has attracted a lot of attention in the photonics community recently. In this work, we theoretically evaluate the true potential of such modulators and illustrate this with experimental results for a silicon integrated graphene optical electro‐absorption modulator capable of broadband 10 Gb/s modulation speed. The measured results agree very well with theoretical predictions. A low insertion loss of 3.8 dB at 1580 nm and a low drive voltage of 2.5 V combined with broadband and athermal operation were obtained for a 50 μm‐length hybrid graphene‐Si device. The peak modulation efficiency of the device is 1.5 dB/V. This robust device is challenging best‐in‐class Si (Ge) modulators for future chip‐level optical interconnects.     

Strong optical non-linearities for efficient all-optical switching in GaAlAs waveguides

The light intensity transmission of GaAlAs strip waveguides is sensitively dependent on the strength of the electric field inside the waveguide, when the photon energy is close to the band gap (Franz-Keldysh effect). In a waveguide embedded in a pn-junction the transmitted light itself induces the field changes through the photoelectric effect. This photo-induced Franz-Keldysh effect causes a non-linear intensity transmission of the waveguide. Light power levels far below 1 mW are sufficient to give strong non-linearities. Possible application schemes for modulation and all-optical switching in integrated optics and optoelectronics are discussed.     

Novel integrated optic intensity modulator based on mode coupling

The analysis, design, realization, and measurements of a novel intensity modulator are reported. The operating principle is based on mode coupling between a passive low-loss SiON waveguide and an electro-optic high-loss polymer waveguiding structure. Matching the waveguides is critical and results in severe demands for the technology. Extended simulations by the Coupled Mode Theory, the Leaky Wave Model, and Finite Difference Beam Propagation Method resulted in the design of several modulator structures. After realization, modulation could be demonstrated at 632 nm and at 1523 nm using lossy waveguiding modes and surface plasmon modes.     

Novel integrated optic intensity modulator based on mode coupling

Abstract

The analysis, design, realization, and measurements of a novel intensity modulator are reported. The operating principle is based on mode coupling between a passive low-loss SiON waveguide and an electro-optic high-loss polymer waveguiding structure. Matching the waveguides is critical and results in severe demands for the technology. Extended simulations by the Coupled Mode Theory, the Leaky Wave Model, and Finite Difference Beam Propagation Method resulted in the design of several modulator structures. After realization, modulation could be demonstrated at 632 nm and at 1523 nm using lossy waveguiding modes and surface plasmon modes.     

硅基光导波结构的特性研究

研究了在硅基底上采用等离子增强化学汽相淀积（ＰＥＣＶＤ）氮氧化硅（ＳｉＯＮ）所形成的包括通道波导、条汉志、倒脊型波导等多种结构的特性，通过对测试结果进一步分析，总结出有关结论并提出一些改进方法。     

Design of Planar Optic Sensors for Hydrocarbon Detection

A realistic design of evanescent field optical sensors, constituted by three different kinds of planar waveguides covered by a sensing polymeric overlay, is performed. More precisely, the slab, the embedded strip and the ridge waveguides are considered. The sensor operation is simulated, in both the cases of lossy guided and leaky mode propagation, via a home made computer code. The optimal waveguide transverse section and length are identified, the advantages and drawbacks are shown. The ridge waveguide sensor exhibits appreciable characteristics: for a concentration C _w = 200 ppm of toluene in water, the absorbance pertaining to a device L = 2.6 cm long and for the guided quasi-TE₀₀ mode is A ≅ 5, while it is A ≅ 0.054 for a device long L ≅ 24.1 μm and the leaky quasi-TE₁₀ mode. The simulation results suggest that a selective excitation of the suitable propagation mode can enhance the sensor performance.     

Optical design of bent rib waveguide with MOS cross-section

We provided a single-mode bent MOS-cross-section rib waveguide design with 0.9 dB/cm bending loss at 25 μm bending radius. The peak position for the TE-like mode was tuned to the gate oxide around which the maximum amount of free carriers are accumulated to optimize the free carrier dispersion effect.     

New Criterion for Designing Silica Multimode Interference Power Splitters

We introduce a new criterion for designing 1 × N silica multimode interference power splitters using overlapping-image multimode interference analysis. This criterion requires that widths of multimode waveguides in the devices should be greater than 2 times the product of port number N and effective widths of output waveguides. Better device uniformity can be achieved when the new criterion is satisfied.     

New Criterion for Designing Silica Multimode Interference Power Splitters

We introduce a new criterion for designing 1 × N silica multimode interference power splitters using overlapping-image multimode interference analysis. This criterion requires that widths of multimode waveguides in the devices should be greater than 2 times the product of port number N and effective widths of output waveguides. Better device uniformity can be achieved when the new criterion is satisfied.     

铌酸锂集成光路：孕育自主产业链的前沿基础研究

大数据、人工智能、光量子信息等变革性领域对信息处理能力提出了前所未有的要求,而集成光路技术有望实现更快速、更有效、成本更低廉的信息处理器件,由此带来新的自主产业机会。铌酸锂集成光路技术在近年获得迅猛发展,展示了优越的器件性能,已经吸引了产业界的关注。文章将介绍该领域的研究背景以及若干近期的重要突破。     

Broad band Bragg deflector for optical waveguides on silicon substrates

Technical solutions are described which allow the 500 MHz acousto-optical Bragg deflector integrated onto a silicon substrate to have a good performance and quite high deflection efficiency. This is achieved by diminishing the influence of acoustic propagation losses. As a consequence, is it possible to implement a large bandwidth acousto-optical rf spectrum analyser using fully planar technology.     

Rigorous solutions for nonlinear TE waves guided by a waveguide that has a buried secant hyperbolic profile in the film

Dispersion relations for nonlinear TE waves guided by a waveguide that has a buried secant hyperbolic profile in the film with a self-focusing nonlinear cover medium have been obtained rigorously. It is shown that for the same diffusion depth, the local maximum power flow for TE₀, and TE₁ modes increases as the buying depth is increased.     

高效集成电光调制器和开关的电极与光波导的优化设计

集成电光调制与开关的效率取决于光波导中电光重叠因子Γ的大小，直接影响此因子的有电极宽度、电极间距、光模场尺寸、以及电极与光波导的相对位置等参量。本文利用集成电光调制器电极电场的分布规律，研究了各种结构中影响电光重叠因子的诸参量之间的关系；根据实际工艺条件，应用系统优化方法尽可能对各种参量进行优化计算，得到了实现高效调制和开关的全部参量的优化设计结果。     

熔锥直线型3×3单模光纤定向耦合器的光功率耦合分析

本文利用组合波导理论对熔锥直线型3×3单模光纤定向耦合器中的光功率耦合行为进行了详细的分析,并对该种耦合器的中心端光纤和旁边端光纤注入光能分别进行了讨论,前者得到了预期的结果,后者的结果与前者不同,却是十分有用的.这两种分析结果与实验结果相符.     

集成化导光板下表面微棱镜二维分布设计

集成化导光板下表面微结构分布是影响背光模组出射光均匀性的关键因素,因此是背光模组设计的重点之一.本文针对微棱镜一维分布设计中存在的大面积同一性影响背光模组亮度均匀性的问题,提出一种集成化导光板下表面微棱镜二维分布的设计思想,以提高背光模组的亮度均匀性.利用光学软件Lighttools对5.0英寸集成化导光板下表面微棱镜结构的较佳二维分布进行优化探索,通过与较佳的一维分布仿真结果对比分析可知,优化后的二维分布模式下,背光模组的光能利用率、照度均匀性、亮度均匀性分别达到92.03%,87.07%和91.94%,满足行业标准;其中,照度均匀性比一维分布提高了10%;同时,从亮度图观察,背光模组的整体亮度均匀性得到了有效提升.该研究结果对于背光模组轻薄化、集成化开发具有一定的参考价值.     

空间光学遥感器控制器机电热一体化设计

根据空间电子设备机电热一体化设计思想,设计了高分辨率空间光学遥感器的控制器,以验证一体化设计的优势和效果。概括了空间电子设备的一体化设计流程。针对空间光学遥感器控制器的研制提出了相应的一体化设计原则。说明了控制器的各电路板和大功率元器件的设计方案。通过热、力学仿真分析和试验手段对设计方案进行了验证。结果表明:控制器元器件的最高壳温在51℃以内,整机的前三阶模态均高于100Hz。设计方案完全满足热控、刚度等设计指标要求。     

Realization of optoelectronic integrated transmitter and receiver for POF Applications

The optoelectronic integrated transmitter and receiver for 650 nm plastic optical fiber (POF) communication applications realized in 0.5 μm BCD (Biplor, CMOS and DMOS) process is first described in this paper. The 650 nm resonant cavity light emitting diode (RCLED) is used as light source. It is first proposed for optoelectronic integration of the transmitter by bonding RCLED to the driver chip. Temperature compensation technology is employed in the driver circuit to compensate for the modulation current. In the monolithic optoelectronic integrated receiver, large area multi-finger PIN photodetector (PD) that is compatible with standard IC process, transimpedance amplifier and post amplifier are presented. Measurement results show that the responsivity and capacitance of PD is 0.25 A/W and 5 pF, respectively. The sensitivity of receiver is −14.6 dBm at 180 Mb/s and BER is less than 10⁻⁹ for 650 nm input light by POF. A clear eye diagram is demonstrated for 180 Mb/s PRBS. These indicate that optoelectronic integrated chips can be employed in high-speed POF-based Fast Ethernet systems for broadband access network applications.