光致聚合物用于全息光互联光栅的研究

使用光致聚合物做记录介质,记录用于光互联的全息光栅。激光曝光后衍射效率可达5 5 %左右,用紫外光均匀照射后,在10 0℃下烘烤40分钟,衍射效率可达90 %左右。绘制了衍射效率与曝光时间和烘烤时间曲线,制作具有预期衍射效率的用于全息光互联的光栅。     

平面光波导器件的发展

在光电子技术,计算机技术,通信技术迅速发展的今天,光波导材料和器件得到了越来越多的应用和发展.因此,对于光波导器件现状及发展趋势的叙述,不但对有志于在此方面研究的人具有一定参考价值,同时也是面向未来光电子产业发展的必然要求.因为当今大多器件应用平面光波导材料,所以主要对平面光波导理论进行了讨论.     

Stacked polymeric multimode waveguide arrays for two-dimensional optical interconnects

Two-dimensional (2-D) polymeric multimode waveguide arrays with two reflection-mirrors have been fabricated for optical interconnects between 2-D arrayed vertical-cavity surface-emitting lasers and detectors. Contact printing lithography was adopted for simple and low-cost process using ultraviolet-curable epoxy-based polymers. Fabricated waveguides were diced of the same size and stacked one by one with lateral positional errors less than /spl plusmn/20 /spl mu/m. Two kinds of mirrors were fabricated: single-reflection mirror and double-reflection mirror. Double-reflected mirrors resulted in lower losses with 1.2 dB than single reflected mirrors with 2.1 dB. The average insertion losses of 16-channel arrayed waveguides with two single-reflection mirrors and with two double-reflection-mirrors were measured to be 6.1 and 4.4 dB for 6-cm-long waveguides at a wavelength of 830 nm, respectively. The crosstalk between the waveguides was less than -25 dB. The characteristics of the waveguide arrays are good enough for applications to optical interconnects.     

Silicon oxynitride integrated waveguide for on-chip optical interconnects applications

This work explores the microfabrication technology for realizing miniature waveguide structure for on-chip optical interconnects applications. Thick oxynitride films were prepared by plasma enhanced chemical vapor deposition (PECVD) with N₂O, NH₃ and SiH₄ precursors. The composition and the bonding structure of the oxynitride films were investigated with Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and secondary ion mass spectroscopy. Results showed that the silicon oxynitride deposited with gas flow rates of NH₃/N₂O/SiH₄ = 10/400/10 (sccm) has favorable properties for integrated waveguide applications. The refractive index of this layer is about 1.5 and the layer has comparative low densities of O–H and N–H bonds. The hydrogen bonds can be further eliminated with high temperature annealing of the as-deposited film in nitrogen ambient and the propagation loss can be reduced significantly with thermal annealing. An integrated miniature waveguide with cross-section of 2 μm × 3 μm was realized with the proposed technology. The waveguide is able to transmit signal in either TE or TM mode with propagation loss <0.6 dB/cm (at 1550 nm) and bending radius of about 6 μm.     

Efficient TM-pass multilayer planar optical waveguide polariser

A novel TM-pass polariser using the form birefringence of a stratified periodic medium is proposed. The mode-filter properties of a planar waveguiding structure with form birefringent buffer layer on a lossy substrate are investigated numerically. A structure with TM/sub 0/-mode attenuation of less than 3 dB/cm at lambda /sub 0/=633 nm and TE-mode losses exceeding 300 dB/cm has been demonstrated experimentally.<>     

Highly birefringent and monomode GaAlAs-GaAs planar optical waveguide

A novel optical waveguide exhibiting a layered core region is proposed. Owing to the original design of the core stack and form birefringence in the multilayer, a waveguide supporting both TE and TM lowest-order modes with high confinement has been obtained. It has been designed, fabricated, and characterized and presents a modal birefringence greater than 0.01, which is in good agreement with the calculated values.     

Guided-wave devices for optical communication

We review the current status of guided-wave optical communication devices. The operation and presently demonstrated performance characteristics of waveguides switches, modulators, filters, and polarization transforming devices are discussed. Emphasis is given to recent developments with very high speed modulators and polarization insensitive devices.     

Guided-wave optical time delay network

A hybrid optical time delay unit using lithium niobate switches and precisely produced fiber loops is described. Three prototypes of the device were fabricated and characterized. The measured optical extinction ratio between time slots is typically /spl Lt/25 dB. On average, delay values are within 0.7% of their design values. The device is a 6-b (64 time slot) delay unit with 44 picosecond per increment.     

Guided-wave THz time-domain spectroscopy of highly doped silicon using parallel-plate waveguides

A novel spectroscopy technique that uses parallel-plate waveguides for the characterisation of highly conductive materials in the terahertz (THz) frequency regime is presented. This guided-wave technique resolves some of the fundamental problems associated with standard THz time-domain spectroscopy (THz-TDS) as applied to these optically dense materials. The technique is demonstrated by measuring the conductivity of highly phosphorus doped silicon     

Guided-wave optical gate matrix switch

An optical gate matrix switch that is made by integrating InGaAsP laser diode gates with high-silica guided-wave splitter and combiner circuits in a hybrid fashion is proposed and demonstrated. It provides point-to-multipoint switching. A preliminary experiment for a 4×4 matrix switch shows that the switch is capable of more than 400-Mb/s bandwidth signal switching     

Flexible optical waveguide film fabrications and optoelectronic devices integration for fully embedded board-level optical interconnects

This paper demonstrates a flexible optical waveguide film with integrated optoelectronic devices (vertical-cavity surface-emitting laser (VCSEL) and p-i-n photodiode arrays) for fully embedded board-level optical interconnects. The optical waveguide circuit with 45/spl deg/ micromirror couplers was fabricated on a thin flexible polymeric substrate by soft molding. The 45/spl deg/ couplers were fabricated by cutting the waveguide with a microtome blade. The waveguide core material was SU-8 photoresist, and the cladding was cycloolefin copolymer. A thin VCSEL and p-i-n photodiode array were directly integrated on the waveguide film. Measured propagation loss of a waveguide was 0.6 dB/cm at 850 nm.     

Chip-scale optical interconnects and optical data processing using silicon photonic devices

Recent advances in the density and complexity of photonic integrated circuits have facilitated possible implementation of chip-scale optical communication systems. Chip-scale optical interconnects and optical data processing are two important functions to transmit and process signal in the optical domain. Silicon photonics offers a promising platform to enable chip-scale optical interconnects and optical data processing using silicon photonic devices. In this paper, we review our recent progress in the design, modeling, and fabrication of silicon photonic devices and their applications in chip-scale optical interconnects and optical data processing with advanced modulation formats. For chip-scale optical interconnects, we experimentally demonstrate digital signal transmissions in silicon microring and silicon vertical slot waveguide. Terabit chip-scale optical interconnect is demonstrated in the experiment. Also, we experimentally demonstrate analog signal transmissions in silicon microring and silicon photonic crystal nanocavity. For chip-scale optical data processing, we experimentally demonstrate all-optical wavelength conversion using a silicon waveguide, simultaneous polarization and wavelength demultiplexing using 2D grating coupler connected with microrings, two-mode (de)multiplexing using a tapered asymmetrical grating-assisted contra-directional coupler, and two-/three-mode (de)multiplexing using asymmetrical directional converter. In addition, we propose and simulate chip-scale optical data exchange, chip-scale high-base optical computing, and chip-scale optical coding/decoding by using nonlinear interactions in a silicon-organic hybrid slot waveguide. The obtained theoretical and experimental results of chip-scale optical interconnects and optical data processing indicate possible integration of optical communication functions on a monolithic chip.     

Guided-wave laser based on erbium-doped silica planar lightwave circuit

The Er-doped silica guided-wave laser operating around 1.6 mu m was realised using a low-scattering-loss planar lightwave circuit with an Er-doped silica core which was fabricated by flame hydrolysis deposition and reactive ion etching techniques on an Si substrate. CW lasing was achieved successfully with an incident threshold power of 49 mW for pumping at 0.98 mu m.<>     

Selfrouting optical interconnects

A new type of selfrouting optical interconnect (SROI) is described where an optical signal beam or optical data packet is routed to a destination using an all optical switch where the destination is defined within the optical signal by the autocorrelation function of the optical signal.<>     

Pumping planar waveguide amplifiers using a coupled waveguidesystem

A novel scheme is presented that can be used to efficiently pump optical waveguide amplifiers. It is based on the coupling between two adjacent waveguides, where pump light is gradually coupled from a nonabsorbing pump waveguide into the amplifier waveguide. The coupling between the waveguides in such a configuration is calculated using an improved coupled mode theory (CMT). The proposed distributed coupling scheme can enhance the optical gain in systems that exhibit a reduced pumping efficiency at high pump power. A numerical example is given for a sensitized neodymium-doped polymer waveguide amplifier, in which the optical gain increases from 0.005 dB to 1.6 dB by changing from conventional butt-coupling to distributed coupling     

Analysis and design of integrated optical mirrors in planar waveguide technology

We demonstrate integrated optical mirrors in alumina-based waveguides on oxidized silicon substrates. The finite-element method (FEM) is employed for the design of mirrors operating between 1.31 and 1.55 /spl mu/m at both fundamental polarizations. Excellent agreement between measurement and simulation is achieved for the dispersion behavior of the device. The highly polarization-dependent scattering loss at the reflecting interface is well predicted considering approximate values for the reactive ion etching (RIE) process induced surface roughness.     

平面光波导膜层厚度对传播损耗的影响

根据平面光波导损耗的波动理论，通过分析计算，对于传播损耗随波膜厚度的变化关系提出了新的看法，文中给出了一组以波导膜厚度为参变量的传播损耗曲线，说明在某些波导膜厚度范围内，不能有效地进行光波导传播。     

Analysis of planar optical waveguide fabrication by ion exchange in glass

Fabrication of planar optical waveguides by silver-ion exchange in glass, and the resulting refractive index profiles related to the fabrication conditions, are investigated. The second-order polynomial profile model proposed by Stewart et al. [3] is confirmed, and the dependence of the model characteristics on fabrication conditions is analyzed. Use of the resulting relationships is demonstrated by the compilation of a design table of expected waveguide mode structures for given fabrication conditions. Methods of exchanged-ion concentration profile determination are reviewed and a simple method based on sample angle lapping is proposed.     

Mode determination for planar waveguide using the four-sheeteddispersion relation

A numerical method for the determination of the modes of planar, multilayer waveguides is presented. It is possible, with this algorithm, to guarantee that all the solutions within any finite region of the complex plane representing the propagation constant are found; neither prior knowledge of the number of solutions nor their approximate locations within the region is required. This method is formulated using the four-sheeted Riemann surface of the analytic function that defines the waveguide dispersion relation and whose zeros correspond to the proper and improper modes of the structure. Both TE and TM modes can be determined for guides that incorporate materials with complex indexes     

Microwave phase shifter using optical waveguide structure

A microwave phase shifter with an integrated optics structure with high efficiency is discussed. The structure and the performance of the device are discussed. Microwave phase shifting was carried out using the fabricated phase shifter of titanium diffused LiNbO₃ optical waveguides. The measured voltage to obtain halfwave phase shift for a 800 MHz microwave signal was 7.0 V. The input microwave power was 21 dBm, and the detected output microwave power was -24 dBm, so the microwave insertion loss was calculated to be approximately -45 dB. The optical insertion loss of the device was -12 dB