平面交叉型微透镜阵列的制作及成像特性研究

介绍了采用光刻离子交换工艺制作平面交叉型微透镜阵列的方法。利用积分形式的光线方程式讨论了平面交叉型微透镜的近轴光学特性，研究了微透镜的光线轨迹方程式和一些重要的近轴成像特性，利用ABCD定理得到了平面交叉型微透镜像距、焦距、像高、横向放大率和主平面位置的数学表达式，焦距的理论计算结果和实验数据吻合得很好。

Characteristics of 980/1550 nm WDM coupler based on planar curved waveguides

A wavelength division multiplexer (WDM) for 980/1550 nm based on planar curved waveguide coupler (CWC) is proposed. Compared with conventional parallel straight waveguide coupler (SWC), this structure has more flexibility with two variable parameters of bending radius R and minimum edge-to-edge spacing do, which are the two main parameters for the splitting ratio of coupler and decrease the complexity of device design and fabrication. Based on coupled mode theory (CMT) and waveguide theory, R and do of the WDM CWC are designed to be R = 13.28 m and d(0) = 4.39 mu m. The contrast ratio (CR) and insertion loss (IL) for 980 and 1550 nm are CR1 = 24.62 dB, CR2 = 24.56 dB and IL1 = 0.014 dB, IL2 = 0.015 dB, respectively. The 3D beam propagation method (BPM) is used to verify the validity of the design result. The influence of R and d(0) variations on the device performance is analyzed. For CR > 20 dB, the variation ranges of R and d(0) should be within -0.10 to +0.44 m and -0.05 to + 0.02 mu m, respectively. (c) 2006 Elsevier GmbH. All rights reserved.

Spectroscopic properties and thermal stability of Er3+-doped tungsten-tellurite glass for waveguide amplifier application

Tungsten-tellurite glass with molar composition of 60TeO(2)-30WO(3)-10Na(2)O has been investigated for developing planar broadband waveguide amplifier application. Spectroscopic properties and thermal stability of Er3+-doped tungsten-tellurite glass have been discussed. The results show that the introduction Of WO3 increases significantly the glass transition temperature and the maximum phonon energy. Er3+-doped tungsten-tellurite glass exhibits high glass transition temperature (377 degrees C), large emission cross-section (0.91 x 10(-20) cm(2)) at 1532 nm and broad full width at half maximum (FWHM), which make it preferable for broadband Er3+-doped waveguide amplifier application. (c) 2005 Elsevier B.V. All rights reserved.

平面弯曲波导耦合器的特性分析

根据耦合模理论和弯曲波导耦合器的结构特点,对平面弯曲波导耦合器的特性进行了分析,结果表明弯曲波导耦合器的弯曲半径和最小间距两个可调变量,增加了波导器件设计的灵活性;同时由于等效耦合长度的调制作用使得弯曲波导耦合器在波分复用/解复用中比平行直波导耦合器具有更大的复用带宽;分析了弯曲半径和最小间距对弯曲波导耦合器复用带宽的影响,为实际波导器件的设计制作提供了一定的理论依据.

后处理对离子交换磷酸盐玻璃平面光波导的影响

研究了退火和二次离子交换对Er^3＋／Yb^3＋共掺的磷酸盐玻璃平面光波导传输特性的影响。在退火过程中，由于热效应和波导层Ag^＋离子的浓度差使得Ag^＋离子重新分布；随着退火时间的延长和温度的升高，光波导模式数目逐渐增加，波导层深度加深，且波导表面折射率与玻璃基质折射率差减小，退火扩散深度与退火时间的平方根成正比。电子探针结果显示在二次离子交换后形成了掩埋式的光波导，Ag^＋离子浓度接近二次方分布，而掩埋式的光波导有助于降低光波导的传输损耗。

Electric field distribution in resonant reflection filters under normal incidence

Electric field distributions inside resonant reflection filters constructed using planar periodic waveguides are investigated in this paper. The electric fields may be intensified by resonance effects. Although the resonant reflection peaks can be quite narrow using weakly modulated planar periodic waveguides, the strong electric field enhancement limits their use in high-power laser systems. Strongly modulated waveguides may be used to reduce the electric field enhancement and a cover layer may be used to narrow the bandwidth at the same time. Desired results (i.e. almost no electric field enhancement together with narrow bandwidth) can be realized using this simple structure.

Sensitivity to alcohols of a planar waveguide ring resonator fabricated by a sol-gel method

A planar waveguide ring resonator was fabricated by organic-inorganic hybrid sol-gel materials; its sensitivity to ethanol vapor was experimentally investigated. It was found that dips in the transmission spectrum of the device shifted to longer wavelengths with increasing the ethanol concentration, and its sensitivity showed a linear relation with the ethanol concentration, showing a coefficient of 1.13 pm/ppm. In addition, the transmission loss of the ring resonator decreased with increasing the ethanol concentration. The measured characteristics suggest that the device may be considered as one of the candidates of alcohol vapor sensors. (c) 2006 Elsevier B.V. All rights reserved.

A planar waveguide Nd : YAG laser using active Q-switching of a hybrid unstable resonator

A planar waveguide laser operating in a negative branch unstable resonator is Q-switched by an acoustooptic mod latorin anew configuration, providing effective, high-speed switching. The laser using a 200-mu m Nd:YAG core, face pumped by 10 laser diode bars, has produced 100-W output in a good beam quality at 100-kHz pulse rate, and 4.5 mJ at lower frequency with 15-ns pulse duration.

Output beam quality of edge pumped planar waveguide lasers with confocal unstable resonators

Output beam quality of edge pumped planar waveguide lasers with confocal unstable resonators is investigated by diffraction methods, taking into account gain saturation, asymmetric pumping, and beam interaction. The influences of pumping uniformity, doping concentration, cavity length and effective Fresnel number are analyzed with respect to output beam quality and pumping efficiency. It is found that good beam quality and high efficiency can be obtained with asymmetric pumping and optimized negative branch confocal unstable resonators. (c) 2005 The Optical Society of Japan.

Quasi-self-imaging planar waveguide lasers with high-power single-mode output

We describe high-power planar waveguide laser which can achieve single-mode output from a multi-mode structure. The planar waveguide is constructed with incomplete self-imaging properties, by which the coupling loss of each guided mode can be discriminated. Thermal lens effects are evaluated for single-mode operation of such high-power diode-pumped solid-state lasers. (c) 2005 Elsevier B.V. All rights reserved.

Mode competition in acousto-optically Q-switched planar waveguide lasers

Multi-mode rate equations have been developed to investigate mode competition in high-power acousto-optically Q-switched planar waveguide lasers. The mode competition arises from coupling effects and temporal losses in the transform between guided modes and free-space propagation. Pulse-to-pulse instability and temporal beam distortions are enlarged by mode competition when the laser works in the multi-mode regime. The influence of parasitic oscillation is also discussed. A Nd:YAG planar waveguide laser has been established with a folded hybrid/unstable resonator. A maximum average power of 83 W with a beam propagation factor M-x(2) x M-y(2) = 1.2 x 1.4 is obtained. The theoretical simulation agrees well with the experimental observation. (c) 2006 Elsevier Ltd. All rights reserved.

High-power Nd:YAG planar waveguide laser with YAG and Al2O3 claddings

Thermal effects in Nd:YAG planar waveguide lasers with non-symmetrical claddings are discussed. The heat generated in the active core can be removed more efficiently by directly contacting the active core to the heat sink. Several cladding materials are compared to optimize the heat removal. Furthermore, uniform pumping is achieved with oblique edge-pumping technique. Using quasi-CW pumping at 1 KHz repetition rate, an average output power of 280 W with a slope efficiency of 38% is obtained with a positive unstable resonator. (C) 2008 Elsevier B.V. All rights reserved.

Effect of processing parameters on the optical properties of TiO2/ormosil planar waveguide

Hybrid TiO2/ormosil waveguiding films have been prepared by the sol-gel method at low thermal treatment temperature of 150° C. The influence of processing parameters including the molar ratios of titanium butoxide (Ti(OBu)(4))/3-glycidoxypropyltrimethoxysilane (GLYMO) and H2O/Ti(OBu)(4) (expressed as R), especially aging of sot on the optical properties was investigated. The optical properties of films were measured with scanning electron microscope (SEM), UV/VIS/NIR spectrophotometer (UV-Vis), m-line and the scattering-detection method. The results indicate that the film thickness increases with the increase of sol aging time, but the variation of refractive index as a function of sot aging time depends on the relative ratios of GLYMO to Ti(OBu)(4). Higher transmittance and lower attenuation of the planar waveguide can be obtained in the sol with lower Ti(OBu)(4) contents and shorter aging time.

Optical and surface properties of hybrid TiO2/ormosil planar waveguide prepared by the sol-gel process

Two kinds of silanes, 3-glycidoxypropyltrimethoxysilane (GLYMO) and 3-trimethoxysililpropylmethacrylate (TMSPM), were used to prepare ormosil waveguide films by the sol-gel method. Thirty percent Ti(OBu)(4) and 70% silane were contained in the precursor sets. The properties of films were measured by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), UV/VIS/NIR spectrophotometer (UV-vis), atomic force microscopy (AFM), m-line and scattering-detection method. The films from GLYMO and TMSPM precursors exhibit similar thickness (2.58 mu m for GLYMO, 2.51 mu m for TMSPM) and refractive index (1.5438 for GLYMO, 1.5392 for TMSPM, lambda=632.8 nm), but the film from TMSPM precursor has higher propagation loss (1.024 dB/cm, lambda=632.8 nm) than the film prepared from GLYMO (0.569 dB/cm, lambda=632.8 nm). Furthermore, the film prepared from TMSPM is easy to be opaque and cracks during coating whereas the same phenomenon was not found for the film prepared with GLYMO. It is confirmed that GLYMO is a better precursor than TMSPM for waveguide film preparation. (C) 2005 Elsevier Ltd and Techna Group S.r.l. All rights reserved.