Optical directional coupler using deposited silica waveguides (DS guides)

A new optical directional coupler using embedded single-mode glass waveguides is presented. The glass waveguides, called deposited silica waveguides (DS guides), were fabricated by depositing doped glass on a silica substrate after forming grooves by reactive sputter etching. Waveguide transmission loss was measured to be 1.3 dB/cm, and fiber-to-waveguide coupling loss was 0.1 dB. Using a tunable monochromatic light source, 96 percent power transfer or 14 dB isolation was measured. The DS guide directional coupler is compatible with single-mode fiber and is expected to be a useful component for future wavelength division multiplexing transmission systems.     

Multimode deposited silica waveguide and its application to an optical branching circuit

A fabrication procedure has been developed for multimode deposited silica waveguide (DS guide), consisting of uniform and thick glass layer formation for core and cladding, and amorphous Si mask film for reactive sputter etching. The embedded multimode DS guide with a square core cross section has a transmission loss of 1.3 dB/cm at 633 nm wavelength. Waveguide parameters, such as core dimension, refractive index, and index difference, are similar to those of a multi-mode silica fiber. A multimode optical branching circuit with eight output ports was demonstrated by the above fabrication procedure. Excess insertion loss was 2 dB.     

Single-mode 1×3 integrated optical branching circuit designusing phase-front accelerators

Proposes a novel design for symmetric single-mode 1×3 integrated optical branching circuits as optical power dividers using relatively low-index phase-front accelerator regions in the Y-branch structures. By varying the location and the area of such regions, an equally distributed power can be obtained at the three output ports     

Single-mode optical isolator at 1.3 ?m using all-fibre components

An optical isolator for use at 1.32 ?m has been fabricated using standard communication-grade single-mode fibre as an optical rotator fitted with high-birefringence fibre pigtails containing an in-line tapered fibre polariser. A novel adjustment procedure ensures isolation levels are limited only by the polariser extinction ratio. Isolation levels in excess of 21 dB have been recorded with an insertion loss of less than 3 dB.     

Single-mode guided-wave optical gate matrix switch using Mach-Zehnder interferometer gates

A 4 × 4 optical gate matrix switch is fabricated from high-silica single-mode guided-wave optical circuits. Mach-Zehnder interferometer circuits operated by electrical heating are used as optical gates. The switch has a 400 Mbit/s switching bandwidth.     

Genetic algorithm-based characterization of the optical properties of flame-hydrolysis deposited silica waveguides

Genetic algorithms have been demonstrated to be a robust method for the calculation of the refractive-index profile of annealed germanium-doped flame-hydrolysis deposited (FHD) silica layers using measurements of the effective refractive indexes of the different modes of propagation. A nonuniform refractive-index profile in depth was obtained, which agrees well with the germanium concentration and density profiles measured for the films.     

New method for low cost and efficient optical connections between singlemode fibres and silica guides

A new method is presented of using dry etched U grooves in silicon able to give low cost and efficient optical connections without any active alignment between singlemode fibres and silica waveguides fabricated on silicon substrates. A rugged assembly including a 35 mm long channel guide with two pigtails and exhibiting total power loss lower than 0.8 dB has been demonstrated.<>     

Fundamental studies on ultra-high-speed optical LAN using optical circuit switching

We study the fundamental properties of the hybrid combination of optical circuit switching (OCS) and electrical packet switching (EPS) used in an ultra-high-speed local area network (LAN) of the future, where chunks of data such as those containing non-compressed super-high-definition images are frequently transmitted as well as text-based data. We assume the logical topology of the OCS network in such a LAN to be single star in which the end-to-end connections are provided through a non-blocking optical matrix switch located at the center, while a conventional modest-speed EPS-based network such as Ethernet is co-installed to function as another data plane as well as the control plane of the OCS network. We refer to queueing theory in order to understand the fundamental performances issues of OCS and packet switching, and show that the hybrid use of OCS and EPS is very preferable especially when the variance of file size is very large. Simulation results show that the hybrid configuration can significantly outperform a network based on OCS only.     

Single-mode propagation in 2-mode region of optical fibre by using mode filter

The effect of a mode filter using fibre bend has been clearly shown experimentally. The mode filter effectively removes the LP11-mode, and has a negligibly small effect on the attenuation of the LP01-mode. The single-mode propagation was attained at the V-value of 2.8 by using the filter.     

All-optical timing extraction using an optical tank circuit

An ultrafast all-optical timing extraction method using an optical tank circuit is described, and experimental results at 2 Gb/s are reported. A Fabry-Perot resonator, whose free spectral range is equal to the clock frequency of the incoming optical data stream, is utilized as the optical tank circuit. Its fully passive structure and ultra-high-bit-rate operation (~Tb/s) is possible through decreasing resonator length     

基于二氧化硅平面光波导的强度均衡的光脉冲对的产生

提出了一种基于平面光波导工艺的带有可调定向耦合器的非对称MZI结构.模拟结果显示,当定向耦合器的两个耦合臂的折射率独立改变时,定向耦合器的调制效果较好;当调制电极与耦合区的波导间距为0时,两个耦合臂的温度差达到最大.测试得到,AMZI的插入损耗为2.05 dB,延迟时间为151.4 ps,脉冲对的功率比近似为1.该器件有助于提高集成QKD器件的性能.     

Hybrid optical vector modulator utilising AlGaInAs reflective EAMs and high index-contrast silica circuit

A new compact photonic-integrated modulator utilising a four-element reflective electro-absorption modulator-semiconductor optical amplifier (EAM-SOA) array and silica interferometric guide arrangement is presented. The EAM-SOA active layer consists of AlGaInAs quantum wells designed in selective area growth technology, which enables an insertion gain, and the mature silica platform provides reduced optical losses. As a result, error-free 50 Gbit/s RZ-QPSK signal generation is shown.     

Analysis of semiconductor fault using DS (damped sinusoidal) HPEM injection

Electronic systems based on solid state devices have changed to be more complicated and miniaturized as the systems developed. The evaluation of HPEM (High Power Electromagnetics) has been mainly carried out in the system level, and the case of failure analysis on the device is very rare.If the electronic components (semiconductor) are exposed to HPEM, the semiconductor will be destroyed by the coupling effects of electromagnetic waves. Because the HPEM has fast rise time and high voltage of the pulse, the semiconductor is vulnerable to external stress factor such as the coupled electromagnetic pulse. By injecting Damped Sinusoidal Pulse to the semiconductor devices, were observed the increase of leakage current and the physical damage.     

Three-dimensional optical storage in fused silica using modulated femtosecond pulses

Three-dimensional bitwise optical recording with a density of 500 Gb/cm3 in fused silica using a Ti:sapphire femtosecond laser modulated by binary digits is demonstrated. Laser pulses modulation is realized by modulating two circuits of trigger pulses signal which are used to control laser pulses trapping and switching out from cavity, respectively. Bits are optically readout in both a parallel reading (phase-contrast) and a serial reading (confocal-type) methods. The method for modulating laser pulses can also be used in all of pulsed laser systems which operate in cavity-dumping configuration.     

Integrated optical inverter using light amplifying optical switch (LAOS)

An integrated optical inverter is demonstrated. Experimental results show good static input/output characteristics and an on/off ratio suitable for integrated optical logic. The simplicity of this circuit allows compact integration.<>     

光纤复合架空地线(OPGW)短路电流试验

文章介绍了光纤复合架空地线短路电流试验及试验结果的分析.     

Mode coupling of microstructured optical fibers using temperature-dependent nitrogen-doped silica fibers

A promising method for the diminishing of loss upon the welding of microstructured optical fibers with suspended core is proposed. The method is based on the application of the nitrogen-doped optical fiber whose thermally expanding core serves as the mode coupler. The loss related to the welding of the conventional fiber (Corning SMF-28 and OFS Clearlite 980) and the suspended-core microstructured fiber (with a core diameter of about 2 μm at wavelengths of 1060, 1310, and 1550 nm) using a conventional welding device is experimentally studied. The welding loss (less than 0.5 dB) in a wide spectral range is several times less than the loss corresponding to the existing methods for the coupling of conventional and microstructures fibers.     

Variable optical delay circuit using highly nonlinear fibre parametric wavelength converters

A variable optical delay circuit that employs a fibre loop with highly nonlinear fibre parametric wavelength converters is described. The delay time is determined from the number of circulations, which is controlled by the initially selected wavelength of the signal. No additional amplifier to compensate for the circulation loss is required.     

Wideband planar lightwave circuit type variable optical attenuator using phase-generating coupler

A novel wideband planar lightwave circuit type variable optical attenuator (VOA) that incorporates a phase-generating coupler is proposed. The proposed VOA was fabricated on a 1.5%-/spl Delta/ silica-based waveguide, and obtained a low insertion loss of less than 1.2 dB and a low wavelength dependent loss of less than 0.8 dB at attenuation levels of 0 to 25 dB over the C- and L-band wavelength range.     

Spatial frequency doubling lithography (SFDL) of periodicstructures for integrated optical circuit technology

A novel technique for fabricating gratings useful for integrated optical circuits (IOCs) is described. The technique combines optical projection lithography, partially coherent illumination, and spatial filtering. With this technique, only the first two orders diffracted by the mask grating are allowed to pass through the lens. This produces a grating pattern in the image plane that has a high contrast (near 100%), a large depth of focus, and a period half of what would have been obtained in normal imaging. Gratings of different periods, sizes, locations, orientations, and configurations (chirped, phase-shifted, etc.) can all be produced on the same chip with a single exposure. Using a deep UV lens with 248-nm KrF excimer laser for illumination, the authors printed high-quality 0.5-μm period gratings in an oxide layer on 10 mm×10 mm silicon chips. Extended depth of focus was observed. This technique opens up the possibility of high-volume production of IOC chips with Bragg filters using standard IC fabrication facilities