Polymeric optical waveguide switch using the thermooptic effect

An all-polymeric optical waveguide switch which uses total internal reflection from a thermally induced index barrier is discussed. Very large effective index changes ΔN=2×10^-2 were found in the polymeric waveguide. The temperature under the evaporated stripe heater was measured from the change in its resistance. The effective index change due to the temperature increase agrees well with values calculated from the deflection angles. The operation of the switch is, apart from a small waveguide dispersion effect, polarization-insensitive. Switching times of about 10 ms were measured. It should be possible to reduce them to a few milliseconds in optimized thermal designs and with regulated power dissipation in the heater     

Losses in optical waveguide formed by silver-sodium ion exchange

Propagation losses of optical waveguides formed by ion exchange from molten salts of silver nitrate are discussed. The refractive index in pyrex glass substrates is shown to obey an exponential profile and the resultant mode functions are also examined for the graded-index surface waveguide in order to understand the mechanism of a scattering loss. The attenuation of the sample waveguides is found to range from 2.0 to 2.5 dB/cm for TE0mode excitation and to be decreasing with increasing both the mode number of the guided beam and the waveguide thickness that is proportional to a square root of diffusion time. These results indicate that the predominant loss origin is silver ion concentration diffused in the glass.     

High-speed coating of optical fibres with thermally curable silicone resin using a pressurised die

A high-speed optical fibre coating technique using thermally curable silicone resin was studied. By developing a pressurised die, a smooth coating layer, more than 100 ?m thick, can be successfully achieved at a coating speed of 360 m/min. The coating thickness can also be controlled by adjusting the pressure in the die.     

Waveguides take to the sky [Polymeric waveguide circuits forairborne photonic phased-array antennas]

Phased-array antennas based on optical true-time-delay (TTD) lines can quickly track several satellites using the slightly different signals received by the array of antennas without physically moving. This article provides an overview of recent developments in wireless and airborne communications technology and presents the authors' research activities in invoking advanced polymeric waveguide circuits for building key blocks of wide-bandwidth phased-array antenna systems. The advantages of polymeric waveguides for microwave signal distribution are also explored     

Novel micromirror for vertical optical path conversion formed insilica-based PLC using wettability control of resin

A novel technique has been developed for fabricating a micromirror in a single-mode silica-based planar lightwave circuit (PLC), in which the flat slope for the mirror is made of resin by utilizing wettability control and the surface tension effect. It was shown that the mirror could be designed by numerical calculation based on the equation of Young and Laplace for a liquid surface. A controllable mirror angle range from 30 to 60° was achieved experimentally by changing the position of the boundary line between high and low wettability regions using oblique evaporation. The characteristics of a fabricated 45° mirror installed in a silica-based PLC were evaluated by coupling it vertically to a single-mode fiber. The obtained coupling losses between waveguides and a fiber were 0.60-1.15 dB for mirrors with widths of more than 200 μm, and 0.92 1.62 dB for 190 μm wide mirrors, at a wavelength of 1.55 μm. The experimental minimum losses of 0.6 and 0.92 dB coincided with the calculated values     

Integrated bistable optical device using mach-zehnder interferometric optical waveguide

An integrated mirrorless bistable optical device based on the Mach-Zehnder interferometric optical switch has been proposed and demonstrated experimentally using a Ti: LiNbO3 waveguide. The resulting device is capable of combining more than two of them to realise multifunctional optical devices such as optical multivibrators.     

应用模拟退火算法建立共面波导结构的等效电路

对中心导带和地渐变的共面波导结构提出了一种简单通用的方法,建立了其等效电路,通过模拟退火算法优化提取了电路参数.将这种方法应用于分析两种周期性共面波导结构,比较了由等效电路模型与实验得出的散射参数,得到了很好的一致性.     

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     

Synthesis of optical circuits using binary decision diagrams

The advances in silicon photonics motivated the consideration of optical circuits as a new and emerging circuit technology. In particular for ultra-fast interconnects, optical circuits may provide a suitable alternative since it avoids the conversion of signals from the optical to the electrical domain. Accordingly, design automation of this kind of circuits received significant attention. In this work, we consider synthesis of optical circuits based on Binary Decision Diagrams (BDDs). Although BDDs allow for a direct mapping of the function representation to an optical circuit (and, hence, a scalable synthesis), they have their shortcomings with respect to dedicated cost metrics. In this work, we investigate this issue and provide an overview of the BDD-based synthesis schemes which are available thus far. Afterwards, we propose new solutions based on a dedicated BDD optimization which aim for addressing the known shortcomings. Experimental results confirm the benefits of the proposed approach.     

Ferroelectric liquid crystal optical waveguide switches using thedouble-refraction effect

We propose an optical waveguide device with a bistable ferroelectric liquid crystal as the core. The liquid crystal electrooptic effect device induces a double-refraction phenomenon and the associated optical beamsteering provides a very simple 1×N optical switch. Beamsteering has been experimentally demonstrated and characterized. It exhibits very large angles (φ=40-60 for respective wavelengths λ=0.850-0.632 μm). In the same way, we propose a design that includes polymer integrated lenses for a compact device with a large number of outputs     

Fabrication of channel optical waveguide using CO2 laser

A CO2-laser-irradiated SiO2-Ta2O5 optical-film waveguide has been found to produce up to 2% refractive-index decrease. The usefulness of the CO2 technique has been demonstrated by fabricating a curved multimode channel waveguide with 1 dB/cm propagation loss in the thin film.     

TM-mode selective filter using lossy layer cladding optical waveguide

Mode-filter properties have been investigated using a complex coefficient eigenvalue equation on a simple structure having an extremely low refractive-index layer as a buffer layer between the guiding layer and the cladding lossy layer. As a result, it is revealed that the attenuation constants become at least an order of magnitude larger for the TE mode than for the TM mode.<>     

Guided-wave planar optical interconnects using highly multiplexedpolymer waveguide holograms

An intraplanar interconnection scheme using substrate guided modes in conjunction with a highly multiplexed waveguide volume hologram is proposed. Acoustooptically addressed 1-to-50 passive and 1-to-2-to-100 reconfigurable interconnections with a fan-out diffraction efficiency of 55% at 514-nm wavelength are demonstrated. A coordinate transformation converts the 3-D diffraction problem into a 2-D one, which significantly simplifies the theoretical calculation. Intraplane massive fan-out optical interconnection using substrate guided mode provides both collinear and coplanar fan-out capability for data and clock signals. Colinearity of signal distribution allows the 2-D input signal array to be processes. The laminated waveguide device containing a highly multiplexed dichromated gelatin (DCG) hologram has been evaluated     

Integrated optical circuits

Research on optical communication systems indicates the future need for a compact, rugged, and economical medium for circuit realization. Encapsulated planar arrays of rectangular dielectric waveguides are attractive for this purpose. The individual guides would have dimensions on the order of a few micrometers while the planar arrays might cover an area of a few square centimeters. Integrated circuit technology appears adaptable to batch processing such circuits. Recent theoretical and experimental results are surveyed which support this viewpoint.     

Optical loss increase in optical fibre coated with silicone resin containing Si?D

One possible origin of the loss increase phenomenon with heat treatment at 200°C (H2 evolution from the coating material) has been investigated, using optical fibre coated with silicone resin containing the Si?D group. Although OH absorption at 1.4 ?m increases with 200°C heat treatment, no OD peak is observed. It is suggested that silicone resin containing no Si?H and Si?CH2?CH2?Si groups is appropriate as a coating material as no H2 evolution is present.     

Numerical study of inhomogeneous optical waveguide problems using predictor-corrector method

The predictor-corrector method is used for the study of the inhomogeneous optical waveguide problems. Its accuracy and efficiency have been tested with the inhomogeneous slab waveguide with a finite homogeneous cladding, and compare favourably with the Runge-Kutta and collocation methods, more than halving the computing time for the former. The method also correctly brings out the field behaviour at a caustic.     

15 Gbit/s optical receiver using waveguide pin photodiode

The authors report the first optical receiver to use a waveguide pin photodiode as a high-power and high-speed photodiode. Its measured receiver sensitivity of 15 Gbit/s confirms that waveguide pin photodiodes have high-speed potential and flat frequency response under high input powers beyond +10 dBm     

光波导TE-TM模干涉调制光学双稳态装置

报道一种在钛扩散铌酸锂光波导电光调制器中同时激励TE模和TM模,使它们相干涉,并反馈控制电场从而实现光学双稳运转的新方法。     

激光前向散射图形应用于硅树脂涂复石英光纤的同心度监视

激光前向散射技术也能用来保证硅树脂涂复石英光纤的同心度。本文用射线光学的原理解释了散射图形的产生及其变化,介绍了同心度监视方法在随机拉丝中的应用结果。