Optical Waveguide Switch Research Articles

2 V drive-voltage switching operation in 1.55 μm GaInAs/InP MQW intersections waveguide optical switch

A low switching voltage of less than 2 V was achieved in a GaInAs/InP MQW intersectional waveguide optical switch operating at 1.55 μm. This switch was fabricated by only one-step epitaxial growth followed by a pattern etching process using electron beam lithography for electrical isolation and photolithography for waveguide formation.

Low-drive voltage intersectional waveguide optical switch using GaInAs/InP MQW structure

A low-drive voltage intersectional waveguide optical switch using 1.6 mu m GaInAs/InP MQW (multiple quantum well) structure, which was fabricated by only one-step epitaxial growth of MQW structure followed by a one-step pattern etching of the waveguide is demonstrated. Extinction ratio at the straight port of 9.9 dB and that at the reflection port of 4.4 dB were obtained at an applied voltage of -4 V. >

Monolithic integration of GaAs MESFET and Inp/InGaAsP 2×2 optical switch

An optical switching OEIC (optoelectronic integrated circuit), consisting of a GaAs MESFET and an InP/InGaAsP 2×2 buried waveguide optical switch, is reported for the first time. Fully monolithic integration is obtained by heteroepitaxial GaAs-on-InP growth and photolithographical interconnection. The combined OEIC allows switching voltages of about 1 V with an extinction ratio of −6dB.

Application of bipolar transistor structures to optical waveguide modulators and switches

Basic experimental results obtained with a GaAs/AlGaAs double-heterojunction bipolar transistor (DHBT) waveguide structure carrier-injected optical intensity modulator/switch are fully described. Typical common-emitter dc current gain obtained with a 0.25-μm-thick base/waveguide was ∼40, and the switching times have been determined as 1.5 ns. Optical on/off modulation ratios of up to 2.1:1 have been demonstrated at an input base current of as small as 3 mA for a device with emitter/waveguide width of 7 μm and length of 190 μm. Design and analysis of the optical switching characteristics expected for a reflection-type X-crossing optical switch of DHBT waveguide structure are also presented on the basis of these experimental results.

Bistable optical switching using electrochemically generated bubbles

We demonstrate a novel bistable optical waveguide switch, which may be suitable for incorporation in large-dimension optical cross connects. The switching is based on the electrolytic creation and catalytic destruction of bubbles and is both wavelength and polarization independent. Calculations indicate that low losses and cross talk, which are crucial for large switching arrays, can be achieved with the combination of materials used in the prototype. The intrinsic bistability of the switch eliminates the need for a holding voltage and permits matrix addressing.

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 Delta N=2*10/sup -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.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Theoretical and experimental investigation of an active three-branch Ti:LiNbO_3 optical waveguide switch

A theoretical and experimental investigation of an active three-branch multimoded Ti:LiNbO(3) waveguide switch is presented. The theoretical study covers the efficiency of the electrooptic index change in a multimoded waveguide, the mode conversion occurring in a tapered transition and, finally, the power division among the branches of the switch. For the experimental characterization, the optical measurements of a device fabricated in a Z-cut LiNbO(3) crystal are presented and discussed. Several improvements as well as applications are pointed out.

Low-drive-voltage and low-loss polarisation-independent LiNbO 3 optical waveguide switches

A simple and practical polarisation-independent directional coupler switch has been developed. The switch has an 18 V drive voltage, a below -17dB crosstalk and a 2.8 dB insertion loss between single-mode fibres at any incident polarisations with 1.3 μm wavelength.

Optical intensity modulation to 40 GHz using a waveguide electro-optic switch

We report the intensity modulation of an optical carrier at frequencies as high as 40 GHz using a Ti:LiNbO3 optical waveguide switch. The device is shown to exhibit a small-signal electrical 3 dB bandwidth of &amp;gt;22 GHz and −8 dB response at 40 GHz. A high-speed self-electro-optic-sampling arrangement based on a mode-locked injection laser is used to observe the modulation in the time domain.

Optical switching networks using tree‐structured waveguide optical switches

AbstractTo make a large‐sized optical matrix is an important subject in realizing optical switching systems. Although optical matrices using waveguide optical switches have potential from the viewpoint of high speed and circuit integration, they are limited in the number of input/output terminals (up to between 4 and 8) due to the insertion loss and multiple crosstalk noise. To reduce these disadvantages, this paper offers optical switching networks using tree‐structured N x 1 waveguide switches as fundamental elements. Approximated equations for the insertion loss and the multiple crosstalk are given and it is shown that those in the proposed networks are approximately proportional to the number of stages in the tree structure. A 4 × 4 optical highway switch using Ti:LiNbO3 tree‐structured directional couplers was tested to confirm its switching capability. The experimental results obtained have a good agreement with the equations of the insertion loss and the multiple crosstalk characteristic. By using these equations, the size of the realizable switching system was estimated; a highway switch having 32 to 64 terminals is found to be possible with the present technology.

InGaAsP/InP optical waveguide switch operated by a carrier-induced change in the refractive index

Waveguided semiconductor optical switches operated by a carrier-induced change in the refractive-index associated with the plasma dispersion are proposed. InGaAsP/InP four-port switches having two intersecting single-mode channel waveguides are fabricated by selective liquid-phase epitaxy and investigated at 1.5μm wavelength. Optical switching is observed as a result of mode interference in the waveguide intersection region.

Optical waveguide 2 × 2 matrix switch using dielectric chip motion

Input and output light angles in a total internal reflection optical waveguide switch, in which a guided light beam is switched by dielectric chip contact with a low-index channel built in a waveguide film, are studied to construct a matrix switch. Output angle depends on channel width, chip contact width, chip position, and input angle. In a single switch experiment, the output angle is larger than the total reflection critical angle for the channel due to narrow chip contact width. By utilizing this property, a nonblocking 2 x 2 matrix switch, driven by PZT bimorphs, is fabricated. Insertion losses of 2.9-6.0 dB, cross talk values of 10.8-28.1 dB, and switching time of 6 msec are obtained for the TE(0) mode at 0.633-microm wavelength.

Total reflection optical waveguide switching through dielectric chip motion

An optical waveguide switch has been realized utilizing the total reflection critical angle controlled by the motion of a dielectric chip set on a waveguide surface. By the contact-noncontact of a GGG chip with the SiO(2)-Ta(2)O(5) waveguide film having a built-in low refractive-index channel, a switching angle of 22.5x and extincion ratio of 12-16 dB were obtained for the TE(0) mode at 0.633-microm wavelength. A 1 x 3 switch that includes two switching positions driven by 6-V electromagnets is demonstrated.

Optical waveguide switch (3 × 3) for an optical switching system

A new optical switch element is proposed for a switching system which exchanges optical signals in optical transmission lines without optoelectric conversion. It consists of three parallel equidistant straight singlemode waveguides fabricated of an electrooptic material with electrodes deposited on them. The element, whose interaction length is pi/(2)((1/2))k (k is the coupling coefficient of neighboring guides), serves as a 3 x 3 optical switch by control of the differences in propagation constants between those waveguides. Control conditions to realize all the six connecting states of a 3 x 3 switch are discussed with the solution of the coupling equation for those guides.

A new waveguide switch/modulator for integrated optics

A waveguide optical switch and/or modulator device is described that uses a single-mode waveguide version of the Mach-Zehnder interferometer. A mode selective branching waveguide is used for switching, and modulation can be accomplished without external polarizers in single-mode waveguides. The operation of a 1×2 switch fabricated by diffusion techniques in ZnSe is described.

Mach-Zehnder Interferometer

Beam propagation method (BPM) was used to study 2x2 Mach-Zehnder interferometer switch with electro-optical effects in titanium diffused lithium niobate based directional coupler was used to develop the design. This design is capable of de-multiplexing the wavelength1300nm. This project intends to design high performance NxN electro-optic switch. This optical device is widely used in optical network, especially in the optical link of fiber-to-the-home (FTTH). The design is carried out using BPM_CAD, which is a very powerful and user-friendly optics waveguides modeling method as it core element. Research on optical waveguide switching using directional coupler (DC) and Mach-Zehnder interferometer (MZI) has been going on and already created great interest among the researchers. There are different types of material being used in much different way apart from the most common electro-optic materials such as lithium niobate. Recently, the study was also confined to the use of silica on silicon technology considering that the cost of the technology. Other non-linear-optic materials such as polymers have been embedded into part of the silica waveguide.