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Showing papers on "Optical switch published in 1998"


Journal ArticleDOI
TL;DR: In this article, a categorization of optical buffering strategies for optical packet switches is presented, and a comparison of the performance of these strategies both with respect to packet loss/delay and bit error rate (BER) performance is made.
Abstract: This paper consists of a categorization of optical buffering strategies for optical packet switches, and a comparison of the performance of these strategies both with respect to packet loss/delay and bit error rate (BER) performance. Issues surrounding optical buffer implementation are discussed, and representative architectures are introduced under different categories. Conclusions are drawn about packet loss and BER performance, and about the characteristics an architecture should have to be practical. It is shown that there is a strong case for the use of optical regeneration for successful cascading of these architectures.

541 citations


Posted Content
TL;DR: The Tiny Tera is a CMOS-based input-queued, fixed-size packet switch suitable for a wide range of applications such as a highperformance ATM switch, the core of an Internet router or as a fast multiprocessor interconnect.
Abstract: In this paper, we present the Tiny Tera: a small packet switch with an aggregate bandwidth of 320Gb/s. The Tiny Tera is a CMOS-based input-queued, fixed-size packet switch suitable for a wide range of applications such as a highperformance ATM switch, the core of an Internet router or as a fast multiprocessor interconnect. Using off-the-shelf technology, we plan to demonstrate that a very highbandwidth switch can be built without the need for esoteric optical switching technology. By employing novel scheduling algorithms for both unicast and multicast traffic, the switch will have a maximum throughput close to 100%. Using novel highspeed chip-to-chip serial link technology, we plan to reduce the physical size and complexity of the switch, as well as the system pin-count.

345 citations


Journal ArticleDOI
TL;DR: In this article, the free-space micromachined optical switches (FS-MOS) demonstrated in this paper represent a means of filling this network need by combining the advantages of free-rotating hinged micromirrors with the virtues of integrated optics.
Abstract: Optical crossconnects with large port counts are fast becoming critical components for high-capacity optical transport networks. The free-space micromachined optical switches (FS-MOS) demonstrated in this letter represent a means of filling this network need by combining the advantages of free-space interconnection with the virtues of integrated optics. Featuring free-rotating hinged micromirrors, the switch overcomes the common drawback of mechanical-type switches, namely long switching time. Measurements have revealed switching times less than 700 /spl mu/s, crosstalk less than -60 dB, extinction ratio greater than 60 dB, negligible polarization-dependent loss, and excellent bit-error-rate (BER) performance.

269 citations


Journal ArticleDOI
TL;DR: An overview of recent progress in PLC technology including optical power splitters, arrayed-waveguide gratings, thermooptic switches, and hybrid integrated PLC's can be found in this article.
Abstract: Silica-based planar lightwave circuits (PLC) provide various important devices for both optical wavelength-division-multiplexing networks and optical access network. This paper is an overview of recent progress in PLC technology including optical power splitters, arrayed-waveguide gratings, thermooptic switches, and hybrid integrated PLC's.

238 citations


Journal ArticleDOI
TL;DR: In this article, a detailed traffic analysis of optical packet switch design is performed, where special consideration is given to the complexity of the optical buffering and the overall switch block structure.
Abstract: A detailed traffic analysis of optical packet switch design is performed. Special consideration is given to the complexity of the optical buffering and the overall switch block structure is considered in general. Wavelength converters are shown to improve the traffic performance of the switch blocks for both random and bursty traffic. Furthermore, the traffic performance of switch blocks with add-drop switches has been assessed in a Shufflenetwork showing the advantage of having converters at the inlets. Finally, the aspect of synchronization is discussed through a proposal to operate the packet switch block asynchronously, i.e. without packet alignment at the input.

223 citations


Book
25 Mar 1998
TL;DR: Optical Fiber Propagation Optical Amplifiers Optical Transmission Systems Soliton Optical Communications Repeaterless Systems Long Distance TDM Transmission WDM Optically Amplified Systems Transmission in All-Optical Networks Appendices Index as mentioned in this paper
Abstract: Optical Fiber Propagation Optical Amplifiers Optical Transmission Systems Soliton Optical Communications Repeaterless Systems Long Distance TDM Transmission WDM Optically Amplified Systems Transmission in All-Optical Networks Appendices Index

221 citations


Patent
27 Jan 1998
TL;DR: An optical switch particularly usable as a wavelength-division add/drop multiplexer (WADM) in a multi-wavelength communication system is described in this article, where four multwavelength beams optically coupled to the input, output, add, and drop channels are arranged in parallel in a rectangular array and are incident upon a diffraction grating.
Abstract: An optical switch particularly usable as a wavelength-division add/drop multiplexer (WADM) in a multi-wavelength communication system. Four multi-wavelength beams optically coupled to the input, output, add, and drop channels are arranged in parallel in a rectangular array and are incident upon a diffraction grating. The grating operating in one direction disperses the beams into their wavelength components and operating in the other direction recombines the wavelength components into a multi-wavelength beam. A lens focuses the components of the beams having a particular wavelength upon one of an array of tiltable micro-mirrors integrated on a silicon substrate. In one position, the mirror for a particular wavelength reflects that wavelength component from the input beam back to the output beam. In a second position, that mirror reflects that wavelength component from the input beam back to the drop beam and reflects that same wavelength component from the add beam back to the output beam. The same optics can be used for a second set of beams which are switched in synchronism with the first set. The array of mirrors can be fabricated to be tiltable to more than two positions so that the input beam can be selectively coupled to either the output beam or one of at least two drop beams while the output beam is correspondingly selectively coupled to either the input beam or one of at least two add beams.

219 citations


Journal ArticleDOI
TL;DR: Chapman et al. as discussed by the authors have shown that metal-ion implanted colloid generation in bulk silica glass composites under favourable circumstances has significant enhancement of the third-order optical susceptibility with picosecond temporal responses.
Abstract: Although electronics technologies have made great advances in device speed, optical devices can function in the time domain inaccessible to electronics. In the time domain less than 1 ps, optical devices have no competition. Photonic or optical devices are designed to switch and process light signals without converting them to electronic form. The major advantages that these devices offer are speed and preservation of bandwidth. The switching is accomplished through changes in refractive index of the material that are proportional to the light intensity. The third-order optical susceptibility, χ(3), known as the optical Kerr susceptibility which is related to the non-linear portion of the total refractive index, is the non-linearity which provides this particular feature. Future opportunities in photonic switching and information processing will depend critically on the development of improved photonic materials with enhanced Kerr susceptibilities, as these materials are still in a relatively early stage of development. Optically isotropic materials, e.g. glasses that have inversion symmetry, inherently possess some third-order optical non-linearities. Although this is quite small for silica-glasses at λ=1.06 μm, the absorption coefficient is extremely low, thereby allowing all-optical switching between two waveguides, embedded in a silica fibre, simply by controlling the optical pulse intensity. Different glass systems are now under investigation to increase their non-linearity by introducing a variety of modifiers into the glass-network. The incorporation of semiconductor microcrystallites enhances the third-order optical response. Metal colloids or nanoclusters, embedded in glasses, have also been found to introduce desired third-order optical non-linearities in the composite at wavelengths very close to that of the characteristic surface-plasmon resonance of the metal clusters. Ion implantation is nowadays an attractive method for inducing colloid formation at a high local concentration unattainable by the melt-glass fabrication process and for confining the non-linearities to specific patterned regions in a variety of host matrices. Recent works on metal-ion implanted colloid generation in bulk silica glasses have shown that these nanocluster–glass composites under favourable circumstances have significant enhancement of χ(3) with picosecond temporal responses. The remarkable achievements in developing such novel photonic materials seem to open the way for advances in all-optical switching devices, e.g. in inducing metal-colloids into coupled waveguides acting as a directional coupler. The present paper addresses the phenomena of optical non-linearities in metal nanocluster–glass composites that are synthesized by ion implantation, and the potential uses of these novel composite materials in photonics. © 1998 Chapman & Hall

215 citations


Patent
Rohit Sharma1, Larry R. Mcadams1
09 Feb 1998
TL;DR: In this article, a ring-switched signals propagate around the ring on protection fibers without encountering the terminal equipment at the intervening nodes, to the extent that the protection fiber links between any given pair of nodes are incapable of supporting all the relevant communication regimes, such links are modified to provide such support.
Abstract: Techniques for providing normal operation and service restoration capability in the event of failure of terminal equipment or transmission media in a heterogeneous network, such as a hybrid network containing single- and multi-wavelength lightwave communications systems. An optical switching node (OSN) is placed at each node in the ring network to provide the required connections between various fibers and terminal equipment, but having switch states that allow signals on the protection fibers to bypass the terminal equipment at that node. Ring-switched signals propagate around the ring on protection fibers without encountering the terminal equipment at the intervening nodes. To the extent that the protection fiber links between any given pair of nodes are incapable of supporting all the relevant communication regimes, such links are modified to provide such support.

211 citations


Journal ArticleDOI
TL;DR: In this paper, an architectural concept is discussed and justified mathematically that relies on cascading many small switches to form a bigger switch with a larger buffer depth, providing an economical and feasible hardware solution.
Abstract: Recently, optical packet switch architectures, composed of devices such as optical switches, fiber delay lines, and passive couplers, have been proposed to overcome the electromagnetic interference (EMI), pinout and interconnection problems that would be encountered in future large electronic switch cores. However, attaining the buffer size (buffer depth) in optical packet switches required in practice is a major problem; in this paper, a new solution is presented. An architectural concept is discussed and justified mathematically that relies on cascading many small switches to form a bigger switch with a larger buffer depth. The number of cascaded switches is proportional to the logarithm of the buffer depth, providing an economical and feasible hardware solution. Packet loss performance, control and buffer dimensioning are considered. The optical performance is also modeled, demonstrating the feasibility of buffer depths of several thousand, as required for bursty traffic.

207 citations


Journal ArticleDOI
TL;DR: Three optical cross-connect architectures employing the SAD switch have multicasting capability, are strictly nonblocking and have wavelength or fiber modular structures and are expandable when the number of the fibers and the wavelengths increase a few or by a few times.
Abstract: A new splitter-and-delivery (SAD) switch having multicasting capability is proposed. It is best implemented in a single silicon board using planar silica waveguide technology. Less than -40-dB crosstalk is achievable by an auxiliary action of the optical gate. Three optical cross-connect architectures employing the SAD switch are proposed. They are strictly nonblocking and have multicasting capability. Furthermore, they have wavelength or fiber modular structures and are expandable when the number of the fibers and the wavelengths increase a few or by a few times. The expanding method and other important issues are discussed in detail.

Journal ArticleDOI
TL;DR: This is the first demonstration of 100-Gbit/s bitwise logic in an all-optical semiconductor optical amplifier-based switching device, the ultrafast nonlinear interferometer.
Abstract: We demonstrate 100-Gbit/s bitwise logic in an all-optical semiconductor optical amplifier-based switching device, the ultrafast nonlinear interferometer. To the best of our knowledge this is the first demonstration of 100-Gbit/s AND and INVERT functionality with a 100-GHz optical clock stream and a 100-Gbit/s data stream as the logical inputs to a semiconductor-based switch. Additionally, 100-Gbit/s inverting and noninverting all-optical wavelength conversion are demonstrated.

Proceedings ArticleDOI
02 Jul 1998
TL;DR: In this article, the authors present the state-of-the-art in the field of optical integrated devices and circuits and discuss the trends, guided by applicative goals, not only from the theoretical point of view but also from a practical one.
Abstract: The notorious implication of integrated optics in the nowadays communication systems makes more interesting the development of optical integrated devices and circuits. The evolution of the communication systems was sustained by the integrated optics and it is obvious that the actual interests in the optical communications are also transferred and adapted to integrated optics. The presentation of actual state-of-the-art in this field is a good opportunity both for an evaluation on the above mentioned evolution and for discerning the actual trends and their perspectives. These trends, guided by applicative goals, have to be discussed not only from the theoretical point of view but also from a practical one.

Patent
27 Nov 1998
TL;DR: In this paper, a multilayer structure is proposed to optimize the respective layers independently of one another, which allows the driving part to be optimized so as to achieve an optical switching device capable of operating at high speed with low power consumption.
Abstract: An optical switching device comprises: a light guide including a total reflection plane capable of totally reflecting light thereby transmitting the light; a switching part capable of, at a position where its extraction plane is in close contact with the total reflection plane, capturing evanescent light and reflecting the captured light thereby outputting it; and a driving part for driving the optical switching part. The light guide, the switching part, and the driving part are laminated in this order into a multilayer structure. The employment of the multilayer structure makes it possible to optimize the respective layers independently of one another. The extracted light does not pass through the driving part. This allows the driving part to be optimized so as to achieve an optical switching device capable of operating at a high speed with low power consumption. Thus, it is possible to provide a low-loss and high-contrast optical switching device using an evanescent wave, which can respond at a high speed.

Journal ArticleDOI
TL;DR: In this paper, a multiply-coupled resonator side coupled to a pair of waveguides can switch an optical signal between two ports by means of absorption, and the absorptive mechanism is used to suppress the resonant power transfer, rather than to promote loss.
Abstract: A resonator side coupled to a pair of waveguides can switch an optical signal between two ports by means of absorption. The absorptive mechanism is used to suppress the resonant power transfer, rather than to promote loss. Thus, the input signal only suffers small attenuation, provided that the mode volumes of the resonators can be made small enough. Multiply-coupled resonators lead to improved crosstalk performance for both the ON and OFF switched states. The performance of such devices are analyzed analytically, and universal switching curves are derived.

01 Jan 1998
TL;DR: In this paper, the authors demonstrate that a CCA of dyed particles embedded in a poly acrylamide hydrogel acts as a nanosecond optical Bragg diffraction switching device.
Abstract: Monodisperse, highly charged colloidal particles in low ionic strength solutions self-assemble into bcc or fcc crystalline colloidal arrays (CCAs) due to interparticle repulsive interactions. We demonstrate that a CCA of dyed particles embedded in a poly acrylamide hydrogel acts as a nanosecond optical Bragg diffraction switching device. Under low light intensities the CCA is refractive index matched to the medium and does not diffract. However, high intensity excitation within the dye absorption band heats the spheres within nanoseconds to decrease their refractive index. The array “pops up” to diffract light within 2.5 ns. These intelligent CCA hydrogels may have applications in optical limiting, computing, and nanosecond fast optical switching devices, etc. [S0031-9007(97)03099-8]

Journal ArticleDOI
TL;DR: In this paper, the increasing use of WDM systems in telecommunications networks is highlighted, and the potential role for wavelength conversion in future upgrades of such systems is reviewed, and experimental results obtained at BT Laboratories are used to illustrate the state of the art.
Abstract: In this article the increasing use of WDM systems in telecommunications networks is highlighted, and the potential role for wavelength conversion in future upgrades of such systems is reviewed. Techniques for achieving wavelength conversion by all-optical means using nonlinearities in semiconductor optical amplifiers are explained, and experimental results obtained at BT Laboratories are used to illustrate the state of the art.

Journal ArticleDOI
TL;DR: In this article, the optical physics of the third-order non-linearity in metal nanocrystal composites, to illustrate how material parameters of both quantum dots and host matrix affect the optical nonlinearities, are discussed.
Abstract: It is now well-established that metal nanocrystal composites with attractive third-order non-linear optical properties can be synthesized in various dielectric hosts by ion implantation, ion exchange, sol–gel processes, sputtering, and pulsed-laser deposition. Whether these are appropriate to make practical all-optical switching and wave-guiding devices remains to be seen; however; in particular, techniques for the fabrication of simple device structures based on these materials are largely unexplored. This paper reviews the optical physics of the third-order non-linearity in metal nanocrystal composites, to illustrate how material parameters of both quantum dots and host matrix affect the optical non-linearities. The figures of merit that characterize simple building blocks—such as wave-guide resonators and directional couplers—for all-optical switching circuits are discussed. Novel ways of using ion implantation to enhance the properties of layered nanocluster and nanocrystalline materials are considered, particularly those that complement techniques for building up optical heterostructures, such as ion exchange, sputtering and pulsed-laser deposition.

Journal ArticleDOI
TL;DR: In this article, an all-optical ultrafast switch which operates at a wide wavelength range was demonstrated based on photoinduced changes of real and/or imaginary parts of complex refractive index in a composite thin film of silver and polymer containing photochromic spiropyran dye.
Abstract: An all-optical ultrafast switch which operates at a wide wavelength range has been demonstrated based on photoinduced changes of real and/or imaginary parts of complex refractive index in a composite thin film of silver and polymer containing photochromic spiropyran dye. Very fast switching ON and OFF of a reading beam within 20 ns in a 400–800 nm range was achieved at the incident angle of guided-wave mode using a photochromic spiropyran-doped polystyrene thin film and a ns pulsed UV or visible laser as a writing beam. These responses were caused by the changes of complex refractive index due to photochromism. No applied power was required to hold the switched state. An image was also written to the probe beam by irradiation through a pattern.

Journal ArticleDOI
TL;DR: In this article, an arrayed waveguide grating (AWG) multi/demultiplexer and a digital thermooptic (TO) switch are successfully realized using the silicone resin.
Abstract: Polymeric optical waveguides fabricated using a newly developed silicone resin have a low birefringence as well as low propagation loss and good environmental stability. Optical waveguide circuits including a directional coupler, an arrayed waveguide grating (AWG) multi/demultiplexer, and a digital thermooptic (TO) switch are successfully realized using the silicone resin.

Patent
10 Nov 1998
TL;DR: In this paper, a free-space N by M where N and M > 1 optical signal switch (OXC) requires only transmitter beam steering for controlling to which receiver an optical signal from a transmitter is directed.
Abstract: A free-space N by M where N and M > 1 optical signal switch (OXC) requires only transmitter beam steering for controlling to which receiver an optical signal from a transmitter is directed. In a preferred embodiment the transmitters handle single mode optical signals and the receivers handle multimode optical signals. The OXC may optionally include a fixed optical unit implemented using either a single fixed shared lens or a plurality of M optical elements for further directing each of the M optical signals to their respective receivers.

Patent
05 Feb 1998
TL;DR: In this paper, an optical line termination (OLT) device generates a plurality of optical signals having different respective wavelengths (λ1, λ2), each optical signal carrying data, and wavelength-division-multiplexed optical signals.
Abstract: An optical line termination (OLT) device (12) generates a plurality of optical signals having different respective wavelengths (λ1, λ2), each optical signal carrying data, and wavelength-division-multiplexes the optical signals. A plurality of optical network units (ONUs 14 1 -14 5) are connected to the OLT device (12) by way of a passive optical network (6) so as to receive the wavelength-division-multiplexed optical signals. Each ONU (14) has a wavelength selection unit operable in dependence upon control information sent from the OLT (12) to the ONU (14) concerned by way of the passive optical network (6) to select one of the optical signals of the plurality, and also has a detector for processing the selected optical signal to derive therefrom the data carried thereby. The control information may be included in the data-carrying optical signals themselves as overhead information, or may be sent separately by another optical signal that is wavelength-division multiplexed with the data-carrying optical signals. Such an arrangement can enable the downstream capacity of the passive optical network to be shared flexibly by the different optical receivers.

Patent
04 Dec 1998
TL;DR: In this paper, a wavelength selective add-and-drop multiplexer is described for adding and/or dropping spectral components from a wavelength-division-multiplexed optical signal.
Abstract: A wavelength-selective add-drop multiplexer is disclosed for adding and/or dropping spectral components from a wavelength-division-multiplexed optical signal. (1x1) or (2x2) optical switches are used, either alone or in conjunction with other optical elements, to separate spectral components identified for drop from other spectral components.

Journal ArticleDOI
TL;DR: In this paper, three asymmetries in asymmetric Mach-Zehnder interferometer (MZI) configurations with SOA's on their arms are discussed. And the theoretical predictions are verified and found to be in excellent agreement with experiments for a switch with symmetric MZI splitters in a monolithically integrated InP waveguide version.
Abstract: Asymmetric Mach-Zehnder interferometer (MZI) configurations are proposed to build all-optical space switches with gain and principally ideal extinction ratios. Actually, three asymmetries in MZI configurations with semiconductor optical amplifiers (SOA's) on their arms are discussed. The asymmetries in the all-optical switches are necessary to overcome the extinction ratio limitations that are due to the disturbing gain changes that arise when control signals are introduced into the SOA's to induce the necessary refractive index change for switching. Starting from a generic MZI configuration with SOA's on the arms, a description in terms of transmission matrices is used and applied to identify 1/spl times/2 and 2/spl times/2 all-optical switch configurations with high on-state transmissions and close to ideally large extinction ratios. The theoretical predictions are verified and found to be in excellent agreement with experiments for a switch with symmetric MZI splitters in a monolithically integrated InP waveguide version that allows operation with equally or unequally biased SOA's.

Patent
Alain Blanc1, Sylvie Gohl1, Michel Poret1
02 Dec 1998
TL;DR: In this paper, a fault tolerant switching architecture is provided with two separate switch fabrics each having a switch cure located in a centralized building and a set of SCAL elements distributed in different physical areas.
Abstract: A fault tolerant switching architecture is provided with two separate switch fabrics each having a switch cure located in a centralized building and a set of SCAL elements distributed in different physical areas. Each SCAL element has both a SCAL receive element and a SCAL transmit element for access to a corresponding input and output port of the swatch core. A set of port adapters is distributed at different physical areas, with each connected switch fabrics via a particular SCAL element so that each switch core receives the sequence of cells coming from any port adapter and conversely any port adapter may receive cells from either one of the switch cores. Each switch fabric can detect an internal breakdown condition occurring in one of its element and send an error control signal to the peer element located in the other switch fabric. Each switch core extracts the Switch Routing Header (SRH) from the cells entering the switch core, and a routing table for obtaining a bit map value that indicates the output ports to which the cell should be routed. An additional controllable masking mechanism is used for altering the value of the bit map in response to the detection of the error control signal from the peer switch core. The routing process is then performed with the altered value of the bitmap.

Patent
01 Sep 1998
TL;DR: In this paper, a light-actuated photonic switch with a photogenerator that powers a micro-electromechanical system (MEMS) switch having very low voltage requirements is described.
Abstract: An article comprising a light-actuated photonic switch is disclosed. The light-actuated photonic switch advantageously includes a photogenerator that powers a micro-electromechanical systems (MEMS) switch having very low voltage requirements. The MEMS switch is operable to move a reflector into or out of a path of an optical signal travelling between two waveguides. Since the MEMS switch has such low voltage requirements, a long wave photogenerator, which generates relatively low voltages, can be used. As long wavelength light experiences relatively little attenuation in optical fiber, active lightwave circuits incorporating the present light-actuated photonic switch can have very long fiber runs to remote nodes.

Journal ArticleDOI
TL;DR: Performance issues-such as insertion loss, polarization dependence, pass band shape, passband position, crosstalk, and temperature dependence-are being addressed so that AWGs will be practical for deployment into systems.
Abstract: Wavelength routing can be performed in the optical domain for both long-haul and passive optical networks. Arrayed waveguide gratings (AWGs) can perform wavelength routing for a large number of optical channels and provide a high level of functionality on an integrated chip. The AWG guides light on a planar lightwave circuit into an array of waveguides that provide dispersion to separate the different wavelengths of light. Routing functions can be performed on individual wavelengths. With this technology, optical cross-connects, optical add/drop multiplexers, and passive optical routers have been demonstrated. Performance issues-such as insertion loss, polarization dependence, passband shape, passband position, crosstalk, and temperature dependence-are being addressed so that AWGs will be practical for deployment into systems.

Patent
Kiyoto Kobayashi1
15 May 1998
TL;DR: In this article, a change-over switch selects and switches an optical signal to which the trouble is detected, and the backup light source path 19 is controlled so that the wavelength thereof is substantially coincident with the wavelength of the optical signal in which the troubles are detected.
Abstract: In an output port switching device in an N-WDM system, plural ports are switched by a change-over switch 18 , and a backup light source path 19 linked to the change-over switch 18 has a wavelength-variable light source 23 . A first multiplexer 14 wavelength-multiplexes plural optical signals output from the plural ports, and a trouble-occurring port monitoring mechanism portion 17 monitors occurrence of a trouble on the basis of an optical signal split from the output optical signal. The change-over switch 18 selects and switches an optical signal to which the trouble is detected, and the backup light source path 19 is controlled so that the wavelength thereof is substantially coincident with the wavelength of the optical signal to which the trouble is detected, and the optical signal thus controlled and the output optical signals of the first multiplexer are multiplexed by a second multiplexer 15.

Patent
11 Sep 1998
TL;DR: In this paper, a waveguide substrate having at least two waveguides that intersect at a trench such that optical coupling is dependent upon the presence or absence of an index-matching fluid at the intersection of the waveguide with the trench is provided.
Abstract: A method of fabricating a switching element or a matrix of switching elements includes providing a waveguide substrate having at least two waveguides that intersect at a trench such that optical coupling between the waveguides is dependent upon the presence or absence of an index-matching fluid at the intersection of the waveguides with the trench. Fluid is supplied to the trench via a fluid fill-hole that extends through a heater substrate in a direction that is generally perpendicular to a substrate surface on which at least one heater is fabricated. In the preferred embodiment, the fluid fill-hole is formed in a step of inductively coupled plasma (ICP) reactive ion etching (RIE). The waveguide substrate having at least two waveguides and the heater substrate having the heaters and the fill-hole are bonded together after the substrates are aligned such that the trench is in fluid communication with at least one fluid fill-hole and is in thermal communication with at least one heater. Optical fibers are then coupled to the waveguides. Preferably, a structurally weakened edge portion is formed during the ICP RIE step so that the edge portion can be removed after the two substrates are bonded, allowing uninhibited access of the optical fibers to the waveguides.

Patent
04 Aug 1998
TL;DR: A bypass-exchange switch for switching the path of at least one optical signal includes a telecentric imaging device for high efficiency coupling of the optical signal into either of two outputs as mentioned in this paper.
Abstract: A bypass-exchange switch for switching the path of at least one optical signal includes a telecentric imaging device for high efficiency coupling of the optical signal into either of two outputs. The switch also includes an optical director for changing the operating mode of the switch from an exchange state to a bypass state wherein the different outputs are selected. The optical director is implemented as a variable reflectivity mirror, or a mechanically-actuated mirror. The switch may include a wavelength selective filter for permanently bypassing or exchanging preselected wavelengths of the optical signals.