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Optical selective switch based on silicon photonics offers the advantages of compactness, low power consumption and flexible data management in future optical communication networks. Multi-dimensional (mode, polarization, wavelength) multiplexing transmission has become increasingly important for capacity scaling, while the multi-dimensional selective switch is still full of challenges, especially the integrated solution. Here, we propose and demonstrate on-chip multi-dimensional $1\times \text{N}$ selective switch with simultaneous mode-, polarization- and wavelength-division multiplexing. The monolithic integration on a single silicon chip consists of building blocks of cascaded asymmetrical directional couplers for mode/polarization (de)multiplexing, cascaded microring resonators for wavelength (de)multiplexing, and cascaded thermal-tuning Mach-Zehnder interferometers for selective switching. A multi-dimensional $1\times 4$ selective switch chip on silicon platform is fabricated for proof-of-concept demonstration of simultaneous mode, polarization and wavelength selective switching. The inter-mode/inter-polarization crosstalk and intra-mode/inter-port crosstalk are characterized in the experiment, showing favorable performance with worst crosstalk values of −15.6 and −25.38 dB, respectively. The demonstrations may open up new perspectives for on-chip solutions to multi-dimensional optical signal processing for superior capacity scalable optical communication systems.

This paper outlines the design, performance and application of a highly-integrated stacked wavelength selective switching (WSS) technology platform based on 4k liquid crystal on silicon (LCOS) devices and two-dimensional (2D) beam steering.

A photonic integrated 1×2 Wavelength Selective Switch (WSS) based on a loopback configuration is shown to operate on the C and L-Bands due to the cyclic nature of the employed arrayed-waveguide gratings (AWGs). An average of -22.59 dB and -20.40 dB were observed in the C and L-band channels respectively. Crosstalk levels are kept below -40 dB on the output port A and below -30 dB on output port B. Experimental results on NRZ OOK data indicate a bit-error-rate (BER) below 1×10-11 with very limited penalty at both bands up to a bit rate of 30 Gbps.

A method for creating photorefractive electroholographic gratings with sustained operational longevity is presented and demonstrated. The method circumvents the thermal decay and erasure during readout characteristic of photorefractive devices by augmenting the device with a built-in mechanism that writes and periodically and/or continuously refreshes the space-charge gratings which are the core elements of such devices. The mechanism was demonstrated in a slab waveguide constructed in a KLTN:Cu crystal. The space-charge grating was created by illuminating the slab waveguide through a binary grating mask deposited on top of the surface of the crystal by incoherent illumination from a LED. The electroholographic performance manifested by the grating was similar to that of gratings constructed by interfering beams. This makes electroholography to be the basis for a viable technology for performing wavelength selective switching and electrical wavelength tuning at the device level, and enables their assembly in integrated photonic circuits.

Visible light-responsive reversible color switching systems are attractive to many applications since visible light has superior penetration and causes far less damages to organic molecules than UV. Here we report that self-doping of Sn2+ in SnO2-x nanocrystals red shifts their absorption to visible region and simultaneously produces oxygen vacancies, which can effectively scavenge photogenerated holes and thus enable color switching of redox dyes using visible light. Wavelength selective switching can also be achieved by coupling the photocatalytic activity of the SnO2-x NCs with the color switching kinetics of different redox dyes. The fast light response enables the further fabrication of a solid film that can be repeatedly written freehand using a visible laser pen or projection printing through a photomask. This discovery represents a big step forward towards practical applications, especially in areas with concerns on the safety and photodamage issues of UV light.

We report a configuration of an N-in-1 wavelength selective switch array utilizing on a spatial and planar optical circuit (SPOC) platform. We also demonstrate a novel wavelength crossconnect configuration that provides a simple optical connection.

A new solid-state Wavelength-Selective Switch (WSS) based on a Programmable Micro-Diffractive Grating (PMDG) fabricated over a Lithium-Niobate (LiNbO3) substrate is presented, and its operation described. The device consists of a periodic arrangement of ridge waveguides whose optical phase delay can be individually or collectively tuned through the electro-optics (Pockels) effect. Each waveguide is patterned with a metal electrode and connected to an external microprocessor-based driving unit. By appropriately programming the phase shift induced on each waveguide, the far-field diffraction pattern of the grating can be shaped in order to implement complex all-optical signal processing functions, such as 1-to-M demultiplexing, beam splitting, beam steering or wavelength-selective filtering. Once integrated within a telecommunications infrastructure, this component can clearly enhance the level of flexibility and robustness of the network optical physical layer.

In this letter, the light transfer promoted by long-period gratings (LPGs) inscribed in heterogeneous multicore fibers (HeMCFs) is theoretically analyzed. We determined the power evolution along the LPG in two different four-core HeMCFs. This letter demonstrates the selective switch of optical power between the identical cores of the HeMCFs with less than −40 dB of crosstalk to the other cores, regardless the position of the identical cores. The results show that the proposed technique can be used to produce inline selective core switching for multicore space division multiplexing.

100-GHz cross-cascaded arrayed waveguide gratings (AWGs)-based wavelength selective optical switching optical cross-connects (OXCs) modules with Mach-Zehnder interferometer (MZI) thermo-optic (TO) variable optical attenuator (VOA) arrays and optical true-time-delay (TTD) line arrays is successfully designed and fabricated using polymer photonic lightwave circuit. Highly fluorinated photopolymer and grafting modified organic-inorganic hybrid material were synthesized as the waveguide core and cladding, respectively. The one-chip transmission loss is ~6 dB and the crosstalk is less than ~30 dB for the transverse-magnetic (TM) mode. The actual maximum modulation depths of different thermo-optic switches are similar, ~15.5 dB with 1.9 V bias. The maximum power consumption of a single switch is less than 10mW. The delay time basic increments are measured from 140 to 20 ps. Proposed novel module is flexible and scalable for the dense wavelength division multiplexing network.

We investigate the performance of a chip-enhanced wavelength selective switch (EWSS) in multipass add/drop experiments. The demonstrated EWSS device uses a ring-assisted Mach–Zehnder interferometer chip as a wavelength interleaver, to preprocess the incoming super channel before launch into a commercial wavelength selective switch. We show that a 4% guardband, quadrature-phase-shift-keying encoded Nyquist wavelength division multiplexing super channel can successfully pass through seven EWSS nodes. We further investigate the number of reachable nodes with varied guardbands, showing that a modest increase in guardband can translate to a significant increase in the number of reachable EWSS nodes.

In the past three decades, the volume of global data traffic has been growing at an astonishing rate with little sign to slow down. In responding to this need, the backbone of the network for long distance data communication has evolved from all electrical based on copper wires or radio, mixed optical and electrical with optical fibers in data transportation and electronics in switches and end-nodes, to all optical in which information is kept in the optical domain throughout the network until it reaches its final destination. To make use of the vast bandwidth available, concurrency among multiple channels of optical transmission is necessary, and the wavelength division multiplexing (WDM) is the main technique in use. A wavelength selective switch (WSS) is able to route selectively individual WDM channels of any formats entering its input fibre port to any of the output fibre ports according to the optical configuration controlled via software by the service providers. Phase-only liquid crystal on silicon (LCOS) spatial light modulator (SLM) is currently the most flexible optical engine for WSSs, one of the key enabling technologies for software defined reconfigurable all optical networks. We will review the advantages of LCOS WSSs and the use of holographic wavefront modulation for advanced switching functionalities and delivery of the key performance matrix. We will then introduce a new stacked WSS architecture based on 2D beam steering, where multiple independent WSSs can be integrated on a single LCOS device with common optics. This approach can significantly reduce the cost, footprint and power consumption and allow the WSSs to be reconfigured as ultra-high port count switches or non-blocking wavelength cross-connects (WXCs). Finally, we will address how this stacked WSS architecture can be utilized to meet the optical switching demand in large-scale data centres.

We demonstrate the feasibility of an integrated fractional joint switching wavelength-selective-switch that is applicable for few-mode multicore fibers. The feasibility is verified using wavelength-swept insertion loss measurements and an evaluation of the bit-error-rate performance in experiments using 200 Gb/s spatial superchannel switching.

Cost-effective and tunable chromatic dispersion compensation in a fiber link are still an open issue in metro and access networks to cope with increasing costs and power consumption. Intrinsic chromatic dispersion compensation functionality of optical fractional orthogonal frequency division multiplexing is discussed and experimentally demonstrated using dispersion-tunable transmitter and receiver based on wavelength selective switching devices.

Transmission characteristics of a thermally tunable optical filter system composed of two 1D silicon–air photonic crystals with different periods have been explored by transfer matrix method. The proposed structure is capable of separating and switching unique wavelength channel without interfering with others amongst 11 equally spaced wavelength channels. Each channel has full width at half maximum of 1 nm as per the wavelength-division multiplexing standards developed by the International Telecommunication Union specifying channel spacing between the adjacent channels in terms of wavelength for wavelength-selective switching applications. The refractive index of silicon is known to be dependent on both temperature and wavelength. Thus, any change in the operating temperature of both photonic crystals by same amount causes their photonic band gaps to alter simultaneously and significantly in such a way as to switch the wavelength-division multiplexing channels one by one as per requirement. The working of the proposed filter system is dependent only on tuning the photonic band gaps and is completely different from the conventional photonic crystals with defect.

A wavelength selective switch (WSS) is proposed based on a Bragg reflector waveguide array, which has a footprint of only 2 × 6 mm2. We demonstrated arbitrary switching among 182 output ports by using a liquid crystal on silicon as a switching engine. The proposed WSS module length is only 10 cm, taking an advantage of the large angular dispersion in the Bragg reflector waveguide. Wavelength selective switching of 60 channels is carried out, exhibiting the device's excellent capability in providing ultra-large number of port count and wavelength channel operations at the same time. The crosstalk between adjacent ports are below –20 dB by a suitable alignment, which can be further improved by optimizing the module optics and alignments. The flexible lithography defined waveguide array design also reveals versatile potentials in integrating with other functional components.

A novel design of a single-channel thermally tunable photonic filter by cascading two one-dimensional (1D) superconductor-dielectric photonic crystals (SDPCs) through low loss silica fiber for wavelength selective switching (WSS) application is being presented theoretically. This filter is capable to separate and switch unique wavelength channel (without interfering with each other) from 12 equally spaced wavelength channels adopted by the International Telecommunication Union (ITU). It may be used in wavelength division multiplexing (WDM)-based optical networks for routing signals at specific wavelengths into an optical fiber with minimum distortion. This idea may also be explored in the design of very precise thermal sensing devices for remote sensing applications.

We achieved a reconfigurable inter-core signal switching using directional bending of long period grating in multicore fibers. Wavelength selective switching of 6×224 Gb/s OFDM signals in 3 cores is experimentally demonstrated.

Mode multiplexed communication channels may incur mixing in transmission, hence must be routed as an inseparable entity per wavelength. We review wavelength-selective switch designs to fulfill this role based on spatial diversity or multimode beams.

Design based routing (DBR) is originally proposed for wavelength division multiplexing (WDM) networks with the objective to minimize the total link cost subject to the constraints based on traffic demands in terms of the maximum acceptable end-to-end blocking probability. In DBR, optimized routing is computed off-line based on prior information on traffic demand statistics, and are utilized for on-line routing of dynamic lightpath requests. However, the integer linear programming (ILP) formulation of DBR allocates, on each link, dedicated portions of the link capacity to utilizing source-destination (s-d) pairs without considering the effects of statistical multiplexing. The lack of consideration of the multiplexing gain on transmission links leads to an unnecessary limitation on the applicability of DBR in networks with high traffic loads from a large number of s-d pairs. In such traffic scenarios, the ILP problem of DBR can become infeasible even though the traffic can still be supported without violating the blocking probability constraint. In this paper, we provide an alternative approach to DBR, referred to as link-based DBR (LDBR), by considering the multiplexing gain on each link. Unlike the ILP formulation for DBR, which imposes constraints on end-to-end blocking probabilities, the blocking probability constraints for LDBR are imposed on individual links with the end-to-end blocking probabilities estimated using the union bound. Compared to DBR, LDBR is attractive when individual links carry traffic from a large number of s-d pairs since there are a lot of opportunities for utilizing the multiplexing gain. Simulation results demonstrate that, subject to the same end-to-end blocking probability constraints, the proposed LDBR can extend the applicability of DBR to higher traffic loads when there are a lot of active s-d pairs, which are expected in typical backbone networks.

A reconfigurable WDM–OFDM–PON employing a WSS as a remote node is proposed. The system, which employs an optical comb source at the transmitter, is shown to support both spectrally efficient SSB-OFDM and high bit rate DDO-OFDM. Transmission over 30 km of SSMF is performed and we show that DDO-OFDM with a virtual carrier offers three times the data rate for similar receiver sensitivities and the same DAC. A raw data rate of 31.25 Gb/s/ λ is achieved in the case where DDO-OFDM is employed.

Most of the present communication applications have switched onto the photonic filtering as it gives numerous advances over its counterparts. Reconfigurable filter design is gaining popularity for applications having complex hardware circuitry. The paper discusses about a reconfigurable optical filter by Wavelength Selective Switching using Liquid Crystal on Silicon technology for filtering of Radio and Microwave frequency signals. The main aim of the work is to explore the feasibility of usage of photonic filters along with fiber links in radar signal distribution networks.

We present wavelength selective switching with a rise time of 25 ns implemented in a slab waveguide constructed in a KLTN:Cu crystal. The waveguide was fabricated by implantations of alpha particles at 2.1 MeV which produced a 0.5 μm thick cladding layer with reduced refractive index at 4.5 μm underneath the crystal surface. This demonstrates the feasibility of implementing electroholography in waveguides maintaining the performance obtained in bulk crystals, providing in potential the basis for constructing integrated photonic circuits which incorporate interconnected electroholographic wavelength selective switches and electrical wavelength tuning devices for employing wavelength addressing routing schemes in computer networks, in particular for relieving the bandwidth bottlenecks in data center networks.

Among several optical devices, fundamental characteristics and processing systems of collinear optical switching device have been studied about optical dielectric waveguides on LiNbO3 crystal substrates. Conventional waveguide-type A-O devices use collinear interaction with mode coupling based on Bragg condition between optical waves and SAW both propagating in same directions. Collinear A-O devices of waveguide-type show sufficient performance for wavelength selective switching with narrow bandwidths in case of low switch speed. However, in these collinear A-O devices, since SAW propagation speed is very slow, interaction time is several micro seconds for 10mm waveguide device length.

WSS (wavelength selective switching) has become the preferred technology for constructing hybrid electronic/optical data center networks, in which bursty data are sent through an electronic packet network and bulk data are sent through an optical circuit network. In this paper we develop theory and methods that can make such a distributed WSS network nonblocking.

A new approach to design digitally tunable optical fllter system by using semiconductor optical ampliflers (SOAs) and Dense Wavelength Division Multiplexed (D.W.D.M.) thin fllm fllter based wavelength selection elements is presented. The system designed with this approach is very easy to conflgure and expand, smaller in size, lesser in weight, cheaper in cost and consuming less power as compared to design suggested by other researchers recently.

The gain spectrum of an Erbium Doped Fiber Amplifier (EDFA) has a peak centered at 1532nm and a broad peak with relatively low gain centered at 1550nm. In many applications like soliton based systems which makes use of EDFA repeaters and Dense Wavelength Division Multiplexing (DWDM) systems where EDFA is used for amplifying a large number of wavelengths, gain fluctuations in EDFA has to be confined within specified limits over a wide span of wavelengths. Many methods of gain stabilization in EDFA has already been proposed in the recent past. In our work, we propose a novel method for gain contouring and output power stabilization in Erbium Doped Fiber Amplifiers. The amplifier with gain control is designed and simulated. The flattening of gain spectrum of EDFA is achieved by photonic switching using Optical Add Drop Multiplexers (OADM) and Fiber Bragg Gratings (FBG). The stabilization of gain and output power of EDFA is also experimentally verified. In the proposed feedforward technique, the output power stabilization is achieved by proper selection of modulator parameters.

A simple design of thermally tunable single channel optical filter is suggested by using transfer matrix method (TMM) at normal incidence. This filter is composed of one-dimensional photonic crystal with low temperature superconductor defect for switching optical communication wavelengths used in coarse wavelength division multiplexing (CWDM) based optical networks. It is capable of selecting and switching any one wavelength channel at a time centered at particular wavelength out of 9 CWDM wavelength channels as per the international telecommunication union (ITU) grid G.694.2. Though the spectral width of each channel of conventional CWDM channels should be between 13-15 nm, the spectral width of the defect mode of the proposed thermally tunable optical filter varies from 3-6 nm. Thus it makes the contraption to be used efficiently for narrowband wavelength selective switching (WSS) application. Such filters have potential applications in remote sensing and thermal imaging.

Orthogonal time-frequency domain multiplexing (OTFDM) enables ultra-wideband high-spectral-efficiency multicarrier transmission without relying on optical filters for multiplexing/demultiplexing of subchannels. Impact of tight filtering on OTFDM signal is investigated, assuming bandwidth narrowing in wavelength-selective switching networks.

A novel design of a two-bus coupled-rings 2 × 2 switch with inter-ring coupling enabled by a three-waveguide (3w) directional coupler is proposed. The device is analyzed using a theoretical model based on coupled mode theory and optical transfer formulae. We show that injected free-carriers tuning of the central waveguide in the 3w coupler affects only the bonding resonance mode while the other anti-bonding mode is transparent. This feature can be used to perform selective optical switching, and a numerical design example is given on the silicon photonics platform. The selective switch can be employed in a two-color duplex bidirectional communication system which conveniently separates the simultaneous transmitted and received signals in a single fiber-optic waveguide.

Optical transport capacities have grown significantly in the last decade to meet the increased demands on communications networks. This growth has been achieved both by increases in individual channel rates, which are based on time division multiplexing (TDM), and by increased channel counts, through the use of dense wavelength division multiplexing (DWDM). Yet increasing optical transport capacity alone is insufficient to scale the network; the underlying data needs to be delivered from numerous geographically diverse originating locations to similarly diverse terminating locations, requiring increasing switching capacity to facilitate this networking need. Since the growth in the individual TDM channel rates is driven by the capabilities of electronics, it is reasonable to expect that the switching capacity of electronics will tend to track this trend, although because of the challenges in high data rate interconnects it is unlikely to exceed it. This leaves the challenge of managing the increased bandwidth attained through the use of DWDM. Management of this bandwidth in the optical layer is an attractive proposition if eliminating unnecessary high-speed electronics in the path of an optical signal can reduce the complexity of the network and the associated equipment costs. These optical bandwidth management elements are classified according to the degree of switching, as either reconfigurable optical add/drop multiplexers (ROADM) or wavelength selective cross-connects (WSXC), analogous to the add/drop multiplexers and digital cross-connects of the TDM domain. We generalize these elements and describe whether the switching provides functions that are multicolored, colorless, or colored, and whether the channels are fixed data rate or rateless. We review the wavelength selective switch (WSS) components that perform the necessary switching function and present two successful technology platforms that can be used to construct them: planar lightwave circuits (PLC) and micro-electromechanical systems (MEMS). We also discuss future directions for WSS technologies and device functionality to more flexibly manage bandwidth in the optical layer.

We propose a new optical switch that can enable wavelength-selective high-speed switching for applications to photonic wavelength-division multiplexing (WDM) Internet protocol (IP) packet routing. The switch utilizes characteristics of waveguide-type Raman amplifiers and 3-dB couplers, and so it operates all-optically at a few tens of picosecond or faster speed. The operation of the switch is studied by coupled-mode theory and is verified numerically using a beam-propagation method (BPM). As a result, we found that optical waves having arbitrary wavelengths among those of incident WDM waves are amplified and switched when the amplification rate of each waveguide-type Raman amplifier is set to the proper value by pump wave injection. Moreover, the dynamic range over 30 dB was also obtained from the simulation results of the switch.

This paper provides an overview of OFC 2003 Workshop on Wavelength Selective Switching Based Optical Networks, from the perspective of the co-organizers. The Workshop was held on Monday 24 March 2003.

We proposed a resource sharing architecture for cloud radio access network based on wavelength selective switching and parallel uplink signal detection, which features flexible resource allocation and efficient resource saving for bidirectional fronthaul transmission.

The principles of optical communication systems are being increasingly used for accomplishing long-haul transmission as well as higher data rate transmission. Although, the optical networking is being in used, but it encounters various research issues, especially when the crowd of the traffic is abnormal. Hence, a problem has been identified which states that it is quite challenging to model the dynamic traffic scenario and difficult to analyse the impact of the abnormal and uncertain traffic scene on performance of optical network. The proposed system introduces a routing technique called as ORPT i.e. Optimal Routing in Peak Traffic that uses the enhanced modelling of Reconfigurable Optical Add/Drop Multiplexer (ROADM), Wavelength Selective Switching (WSS), and Optical Burst Switching (OBS). The benchmarked outcome of the technique is evaluated using Average request blocking with respect to traffic load.

A multichannel optical wavelength selective switch is investigated, which can switch signals at arbitrary wavelengths between multichannels in wavelength division multiplexing systems. It is based on the combination of an arrayed-waveguide grating (AWG) multiplexer and an array of optical space-division switches. A monolithically integrated 2/spl times/2 optical wavelength selective switch is successfully fabricated for four multiplexed signals in the 1.55 /spl mu/m wavelength region. Here, an AWG and four 2/spl times/2 thermooptic switches are laid out on a 30/spl times/60 mm/sup 2/ chip. Wavelength selective switching operations for four wavelength signals between two lines are demonstrated in a time slot of 40 ms with a switching speed of 1 ms.

We present an enhanced n-ary, 2 flat distributed optical switching architecture for intra-DC interconnection which using existing WSS components. The proposed architecture is highly scalable, topology adaptive and suitable for dynamic and diverse traffic pattern.

Optical switching of high-bit-rate QPSK pulse trains using collinear acoustooptic (AO) devices is theoretically discussed. Since the collinear AO devices have wavelength selectivity, the switched optical pulse trains suffer from distortion when the bandwidth of the pulse train is comparable to the pass bandwidth of the AO device. As the AO device, a sidelobe-suppressed device with a tapered surface-acoustic-wave (SAW) waveguide and a Butterworth-type filter device with a lossy SAW directional coupler are considered. Phase distortion of optical pulse trains at 40 to 100 G symbol/s in quadrature phase-shift-keying format is numerically analyzed.

A theoretical study of temperature dependent tuning of defect mode inside photonic bandgap of one-dimensional photonic crystal with binary defect for optical communication applications based on coarse wavelength division multiplexing (CWDM) is presented. The transmission properties of the proposed structure are investigated through the transfer matrix method (TMM) at normal incidence. The proposed contraption is capable of selecting and switching any one wavelength channel at a time centered at particular wavelength out of 12 CWDM channels as per the international telecommunication union (ITU) grid G.694.2. It is very useful for narrowband wavelength selective switching (NWSS) applications based on CWDM. This study also provides some insight to design new kind of thermally tunable optical filters which can be used effectively in remote sensing and thermal imaging applications.

We report on Fabry-Perot (FP) filters based on silicon cylindrical Bragg reflectors. Such filters exhibit unusual periodicity of the spectral response due to transverse resonance modes. The optical microcavities are also unusually long (L>210µm) while maintaining reasonably high quality factors (Q), above 1000. The presented device behaves as a mode-selective filter wherein the excited mode is controlled by varying the excitation wavelength. The device can also be used as a wavelength-selective MEMS switch, with extinction ratio of 7∶1. Cavities with different radii of curvature have been evaluated experimentally, their corresponding Q-factors and effective cavity lengths (L eff ) have been determined.

Spatial light modulators based around liquid crystal on silicon have found use in a variety of telecommunications applications, including the optimization of multimode fibers, free-space communications, and wavelength selective switching. Ferroelectric liquid crystals are attractive in these areas due to their fast switching times and high phase stability, but the necessity for the liquid crystal to spend equal time in each of its two possible states is an issue of practical concern. Using the highly parallel nature of a graphics processing unit architecture, it is possible to calculate DC balancing schemes of exceptional quality and stability.

Polarization-independent wavelength path switching is demonstrated with one-chip silicon photonic circuit including 64 thermo-optical switch elements within 12mm × 3mm. Owing to uniformity, any path can be constructed by simply turning on one switch element.

The analysis of the gain behaviour in active GaInNAs–GaInAs Photonic Band Gap (PBG) ridge waveguides is reported. The analysis is performed using proprietary codes, based on the Bidirectional Beam Propagation Method with the Method of Lines, introducing the rate equations. The bandstructure of the active material is modelled using the k · p theory for the valence band mixing effects and the band anticrossing model for the conduction band. A wavelength selective switch configuration is proposed exploiting a periodic grating patterned on a ridge waveguide in which an active defect is inserted. The presence of the active defect allows the localization of states and the transmission of the optical signal within the PBG. The wavelength selective switching mechanism stems from the possibility of shifting the wavelength of the localized state by properly choosing the defect length and the injected current density. From the numerical analysis, the proposed device exhibits, at the switching wavelength λB = 1.289 µm, good values of the crosstalk CT = −11.55 dB, the contrast ratio CR = 14.29 dB, the modulation depth MD = 0.93, and the bandwidth Δλ = 0.8 nm.

An active optical switch based on the InGaAsP/InP photonic bandgap (PBG) buried waveguide is proposed. The device, which is made of a periodic grating patterned on a buried waveguide, exploits the localization of states in the PBG induced by the presence of an active defect. The wavelength of the localized state can be shifted by properly choosing the defect length and the injected current density in order to achieve a wavelength-selective switching behavior. Proprietary codes based on the bidirectional beam propagation method and the method of lines (BBPM-MoL) were used for the simulations of the optical device taking into account the rate equations to model the interaction between the optical signal and the active medium. Design curves are provided and parameterized to give general design rules. From the numerical analysis, the proposed device exhibits good theoretical performances in terms of crosstalk (CT < -20 dB), modulation depth (MD >0.9), response time (in the subnanosecond range), and maximum size (

Wavelength-selective processing of optical high-bit-rate WDM pulses is a key function in photonic routers. Switching characteristics of short pulses with weighted acoustooptic devices are discussed with simulation results.