Showing papers on "Multiplexer published in 2013"
TL;DR: A novel on-chip two-mode division multiplexing circuit using a tapered directional coupler-based TE(0)&TE(1) mode multiplexer and demultiplexer on the silicon-on-insulator platform is demonstrated.
Abstract: We demonstrate a novel on-chip two-mode division multiplexing circuit using a tapered directional coupler-based TE(0)&TE(1) mode multiplexer and demultiplexer on the silicon-on-insulator platform. A low insertion loss (0.3 dB), low mode crosstalk (< -16 dB), wide bandwidth (~100 nm), and large fabrication tolerance (20 nm) are measured. An on-chip mode multiplexing experiment is carried out on the fabricated circuit with non return-to-zero (NRZ) on-off keying (OOK) signals at 40 Gbit/s. The experimental results show clear eye diagrams and moderate power penalty for both TE(0) and TE(1) modes.
373 citations
TL;DR: A fabricated mode (de)multiplexer with cascaded asymmetrical directional couplers with low excess loss as well as low crosstalk over a broad wavelength range (~20 nm) is demonstrated experimentally.
Abstract: A small silicon mode (de)multiplexer with cascaded asymmetrical directional couplers is demonstrated experimentally. As an example, a four channel mode (de)multiplexer is designed and realized for TM polarization. The fabricated mode (de)multiplexer has a low excess loss (<1 dB) as well as low crosstalk (≤23 dB) over a broad wavelength range (~20 nm). More channels can be achieved with two sets of orthogonal-polarization modes (e.g., 2N=8) multiplexed when desired.
349 citations
IBM1
TL;DR: 1-to-8 wavelength (de-)multiplexer devices based on a binary tree of cascaded Mach-Zehnder-like lattice filters, and manufactured using a 90 nm CMOS-integrated silicon photonics technology, demonstrate that they combine a flat pass-band over more than 50% of the channel spacing with low insertion loss.
Abstract: We present 1-to-8 wavelength (de-)multiplexer devices based on a binary tree of cascaded Mach-Zehnder-like lattice filters, and manufactured using a 90 nm CMOS-integrated silicon photonics technology. We demonstrate that these devices combine a flat pass-band over more than 50% of the channel spacing with low insertion loss of less than 1.6 dB, and have a small device size of approximately 500 × 400 µm. This makes this type of filters well suited for application as WDM (de-)multiplexer in silicon photonics transceivers for optical data communication in large scale computer systems.
319 citations
TL;DR: A simple and low-crosstalk 1 × 4 silicon mode (de)multiplexer based on multimode grating-assisted-couplers is proposed, which can be flexibly controlled by designing the grating period at the phase-matching condition.
Abstract: A simple and low-crosstalk 1 × 4 silicon mode (de)multiplexer based on multimode grating-assisted-couplers is proposed. Mode transitions can be flexibly controlled by designing the grating period at the phase-matching condition. Due to the contra-directional coupling, precise control of the coupling strength and the coupling length are not needed in the system. Calculation results show that the insertion loss and the 3 dB bandwidths of the device are 0.2 dB and 3.7 nm, 0.34 dB and 7.6 nm, and 0.21 dB and 11.8 nm for the channels which (de)multiplex to the 1st, 2nd, and 3rd modes of the bus waveguide, respectively.
162 citations
TL;DR: A two-mode (de)multiplexer based on adiabatic couplers that is fabrication-tolerant, and the insertion loss can be further improved in the future.
Abstract: A two-mode (de)multiplexer based on adiabatic couplers is proposed and experimentally demonstrated. The experimental results are in good agreement with the simulations. An ultralow mode cross talk below -36 dB and a low insertion loss of about 0.3 dB over a broad bandwidth from 1500 to 1600 nm are measured. The design is also fabrication-tolerant, and the insertion loss can be further improved in the future.
145 citations
TL;DR: In this article, a high-dimensional quantum key distribution (QKD) protocol that employs temporal correlations of entangled photons is proposed, which relies on measurements by Alice and Bob in one of two conjugate bases, implemented using dispersive optics.
Abstract: We propose a high-dimensional quantum key distribution (QKD) protocol that employs temporal correlations of entangled photons. The security of the protocol relies on measurements by Alice and Bob in one of two conjugate bases, implemented using dispersive optics. We show that this dispersion-based approach is secure against collective attacks. The protocol, which represents a QKD analog of pulse position modulation, is compatible with standard fiber telecommunications channels and wavelength division multiplexers. We describe several physical implementations to enhance the transmission rate and describe a heralded qudit source that is easy to implement and enables secret-key generation at $g4$ bits per character of distilled key across over 200 km of fiber.
139 citations
TL;DR: In this paper, a review and discussion on multimode photonic integrated devices for mode-multiplexed optical-interconnects is presented, where light propagation and mode conversion in tapered waveguides are discussed.
Abstract: Multimode spatial-division multiplexing (SDM) technol- ogy has attracted much attention for its potential to enhance the ca- pacity of an optical-interconnect link with a single wavelength car- rier. For a mode-multiplexed optical-interconnect link, the functional elements are quite difierent from the conventional ones as multiple modes are involved. In this paper we give a review and discussion on multimode photonic integrated devices for mode-multiplexed optical- interconnects. Light propagation and mode conversion in tapered waveguides as well as bent waveguides are discussed flrst. Recent progress on mode converter-(de)multiplexers is then reviewed. The demands of some functional devices used for mode-multiplexed optical- interconnects are also discussed. In particular, the fabrication toler- ance is analyzed in detail for our hybrid demultiplexer, which enables mode-/polarization-division-(de)multiplexing simultaneously.
120 citations
TL;DR: A mode-(de)multiplexer with low loss and large spectral bandwidth is proposed, designed by utilizing a structure with cascaded asymmetric Y-junctions, where the fundamental mode of a narrow arm excites the higher-order mode of its stem in the multiplexing case.
Abstract: A mode-(de)multiplexer with low loss and large spectral bandwidth is proposed. The device is designed by utilizing a structure with cascaded asymmetric Y-junctions. By carefully controlling the widths of the wide and narrow arms of the Y-junctions, the fundamental mode of a narrow arm excites the higher-order mode of its stem in the multiplexing case, and a high-order mode of the stem separated from other lower-order modes evolves into the fundamental mode of the narrow arm in the demultiplexing case. As an example, a 1 × 4 mode-(de)multiplexer is analyzed by using the beam propagation method. Simulation results show the demultiplexed crosstalk is lower than –21.8 dB, under a common spectral bandwidth of 140 nm. The insertion loss is negligible.
113 citations
TL;DR: In this paper, the authors demonstrate compact silicon-on-insulator-based arrayed waveguide gratings for (de)multiplexing applications with a large free spectral range (FSR).
Abstract: We demonstrate compact silicon-on-insulator-based arrayed waveguide gratings (AWGs) for (de)multiplexing applications with a large free spectral range (FSR). The large FSR is obtained by reducing the arm aperture pitch without changing the device footprint. We demonstrate 4×100 GHz, 8×250 GHz, and 12×400 GHz AWGs with FSRs of 6.9, 24.8, and 69.8, respectively. We measured an insertion loss from −2.45 dB for high to −0.53 dB for low-resolution AWGs. The crosstalk varies between 17.12 and 21.37 dB. The bandwidth remains nearly constant, and the nonuniformity between the center wavelength channel and the outer wavelength channel improves with larger FSR values.
93 citations
TL;DR: In this paper, the authors presented two novel multiplexer topologies based on all-resonator structures, which remove the need for conventional transmission-line-based splitting networks.
Abstract: This paper presents two novel multiplexer topologies based on all-resonator structures. Such all-resonator structures remove the need for conventional transmission-line-based splitting networks. The first topology is a diplexer with transmission zeros in the guard band, shared by both channels. These transmission zeros are generated by introducing a cross coupling in a quadruplet in resonators common to both channels. A twelfth-order diplexer with a pair of transmission zeros is presented here as an example. The second topology is a multiplexer with a bifurcate structure that limits the connections to any resonator to three or less, regardless of the number of output channels. A sixteenth-order four-channel multiplexer is presented as an example. Both topologies have been demonstrated at X-band using waveguide technology. Good agreements between measurements and simulations have been achieved.
86 citations
TL;DR: It is shown how a spatial mode can be extracted from a light beam, leaving the other orthogonal modes undisturbed, and allowing a new signal to be retransmitted on that mode, allowing reconfiguration without interrupting the transmission of any channel.
Abstract: We show how a spatial mode can be extracted from a light beam, leaving the other orthogonal modes undisturbed, and allowing a new signal to be retransmitted on that mode. The method is self-aligning, avoids fundamental splitting losses, and uses only local feedback loops on controllable beam splitters and phase shifters. It could be implemented with Mach-Zehnder interferometers in planar optics. The method can be extended to multiple simultaneous mode extractions. As a spatial reconfigurable optical add-drop multiplexer, it is hitless, allowing reconfiguration without interrupting the transmission of any channel.
Patent•
28 Jun 2013TL;DR: In this article, a dual 4×4 multiplexer is adapted to selectively couple any one of the antennas to any plurality of RF switching ports, and an RF switch matrix is coupled between the antenna ports and the RF front end ports.
Abstract: Radio frequency (RF) front end circuitry includes one or more antenna ports, one or more RF switching ports, and an RF switch matrix coupled between the antenna ports and the RF front end ports. The RF switch matrix comprises a dual 4×4 multiplexer, and is adapted to selectively couple any one of the antennas to any one of the plurality of RF switching ports.
Patent•
13 Mar 2013TL;DR: In this paper, a circuit architecture for a sensing component of a Light Detection and Ranging (LIDAR) device can provide a wide dynamic range, which includes at least one photosensor, each photosensor including an input that is configured to receive an optical signal; a respective diode corresponding to each photo sensor, each corresponding diode including an output that is coupled to an output of the corresponding photosensor; a multiplexer including the input and output of each of the photosensors; and an amplifier including the inputs and outputs of the multiplexers.
Abstract: A circuit architecture for a sensing component of a Light Detection and Ranging (LIDAR) device can provide a wide dynamic range. The circuit architecture includes at least one photosensor, each photosensor including an input that is configured to receive an optical signal; a respective diode corresponding to each photosensor, each respective diode including an input that is coupled to an output of the corresponding photosensor; a multiplexer including an input that is coupled to the output of each of the at least one photosensors; and an amplifier including an input that is coupled to the output of the multiplexer.
TL;DR: In this article, a novel silicon photonic integrated circuit enabling multiplexing of orthogonal modes in a few-mode fiber (FMF) was proposed and demonstrated by selectively launching light to four vertical grating couplers.
Abstract: We propose and demonstrate a novel silicon photonic integrated circuit enabling multiplexing of orthogonal modes in a few-mode fiber (FMF). By selectively launching light to four vertical grating couplers, all six orthogonal spatial and polarization modes supported by the FMF are successfully excited independently.
TL;DR: A divide-and-conquer Synthetic Biology Reusable Optimization Methodology (SBROME) is proposed, which successfully applied SBROME toward two alternative designs of a modular 3-input multiplexer that utilize pre-existing logic gates and characterized biological parts.
Abstract: The development of a scalable framework for biodesign automation is a formidable challenge given the expected increase in part availability and the ever-growing complexity of synthetic circuits. To allow for (a) the use of previously constructed and characterized circuits or modules and (b) the implementation of designs that can scale up to hundreds of nodes, we here propose a divide-and-conquer Synthetic Biology Reusable Optimization Methodology (SBROME). An abstract user-defined circuit is first transformed and matched against a module database that incorporates circuits that have previously been experimentally characterized. Then the resulting circuit is decomposed to subcircuits that are populated with the set of parts that best approximate the desired function. Finally, all subcircuits are subsequently characterized and deposited back to the module database for future reuse. We successfully applied SBROME toward two alternative designs of a modular 3-input multiplexer that utilize pre-existing logic ...
TL;DR: The evolvable hardware system, fully contained in an FPGA, which is capable of autonomously generating digital processing circuits, implemented on an array of processing elements (PEs) is presented, a step toward fully autonomous, adaptive systems.
Abstract: This paper presents an evolvable hardware system, fully contained in an FPGA, which is capable of autonomously generating digital processing circuits, implemented on an array of processing elements (PEs). Candidate circuits are generated by an embedded evolutionary algorithm and implemented by means of dynamic partial reconfiguration, enabling evaluation in the final hardware. The PE array follows a systolic approach, and PEs do not contain extra logic such as path multiplexers or unused logic, so array performance is high. Hardware evaluation in the target device and the fast reconfiguration engine used yield smaller reconfiguration than evaluation times. This means that the complete evaluation cycle is faster than software-based approaches and previous evolvable digital systems. The selected application is digital image filtering and edge detection. The evolved filters yield better quality than classic linear and nonlinear filters using mean absolute error as standard comparison metric. Results do not only show better circuit adaptation to different noise types and intensities, but also a nondegrading filtering behavior. This means they may be run iteratively to enhance filtering quality. These properties are even kept for high noise levels (40 percent). The system as a whole is a step toward fully autonomous, adaptive systems.
TL;DR: In this paper, a multiplexer is used to contact an array of 256 split gates on a GaAs/AlGaAs heterostructure, in which each split gate can be measured individually, leading to the appearance of conductance plateaux at intervals of 2e2/h.
Abstract: We present a multiplexing scheme for the measurement of large numbers of mesoscopic devices in cryogenic systems. The multiplexer is used to contact an array of 256 split gates on a GaAs/AlGaAs heterostructure, in which each split gate can be measured individually. The low-temperature conductance of split-gate devices is governed by quantum mechanics, leading to the appearance of conductance plateaux at intervals of 2e2/h. A fabrication-limited yield of 94% is achieved for the array, and a “quantum yield” is also defined, to account for disorder affecting the quantum behaviour of the devices. The quantum yield rose from 55% to 86% after illuminating the sample, explained by the corresponding increase in carrier density and mobility of the two-dimensional electron gas. The multiplexer is a scalable architecture, and can be extended to other forms of mesoscopic devices. It overcomes previous limits on the number of devices that can be fabricated on a single chip due to the number of electrical contacts avai...
Patent•
01 Jul 2013TL;DR: In this paper, a system, methods and apparatus that facilitate transmission of data, particularly between two devices within an electronic apparatus, is described, where data is selectively transmitted as N-phase polarity encoded symbols or as packets on differentially driven connectors.
Abstract: A system, methods and apparatus are described that facilitate transmission of data, particularly between two devices within an electronic apparatus. Data is selectively transmitted as N-phase polarity encoded symbols or as packets on differentially driven connectors. A desired operational mode for communicating between the two devices is determined, an encoder is selected to drive a plurality of connectors communicatively coupling the two devices, and a plurality of drivers are configured to receive encoded data from the encoder and drive the plurality of connectors. Switches may couple outputs of the selected encoder to the plurality of drivers. One or more outputs of another encoder may be caused or forced to enter a high impedance mode.
02 May 2013
TL;DR: In this article, a hybrid multiplexing technology combining polarization multiple-and mode multiple-multiplexing is presented to expand the capacity of photonic networks-on-chip by 2N times with a multimode optical waveguide which supports 2N guided-modes.
Abstract: Hybrid multiplexing technology combining polarization multiplexing and mode multiplexing is presented to expand the capacity of photonic networks-on-chip by 2N times with a multimode optical waveguide which supports 2N guided-modes. Only one laser diode is needed for such a multiplexing system. A novel mode-(de)multiplexer with low excess-loss and low crosstalk is proposed by utilizing a structure with cascaded asymmetrical directional couplers. A 1×4 mode-(de)multiplexer is designed as an example. It is possible to achieve more channels (e.g., 2N=16) with two orthogonal polarizations. When an array of high-speed optical modulators (e.g., 70Gbps) is integrated, the total capacity of an on-chip photonic link can be over 1Tbps with a single-wavelength-carrier light.
11 Feb 2013
TL;DR: This work proposes that a virtual overlay network is built to multiplex all on-chip signals to all on -chip trace-buffers, and shows that any subset of on- chip signals can be connected to 80-90% of the maximum trace-buffer capacity in less than 50 seconds.
Abstract: The rising complexity of verification has led to an increase in the use of FPGA prototyping, which can run at significantly higher operating frequencies and achieve much higher coverage than logic simulations. However, a key challenge is observability into these devices, which can be solved by embedding trace-buffers to record on-chip signal values. Rather than connecting a predetermined subset of circuits signals to dedicated trace-buffer inputs at compile-time, in this work we propose that a virtual overlay network is built to multiplex all on-chip signals to all on-chip trace-buffers. Subsequently, at debug-time, the designer can choose a signal subset for observation. To minimize its overhead, we build this network out of unused routing multiplexers, and by using optimal bipartite graph matching techniques, we show that any subset of on-chip signals can be connected to 80-90% of the maximum trace-buffer capacity in less than 50 seconds.
TL;DR: In this paper, the scaling factor for relating coupling value M to its corresponding impedance inverter K in a stepped cavity is derived for full-wave EM design, and four design examples are presented.
Abstract: A stepped circular waveguide dual-mode (SCWDM) filter is fully investigated in this paper, from its basic characteristic to design formula. As compared to a conventional circular waveguide dual-mode (CWDM) filter, it provides more freedoms for shifting and suppressing the spurious modes in a wide frequency band. This useful attribute can be used for a broadband waveguide contiguous output multiplexer (OMUX) in satellite payloads. The scaling factor for relating coupling value M to its corresponding impedance inverter K in a stepped cavity is derived for full-wave EM design. To validate the design technique, four design examples are presented. One challenging example is a wideband 17-channel Ku-band contiguous multiplexer with two SCWDM channel filters. A triplexer hardware covering the same included bandwidth is also designed and measured. The measurement results show excellent agreement with those of the theoretical EM designs, justifying the effectiveness of full-wave EM modal analysis. Comparing to the best possible design of conventional CWDM filters, at least 30% more spurious-free range in both Ku-band and C-band can be achieved by using SCWDM filters.
TL;DR: In this paper, a network-embedded colorless self-tuning transmitter for WDM networks is experimentally demonstrated from 2.5- up to 10.7-Gb/s data rates.
Abstract: The operation of a network-embedded colorless self-tuning transmitter for WDM networks is experimentally demonstrated from 2.5- up to 10.7-Gb/s data rates. Colorless operation is achieved by self-seeding an ultra-fast reflective semiconductor optical amplifier (RSOA) with the feedback signal reflected at the WDM multiplexer filter. In particular, the transmitter exploits a 2-Faraday rotators configuration to ensure polarization insensitive operation and allowing for the exploitation of high gain RSOAs, which can be designed to operate on a single polarization. The impact on the transmission of the fiber chromatic dispersion at different bit-rates and with different channel bandwidths of the WDM multiplexer filter is experimentally investigated up to 10.7 Gb/s. The tolerance to positive and negative dispersive loads is also assessed.
TL;DR: In this paper, the multiplexing and demultiplexing of the spatial modes of few-mode fiber is demonstrated using few-core couplers, and mode combination/separation is achieved through mode-selective evanescent coupling.
Abstract: The multiplexing and demultiplexing of the spatialmodes of few-mode fiber is demonstrated using few-core couplers. The mode combination/separation is achieved through mode-selective evanescent coupling. In particular, multiplexers/demultiplexers for three fiber modes are simulated that use either circular (fiber) or rectangular (planar) cores. The demultiplexing can be made independent of the spatial-orientations of the fiber modes by judicious choice of core configuration.
26 Aug 2013
TL;DR: This work examines the potential benefits of using flexible-grid ROADMs and compares this approach with alternative strategies, and discusses the technologies required to enable flexible- grid networks.
Abstract: Due to claims of enhanced spectral efficiency and the ability to accommodate future modulation formats, flexible-grid networks in which the center wavelength and passband width of the optical channels can be set on the fly have attracted wide attention. A flexible-grid reconfigurable optical add/drop multiplexer (ROADM) requires more than a flexible-grid wavelength-selective switch, and a flexible-grid network requires far more than flexible-grid ROADMs. We discuss the technologies required to enable flexible-grid networks. We examine the potential benefits of using flexible-grid ROADMs and compare this approach with alternative strategies.
07 Jul 2013
TL;DR: It is shown that polarization does occur at infinity for three types of channel multiplexers, and the polarization process is not unique, as it is shaped by the choice of the multiplexer.
Abstract: This work investigates polar coding for block-fading channels. We show that polarization does occur at infinity for three types of channel multiplexers. Nevertheless, the polarization process is not unique, as it is shaped by the choice of the multiplexer. The fading-plane approach is used to study the outage behavior of polar coding at a fixed transmission rate. Two types of multiplexers are shown to provide full diversity at finite and infinite code length.
TL;DR: In this article, a coarse wavelength (de)multiplexing structure on the silicon-on-insulator platform is presented, which comprises two 4-channel angled multimode interferometers interleaved with an imbalanced Mach-Zehnder interferometer (MZI) leading to an 8-channel multiplexing device.
Abstract: We have demonstrated a coarse wavelength (de)multiplexing structure on the silicon-on-insulator platform. It comprises two 4-channel angled multimode interferometers interleaved with an imbalanced Mach-Zehnder interferometer (MZI) leading to an 8-channel multiplexing device. The device requires only single lithography and etching steps for fabrication and has a good tolerance to fabrication errors in terms of waveguide width. The insertion loss and crosstalk achieved are 3-4 dB and –(15–20) dB, respectively. Potential is shown for achieving improved performance using larger waveguide bending radii in the MZI arms and/or (a) local heater(s) for refractive index tuning.
TL;DR: In this paper, the performance of the WDM-PON system with self-seeded reflective semiconductor optical amplifiers (RSOAs) is investigated and the impacts of the self-seeding power, stable seeding power, and the shape factor of the wavelength multiplexer on the transmission performance are investigated.
Abstract: The transmission performances of the wavelength-division-multiplexed passive optical networks based on directly modulated self-seeded reflective semiconductor optical amplifiers (RSOAs) are investigated and analyzed. The impacts of signal extinction ratio (ER), stable seeding power, pattern length dependency, bandwidth and shape factor of the wavelength multiplexer within the self-seeding cavity, and length of the self-seeding cavity on the transmission performance are investigated. The ER is optimized to bring the best receiver sensitivity when the loss of the self-seeding cavity is fixed. The optimal ER and the corresponding receiver sensitivity are improved with the stable seeding power which decreases with the loss of the self-seeding cavity. Compared to the Gaussian-shaped pass band, the wavelength multiplexer with a flat-top pass band brings better transmission performances and enables error-free transmission with a smaller pass band bandwidth. The transmission performance of the directly modulated self-seeded RSOA is robust against the phase perturbation induced by the micro change in the cavity length but is degraded remarkably when the cavity length is extended to several kilometers. Nevertheless, error-free transmission is achieved when the cavity length is extended to 4 km. The findings of this paper provide a better understanding of the mechanism of the directly modulated self-seeded RSOAs and also guidance on designing the WDM-PON systems using the self-seeded RSOAs.
Patent•
27 Feb 2013
TL;DR: In this article, a beam splitter and a PBS are configured to combine first and second polarized optical signals by reflecting a first polarized optical signal towards a first target and allowing a second polarized signal to pass through towards the first target.
Abstract: An optical multiplexer and methods of making and using the same are disclosed. The multiplexer generally includes a beam splitter and a polarization beam splitter. The beam splitter is generally configured to combine first and second polarized optical signals by reflecting a first polarized optical signal towards a first target and allowing a second polarized optical signal to pass through towards the first target. The polarization beam splitter is generally configured to combine the first and second polarized optical signals with a third polarized optical signal by either (i) reflecting the third polarized optical signal towards a second target and allowing the first and second polarized optical signals to pass through towards the second target, or (ii) reflecting the first and second polarized optical signals towards the second target and allowing the third polarized optical signal to pass through towards the second target.
TL;DR: In this article, a microwave SQUID multiplexer was designed for the purpose of reliable design applicable for a future large-format array of transition edge sensors (TESs).
Abstract: Resonant frequencies and SQUID inductances LS in a microwave SQUID multiplexer are studied for the purpose of reliable design applicable for a future large-format array of transition edge sensors (TESs). The key element of the multiplexer chip is a quarter-wave-length resonator terminated by a dissipationless rf SQUID connected to TES. For the resonator, we found that a small correction to the effective length of the resonators made the designed resonant frequencies fit the experimental one over the whole readout band of 4-8 GHz covered by our cryogenic amplifier. We also found that microstrip-type SQUIDs with vertical loops are suitable for accurate design of small inductance LS <; 10<; pH to operate the rf SQUID in dissipationless regime. Based on these well-designed resonators and SQUIDs, we have successfully demonstrated the multiplexing of three pulsed signals with 1-ms width and spacing given at the input ports of three SQUIDs. The equivalent noise current refer to the SQUID input is not dominated by SQUIDs and estimated to be 200-270 pA/ √Hz, whose improvement approach is quantitatively discussed.