Showing papers on "Insertion loss published in 2002"
TL;DR: In this article, a novel integrated mode size converter for single-mode Si wire waveguides is presented, which is constructed with two-dimensional tapered Si waveguide and overlaid high-index polymer waveguide.
Abstract: A novel integrated mode size converter for single-mode Si wire waveguides is presented. The mode size converter is constructed with two-dimensional tapered Si waveguides and overlaid high-index polymer waveguides. We calculated the proposed mode size converter characteristics, and fabricated 1.09 mm length Si wire waveguides with the converters. The measured loss of the mode size converter was 0.8 dB per conversion, and the total insertion loss through the sample with an Si wire waveguide was 3.5 dB.
502 citations
TL;DR: Polymeric electro-optic modulators can be operated for long periods of time at temperatures on the order of 100 °C as discussed by the authors, and the role of electrostatic interactions in influencing the choice of processing conditions is also discussed.
Abstract: Polymeric electro-optic materials have recently been developed that, when fabricated into devices such as Mach-Zehnder interferometers, permit drive ( Vπ) voltages of less than 1 V to be realized at the telecommunications wavelength of 1.3 and 1.55 microns. Operation of polymeric electro-optic modulators to frequencies (bandwidths) of greater than 100 GHz has been demonstrated. The total insertion loss of polymeric electro-optic modulators has been reduced to values as low as 5 dB, which is competitive with values obtained for lithium niobate modulators and is much lower than that obtained for gallium arsenide electro-absorptive modulators. Polymeric electro-optic modulators can be operated for long periods of time at temperatures on the order of 100 °C. Techniques have been developed for seamlessly integrating polymeric electro-optic circuitry with passive low loss optical circuitry (e.g., silica long-haul transmission fiber and medium-range fluoropolymer fibers) and with very large scale integration (VLSI) semiconductor electronics. These advances have created a considerable interest in the commercialization of polymeric electrooptic materials. Polymeric electro-optic materials are now being evaluated for applications such as phased array radar, satellite and fiber telecommunications, cable television (CATV), optical gyroscopes, electronic counter measure (ECM) systems, backplane interconnects for high-speed computers, ultrafast (100 Gbit/s) analog-to-digital (A/D) converters, land mine detection, radio frequency (rf) photonics, and spatial light modulators. This review discusses the structure-function relationships that had to be defined and the synthesis and processing advances achieved before materials appropriate for commercialization could be produced. Topics discussed include the design and synthesis of chromophores that simultaneously exhibit large molecular hyperpolarizability, low optical absorption, processability (e.g., solubility in various processing media), and the prerequisite (thermal, chemical, electrochemical, and photochemical) stability to survive conditions encountered in the fabrication and operation of polymeric electro-optic devices. Chromophore-chromophore intermolecular electrostatic interactions have been shown to be the most serious problem impeding the optimization of electro-optic activity in organic materials. The quantitative theoretical treatment of such interactions by equilibrium and Monte Carlo statistical mechanical methods is discussed. Rules for designing chromophores with shapes leading to maximum obtainable electro-optic activity are discussed and the synthetic realization of such structures is reviewed. The role of electrostatic interactions in influencing the choice of processing conditions is also discussed. A number of processing steps, including spin casting, electric-field poling, lattice hardening, fabrication of buried channel waveguides (including deposition of cladding layers), electrode deposition and connection with electronic circuitry, and integration of active and passive optical circuitry, are required. Each of these steps can affect device performance (e.g., influence optical loss, electro-optic activity, and stability). The systematic optimization of each of these steps is reviewed. Finally, device design and operation are reviewed and speculation on the future of the field is expressed.
279 citations
TL;DR: In this article, the authors report the miniaturization of a planar Wilkinson power divider by capacitive loading of the quarter wave transmission lines employed in conventional Wilkinson power dividers.
Abstract: The authors report the miniaturization of a planar Wilkinson power divider by capacitive loading of the quarter wave transmission lines employed in conventional Wilkinson power dividers. Reduction of the transmission line segments from /spl lambda//4 to between /spl lambda//5 and /spl lambda//12 are reported here. The input and output lines at the three ports and the lines comprising the divider itself are coplanar waveguide (CPW) and asymmetric coplanar stripline (ACPS), respectively. The 10 GHz power dividers are fabricated on high resistivity silicon (HRS) and alumina wafers. These miniaturized dividers are 74% smaller than conventional Wilkinson power dividers, and have a return loss better than +30 dB and an insertion loss less than 0.55 dB. Design equations and a discussion about the effect of parasitic reactance on the isolation are presented for the first time.
264 citations
TL;DR: In this work, a method for fabricating fine-scale 2-2 composites suitable for 30-MHz linear array transducers was successfully demonstrated and high thickness coupling, low mechanical loss, and moderate electrical loss were achieved.
Abstract: Ultrasound imaging at frequencies above 20 MHz is capable of achieving improved resolution in clinical applications requiring limited penetration depth. High frequency arrays that allow real-time imaging are desired for these applications but are not yet currently available. In this work, a method for fabricating fine-scale 2-2 composites suitable for 30-MHz linear array transducers was successfully demonstrated. High thickness coupling, low mechanical loss, and moderate electrical loss were achieved. This piezo-composite was incorporated into a 30-MHz array that included acoustic matching, an elevation focusing lens, electrical matching, and an air-filled kerf between elements. Bandwidths near 60%, 15-dB insertion loss, and crosstalk less than -30 dB were measured. Images of both a phantom and an ex vivo human eye were acquired using a synthetic aperture reconstruction method, resulting in measured lateral and axial resolutions of approximately 100 /spl mu/m.
244 citations
TL;DR: In this article, a new device topology has been proposed to implement parallel plate capacitors using Ba/sub x/Sr/sub 1-x/TiO/sub 3/ (BST) thin films.
Abstract: In this paper, a new device topology has been proposed to implement parallel plate capacitors using Ba/sub x/Sr/sub 1-x/TiO/sub 3/ (BST) thin films. The device layout utilizes a single parallel capacitor and minimizes conductor losses in the base electrode. The new design simplifies the monolithic process and overcomes the problems associated with electrode patterning. An X-band 180/spl deg/ phase shifter has been implemented using the new device design. The circuit provided 240/spl deg/ phase shift with an insertion loss of only 3 dB at 10 GHz at room temperature. We have shown a figure of merit 93/spl deg//dB at 6.3 GHz and 87/spl deg//dB at 8.5 GHz. To our knowledge, these are the best figure of merit results reported in the literature for distributed phase shifters implemented using BST films at room temperature.
197 citations
TL;DR: In this paper, the authors demonstrate a 2/spl times/2 optical cross connector (OXC) with insertion loss of about 0.4 dB at a switching time of 500 /spl mu/s and its extension to a 4 /spl times 4 OXC, which has an attenuation range of more than 50 dB and a Fourier transform spectrometer (FTS) with a spectral resolution of 6 nm in the visible.
Abstract: After microelectromechanical systems (MEMS) devices have been well established, components of higher complexity are now developed. Particularly, the combination with optical components has been very successful and have led to optical MEMS. The technology of choice for us is the silicon-on-insulator (SOI) technology, which has also been successfully used by other groups. The applications presented here give an overview over what is possible with this technology. In particular, we demonstrate four completely different devices: (a) a 2 /spl times/ 2 optical cross connector (OXC)with an insertion loss of about 0.4 dB at a switching time of 500 /spl mu/s and its extension to a 4 /spl times/ 4 OXC, (b) a variable optical attenuators (VOA), which has an attenuation range of more than 50 dB (c) a Fourier transform spectrometer (FTS) with a spectral resolution of 6 nm in the visible, and (d) an accelerometer with optical readout that achieves a linear dynamic range of 40 dB over /spl plusmn/6 g. Except for the FTS, all the applications utilized optical fibers, which are held and self-aligned within the MEMS component by U-grooves and small leaf springs. All devices show high reliability and a very low power consumption.
138 citations
TL;DR: In this paper, a 3-pole Chebyshev bandpass filter with Q-enhancement is presented, which achieves an insertion loss of 0 dB and a passband of 60 MHz around a center frequency of 2140 MHz.
Abstract: A 3-pole Chebyshev bandpass filter, that employs on-chip passive elements with Q-enhancement technique, achieves an insertion loss of 0 dB and a passband of 60 MHz around a center frequency of 2140 MHz. The Q-enhancement technique is based on coupled-inductor negative resistance generator. In contrast to conventional negative resistance generator, this technique compensates resonator loss without introducing distortion in the filter response in the passband. Fabricated in a 0.25-/spl mu/m CMOS, the filter consumes 7 mA from a 2.5-V supply. The filter occupies an area of 1.3 mm/spl times/2.7 mm.
127 citations
Patent•
19 Jul 2002
TL;DR: In this article, the metal column-like elements are used to improve the return loss bandwidth, probe-to-probe isolation, insertion loss bandwidth and higher order mode suppression and cross-polarization generation.
Abstract: A phased array antenna system including a plurality of metal, column-like elements formed adjacent the RF probes for improving the electrical performance of the system. In one embodiment a hole is formed in a multi-layer, probe-integrated printed wiring board of the system and metal material is plated thereon to fill the hole. The metal, column-like elements are each disposed generally in between associated pairs of the RF probes. The metal, column-like elements essentially form metal pins that improve the return loss bandwidth, probe-to-probe isolation, insertion loss bandwidth, higher order mode suppression and cross-polarization generation.
123 citations
TL;DR: In this article, a 2D photonic crystal waveguide was optically characterised and the measured total insertion loss is below 19 dB in the waveguides with unpolarised light.
Abstract: Silicon-on-insulator-based 2D photonic crystal waveguides have been optically characterised. The measured total insertion loss is below 19 dB in the waveguides with unpolarised light. With the length mask technique, it is found that the photonic crystal waveguides show propagation losses below 4 dB/mm.
110 citations
TL;DR: In this paper, a method was investigated to reduce the insertion loss and response time in the phase shift in a microwave variable delay line using liquid crystal (LC) in which the alignment of the LC can be controlled with a control voltage and its frequency.
Abstract: A method was investigated to reduce the insertion loss and response time in the phase shift in a microwave variable delay line using liquid crystal (LC). In variable delay lines using conventional nematic LC, reducing the insertion loss conflicts with reducing the phase-shift response-time dependence on the thickness of the LC layer; thus, it is very difficult to simultaneously satisfy both requirements. Here, the use of dual-frequency switching-mode liquid crystal (DFSM LC) for the variable delay line is demonstrated as one approach to solving this problem. By using the characteristics of DFSM LC, in that the alignment of the LC can be controlled with a control voltage and its frequency, it becomes possible to control the LC alignment to be in an always electrically driven condition by applying a combination of control voltages of dc and several kilohertz. Experimental results of a microwave variable delay line using DFSM LC show that it is possible to reduce both the phase-shift response time and insertion loss.
106 citations
TL;DR: In this article, the authors demonstrate a novel RF switch based on a multifinger AlGaN/GaN MOSHFET, which achieves 0.27 dB insertion loss and more than 40 dB isolation.
Abstract: We demonstrate a novel RF switch based on a multifinger AlGaN/GaN MOSHFET. Record high saturation current and breakdown voltage, extremely low gate leakage current and low gate capacitance of the III-N MOSHFETs make them excellent active elements for RF switching. Using a single element test circuit with 1-mm wide multifinger MOSHFET we achieved 0.27 dB insertion loss and more than 40 dB isolation. These parameters can be further improved by impedance matching and by using submicron gate devices. The maximum switching power extrapolated from the results for 1A/mm 100 /spl mu/m wide device exceeds 40 W for a 1-mm wide 2-A/mm MOSHFET.
TL;DR: In this paper, a phase shifter fabricated on Ba/sub 0.4/TiO/sub 3/ (BST)/sapphire consists of a coplanar waveguide Lange coupler, a series resonated LC termination, and a bias network.
Abstract: The design and experimental results of a wide-band monolithic reflection-type phase shifter are presented in this paper. The phase shifter fabricated on Ba/sub 0.6/Sr/sub 0.4/TiO/sub 3/ (BST)/sapphire consists of a coplanar waveguide (CPW) Lange coupler, a series resonated LC termination, and a bias network. The CPW Lange coupler results in a power split of 3.5 dB/spl plusmn/0.5 dB in the range of 1.6-3.2 GHz. The BST interdigital capacitor has a tunability (C/sub max//C/sub min/) of 3.1 with 140 V. Measured and simulated performance of a series resonated LC termination was described. The phase shifter has achieved a phase-shift range of over 90/spl deg/ with an insertion loss of better than 2.0 dB and a return loss of higher than 14 dB in the frequency range of 1.9-2.5 GHz over a bias voltage range from 0 to 160 V. A figure-of-merit of maximum 72/spl deg//dB at 2 GHz was obtained. The smaller phase shifter using the folded-type CPW Lange coupler, which maintains a smaller aspect ratio for easier packaging, has an insertion loss of better than 2.3 dB with a phase-shift range of over 130/spl deg/ at 2.5 GHz. Two-tone measurements of the phase shifter indicate an input IP/sub 3/ of 32 dBm with 0 V and 41.9 dBm with 60 V. Total size of the monolithic BST phase shifter is 11.2 mm /spl times/ 4.9 mm /spl times/ 0.43 mm for the straight coupler design and 5.4 mm /spl times/ 6.5 mm /spl times/ 0.43 mm for the folded-type design.
TL;DR: In this article, a tandem electroabsorption modulator with an integrated semiconductor optical amplifier was developed for both non-return-to-zero and return-tozero (RZ) data transmission at 40 Gb/s.
Abstract: In this letter, we have developed a tandem electroabsorption modulator with an integrated semiconductor optical amplifier that is capable of both nonreturn-to-zero and return-to-zero (RZ) data transmission at 40 Gb/s. The tandem modulator consists of a broad-band data encoder and a narrow-band pulse carver. The pulse carver is able to produce 5-ps pulses with more than 20 dB of extinction. The on-chip semiconductor optical amplifier provides up to 8.5 dB of fiber-to-fiber gain and enables the modulator to be operated with zero insertion loss. Devices have been realized with greater than 40-GHz bandwidth, and 13-dB dynamic extinction for a 2.5-V swing. For optimized designs bandwidths of nearly 60 GHz: have been realized. Using these devices penalty free RZ data transmission over a 100-kin dispersion compensated fiber link has been demonstrated with a received power sensitivity of -29 dBm.
TL;DR: In this paper, a 3D-deployed RF front-end system-on-package (SOP) in a standard multi-layer low temperature co-fired ceramic (LTCC) technology is presented.
Abstract: Presents design, implementation, and measurement of a three-dimensional (3-D)-deployed RF front-end system-on-package (SOP) in a standard multi-layer low temperature co-fired ceramic (LTCC) technology. A compact 14 GHz GaAs MESFET-based transmitter module integrated with an embedded bandpass filter was built on LTCC 951AT tapes. The up-converter MMIC integrated with a voltage controlled oscillator (VCO) exhibits a measured up-conversion gain of 15 dB and an IIP3 of 15 dBm, while the power amplifier (PA) MMIC shows a measured gain of 31 dB and a 1-dB compression output power of 26 dBm at 14 GHz. Both MMICs were integrated on a compact LTCC module where an embedded front-end band pass filter (BPF) with a measured insertion loss of 3 dB at 14.25 GHz was integrated. The transmitter module is compact in size (400 /spl times/ 310 /spl times/ 35.2 mil/sup 3/), however it demonstrated an overall up-conversion gain of 41 dB, and available data rate of 32 Mbps with adjacent channel power ratio (ACPR) of 42 dB. These results suggest the feasibility of building highly SOP integrated RF front ends for microwave and millimeter wave applications.
02 Jun 2002
TL;DR: In this paper, the authors presented the design, fabrication and testing of capacitive copper RF MEMS switches with various hinge geometries, fabricated on high-resistivity silicon substrates.
Abstract: This paper presents the design, fabrication and testing of capacitive copper RF MEMS switches with various hinge geometries, fabricated on high-resistivity silicon substrates. The switches were fabricated using a simple low-cost four-mask process and 0.6-1.0 /spl mu/m thick membranes were made out of sputtered copper. The capacitive airgap in between the membrane and the signal line is 1.5-2.0 /spl mu/m. The lowest actuation voltage measured on the fabricated switches is 9 V. The measured insertion loss of a fabricated switch and its associated transmission time was 0.9 dB (mainly contributed by the transmission line itself) and the isolation was measured to be 25 dB at 40 GHz.
TL;DR: In this paper, the insertion loss and return loss were measured in a high-frequency range (X-band) with a network analyzer, and the results indicated a relatively low frequency dependence.
Abstract: The preparation and characterization of ferrite- and carbon black-filled ethylene-propylene-ethylidene norborene terpolymer rubber composites were studied for microwave applications. Both the insertion loss and return loss were measured in a high-frequency range (X-band) with a network analyzer. The results indicated a relatively low frequency dependence. The difference in the insertion losses measured for all samples, except for one containing 100 phr ferrite and 75 phr carbon black (B75), was ±3 dB. Sample B75 showed broadband absorption in the aforementioned frequency band. Furthermore, the incorporation of both ferrite and carbon black powder into the rubber matrix altered the electrical and microwave properties, that is, the insertion loss and return loss; this could be helpful in the design of suitable absorbing materials for microwave applications at high frequencies. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 145–150, 2002
TL;DR: In this article, a multichannel tunable dispersion compensator (TDC) based on multicavity all-pass etalons was proposed to compensate up to 45 km of nonzero dispersion shifted fiber.
Abstract: We present a multichannel tunable dispersion compensator (TDC) based on multicavity all-pass etalons that is capable of operation at 40 Gb/s. The device has a tuning range of +200/-220 ps/nm with a group delay ripple < /spl plusmn/5 ps over a channel bandwidth of 80 GHz, an overall loss of < 5.2 dB, very low insertion loss ripple, and can operate on any channel on a 200-GHz grid over the C-band. In addition, we present system performance results at 40 Gb/s using NRZ, RZ, and CS-RZ modulation, compensating up to 45 km of nonzero dispersion shifted fiber (NZDSF). Our results show that this device introduces very little excess system penalty with signal frequency drifts of up to 20 GHz when operated near the center of its tuning range. For single channel experiments with fiber, the system penalty increase versus signal detuning is more significant, but can be reduced by dynamically optimizing the device dispersion during detuning. Finally, we demonstrate simultaneous compensation of 4 channels across the C-band over 25 km of NZDSF.
TL;DR: In this paper, the authors proposed a new class of slow-wave bandpass filters that uses a microstrip line periodically loaded with microstrip ring or stepped-impedance hairpin resonators.
Abstract: This paper proposes a new class of slow-wave bandpass filters that uses a microstrip line periodically loaded with microstrip ring or stepped-impedance hairpin resonators. The new slow-wave periodic structures utilize the parallel and series resonance characteristics of the resonators to construct a bandpass filter. Unlike conventional slow-wave filters, the proposed bandpass filters are designed to produce a narrow passband at the fundamental mode of the resonators. The new filters provide lower insertion loss than that of parallel- or cross-coupled ring and stepped-impedance hairpin bandpass filters. The calculated frequency responses of the filters agree well with experiments.
07 Nov 2002
TL;DR: In this paper, the authors introduce three fiber-optic sensor system designs to attain real-time sample data such as blood flow rates via Doppler and reflectance measurements over a spatial domain of interest.
Abstract: In this paper, we introduce three novel fiber-optic sensor system designs to attain real time sample data such as blood flow rates via Doppler and reflectance measurements over a spatial domain of interest. In addition, we discuss the design and functionality of novel no-moving parts sensor heads. These front-end sensors include our miniaturized head (e.g., 1.8 mm cross-sectional diameter) for intra-cavity probing and a hand-held optical scanning head for external cavity sensing via Doppler and reflectance measurements. The non-coherent miniaturized fiber-optic scanning probe can also function as real time precision optical knife to remove fat in blood vessels or to make intra-cavity incisions with pinpoint accuracy. On the other hand, our nonscanning coherent fiber-optic probe system (using a broadband source) has the unique capability of producing multiple reconfigurable simultaneous beams and operating in slow and fast acquisition mode at the same time. System issues such as front-end probe beam angular scan, scan distance, and system insertion loss are addressed.
Patent•
02 Apr 2002TL;DR: In this article, an integrated circuit incorporating a transmit/receive antenna switch capable of being integrated using silicon based RF CMOS semiconductor processes and a power amplifier on the same substrate is constructed whereby the substrate (i.e. bulk) terminals of the FETs are left floating thus improving the isolation and reducing the insertion loss of the switch.
Abstract: A novel integrated circuit incorporating a transmit/receive antenna switch capable of being integrated using silicon based RF CMOS semiconductor processes and a power amplifier on the same substrate. The switch circuit is constructed whereby the substrate (i.e. bulk) terminals of the FETs are left floating thus improving the isolation and reducing the insertion loss of the switch. Floating the substrate of the transistors eliminates most of the losses caused by leakage paths through parasitic capacitances internal to the transistor thus improving the isolation and reducing the insertion loss of the switch. Alternatively, the substrate can be connected to the source or to ground via a resistor of sufficiently high value to effectively float the substrate.
TL;DR: In this paper, the two-pole filters were designed using the lumped-elements topology with metal-air-metal (MAM) bridge-type capacitors as tuning elements.
Abstract: This paper presents compact V-band MEMS-based analog tunable bandpass filters with improved tuning ranges and low losses. For compact size and wide tuning range, the two-pole filters are designed using the lumped-elements topology with metal-air-metal (MAM) bridge-type capacitors as tuning elements. Capacitive inter-resonator coupling has been employed to minimize the radiation loss, which is the main loss contributor at high frequencies. Two filters have been demonstrated at 50 and 65 GHz. The 65-GHz analog tunable filter showed a frequency tuning bandwidth of 10% (6.5 GHz) with low and flat insertion losses of 3.3 /spl plusmn/ 0.2 dB over the entire tuning range.
TL;DR: In this article, a high performance acoustooptic tunable filter for add-drop application and for signal equalization in WDM telecommunication crossconnects is described, which results from a thorough investigation in TeO/sub 2/ of bulk collinear interaction.
Abstract: We describe a high performance acoustooptic tunable filter for add-drop application and for signal equalization in WDM telecommunication crossconnects. It results from a thorough investigation in TeO/sub 2/ of bulk collinear interaction, the geometry of which, particularly the direction of propagation of the acoustic wave, has been chosen in order to obtain the best compromise between the spectral resolution of the device and the acoustooptic figure of merit. Less than 40 mW of electric power is needed either to deviate 100% of a selected light wavelength /spl lambda/ at resonance, or to induce a 30-dB attenuation of its intensity. The sidelobes practically vanish for this configuration and the resolution is equal to 0.75 nm (or 94 GHz) for /spl lambda/=1.55 /spl mu/m. Polarization splitters combined with half-wave plates allow to completely get rid of polarization sensitivity problems. The use of optical fibers to collect the signal at the filter outputs, actually contributes to the high performance of the device as a whole. Experiments have been performed by multiplexing three signals in the input fiber, separated by 4, 2, and 1 nm. The transmission of the filter has been examined through the bar and cross state.
TL;DR: Thin film bulk acoustic wave resonators are fabricated on a silicon nitride bridge using a ZnO piezolayer on a glass substrate and surface micromachining by standard thin film technology and can be used to manufacture miniature microwave filters without any additional inductances.
Abstract: Thin film bulk acoustic wave (BAW) resonators (FBAR) are fabricated on a silicon nitride bridge using a ZnO piezolayer on a glass substrate and surface micromachining by standard thin film technology. These resonators exhibit a coupling constant k/sub t//sup 2/=7.8% at the first thickness extensional wave mode and are used as impedance elements in a ladder filter in the 1-GHz frequency band of mobile telecommunications. An electrical equivalent circuit is used to characterize the properties of the resonators and to show how the performance of the filter depends on the parameters of the resonators. 2.5% bandwidth, 2.8-dB insertion loss, and 35-dB selectivity are obtained in a filter with six resonators. The technology can be used to manufacture miniature microwave filters without any additional inductances.
TL;DR: In this article, an electric arc-induced long-period fiber gratings with low insertion loss (<0.2 dB) and high isolation peaks (−24 dB) have been fabricated in standard singlemode fiber (Corning SMF28).
Patent•
11 Feb 2002TL;DR: In this article, a wavelength-selective optical device for coupling of light at a predetermined wavelength from one optical fiber waveguide to another using at least two gratings (22, 24) and cladding-mode assisted coupling is disclosed.
Abstract: A wavelength-selective optical device for coupling of light at predetermined wavelength from one optical fiber waveguide (16) to another (18) using at least two gratings (22, 24) and cladding-mode assisted coupling is disclosed. The transfer of light is performed using intermediate coupling to one or more cladding mode of the waveguides (16, 18). In the case when the fibers have physically different claddings, an arrangement for transfer of light from one cladding to another is required. The disclosed coupler has no back-reflection, small insertion loss, and very high channel isolation. The device can be used in wavelength-division multiplexing networks.
TL;DR: In this article, the authors proposed a novel structure that reduces the switching power of a silica-based thermooptic switch, which consists of silicon trenches and heat insulating grooves, which are formed beneath and beside the arms of a Mach-Zehnder interferometer.
Abstract: We propose a novel structure that reduces the switching power of a silica-based thermooptic switch (TOSW). The structure consists of silicon trenches and heat insulating grooves, which are formed beneath and beside the arms of a Mach-Zehnder interferometer, respectively. We optimize the structure using the differential-element method (DEM) and fabricate a 2 /spl times/ 2 TOSW with a switching power of only 90 mW, namely, 75% less than that of a conventional TOSW. We also obtain an insertion loss of about 1 dB and an extinction ratio of over 30 dB with a response time from 0% to 90% of 4.9 ms. We then use the structure to fabricate an 8 /spl times/ 8 matrix switch and confirm a total power consumption of 1.4 W with an average insertion loss of 7.4 dB and an extinction ratio of 50.4 dB for 64 possible optical paths.
17 Mar 2002
TL;DR: In this article, a reconfigurable wavelength-selective switch that independently distributes 128 input WDM channels to four output ports is presented, based on bulk optics and MEMS micro-mirrors, exhibits <5 dB insertion loss and flat-top pass-bands.
Abstract: We present a reconfigurable wavelength-selective switch that independently distributes 128 input WDM channels to four output ports. The switch is based on bulk optics and MEMS micro-mirrors, exhibits <5 dB insertion loss and flat-top pass-bands, and is well suited for transparent switching of 10 Gb/s signals.
TL;DR: In this article, a 10 GHz filter constructed of slot-coupled micromachined cavities in silicon is presented and compared to a finite-element-method model.
Abstract: A 10-GHz filter constructed of slot-coupled micromachined cavities in silicon is presented. The novel character of the filter lies in its structure, which consists of a microstrip feed to cavities via slot apertures and three vertically stacked slot-coupled cavities. The cavities are essentially reduced-height waveguide resonators. The measured results are presented and compared to a finite-element-method model. The simulated model has a bandwidth of 4% with an insertion loss of 0.9 dB at 10.02 GHz. The measured filter yields a 3.7% bandwidth with a deembedded insertion loss of 2.0 dB at 10.01 GHz. Various loss mechanisms are examined to explain the difference between simulated and measured insertion loss.
TL;DR: In this paper, an integrated microstrip low-loss slow-wave line is presented, which replaces the conventional metal strip by composite metals paralleling the electric surface and magnetic surface (MS).
Abstract: This paper presents a novel integrated microstrip low-loss slow-wave line. The new microstrip replaces the conventional metal strip by composite metals paralleling the electric surface and magnetic surface (MS). The MS made of an array of coupled inductors shows a high-impedance state in the stopband, below which the propagation properties can be well controlled by varying the dimensions of the electric surface and MS. The dispersion curves obtained by matrix-pencil analyses closely correspond to those obtained by scattering-parameter extraction. Theoretical results, as confirmed experimentally, indicate that an increase of over 60% in the slow-wave factor can be achieved without sacrificing propagation losses, using the proposed structure. This electric-magnetic-electric (EME) microstrip is insensitive to the alignment position of the periodical structure, and can be constructed using conventional printed-circuit-board fabrication processes and integrated with other microwave components in a multilayered circuit. A compact EME bandpass filter (BPF) with suppressed harmonic responses is presented. The length of the filter is reduced by 26%, and the measured insertion loss and fractional bandwidth is comparable to that of a conventional microstrip BPF on the same substrate.
TL;DR: In this article, coplanar stripline (CPS) resonators and their practical implementations to filters are investigated and compared in terms of Q factor or bandwidth, and a wide-band CPS-to-microstrip transition is developed for the measurements.
Abstract: This paper presents coplanar stripline (CPS) resonators and their practical implementations to filters. Five types of CPS resonator are built using open and short-ended strips. Lumped-element equivalent circuits are presented for each resonator. Their performances are investigated and compared in terms of Q factor or bandwidth. Two types of bandpass filter are developed with the resonators. The bandpass filters have low-passband insertion losses and wide-stopband suppression bandwidths. Lumped-element equivalent circuits are presented for the bandpass filters. A wide-band CPS-to-microstrip transition is developed for the measurements. The back-to-back transition has an insertion loss of less than 3 dB and a return loss of better than 10 dB for the frequency range from 1.3 to 13.3 GHz (1:10.2).