Waveguide Power Research Articles

Highly tunable heterogeneously integrated III-V on silicon sampled-grating distributed Bragg reflector lasers operating in the O-band.

We report on the design, fabrication and performance of the first hetero-integrated III-V on silicon sampled-grating distributed Bragg reflector lasers (SGDBR) operating in the O-band and based on direct bonding and adiabatic coupling. Two devices with different geometric parameters are presented both showing an output power in the Si waveguide as high as 7.5 mW and a continuous tuning range of 27 and 35 nm respectively with a side mode suppression ration higher than 35 dB.

A Generalized Lossy Transmission-Line Model for Tunable Graphene-Based Transmission Lines with Attenuation Phenomenon.

To investigate the frequency shift phenomenon by inserting graphene, a generalized lossy transmission-line model and the related electrical parameter-extraction theory are proposed in this paper. Three kinds of graphene-based transmission lines with attenuation phenomenon including microstrip line, double-side parallel strip line, and uniplanar coplanar waveguide are analyzed under the common conditions where different chemical potentials are loaded on graphene. The values of attenuation constant and phase constant, and the real and imaginary parts of the characteristic impedance of transmission lines are extracted to analyze in details. When the attenuation constant and the reactance part of the characteristic impedance are approximately equal to zero, this kind of transmission line has low or zero insertion loss. On the contrary, the transmission line is under the radiation mode with obvious insertion loss. The phase constant changes linearly under the transmission mode and can be varied with changing of chemical potentials which attributes to the property of frequency tunability. Furthermore, a bandwidth reconfigurable uniplanar coplanar waveguide power divider is simulated to demonstrate that this theory can be applied to the design of three-port devices. In summary, this work provides a strong potential approach and design theory to help design other kinds of terahertz and mid-infrared reconfigurable devices.

An Integratable Planar Waveguide Power Divider With Anti-Phases and Full Bandwidth

A novel integratable planar T-junction waveguide power divider, a so-called TEH(E-plane input and H-plane output) junction waveguide power divider, with anti-phase outputs and full bandwidth is proposed in this letter. It is basically a E-plane waveguide T-junction with its input port rotated around the axis of the two output ports by 90 degrees to form a planar structure. In order to expand its operation bandwidth, several stages of matching sections are added between the coupling cavity and each port. In order to verify the concept, a standard waveguide port TEH junction divider is designed and tested as an example. From the tested results, the reflection coefficient is lower than −20 dB and phase difference between the two output ports is within 177 +/−3 degrees in the full bandwidth from 26.3 to 40 GHz.

ANALYSIS OF TAPERED FINLINE IN POWER COMBINER FOR WIDEBAND APPLICATION

Tapered finline or slotline array has used in Vivaldi antenna design to produce Ultra-wideband (UWB). This paper focuses to design and analysis the structural of tapered finline in order to achieved wideband in rectangular waveguide power combiner at frequency 0.5 GHz to 6 GHz. There are three main parameters are studying in this paper which are of length of radiation region exponential coefficient at curves of radiation and exponential coefficient at curves of directivity. The design of tapered finline in power combiner is simulated using CST Microwave Studio Software. The simulation process is based on the input return loss at port 1 (S11), input return loss at port 2 (S22), isolation (S21) and insertion loss (S12). By studying the effect of the parameter on the design structure, it can be ensure that the tapered finline structures are suitable in wideband design.

A Microwave Transmission Instrument for Rapid Dry Rubber Content Determination in Natural Rubber Latex

We report the design, implementation and testing of an instrument for rapid dry rubber content (DRC) determination in rubber latex. It is composed of rectangular waveguide antennae, microwave generator, power detector, and microcontroller. According to the theory of microwave transmission, the power loss of microwaves passing through latex is related to the DRC. This attenuation is determined by measuring the transmitted microwave intensity with a power detector. The appropriate frequency that gives the best correlation between DRC and attenuation was found to be about 2.36 GHz. The microwave power measurement is processed by the microcontroller using the empirical calibration equation to estimate DRC in rubber latex. The instrument was tested using new latex samples with various DRC, sampled locally in Songkhla province, Thailand, and the DRC estimates by the instrument were compared to the slow but accurate standard oven-drying results. The estimates had an 0.21 % mean error and R2 = 0.9983, indicating good practical performance.

COMPACT MULTI-LAYER FOUR-WAY SIW POWER COMBINERS/DIVIDERS OPERATING AT W-BAND

In this paper, two compact multi-layer four-way substrate integrated waveguide (SIW) power combiners/dividers operating at W-band are analyzed and demonstrated experimen- tally/numerically. Based on the double-layer SIW broadside slot directional coupler, a four-way power combiner/divider is proposed for the first time. And a four-layer four-way SIW power combiner/divider is demonstrated experimentally, by using the transition structure between high-performance multi-layer SIWs and rectangular waveguide. Both SIW power combiners/dividers show high port-isolation, low loss, high efficiency, wide-band, and small lateral size.

Broad Band Equal-Length And Equal-Width Substrate Integrated Waveguide Four Channel Power Divider

In this letter a novel broad band substrate integrated waveguide (SIW) power divider is proposed. It consist of four output channels made by SIW with equal length and equal width. Design equations and process are given with mathematical analysis. The propagation constant of the output signals have been adjusted by utilize only four via in the middle of the output arms. As a result a novel equal output power divider, is obtained accordingly. The experimental results of a prototype at 10 GHz shows 3.1 GHz bandwidth in both simulation and measurement results. Return loss and transmission coefficients have good agreement with simulation results in considered band.

Novel Four-Way Multilayer SIW Power Divider With Slot Coupling Structure

A novel four-way multilayer substrate integrated waveguide (SIW) power divider with slot coupling structure is proposed in this letter. Two rectangular slots located in the right and left arms of SIW T-junction are employed to achieve efficient transition with two microstrip lines. Good impedance matching and signal transmission between SIW and microstrip lines are achieved. Two isolation resistors are used to improve the isolation between output ports. The even- and odd-mode analysis method is used in the proposed circuit. A prototype of the presented power divider is designed, fabricated, and measured. The measured results show a reasonable agreement with the simulated ones.

Millimeter-Wave Thermoelectric Power Transfer Standard

This paper describes a thermoelectric waveguide power sensor for the frequency range 75–110 GHz, which has been calibrated in a waveguide twin-type microcalorimeter. The sensor is suitable as a transfer standard to provide traceablity for high-frequency power calibrations. The design and calibration of the sensor are described. The calibration is based upon a novel measuring quantity, referred to as generalized efficiency. The results of mirocalorimeter measurements and sensor performance are given. The new transfer sensor is tested against conventional thermistor waveguide sensors in a direct comparison setup, showing good agreement within the estimated uncertainties.

On-chip diamond Raman laser

Synthetic single-crystal diamond has recently emerged as a promising platform for Raman lasers at exotic wavelengths due to its giant Raman shift, large transparency window and excellent thermal properties yielding a greatly enhanced figure-of-merit compared to conventional materials. To date, diamond Raman lasers have been realized using bulk plates placed inside macroscopic cavities, requiring careful alignment and resulting in high threshold powers (~W-kW). Here we demonstrate an on-chip Raman laser based on fully-integrated, high quality-factor, diamond racetrack micro-resonators embedded in silica. Pumping at telecom wavelengths, we show Stokes output discretely tunable over a ~100nm bandwidth around 2-{\mu}m with output powers >250 {\mu}W, extending the functionality of diamond Raman lasers to an interesting wavelength range at the edge of the mid-infrared spectrum. Continuous-wave operation with only ~85 mW pump threshold power in the feeding waveguide is demonstrated along with continuous, mode-hop-free tuning over ~7.5 GHz in a compact, integrated-optics platform.

Development of a microfluidic platform with integrated power splitting waveguides for optogenetic neural cell stimulation

We present a microfluidic platform with integrated power splitting waveguides for optogenetic neural cell stimulation. A liquid-core/PDMS-cladding waveguide with a power splitter design was integrated with a neural cell culture chamber to provide a simple way of precise localized optical stimulation. The parallel on-chip excitation of individual neural cells using a single optical fiber input is demonstrated for optogenetic neural cell studies, and the excitation of each individual waveguide can be independently controlled by pneumatic valves. Light delivery and loss mechanisms through the waveguides were studied and characterized. The waveguide power splitter platform is capable of providing sufficient irradiance to evoke spikes in ChR2-expressing neural cells. The system enables high-resolution stimulation of neural cells in a controllable manner. The microfluidic platform described here represents a novel methodology for studying optogenetics in a compact integrated system with high spatial resolutions.

Broadband Millimeter-Wave In-Phase and Out-of-Phase Waveguide Dividers with High Isolation

In this paper, two novel broadband in-phase and out-of-phase waveguide power dividers with high isolation are presented. Based on the substrate-integrated waveguide (SIW) divider and SIW-to-waveguide transition circuit, two kinds of E-plane waveguide dividers have been implemented. Due to the features of in-phase and out-of-phase performances, the proposed waveguide dividers can provide much more flexibilities than that of conventional E-plane waveguide T-junction. A broadband phase and amplitude performances are achieved across the whole Ka-band owing to the wideband characteristic of the SIW divider and transition circuits. To minimize the size and loss of the divider, a compact and low-loss SIW-to-waveguide transition circuit has been developed using the antisymmetric tapered probes. Two prototypes of the Ka-band waveguide dividers, including the in-phase and out-of-phase types, have been fabricated and measured. Measured results show that the isolation, input return loss, output return loss, amplitude imbalance, and phase imbalance of the in-phase divider are better than 15.5, 13.1, 10.8, 0.4 dB, and 3.50, while those of the out-of-phase divider are better than 15.0, 13.4, 10.4, 0.5 dB, and 3.60, respectively, over the frequency range from 26.5 to 40 GHz. The measured results agree well with the simulated ones. Considering their wide bandwidth, high isolation, good port matching performance, and compact configuration, the two types of waveguide dividers can be good candidates for broadband applications in millimeter-wave waveguide systems.

Design of a wideband eight‐way single ridge substrate integrated waveguide power divider

Recently, a low-loss X-band eight-way compact substrate-integrated-waveguide (SIW) power combiner was developed with about 40% bandwidth. To further widen the operating bandwidth, ridges can be added to form a ridge SIW (RSIW). RSIW has many advantages, such as a low profile, light weight, low cost and planar structure and wide bandwidth. In this study, a 1 to 8 splitter for an array antenna feed based on RSIW technology has been designed and fabricated that encompasses an extended bandwidth beyond that of the conventional guides. The divider is comprised of a GCPW to RSIW transition, RSIW T-junction and 90° bend and has demonstrated over a 65% bandwidth with better than 10 dB return loss from 5 to 10 GHz. In particular, it demonstrated excellent amplitude and phase uniformity with less than ±0.3 dB and ±5° imbalance, respectively, within 5.5 to 9.6 GHz.

A Wideband High-Gain High-Efficiency Hybrid Integrated Plate Array Antenna for V-Band Inter-Satellite Links

A wideband high-gain high-efficiency hybrid integrated plate array antenna for inter-satellite links is presented in this paper. This antenna consists of microstrip patches, substrate integrated waveguide (SIW) and waveguide power dividers. A novel feeding structure is proposed to excite the microstrip sub-array with a wideband characteristic. The radiation efficiency of SIW arrays with different sizes is compared by experiment. The hybrid SIW-waveguide feeding topology is optimized to realize high efficiency, low cost and compact configuration at the same time. The array antenna is fabricated through standard multi-layer PCB process and milling technology. Measured results demonstrate about 14.6% of reflection coefficient bandwidth ( |S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> |<;-10 dB) in the frequency band of 57-66 GHz. The gain fluctuates less than 3 dB within the same band. The 1 dB gain bandwidth is 8.1% within the frequency band of 59-64 GHz. The maximum gain is 39.2 dBi at 59 GHz with the efficiency of 41%.

1310 nm hybrid InP/InGaAsP on silicon distributed feedback laser with high side-mode suppression ratio.

We report on the design, fabrication and performance of a hetero-integrated III-V on silicon distributed feedback lasers (DFB) at 1310 nm based on direct bonding and adiabatic coupling. The continuous wave (CW) regime is achieved up to 55 °C as well as mode-hop-free operation with side-mode suppression ratio (SMSR) above 55 dB. At room temperature, the current threshold is 36 mA and the maximum coupled power in the silicon waveguide is 22 mW.

Fiber-to-Waveguide Alignment Assisted by a Transparent Integrated Light Monitor

A novel fiber-to-waveguide alignment technique assisted by a transparent integrated light monitor is presented. The waveguide power is measured near the chip input facet by the contactless integrated photonic probe, which provides a feedback electrical signal steering the fiber positioning system. Automated single fiber to silicon nanowaveguide coupling is demonstrated with 40-nm resolution in a time scale of few seconds. The presented approach makes the fiber alignment procedure independent of the optical circuit integrated on the photonic chip, avoiding the need for simultaneous alignment of an output fiber, and thus easing optical chip characterization, wafer-level testing, and packaging of photonic devices.

High‐efficiency millimetre‐wave spatial power combining structure

A high-efficiency millimetre-wave spatial power combining structure that is a waveguide power combining network is proposed. High phase and amplitude consistency and isolation between the output ports are the key factors for the high-efficiency power combining structure. The phase and amplitude consistency is guaranteed by the symmetry of this structure. As a sample, an eight-way power splitting and combining network in the Ka-band is designed, fabricated and measured. In a fractional bandwidth of 20% around a centre frequency of 33 GHz, the measured results show that the phase and amplitude differences between the output ports are smaller than ±1.5° and ±0.1 dB, isolation between the output ports is higher than 17 dB, insertion loss is lower than 0.1 dB, and the return loss of the input and output ports is better than 18 dB. The proposed broadband eight-way power combining network can improve the spatial power combining efficiency to a great extent with excellent performance.

Broadband six-way out-of-phase SIW power divider

A broadband six-way out-of-phase substrate-integrated waveguide (SIW) power divider was designed, analyzed, and fabricated for low loss and out of phase dividing applications. The SIW technology was used to realize the power divider; where it consists of a central dual-disc probe connected with coaxial outer-conductor impedance matching transformer and six SIW-to-microstrip transitions as output probes. Three of the SIW-to-microstrip transitions are located at the top plane, whereas the other three are at the bottom plane of the power divider to achieve the out-of-phase dividing functioning. These transitions are all the same in size and shape for symmetry reason. Good transmissions from coaxial input port to six-way SIW power divider were also achieved. There is a reasonable agreement between measured and simulated results.

High-Gain and Low-Loss Millimeter-Wave LTCC Antenna Array Using Artificial Magnetic Conductor Structure

A novel method based on an artificial magnetic conductor (AMC) structure is presented to improve radiation performances of low-temperature co-fired ceramics (LTCC) antennas. A millimeter-wave (mmW) LTCC patch antenna using AMC structures is designed, achieving a wide bandwidth of 26%, a high gain of 8.27 dBi, and a high radiation efficiency of 86.2%. Based on the antenna element, an 4 × 4 array with an AMC is developed. A low loss multilayer laminated waveguide (LWG) power divider is proposed to feed the array. Simulation and measurement results for the proposed array are in good agreement, and demonstrate a good and stable performance in terms of 13.96% matching bandwidth, high gain of 19.1 dBi, and flat gain response with variation of 2 dB. Furthermore, the efficiency can reach 63.1% which is higher than other designs available in the literature. A very high efficiency of more than 45% is achieved across a wide frequency band from 34 to 37 GHz.

New Advances on Heterogeneous Integration of III–V on Silicon

Recent advances on hybrid III–V/Si lasers and semiconductor optical amplifiers using wafer bonding are reported. Hybrid optical amplifiers exhibit 28 dB internal gain, 9 dBm saturation power in the output silicon waveguide, and 10–11 dB of internal noise factor. Moreover, using optical amplifiers as optical gates, we demonstrate a successful switching operation of optical packet/burst without penalties compared to classical optical amplifiers. The hybrid silicon lasers allow single mode operation and wavelength tunability over 30 nm by exploiting silicon ring resonators thermo-optical effect. Moreover transmission over 60 km single-mode fiber at 10 Gb/s from a directly modulated III–V on Silicon hybrid laser is also demonstrated. Finally, we achieved 21.4 Gb/s modulation over 12 wavelengths using a high-speed directly modulated silicon hybrid laser with improved E/O bandwidth.