scholarly journals Phase Variation Measurement in Mach–Zehnder Interferometric Switch

2021 ◽  
Vol 21 (6) ◽  
pp. 180-184
Author(s):  
Sichen Fan ◽  
Jun Ruan ◽  
Dandan Liu ◽  
Xinliang Wang ◽  
Fan Yang ◽  
...  
Keyword(s):  
Extinction Ratio ◽  
Phase Fluctuation ◽  
Phase Variation ◽  
Transient Effects ◽  
Rf Switch ◽  
Phase Fluctuations ◽  
Phase Variations ◽  
Ramsey Type ◽  
Lock In ◽  
Better Than

Abstract Phase variations of the interrogation field lead to frequency shifts in Ramsey-type atomic clocks. This paper reports the development of a 300 MHz Mach–Zehnder (MZ) switch that effectively suppresses phase-transient effects. Similar to MZ interferometers, this radio-frequency (RF) MZ switch comprises two arms that are power- and phase-matched with each other. By inserting a PIN diode RF switch in one arm, the other arm remains undisturbed, freeing it of the phase transient. Trigger phase fluctuation measurements are implemented by using a lock-in amplifier to extract the in-phase and quadrature (I/Q) demodulation data. The results show that the extinction ratio of the RF MZ switch phase fluctuations is <5 μrad, which is significantly lower than that of a PIN (50 μrad). When applied to a cesium fountain clock, the RF MZ switch produces a frequency shift better than 1.73 × 10−16.

Analysis of a Tunable CMOS-compatible Multilayer Waveguide Structure for Dual Polarizer-modulator Operation

2021 ◽  
Author(s):  
Renan Silva Santos ◽  
Maria A. G. Martinez
Keyword(s):  
Chemical Potential ◽  
Extinction Ratio ◽  
Silicon Layer ◽  
Individual Case ◽  
Waveguide Structure ◽  
Potential Range ◽  
Figures Of Merit ◽  
Silicon Waveguide ◽  
The One ◽  
Better Than

Abstract A multilayer structure using graphene on a silicon waveguide is introduced and optimized to operate as a tunable TE-pass polarizer at 1310 nm or 1550 nm, a tunable TE/TM modulator at 1310 nm or 1550 nm, and a dual operation as a modulator at 1310 nm and a polarizer at 1550 nm. The analysis is based on the waveguide structure modal loss, the 2D graphene layer optical properties and its dependency on the applied chemical potential. The optimization is done by varying waveguide height and choosing the one with best figures of merit for each individual case and for the dual operation, the value that causes the least impairment overall is chosen. The polarizer tunability at 1310 nm or 1550 nm is attainable setting the applied chemical potential range from 0.55–0.65 eV or 0.45–0.55 eV, respectively. For the modulator tunability at 1310 nm or 1550 nm, the applied chemical potential range from 0.45–0.55 eV or 0.35–0.45 eV, respectively. The optimized waveguide silicon layer around 210 nm guarantees an extinction ratio better than 0.056 dB/µm for the polarizer and better than 0.045/0.133 dB/µm for the TE/TM modulator at 1310 nm, and better than 0.034 dB/µm for polarizer and better than 0.053/0.137 dB/µm for TE/TM modulator at 1550 nm. Further, the setting the chemical potential range at 0.45–0.55 eV, allows dual polarizer-modulator operation, with the modulator operating at 1310 nm and the polarizer operating at 1550 nm, presenting an extinction ratio better than 0.045 dB/µm and 0.034 dB/µm respectively. In all situations analyzed, insertion loss is lower than 0.007 dB/µm. The advantage of the structure in comparison with other similar devices relies in its versatility to operate as both modulator and polarizer, in different wavelengths, via a proper choosing of the applied chemical potential.

Quasi-Common-Path Laser Feedback Interferometers for Precision Measurement of Non-Cooperative Targets

2008 ◽  
Vol 381-382 ◽  
pp. 49-52
Author(s):  
X.J. Wan ◽  
Shu Lian Zhang
Keyword(s):  
Optical Path ◽  
Heterodyne Detection ◽  
Reference Mirror ◽  
Phase Fluctuations ◽  
Common Path ◽  
Laser Instability ◽  
Phase Variations ◽  
Path Lengths ◽  
Contact Displacement ◽  
Feedback Light

In this paper, we report a novel quasi-common-path laser feedback interferometer (QLFI) for highly stable, high-resolution and non-contact displacement measurement. QLFI measures the displacement of the target by measuring the phase of feedback light. In addition to the target-generated feedback light (frequency shifted by 2#), a reference mirror generates a reference feedback light which is frequency shifted by #. The phase variations of both feedback lights are measured by heterodyne detection simultaneously and their difference offers the phase variations caused only by target displacement. When the optical path lengths of the reference and measuring feedback light are nearly the same, the phase fluctuations caused by the environment and laser instability are effectively removed. The heat-induced deformation of a He-Ne laser tube is successfully in-line measured using QLFI.

A Highly-Integrated, Switchless and Baluns-Embedded Transceiver with a Differential Structure for C-Band Radar Application

2019 ◽  
Vol 29 (10) ◽  
pp. 2050160
Author(s):  
Guoxiao Cheng ◽  
Zhiqun Li ◽  
Zhennan Li ◽  
Zengqi Wang ◽  
Meng Zhang
Keyword(s):  
Output Power ◽  
Noise Figure ◽  
Low Noise ◽  
Cmos Process ◽  
Image Rejection ◽  
Rf Switch ◽  
Differential Structure ◽  
Noise Amplifier ◽  
Image Rejection Ratio ◽  
Better Than

This paper presents a highly-integrated transceiver with a differential structure for C-band (5–6[Formula: see text]GHz) radar application using a switchless and baluns-embedded configuration. To reduce the noise figure (NF) in receiver (Rx) mode and enhance the output power in transmitter (Tx) mode, the balun at RF port is embedded into the low-noise amplifier (LNA) and the power amplifier (PA), respectively. Besides, the RF switch is removed by designing the matching networks that both LNA and PA can share. The same topology is also adopted at the IF port. To achieve a high image rejection ratio (IRR), a Hartley architecture using polyphase filters (PPFs) is adopted. The proposed transceiver has been implemented in 1P6M 0.18-[Formula: see text]m CMOS process. The receiver achieves 6.9-dB NF, [Formula: see text]7.5-dBm IIP3 and 26.3-dB gain with three-step digital gain controllability. Also the measured IRR is better than 41[Formula: see text]dBc. The transmitter achieves 9.6-dBm output power and 19.2-dB gain. The chip consumes 106[Formula: see text]mA in the Rx mode and 141[Formula: see text]mA in the Tx mode from the 3.3-V power supply.

scholarly journals Microwave Photonic ICs for 25 Gb/s Optical Link Based on SiGe BiCMOS Technology

Symmetry ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1453 ◽  
Author(s):  
Andrey A. Kokolov ◽  
Dmitry A. Konkin ◽  
Artyom S. Koryakovtsev ◽  
Feodor I. Sheyerman ◽  
Leonid I. Babak
Keyword(s):  
Extinction Ratio ◽  
Single Chip ◽  
Microwave Photonic ◽  
Half Wave Voltage ◽  
Bicmos Technology ◽  
Sige Bicmos ◽  
Driver Amplifier ◽  
Integrated Transmitters ◽  
Optical Divider ◽  
Better Than

The design, simulation and experimental results of the integrated optical and electronic components for 25 Gb/s microwave photonic link based on a 0.25 µm SiGe:C BiCMOS technology process are presented. A symmetrical depletion-type Mach-Zehnder modulator (MZM) and driver amplifier are intended for electro-optical (E/O) integrated transmitters. The optical divider and combiner of MZM are designed based on the self-imaging theory and then simulated with EM software. In order to verify the correctness of the theory and material properties used in the simulation, a short test (prototype) MZM of 1.9 mm length is produced and measured. It shows an extinction ratio of 19 dB and half-wave voltage-length product of Vπ ∙ L = ~1.5 V·cm. Based on these results, the construction of the segmented modulator with several driver amplifier units is defined. The designed driver amplifier unit provides a bandwidth of more than 30 GHz, saturated output power of 6 dBm (output voltage of Vpp = 1.26 V), and matching better than −15 dB up to 35 GHz; it dissipates 170 mW of power and occupies an area of 0.4 × 0.38 mm2. The optical-electrical (O/E) receiver consists of a Ge-photodiode, transimpedance amplifier (TIA), and passive optical structures that are integrated on a single chip. The measured O/E 3 dB analog bandwidth of the integrated receiver is 22 GHz, and output matching is better than −15 dB up to 30 GHz, which makes the receiver suitable for 25 Gb/s links with intensity modulation. The receiver operates at 1.55 μm wavelength, uses 2.5 V and 3.3 V power supplies, dissipates 160 mW of power, and occupies an area of 1.46 × 0.85 mm2.

scholarly journals Efficient and Optimal Service Component Distribution across Multiple Clouds

2018 ◽  
Vol 6 (3) ◽  
pp. 44 ◽  
Author(s):  
Driss Riane ◽  
Ahmed Ettalbi
Keyword(s):  
Cloud Services ◽  
Main Step ◽  
Service Component ◽  
Component Distribution ◽  
Cloud Broker ◽  
Optimal Service ◽  
Multiple Clouds ◽  
Lock In ◽  
Better Than

<span class="fontstyle0">Cloud computing technology is one of the key considerations for business willing to access to different cloud services over the Internet and to benefit from the diversity of IaaS offers and pricing models. Although several solutions are available in the market, there are still some issues to solve. The main important aspect to address is the user’s request complexity, the vendor lock-in risk and the SLA fulfillment. In this paper, we propose a Multi-Cloud Broker called MCB that allows an efficient and optimal service component distribution among different clouds in flexible and dynamic infrastructure provisioning environment, in order to achieve better Quality of Service and cost efficiency. The request partitioning is the main step of our approach, this step is performed using Gomory-Hu tree based algorithm. Our simulation results show how our algorithm is better than existing partitioning algorithms in terms of running time.</span>

The effect of phase variations and cross-shear on vortical structures in a plane mixing layer

1994 ◽  
Vol 276 ◽  
pp. 21-59 ◽  
Author(s):  
Kris J. Nygaard ◽  
Ari Glezer
Keyword(s):  
Shear Layer ◽  
Phase Distribution ◽  
Surface Film ◽  
Transverse Velocity ◽  
Excitation Frequency ◽  
Phase Variation ◽  
Two Dimensional ◽  
Oblique Waves ◽  
Phase Variations ◽  
Secondary Vortices

The evolution of spanwise phase variations of nominally two-dimensional instability modes in a plane shear layer is studied in a closed-return water facility using time-harmonic excitation having spanwise-non-uniform phase or frequency distributions. The excitation waveform is synthesized by a linear array of 32 surface film heaters flush-mounted on the flow partition. A span wise-linear phase distribution leads to the excitation of oblique waves and to the rollup of oblique primary vortices. When the prescribed phase distribution is piecewise-constant and spanwise-periodic, the flow is excited with a linear combination of a two-dimensional wavetrain and pairs of equal and opposite oblique waves, the amplitudes of which depend on the magnitude of the phase variation ΔΦ. As a result of the excitation, the primary vortices undergo spanwise-non-uniform rollup and develop spanwise-periodic deformations that induce cross-shear and secondary vortices in the braid region. The amplitude of the deformations of the primary vortices and the shape and strength of the secondary vortices depend on the magnitude of ΔΦ. When ΔΦ is small, the secondary vortices are counter-rotating vortex pairs. As ΔΦ increases, cross-shear induced by oblique segments of the primary vortices in the braid region results in the formation of single secondary vortex strands. The flow is not receptive to spanwise phase variations with wavelengths shorter than the streamwise wavelength of the Kelvin–Helmholtz instability. When the phase variation is ΔΦ = ϕ, the flow is excited with pairs of oblique waves only and undergoes a double rollup, resulting in the formation of spanwise-deformed vortices at twice the excitation frequency. Measurements of the streamwise velocity component show that the excitation leads to a substantial increase in the cross-stream spreading of the shear layer and that distortions of transverse velocity profiles are accompanied by an increase in the high-frequency content of velocity power spectra. Detailed schlieren visualizations shed light on the nature of ‘vortex dislocations’ previously observed by other investigators. Complex spanwise-non-uniform pairing interactions between the spanwise vortices are forced farther downstream by spanwise-amplitude or phase variations of subharmonic excitation wavetrains.

Experimental determination of electric-field-induced differences in structure-factor phases of the order of 2%

1999 ◽  
Vol 55 (6) ◽  
pp. 1034-1037 ◽  
Author(s):  
J. Stahn ◽  
A. Pucher ◽  
U. Pietsch ◽  
J. Zellner ◽  
E. Weckert
Keyword(s):  
Electric Field ◽  
Structure Factor ◽  
Phase Variation ◽  
Bonded Materials ◽  
Charge Model ◽  
Covalently Bonded ◽  
Phase Variations ◽  
Bond Charge ◽  
Semi Empirical

In order to understand the induced electron-density response of covalently bonded materials to an externally applied electric field, the change of structure-factor phases of several weak reflections of GaAs has been measured by three-beam interferences. Using a modulation technique, phase variations of the order of 1° for a field strength of 1 kV mm−1 were determined. Although the statistics of these first experiments are rather poor, the experiment verifies qualitatively the predictions of a semi-empirical bond-charge model. The measured phase variation is the smallest value determined up to now.

scholarly journals Phase Variations of the Mycoplasma penetrans Main Surface Lipoprotein Increase Antigenic Diversity

1999 ◽  
Vol 67 (4) ◽  
pp. 1569-1578 ◽  
Author(s):  
Olivier Neyrolles ◽  
Isabelle Chambaud ◽  
Stéphane Ferris ◽  
Marie-Christine Prevost ◽  
Tsuguo Sasaki ◽  
...  
Keyword(s):  
Point Mutations ◽  
Phase Variation ◽  
Antigen Expression ◽  
Polyclonal Antiserum ◽  
Humoral Immune ◽  
Immunodeficiency Virus ◽  
Surface Antigen Expression ◽  
Major Antigen ◽  
Phase Variations ◽  
Triton X

ABSTRACT Mycoplasma penetrans is a recently identified mycoplasma, isolated from urine samples collected from human immunodeficiency virus (HIV)-infected patients. Its presence is significantly associated with HIV infection. The major antigen recognized during natural and experimental infections is an abundant P35 lipoprotein which, upon extraction, segregates in the Triton X-114 detergent phase and is the basis of M. penetrans-specific serological assays. We report here that the P35 antigen undergoes spontaneous and reversible phase variation at high frequency, leading to heterogeneous populations of mycoplasmas, even when derived from a clonal lineage. This variation was found to be determined at the transcription level, and although this property is not unique among the members of the class Mollicutes, the mechanism by which it occurs in M. penetrans differs from those previously described for other Mycoplasma species. Indeed, the P35 phase variation was due neither to a p35 gene rearrangement nor to point mutations within the gene itself or its promoter. The P35 phase variation in the different variants obtained was concomitant with modifications in the pattern of other expressed lipoproteins, probably due to regulated expression of selected members of a gene family which was found to potentially encode similar lipoproteins. M. penetrans variants could be selected on the basis of their lack of colony immunoreactivity with a polyclonal antiserum against a Triton X-114 extract, strongly suggesting that the mechanisms involved in altering surface antigen expression might allow evasion of the humoral immune response of the infected host.

scholarly journals Characterising phase variations in MALDI-TOF data and correcting them by peak alignment

2005 ◽  
Vol 1 ◽  
pp. 117693510500100 ◽  
Author(s):  
Simon M Lin ◽  
Richard P Haney ◽  
Michael J Campa ◽  
Michael C Fitzgerald ◽  
Edward F Patz
Keyword(s):  
Data Analysis ◽  
Phase Variation ◽  
Principal Component ◽  
Microarray Data Analysis ◽  
Alignment Algorithm ◽  
Data Set ◽  
Peak Alignment ◽  
Maldi Tof ◽  
Biological Interest ◽  
Phase Variations

The use of MALDI-TOF mass spectrometry as a means of analyzing the proteome has been evaluated extensively in recent years. One of the limitations of this technique that has impeded the development of robust data analysis algorithms is the variability in the location of protein ion signals along the x-axis. We studied technical variations of MALDI-TOF measurements in the context of proteomics profiling. By acquiring a benchmark data set with five replicates, we estimated 76% to 85% of the total variance is due to phase variation. We devised a lobster plot, so named because of the resemblance to a lobster claw, to help detect the phase variation in replicates. We also investigated a peak alignment algorithm to remove the phase variation. This operation is analogous to the normalization step in microarray data analysis. Only after this critical step can features of biological interest be clearly revealed. With the help of principal component analysis, we demonstrated that after peak alignment, the differences among replicates are reduced. We compared this approach to peak alignment with a model-based calibration approach in which there was known information about peaks in common among all spectra. Finally, we examined the potential value at each point in an analysis pipeline of having a set of methods available that includes parametric, semiparametric and nonparametric methods; among such methods are those that benefit from the use of prior information.

scholarly journals Numerical Investigation of a Short Polarization Beam Splitter Based on Dual-Core Photonic Crystal Fiber with As2S3 Layer

Micromachines ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 706
Author(s):  
Nan Chen ◽  
Xuedian Zhang ◽  
Xinglian Lu ◽  
Zheng Zhang ◽  
Zhangjian Mu ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Photonic Crystal Fiber ◽  
Beam Splitter ◽  
Extinction Ratio ◽  
Polarized Light ◽  
Polarization Beam Splitter ◽  
Optical Fields ◽  
Crystal Fiber ◽  
Dual Core ◽  
Better Than

A polarization beam splitter is an important component of modern optical system, especially a splitter that combines the structural flexibility of photonic crystal fiber and the optical modulation of functional material. Thus, this paper presents a compact dual-core photonic crystal fiber polarization beam splitter based on thin layer As2S3. The mature finite element method was utilized to simulate the performance of the proposed splitter. Numerical simulation results indicated that at 1.55 μm, when the fiber device length was 1.0 mm, the x- and y-polarized lights could be split out, the extinction ratio could reach −83.6 dB, of which the bandwidth for extinction ratio better than −20 dB was 280 nm. It also had a low insertion loss of 0.18 dB for the x-polarized light. In addition, it can be completely fabricated using existing processes. The proposed compact polarization beam splitter is a promising candidate that can be used in various optical fields.

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