Measurement of carrier envelope offset frequency for a 10 GHz etalon-stabilized semiconductor optical frequency comb

We report Carrier Envelope Offset (CEO) frequency measurements of a 10 GHz harmonically mode-locked, Fabry-Perot etalon-stabilized, semiconductor optical frequency comb source. A modified multi-heterodyne mixing technique with a reference frequency comb was utilized for the measurement. Also, preliminary results from an attempt at f-2f self-referencing measurement are presented. The CEO frequency was found to be similar to 1.47 GHz for the particular etalon that was used

Angular velocimetry for fluid flows: an optical sensor using structured light and machine learning

Most velocimetry approaches for fluid flows measure linear components of the velocity vector; yet, the angular velocity components, particularly at small scales in turbulent flows, also need to be resolved to study energy transfer and other important flow characteristics. Here, we detail an optical sensor approach to determine a component of the angular velocity vector. This approach uses beams of structured light and a machine learning-based analysis. We discuss the methodology to train the machine learning model and test it in experimentally validated simulations. This approach represents an interesting new direction for fluid flow velocimetry which may be extended to sense other flow parameters by selecting different light structures. &nbsp;</p

Immunodiagnostic confirmation of hydatid disease in patients with a presumptive diagnosis of infection

Information obtained from the routine application of hydatid immunodiagnostic techniques in different clinical situations over a seven-year period is presented. The Immunoelectrophoresis test was used until it was replaced by the simpler, more sensitive and equally specific arc 5 double diffusion (DD5) test. Examination of sera from 1,888 patients with signs and/or symptoms compatible with hydatid disease revealed that the presurgical confirmation of Echinococcus granulosus infection is only obtained by detection of anti-antigen 5 antibodies. The latter were not found in 1,539 presumptive hydatidosis patients whose definitive diagnoses corresponded to other disease conditions. However, false positive latex agglutination test results were obtained in two cases. In all patients whose preoperative serum showed three or more uncharacteristic bands in the absence of anti-antigen 5 antibodies, hydatid cysts were found sur gically. DD5 testing of a fluid sample collected by puncture established its hydatid etiology. Post-operative monitoring of hydatidosis patients demonstrated that persistence of DD5-positivity two years after surgery established the presence of other cysts. Further evidence was obtained in patients with hydatid cysts in intrathoracic, abdominal or other locations associating cyst membrane integrity, antigen release and immunodiagnostic test positivity

Theoretical Study Of Spur-Free Dynamic Range Of A Semiconductor Resonant Cavity Linear Interferometric Intensity Modulator

Simulation results of the performance of a semiconductor resonant cavity linear interferometric intensity modulator are presented. Starting from the rate equations of an injection locked semiconductor laser, the phase response and stable locking range of the injection locked semiconductor laser were obtained. Within the stable locking range without any approximation on the injection power level, effects of the alpha parameter or linewidth enhancement factor of the injection locked semiconductor slave laser, injection ratio, refractive index, and the residual amplitude modulation on the spur-free dynamic range (SFDR) of the modulator are studied. © 2011 SPIE

Injection locked VCSELs for microwave photonic applications in analog RF links and real time arbitrary waveform generation

In this paper, we show recent results in the use of injection locked vertical cavity semiconductor lasers (VCSELs) as novel modulators and narrowband optical filters that can be exploited for applications relevant to microwave photonics. Specifically, we exploit the phase modulation that is imparted onto the injection locked signal by modulating the current to the VCSEL. Optical filtering is realized by noting that there exists a \u27locking range\u27 which determines the amount of optical detuning from the free running VCSEL and the injection seed signal allowed for the injection locked process to work. Using these two salient properties of injection locked VCSELs, we show that one can simultaneously select single components from a frequency comb and realize either modulation or detection functionality. Furthermore, we show how injection locked VCSELs can be used in highly linear RF analog links and how VCSELs can be used with an optical comb to perform real time waveform generation [1]. © 2012 IEEE

Injection Locked Vcsels For Microwave Photonic Applications In Analog Rf Links And Real Time Arbitrary Waveform Generation

In this paper, we show recent results in the use of injection locked vertical cavity semiconductor lasers (VCSELs) as novel modulators and narrowband optical filters that can be exploited for applications relevant to microwave photonics. Specifically, we exploit the phase modulation that is imparted onto the injection locked signal by modulating the current to the VCSEL. Optical filtering is realized by noting that there exists a \u27locking range\u27 which determines the amount of optical detuning from the free running VCSEL and the injection seed signal allowed for the injection locked process to work. Using these two salient properties of injection locked VCSELs, we show that one can simultaneously select single components from a frequency comb and realize either modulation or detection functionality. Furthermore, we show how injection locked VCSELs can be used in highly linear RF analog links and how VCSELs can be used with an optical comb to perform real time waveform generation [1]. © 2012 IEEE

Isolation and purification of Echinococcus granulosus antigen B from hydatid cyst fluid using three different methods

Hydatid cyst, the larval stage of cestodes Echinococcus spp., is recognized as a zoonotic infection in the world. The World Health Organization (WHO) has recently classified echinococcosis in a group of neglected tropical diseases. The prevalence of Echinococcus granulosus infection is high in Iran due to the presence of various intermediate hosts in this country. Considering the rising trend of this zoonotic parasitic disease based on national epidemiological studies, diagnosis is of great significance. WHO has suggested the use of specific antigens, especially antigen B (AgB) for serological diagnostic tests. In general, AgB is a polymeric lipoprotein, which disintegrates into 8.12, 16, and 20.24 kDa subunits. In the present study, we applied three different methods for AgB isolation from hydatid cyst fluid (HCF) and compared their efficacy in AgB isolation. Finally, the protein concentration of this antigen was measured by Bradford assay and confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The results showed that the application of polyethylene glycol (PEG 4000) as a thickener agent beside purification of HCF in dialysis bag and filtering and also dialysis against acetate buffer leading to the best quantity in purified antigen B

Coherent Optical Signal Processing Using Optical Frequency Combs

In this paper, we show recent results in the use of stabilized optical frequency combs from mode-locked diode lasers operating in the telecommunication C-band for applications in coherent parallel signal processing architectures [1]. For selecting and modulating single components within the frequency comb, novel approaches that rely on the properties of injection locked oscillators will be used. These approaches will show that one can simultaneously select single components from a frequency comb and realize either modulation or detection functionality. To demonstrate how stabilized frequency combs can be used in a coherent signal processing scenario, we use the frequency combs and injection locked microcavity lasers to perform real time waveform generation, measurement, and matched filtering. © 2012 IEEE