Complicated Lemierre Syndrome Caused by Streptococcus gordonii and Possible Rickettsial Co-Infection in a Patient with Thrombophilia Predisposition

Aims: Lemierre syndrome is a life-threating condition characterized by recent oropharyngeal infection, internal jugular vein thrombosis, and anaerobic septicemia. It is usually caused by Fusobacterium necrophorum. Methods: A young Romanian male presented with fever and rigors, mild tachypnea, hypoxia, sore throat, decayed teeth, and tenderness of the left carotid triangle. Laboratory examination indicated severe sepsis with disseminated intravascular coagulation, acute renal failure, and acute respiratory distress syndrome while the Doppler ultrasonography of the carotids revealed left internal jugular venous thrombosis. The patient was administered piperacillin/tazobactam and vancomycin intravenously, doxycycline orally, and anti-coagulation by enoxaparin based on the diagnosis of Lemierre syndrome. Meanwhile, he was complicated by bilateral diffuse pulmonary cavities and encapsulated pleural effusions and so transcutaneous drainage was performed. The patient was discharged after a month and continued his treatment with oral phenoxypenicillin and doxycycline until full radiographic improvement. He was switched to oral anti-coagulation by vitamin-K antagonists and was referred to a hematologist, a vascular-surgeon, and a dentist. Results: Streptococcus gordonii was isolated from the patient’s blood and pleural fluid cultures and serology for Rickettsial spp. IgM was positive. Thrombophilia genetic tests revealed three minor mutations for fibrinogen-455, plasminogen activator inhibitor-1, and methylenetetrahydrofolate reductase. According to the literature, S. gordonii is not usually a causative agent and Rickettsial spp. have as yet not been correlated with Lemierre syndrome. The failure of left jugular vein recanalization shows a possible causative role of the underlying thrombophilic predisposition. Discussion: Because of the syndrome’s rarity and the atypical microorganisms isolated in this case, increased awareness is advised for its diagnosis and the underlying mechanisms involved in its genesis. The role of anti-coagulation is debatable

All-in-Fiber Cladding Interferometric and Bragg Grating Components Made via Plane-by-Plane Femtosecond Laser Inscription

We introduce a method of inscribing in-fiber devices using a femtosecond laser that is applicable to crucial components, such as cladding waveguides (CWGs), cladding Mach-Zehnder interferometers (MZIs), embedded waveguide Bragg gratings (WBGs), and waveguide Fabry-Perot cavities using the same key femtosecond laser parameters, via an 'inscribe and step,' plane-by-plane approach, applied as necessary on two orthogonal axes. This leads to femtosecond laser-inscribed cladding waveguides and ultra-compact MZIs that can support functional, integrated fiber Bragg gratings; the unique sensing characteristics of the filters are maintained and provide complementary measure and information. This ensures a single inscription process, offering reliability and repetition in component manufacture, as the basic conditions to inscribe the here-demonstrated elements are common. We characterize CWG-WBG devices for axial strain, bend, and response to refractive index. The MZI-WBG is exposed to temperature and humidity excursions, confirming that the unique sensor responses are maintained for this compact, compound sensor. The MZI exhibits response to external refractive index, a large, negative wavelength response with temperature and high sensitivity to humidity, whereas the MZI-located WBG displays a similar sensitivity to conventional core-based Bragg grating sensors to temperature and no response to relative humidity. We consider that this research is an important step in the development of compact, smart optical fiber sensors

Fibre cladding interferometers and Bragg gratings made via plane by plane femtosecond laser inscription

We present an extremely flexible femtosecond (fs) laser inscription method, applicable to the development of critical filtering and wave-guiding components in optical fibres. We inscribe in-fibre devices, such as cladding waveguides (CWGs), cladding Mach-Zehnder interferometers (MZIs) and embedded waveguide Bragg gratings (WBGs) using the same key femtosecond laser parameters, via an "inscribe and step", plane-by-plane (Pl-by-Pl) approach, applied as necessary on two orthogonal axes. This leads to femtosecond laser-inscribed cladding waveguides and ultra-compact MZIs that can support functional, integrated fibre Bragg gratings (FBGs); the unique sensing characteristics of the filters are maintained and provide complementary measurand information. The flexibility and control in waveguide/grating fabrication leads to sensing device customization, e.g.Tailored bend sensing. We characterize CWG-WBG devices for their bend response, whereas the MZI-WBG is exposed to temperature and humidity excursions, confirming the unique sensor responses are maintained for this compact, compound sensor. The MZI exhibits response to external refractive index, a large, negative wavelength response with temperature and high sensitivity to humidity, whereas the MZI-located WBG displays a similar sensitivity to conventional core-based Bragg grating sensors to temperature and no response to relative humidity. We consider that this research is an important step in developing compact, smart optical fibre sensors

Fibre cladding filters through femtosecond laser inscription

We inscribe several in-cladding-fibre filters using the same key femtosecond laser parameters, via an “inscribe and step”, plane-by-plane (Pl-by-Pl) approach, leading to ultra-compact waveguides and Mach Zehnders (MZs) that can support functional, integrated fibre Bragg gratings (FBGs)

Sensing capabilities of higher order cladding modes

In this work, 5-mm long TFBGs were inscribed in photosensitive single-mode optical fiber using the direct writing plane-by-plane femtosecond laser inscription method; a flexible inscription approach that enables absolute control of the grating period, length, angle, width and depth of the grating planes. This new fabrication method brings important differences compared to classical inscription methods. Firstly, these gratings exhibit very low photo-induced birefringence (measured ∼8pm) and as we rely on a direct writing process, the tilt angle of the inscribed grating does not affect the Bragg wavelength, allowing for precise positioning. In addition, this method enables the high order grating production, allowing a behavioral study of higher order cladding modes located at lower wavelengths in the 1200-1600 nm range. 8th order gratings were produced with cladding and Bragg mode resonances in the C+L bands. The temperature and strain sensitivities were measured for both the Bragg and higher order cladding modes, yielding an exceptional performance. The higher order modes exhibit a negative axial strain, up to-1.99nm (more than two times higher than the standard Bragg peaks) and a solid temperature sensitivity of 10.25 pm/°C: At the same time, for the designed order cladding modes (of the 8th) the refractive index sensitivity is measured at 22 nm/RIU

Low-loss Polymer Optical Components and Cladding Interferometric Devices Inscribed Using Femtosecond Laser Inscription

We present the development of low-loss polymer optical fiber components and interferometric devices in perfluorinated multimode fibers like CYTOP and silica fibers, respectively. This includes the inscription of usable fiber Bragg gratings, chirped gratings and Fabry-Perot cavities in multimode gradient index fiber using a femtosecond laser inscription. We present the successful demonstration of interferometric devices such as Mach-Zehnder filters and Fabry-Perot cavities inscribed in the cladding of a single mode silica optical fiber. The advantages of these particular progressive sensors are discussed

Femtosecond laser inscribed Mach-Zehnder Interferometer: a compound all-in-fiber versatile sensing device

We consider the sensing characteristics of a compact all-in-fiber Mach-Zehnder interferometer (MZI) inscribed using a femtosecond laser. The structure was created in the cladding of a single-mode optical fiber close to the cladding-air interface (<5μm gap) to deviate light from the core and encourage evanescent field interaction with the fiber’s surroundings. This compact device features a refractive index sensitivity beyond 5000 nm/RIU in aqueous solutions. Two fiber Bragg gratings (FBGs) were also manufactured, one in the pristine fiber core and the other in the cladding MZI and are monitored for sensing purposes. We used the plane-by plane (Pl-by-Pl) fabrication method, ensuring reliability and repeatability in the sensor development, as all gratings and MZI were inscribed with the same femtosecond laser parameters. We focus on the device response to changes in temperature, strain, bend, surrounding refractive index and relative humidity. By combining the compound sensor with a core FBG we produced a device capable of measuring multiple parameters using the same demodulation equipment, whilst simultaneously enhancing and individually separating each measurand of interest

Flexible direct write inscription of tilted fibre Bragg gratings using a femtosecond laser

A flexible, plane-by-plane, direct-write, femtosecond-laser inscription method for tailored, tilted fibre Bragg gratings (TFBGs) is presented. We characterize 10th order gratings in the C-to-O bands and their refractometric sensitivity with grating order

All-in-fiber fabrication of cladding devices and components using femtosecond laser pulses

Femtosecond (fs) lasers are well suited for high-resolution inscription in transparent materials of all types, and in particular optical fibres. The 'inscribe and step', Plane-by-Plane (Pl-by-Pl) inscription method enables the fabrication of components, such as cladding waveguides (CWGs), cladding Mach-Zehnder interferometers (MZIs) and embedded waveguide Bragg gratings (MZI-FBGs), using the same key femtosecond laser parameters. The cladding waveguides structures were inscribed in such proximity for the fiber core that allowed evanescent coupling to occur. Having this operational principle, the compound cladding sensor has minimal effect on fiber strength, leading to a robust sensing device. Furthermore, the versatile femtosecond laser-inscribed cladding waveguides and ultra-compact MZIs that can support functional, integrated fibre Bragg gratings (FBGs). This method ensures a single inscription process, offering reliability and repetition in component manufacturing. This hybrid configuration can measure multiple parameters using the same demodulation equipment, with very high sensitivity while minimizing cross sensitivity issues. We focus on the response to changes in temperature, strain, bend, and relative humidity of the developed components