Search

We examine moderate CO2 laser heating as a method of forming negative effective radius variations in conventional optical fiber. Fiber samples were subjected to focused CO2 laser radiation in the form of 100 ms pulses with power 0.36 to 1.3 W and thermalization time up to 2.2 s. Fiber temperatures reached 200 to 300 degrees Celsius in each pulse. The temper atures are significantly smaller than the glass transformation temperature, which is nearly 1500 °C. We show that short CO2 laser pulses may introduce negative variations up to 5 nm. The magnitude of the introduced variation increases roughly linearly for up to 6 pulses, and then fiber saturation is achieved. We reveal that it is possible to produce optical whispering gallery modes resonators in low-temperature heating mode and create a triangular-shape microresonator solely with the negative variations. The negative variations may also occur in peripheral areas of high-temperature heated fiber while introducing positive effective radius variations. To eliminate it, we propose low-temperature fiber annealing before high-temperature variations introducing. The negative variations may also be implemented to develop a new independent approach of shaping optical whispering gallery modes microresonators.

Increased level of CD44 protein in serum is observed in several cancers and is associated with tumor burden and metastasis. Current clinically used detection methods of this protein are time-consuming and use labeled reagents for analysis. Therefore exploring new label-free and fast methods for its quantification including its detection in situ is of importance. This study reports the first optical fiber biosensor for CD44 protein detection, based on a spherical fiber optic tip device. The sensor is easily fabricated from an inexpensive material (single-mode fiber widely used in telecommunication) in a fast and robust manner through a CO2 laser splicer. The fabricated sensor responded to refractive index change with a sensitivity of 95.76 dB/RIU. The spherical tip was further functionalized with anti-CD44 antibodies to develop a biosensor and each step of functionalization was verified by an atomic force microscope. The biosensor detected a target of interest with an achieved limit of detection of 17 pM with only minor signal change to two control proteins. Most importantly, concentrations tested in this work are very broad and are within the clinically relevant concentration range. Moreover, the configuration of the proposed biosensor allows its potential incorporation into an in situ system for quantitative detection of this biomarker in a clinical setting.

Refereed/Peer-reviewed A multifunction, high-sensitivity, and temperature-compensated optical fiber DNA hybridization sensor combining surface plasmon resonance (SPR) and Mach–Zehnder interference (MZI) has been designed and implemented. We demonstrate, for the first time to our knowledge, the dual-parameter measurement of temperature and refractive index (RI) by simultaneously using SPR and MZI in a simple single-mode fiber (SMF)–no-core fiber (NCF)–SMF structure. The experimental results show RI sensitivities of 930 and 1899 nm/RIU and temperature sensitivities of 0.4 and −1.4 nm/°C for the MZI and SPR, respectively. We demonstrate a sensitivity matrix used to simultaneously detect both parameters, solving the problem of temperature interference of RI variation-based biosensors. In addition, the sensor can also distinguish biological binding events by detecting the localized RI changes at the fiber’s surface. We realize label-free sensing of DNA hybridization detection by immobilizing probe DNA (pDNA) onto the fiber as the probe to capture complementary DNA (cDNA). The experimental results show that the sensor can qualitatively detect cDNA after temperature compensation, and the limit of detection (LOD) of the sensor reaches 80 nM. The proposed sensor has advantages of high sensitivity, real time, low cost, temperature compensation, and low detection limit and is suitable for in situ monitoring, high-precision sensing of DNA molecules, and other related fields, such as gene diagnosis, kinship judgment, environmental monitoring, and so on.

Background Early malaria diagnosis and its profiling require the development of new sensing platforms enabling rapid and early analysis of parasites in blood or saliva, aside the widespread rapid diagnostic tests (RDTs). Methods This study shows the performance of a cost-effective optical fiber-based solution to target the presence of Plasmodium falciparum histidine-rich protein 2 (PfHRP2). Unclad multimode optical fiber probes are coated with a thin gold film to excite Surface Plasmon Resonance (SPR) yielding high sensitivity to bio-interactions between targets and bioreceptors grafted on the metal surface. Results Their performances are presented in laboratory conditions using PBS spiked with growing concentrations of purified target proteins and within in vitro cultures. Two probe configurations are studied through label-free detection and amplification using secondary antibodies to show the possibility to lower the intrisic limit of detection. Conclusions As malaria hits millions of people worldwide, the improvement and multiplexing of this optical fiber technique can be of great interest, especially for a future purpose of using multiple receptors on the fiber surface or several coated-nanoparticles as amplifiers.

We report on the design, growth, and fabrication of InAs/InP quantum dash (QD) gain materials and their use in lasers for optical network applications. A noise performance comparison between QD and quantum well (QW) Fabry–Perot (F-P) lasers has been made. By using the QD gain material we have successfully developed and assembled C-band coherent comb laser (CCL) modules with an electrical fast feedback loop control system to ensure a targeted mode frequency spacing. The frequency spacing was maintained within ±100 ppm and the operation wavelengths locked on the desired ITU grid within 0.01 nm over a period of several months. We also investigated a 25-GHz C-band QD CCL with an external cavity self-injection feedback locking (SIFL) system to reduce the optical linewidth of each individual channel to below 200 kHz in the wavelength range from 1537.55 nm to 1545.14 nm. The RF mode beating signal 3-dB bandwidth was also reduced from 9 kHz to approximately 500 Hz with this SIFL system. These QD CCLs with ultra-low relative intensity noise (RIN), ultra-narrow optical linewidth, and ultra-low timing jitter are excellent laser sources for multi-terabit optical networks. Using a 34.2 GHz QD CCL we demonstrate 10.8 Tbit/s (16QAM 48 × 28 GBaud PDM) coherent data transmission over 100 km of standard single mode fiber (SSMF) and 5.4 Tbit/s (PAM-4 48 × 28 GBaud PDM) aggregate data transmission capacity over 25 km of SSMF with error-free operation.

A new biosensing method is presented to detect gene mutation by integrating the MutS protein from bacteria with a fiber optic particle plasmon resonance (FOPPR) sensing system. In this method, the MutS protein is conjugated with gold nanoparticles (AuNPs) deposited on an optical fiber core surface. The target double-stranded DNA containing an A and C mismatched base pair in a sample can be captured by the MutS protein, causing increased absorption of green light launching into the fiber and hence a decrease in transmitted light intensity through the fiber. As the signal change is enhanced through consecutive total internal reflections along the fiber, the limit of detection for an AC mismatch heteroduplex DNA can be as low as 0.49 nM. Because a microfluidic chip is used to contain the optical fiber, the narrow channel width allows an analysis time as short as 15 min. Furthermore, the label-free and real-time nature of the FOPPR sensing system enables determination of binding affinity and kinetics between MutS and single-base mismatched DNA. The method has been validated using a heterozygous PCR sample from a patient to determine the allelic fraction. The obtained allelic fraction of 0.474 reasonably agrees with the expected allelic fraction of 0.5. Therefore, the MutS-functionalized FOPPR sensor may potentially provide a convenient quantitative tool to detect single nucleotide polymorphisms in biological samples with a short analysis time at the point-of-care sites.

Although robot-assisted diagnosis and minimally invasive surgery (MIS) brings distinct benefits, deficient multi-dimensional force feedback remains a noteworthy limitation and challenge in MIS. Aiming for a comprehensive high-fidelity perception of tissue-instrument interactions, we present a Fiber Bragg Grating (FBG)-based 3-axis tactile sensing for surface reaction force mapping, identification and localization of tissue hard-inclusion. The tactile sensing probe consists of five optical fibers inscribed with FBGs and a force-sensitive 3D printed deformable body. All fibers are suspended inside the deformable body in a parallel manner, leading to the direct compression or tension of each FBG. Such configuration can effectively avoid the chirping failure of FBG compared with the pasting FBG-based sensors. A linearized difference model is proposed to calibrate the 3-axis force detection and enhance the resistance to nonlinear interferences. Hard-inclusion identification experiments with varied hard-inclusion sizes and depths have been implemented through discrete palpation and dragging palpation modes. Results indicate that the probe can effectively identify the presence and location of these small hard-inclusions from the force mapping. Furthermore, lengthy vessels embedded in the phantom can be accurately identified through dragging palpation with an arbitrary contact angle. Another novelty of the probe is the reconstruction of the surface profile of a non-planar tissue, which further allows hard-inclusion identification and 3D localization. Ex-vivo tissue palpation on a porcine kidney further validates the effectiveness and feasibility of the probe to map surface reaction forces and localize the hard-inclusions intraoperatively.

In this article, we propose a temperature-based proportional–integral–derivative (PID) controlling algorithm using highly dense fiber Bragg grating (FBG) arrays for laser ablation (LA) of ex vivo pancreatic tissues. Custom-made highly dense FBG arrays with a spatial resolution of 1.2 mm were fabricated with the femtosecond point-by-point writing technology and optimized for LA applications. In order to obtain proper PID gain values, finite element method-based iterative simulation of different PID gains was performed. Then, the proposed algorithm, with numerically derived PID gains, was experimentally validated. In the experiments, the point temperature was controlled at different distances from the laser fiber tip (6.0, 7.2, 8.4, and 10.8 mm). The obtained results report robust controlling and correlation between controlled distance and the resulting area of ablation. The results of the work encourage further investigation of FBG array application for LA control.

Chemiluminescence (CL) is a dominant technology in clinical diagnosis. In order to meet the increasing demand for the sensitive and simultaneous detection of chemiluminescence from multiple samples, the development of multiplex analysis on a single chip is highly desired. However, most chemiluminescence detection systems for multiple samples are still simple lens-based optical imaging systems, and a compromise must always be made between a large aperture (required by the weak chemiluminescence) and a large field of view (required by the size of the sample array). In this paper, we report a fiber bundle-based chemiluminescence detection system for the simultaneous and efficient detection of multiple chemiluminescent samples. In this system, one side of the fiber bundle is directly coupled to the optically active surface of a charge-coupled device (CCD), while the other end is divided into many sub-bundles that are aligned above the samples in a chemiluminescence array to collect their chemiluminescence. Taking advantage of the large numerical aperture and high transmittance of optical fibers, this system shows about a 50 times increase in chemiluminescence collection efficiency over the lens-based imaging system. Moreover, it shows no vignetting effect that is inevitable in a lens-based imaging system with a large field of view. This work provides a promising method for multiple sample chemiluminescence detection, and should find application in bioassays.

Rolling circle amplification (RCA) of DNA can be considered as a great alternative to the gold standard polymerase chain reaction (PCR), especially during this pandemic period, where rapid, sensitive, and reliable test results for hundreds of thousands of samples are required daily. This work presents the first research to date on direct, real-time and label-free isothermal DNA amplification monitoring using a microcavity in-line Mach-Zehnder interferometer (μIMZI) fabricated in an optical fiber. The solution based on μIMZI offers a great advantage over many other sensing concepts - making possible optical analysis in just picoliter sample volumes. The selectivity of the biosensor is determined by DNA primers immobilized on the microcavity's surface that act as selective biorecognition elements and trigger initiation of the DNA amplification process. In this study, we verified the sensing concept using circular DNA designed to target the H5N1 influenza virus. The developed biosensor exhibits an ultrahigh refractive index sensitivity reaching 14 000 nm per refractive index unit and a linear detection range between 9.4 aM and 94 pM of the target DNA sequence. Within a 30 min period, the amplification of as little as 9.4 aM DNA can be effectively detected, with a calculated limit of detection of as low as 0.2 aM DNA, suggesting that this methodology holds great promise in practical disease diagnosis applications in the future.

A miniature flexible photoacoustic endoscopy probe that provides high-resolution 3D images of vascular structures in the forward-viewing configuration is described. A planar Fabry–Perot ultrasound sensor with a − 3 d B bandwidth of 53 MHz located at the tip of the probe is interrogated via a flexible fiber bundle and a miniature optical relay system to realize an all-optical probe measuring 7.4 mm in outer diameter at the tip. This approach to photoacoustic endoscopy offers advantages over previous piezoelectric based distal-end scanning probes. These include a forward-viewing configuration in widefield photoacoustic tomography mode, finer spatial sampling (87 µm spatial sampling interval), and wider detection bandwidth (53 MHz) than has been achievable with conventional ultrasound detection technology and an all-optical passive imaging head for safe endoscopic use.

Technologies for measuring physiological parameters in vivo offer the possibility of the detection of disease and its progression due to the resulting changes in tissue pH, or temperature, etc.. Here, a compact hydrogel-based optical fibre pH sensor was fabricated, in which polymer microarrays were utilized for the high-throughput discovery of an optimal matrix for pH indicator immobilization. The fabricated hydrogel-based probe responded rapidly to pH changes and demonstrated a good linear correlation within the physiological pH range (from 5.5 to 8.0) with a precision of 0.10 pH units. This miniature probe was validated by measuring pH across a whole ovine lung and allowed discrimination of tumorous and normal tissue, thus offering the potential for the rapid and accurate observation of tissue pH changes.

We present the first report on reflectometric optical fiber sensing based on mechanically induced cascaded long-period grating (LPG) structure. This method utilizes in-house designed mechanical casings and a bare fiber. When a fiber is sandwiched between the casings and pressed by tightening screws, an LPG is induced due to a photo-elastic effect. By exploiting Fresnel refection at a fiber end, a cascaded LPG structure can be implemented using a single LPG, enabling reflectometric configuration. When this sensor is subjected to external physical processes, the attenuation bands change clearly, and their shift can be used for non-destructive evaluations. We show experimentally that this sensor can measure loads of up to 10 N without producing any permanent change in the fiber properties, indicating its pressure sensing capability. We also show that this sensor can potentially measure strain and temperature. In our experiments, the strain and temperature sensitivities are 9.4 nm/% and 0.045 nm/°C, respectively.

Purpose The relentless rise in antimicrobial resistance is a major societal challenge and requires, as part of its solution, a better understanding of bacterial colonization and infection. To facilitate this, we developed a highly efficient no-wash red optical molecular imaging agent that enables the rapid, selective, and specific visualization of Gram-positive bacteria through a bespoke optical fiber–based delivery/imaging endoscopic device. Methods We rationally designed a no-wash, red, Gram-positive-specific molecular imaging agent (Merocy-Van) based on vancomycin and an environmental merocyanine dye. We demonstrated the specificity and utility of the imaging agent in escalating in vitro and ex vivo whole human lung models (n = 3), utilizing a bespoke fiber–based delivery and imaging device, coupled to a wide-field, two-color endomicroscopy system. Results The imaging agent (Merocy-Van) was specific to Gram-positive bacteria and enabled no-wash imaging of S. aureus within the alveolar space of whole ex vivo human lungs within 60 s of delivery into the field-of-view, using the novel imaging/delivery endomicroscopy device. Conclusion This platform enables the rapid and specific detection of Gram-positive bacteria in the human lung.

Photoactivation and photodissociation have long proven to be useful tools in tandem mass spectrometry, but implementation often involves cumbersome and potentially dangerous configurations. Here, we redress this problem by using a fiber-optic cable to couple an infrared (IR) laser to a mass spectrometer for robust, efficient, and safe photoactivation experiments. Transmitting 10.6 μm IR photons through a hollow-core fiber, we show that such fiber-assisted activated ion-electron transfer dissociation (AI-ETD) and IR multiphoton dissociation (IRMPD) experiments can be carried out as effectively as traditional mirror-based implementations. We report on the transmission efficiency of the hollow-core fiber for conducting photoactivation experiments and perform various intact protein and peptide analyses to illustrate the benefits of fiber-assisted AI-ETD, namely, a simplified system for irradiating the two-dimensional linear ion trap volume concurrent with ETD reactions to limit uninformative nondissociative events and thereby amplify sequence coverage. We also describe a calibration scheme for the routine analysis of IR laser alignment and power through the fiber and into the dual cell quadrupolar linear ion trap. In all, these advances allow for a more robust, straightforward, and safe instrumentation platform, permitting implementation of AI-ETD and IRMPD on commercial mass spectrometers and broadening the accessibility of these techniques.

A novel light-addressable potentiometric sensor (LAPS), on the micrometer scale, is presented for rapid determination of blood and urine glucose. A LAPS chip with150 μm working diameter is fabricated using standard semiconductor technique, and assembled onto an optical fiber of a laser module to form a micro-sized device. An active circuit design, containing on-board light driver and transimpedance amplifier, is introduced to simplify electronic connection and improve signal quality. Glucose-sensitive layer is obtained by drop-coating glucose oxidase onto the working surface of the LAPS. Under optimized optical and electrochemical conditions, the proposed sensor is used to detect glucose in laboratorial and real samples. In a wide range as 0.01-100 mM, a log-linear relationship is well established, and the response time is less than 10 s. Limit of detection and limit of quantitation of this method are found to be 0.003 and 0.01 mM, respectively. Data from the proposed method are validated with those from a certified clinical analyzer, and no statistic difference is found.

The development of miniaturized continuum robots has a wide range of applications in minimally invasive endoluminal interventions. To navigate inside tortuous lumens without impinging on the vessel wall and causing tissue damage or the risk of perforation, it is necessary to have simultaneous shape sensing of the continuum robot and its tip contact force sensing with the surrounding environment. Miniaturization and size constraint of the device have precluded the use of conventional sensing hardware and embodiment schemes. In this study, we propose the use of optical fibers for both actuation and tension/shape/force sensing. It uses a model-based method with structural compensation, allowing direct measurement of the cable tension near the base of the manipulator without increasing the dimensions. It further structurally filters out disturbances from the flexible shaft. In addition, a model is built by considering segment differences, cable interactions/cross talks, and external forces. The proposed model-based method can simultaneously estimate the shape of the manipulator and external force applied onto the robot tip. Detailed modeling and validation results demonstrate the accuracy and reliability of the proposed method for the miniaturized continuum robot for endoluminal intervention.

[EN] Optical fibers featuring multi-layer refractive index profiles have been widely investigated and developed in a variety of scenarios, including space-division multiplexing transmission, fiber sensing, loss and dispersion management, as well as high-power amplifiers and lasers. For the first time to our knowledge, we present in this paper a general model deriving the universal characteristic equation for multi-layer optical fibers that comprise a set of concentric layers with arbitrary radial dimensions and refractive index values, considering both stepped (as step-index) or continuous (as graded-index) profiles. Expressions for the main fiber propagation parameters are also derived. We validate the model by comparing our results to the ones provided by numerical software tools with excellent matching for a series of particular optical fibers comprising step-index trench-assisted, ring-core, triangular-index and four-cladding profiles. This compact universal characteristic equation serves as a useful tool for optical fiber designers, where one can get valuable physical insights without the need to resort to numerical software tools, and even evaluate the effect of a single layer in isolation without the need to evaluate the whole refractive index structure., This work was supported in part by the European Research Council (ERC) under Consolidator Grant Project 724663, and in part by the Spanish MINECO under TEC2016-80150-R project, BES-2015-073359 scholarship for S. Garcia and Ramon y Cajal fellowship RYC-2014-16247 for I. Gasulla.

We demonstrate an all-fiber ultra-low numerical aperture high power fiber laser system operating in the continuous-wave regime at a central wavelength of 1080 nm. A special Ytterbium-doped fiber preform has been designed and fabricated by using modified chemical vapor deposition technique with the deposition percentages of 0.03mol% of Yb2O3, 1.8mol% of Al2O3, and 2.1mol% of P2O5. Then it has been drawn to obtain an active fiber having core/cladding diameters of 26 μm/410 μm respectively. The numerical aperture of the fiber has been first predicted as 0.034 from refractive index profile of the preform. Afterward, this number has been verified with a simple test setup by altering the bending diameter of the fiber and the excitation conditions of it. To test the high power performance, a laser system has been constructed in a master oscillator power amplifier configuration, and ~ 80 W seed signal power is amplified to 1.05 kW. The quality of the laser output beam has been measured in terms of M 2 value along both x and y coordinates as 1.11 and 1.16 respectively. This work was supported in part by The Scientific and Technological Research Council of Turkey (TUBİTAK)

This study reports a method for humidity sensing based on a specialty microstructured optical fiber (MOF). A suspended tri-core MOF was fabricated using the stack and draw technique. A low finesse sensing head was prepared by depositing a chitosan polymer matrix within the holes of the MOF, forming a Fabry-Pérot interferometer as a sensing platform while the chitosan film acts as the sensing material. The use of the probe for real-time breath monitoring was also successfully demonstrated. The probe possessed a maximum sensitivity of 81.05 pm/(%RH) for 90–95%RH range while the linear region of the sensor ranged from 70–95%RH. The temperature cross correlation was also experimented, and a lower influence of external temperature was observed. The probe shows an ultrafast response during human breath monitoring with a rising time and recovery time of 80 ms and 70 ms, respectively.

The reaction rate of an explosive - also called detonation velocity - is the easiest parameter to measure, and also one of the most important in characterizing the process of detonation front propagation in a 1D approach. This paper presents some peculiarities that were observed during the testing of our passive/active optical methods to measure detonation velocity. Both methods were tested using bare optic fiber probes and optic fiber probes protected with a stainless steel tube. The active optical method uses a laser with a wavelength of 660 nm, and the recording system contains a window filter that blocks any radiation outside the wavelength range of 650 to 665 nm. A plastic‐bonded explosive based on PETN (seismoplast) was used to test both experimental methods. For rectangular cross‐section charges using the passive optical method with the two different probes, the detonation velocities obtained ranged from 7233 to 7324 m/s, with standard deviations between 1.1 and 6.0 %; for the active optical method, the experimental results for detonation velocity varied between 7261 and 7351 and were obtained with a standard deviation of 0.6 to 1.7 %.

Extending the durability of functioning of the sensitive elements of radiation indicators and increasing their reliability and safety are the main requirements for producers of modern radiation reconnaissance and monitoring devices. The proposed solutions for construction improving of products provide for the usage of optical fibers and the corresponding formation of loop-shaped channels in the finished sensitive polymer element. Potential possibilities of using magnetic abrasive polishing for finishing channel surfaces are considered. For the chosen construction of the polishing head, the material and form of the powder particles composition and the process parameters are proposed. The effect of the frequency and amplitude of vibration of abrasive particles on the depth of their penetration into the surface layer of the polymer is investigated. It has been determined that the widest possibilities of using powders of the composition Fe - C - Si - Ti with a diameter of d = 50 – 400 μm have a mode when the pressure of the air flow by feeding particles is maintained at a level of 1 atm, the magnetic induction of the field in the working gap is 0.8 T, the vibration amplitude of the particles is a = 0.4 mm, and the vibration frequency varies in the range f = 25 – 30 Hz, Подовжити довговічність функціонування – головна вимога до виробників сучасних приладів радіаційної розвідки та контролю. Запропоновані рішення щодо вдосконалення конструкції виробів передбачають використання оптичних світловодів та відповідне формування канавок петлеподібного профілю у готовому чутливому полімерному елементі. Розглянуто потенційні можливості використання магнітно-абразивного полірування для фінішної обробки поверхонь канавки чутливих елементів дозиметрів з метою підвищення їх надійності та безпечності. Для вибраної конструкції полірувальної головки запропоновано матеріал та форму порошкової композиції і параметри процесу. Досліджено вплив частоти та амплітуди коливання часточок на глибину їх проникнення у поверхневий шар полімеру.

The three-core photonic crystal fiber (TC-PCF) is proposed to obtain large group-velocity dispersion (GVD) because of the coupling effects between the fundamental modes (FMs) of the central core and higher-order modes (HOMs) of the two side cores. The supermodes of the TC-PCF can provide concave anomalous- and normal-GVD profiles with large peak values at the maximum dispersion wavelengths (MDWs), which can be shifted in three wavelength windows of 1030 nm, 1550 nm and 1900 nm by properly tuning the refractive indexes of the cores or the air-hole diameters. Furthermore, the numerical results show that two segments of the TC-PCFs with large anomalous GVDs and opposite values of the third-order dispersion (TOD) can provide much higher efficiency of pulse compression than one segment of the TC-PCF. Additionally, the TC-PCFs with large normal GVDs can be used to stretch pulses due to their low nonlinearities and short fiber lengths.

© 2013 IEEE. Digital radio-over-fibre transmission has been studied extensively as a way of providing seamless last-mile wireless connectivity by carrying digitised radio frequency (RF) services over broadband optical infrastructures. With the growing demand on wireless capacity and the number of wireless services, a key challenge is the enormous scale of the digital data generated after the digitisation process. In turn, this leads to optical links needing to have very large capacity and hence, high capital expenditure (CAPEX). In this paper, we firstly present and then experimentally demonstrate a multiservice DRoF system for a neutral-host fronthaul link where both forward and reverse links use data compression, multiband multiplexing and synchronisation algorithms. The effect of a novel digital automatic gain control (DAGC) is comprehensively analysed to show an improved RF dynamic range alongside bit rate reduction. In this case, the system allows all cellular services from the three Chinese mobile network operators (MNOs) to be converged onto a single fiber infrastructure. We successfully demonstrate 14 wireless channels over a 10Gbps 20km optical link for indoor and outdoor wireless coverage, showing a minimum error value magnitude (EVM) of < 8% and >60dB RF dynamic range. It is believed that the technology provides an ideal solution for last-mile wireless coverage in 5G and beyond.

At present, optical fiber microducts are coupled together by mechanical types of joints. Mechanical joints are thick, require a large space, and reduce the installation distance in multi-microduct installation. They may leak or explode in the blown fiber installation process. Mechanical joints are subjected to time dependent deterioration under long service times beneath the earth's surface. It may start with a small leakage, followed by damage due to water freezing inside the optical fiber microduct. Optical fiber microducts are made up of high-density polyethylene, which is considered most suitable for thermoelectric welding. For thermoelectric welding of two optical fiber microducts, the welding time should be one second, and should not cause any damage to the inner structure of the microducts that are being coupled. To fulfill these requirements, an LTspice simulation model for the welding system was developed and validated. The developed LTspice model has two parts. The first part models the power input to joule heating wire and the second part models the heat propagation inside the different layers of the optical fiber microduct and surrounding joint by using electro-thermal analogy. In order to validate the simulation results, a battery powered prototype welding system was developed and tested. The prototype welding system consists of a custom-built electrofusion joint and a controller board. A 40 volt 4 ampere-hour Li-Ion battery was used to power the complete system. The power drawn from the battery was controlled by charging and discharging of a capacitor bank, which makes sure that the battery is not overloaded. After successful welding, a pull strength test and an air pressure leakage test were performed to ensure that the welded joints met the requirements set by the mechanical joints. The results show that this new kind of joint and welding system can effectively replace mechanical joints in future optical fiber duct installations.

Detecting ocean-floor seismic activity is crucial for our understanding of the interior structure and dynamic behavior of the Earth. However, 70% of the planet’s surface is covered by water and seismometers coverage is limited to a handful of permanent ocean bottom stations. We show that existing telecommunication optical fiber cables can detect seismic events when combined with state-of-the-art frequency metrology techniques by using the fiber itself as the sensing element. We detected earthquakes over terrestrial and submarine links with length ranging from 75 to 535 km and a geographical distance from the earthquake's epicenter ranging from 25 to 18,500 km. Implementing a global seismic network for real-time detection of underwater earthquakes requires applying the proposed technique to the existing extensive submarine optical fiber network., peer-reviewed

Recently NANF fiber prototypes have shown a steady decrease in loss. Theory predicts they could eventually outperform conventional fibers, in both loss and optical bandwidth. We investigate their potential impact on long-haul optical communication systems.

Remote detection of hydrogen, without the utilization of electronic component or elevated temperature, is one of the hot topics in the hydrogen technology and safety. In this work, the design and realization of the optical fiber-based hydrogen sensor with unique characteristics are proposed. The proposed sensor is based on the gold-coated multimode fiber, providing the plasmon properties, decorated by the IRMOF-20 layer with high selectivity and affinity toward hydrogen. The IRMOF-20 layer was grown by a surface-assisted technique, and its formation and properties were studied using X-ray photoelectron spectroscopy, Raman, X-ray diffraction, and Brunauer-Emmett-Teller techniques. Simultaneous ellipsometry results indicate the apparent changes of the refractive index of the IRMOF-20 layer due to hydrogen sorption. As results, the presence of hydrogen led to the pronounced changes of plasmon band wavelength position as well as its intensity increase. The proposed hydrogen sensors were favorably distinguished by a high response/recovery rate, excellent selectivity toward the hydrogen, very low temperature dependency, functionality at room or lower temperature, insensitivity toward the humidity, and the presence of CO2, CO, or NO2. Additionally, the proposed hydrogen sensor showed good reversibility, reproducibility, and long-term stability.

Dunaliella salina algae are trapped and studied using dual-fiber optical tweezers based on nano-imprinted Fresnel lenses. Different forms of cyclic motion of living algae inside the optical trap are observed and analyzed. A characteristic periodic motion in the 0–35 Hz frequency region reflects the algal flagella activity and is used to estimate the algal vitality, by photomovement. The trap stiffness and optical forces are measured for the case of a dead algal cell. It is shown that the dual-fiber optical tweezers can be used to study the vitality (or viability) property of single cells, a property that is essential and can be scaled up to other applications, such as sperm analysis for fertility tests.

Nearly a decade ago, transverse Anderson localization was observed for the first time in an optical fiber with a random transverse refractive index profile. This started the development of a whole new class of optical fibers that guide light, not in a conventional core-cladding setting based on total internal reflection, but utilizing Anderson localization, where light can guide at any location across the transverse profile of the fiber. These fibers have since been used successfully in high-quality endoscopic image transport. They also show interesting nonlinear and active (lasing) properties with promising applications. This review will cover a brief history of these fibers with personal accounts of the events that led to their development in our research groups. It will then follow with recent progress and future perspectives on science and applications of these fibers.

Label-free optical fiber immunosensors have attracted widespread attention in recent decades due to their high sensitivity. However, nonspecific adsorption in serum has remained a critical bottleneck in existing label-free fiber optic biosensors, which hinders their widespread use in diagnostics. In addition, individual differences in clinical human serum (HS) negatively impact biosensing results. In this work, the modified serum preadsorption strategy was applied to reduce nonspecific adsorption by forming a saturated antifouling interface on an optical microfiber coupler (OMC). Furthermore, to reduce the effect of the differences between individual HS samples, we proposed a new method where Sigma HS was used as a wavelength shift reference due to being close to clinical serum compared to other serums. Sigma HS was used first to reduce the differences in immune sensors before performing a clinical sample test in which quantitative detection was achieved based on the independent calibration of several sensors with wide dynamic ranges via dissociation processes. The individual differences in 25% HS were corrected by 30% Sigma HS. As a proof of concept, the label-free OMC immune sensor demonstrates good sensitivity and specificity for the detection of carcinoembryonic antigen (CEA) in 25% Sigma HS at different concentrations. The detection limit of CEA reached as low as 34.6 fg/mL (0.475 fM). Additionally, label-free quantitative detection of CEA using this OMC immune sensor was verified experimentally according to the calibration line, and the results agree well with clinical examination detection. To our knowledge, it is the first study to employ an OMC immune sensor in point-of-care label-free quantitative detection for clinical HS.

Developing technologies capable of constantly assessing and optimizing day-to-day activities has been a research priority for several years. A key factor in such technologies is the use of highly sensitive sensors to monitor in real-time numerous parameters, such as temperature and load. Due to their unique features, optical fiber sensors became one of the most interesting and viable solutions for applications dependent on those parameters. In this work, we present an optical fiber load sensor, called load cell, based on Fabry–Pérot hollow cavities embedded in a polymeric material. By using the load cells in a parallel configuration with a non-embedded hollow cavity, the optical Vernier effect was generated, allowing maximum sensitivity values of 0.433 nm N−1 and 0.66 nm °C−1 to be attained for vertical load and temperature, respectively. The proposed sensor’s performance, allied with the proposed configuration, makes it a viable and suitable device for a wide range of applications, namely those requiring high thermal and load sensitivities.

Guided waves (GW) and acoustic emission (AE) -based structural health monitoring (SHM) have widespread applications in structures, as the monitoring of an entire structure is possible with a limited number of sensors. Optical fiber-based sensors offer several advantages, such as their low weight, small size, ability to be embedded, and immunity to electro-magnetic interference. Therefore, they have long been regarded as an ideal sensing solution for SHM. In this review, the different optical fiber technologies used for ultrasonic sensing are discussed in detail. Special attention has been given to the new developments in the use of FBG sensors for ultrasonic measurements, as they are the most promising and widely used of the sensors. The paper highlights the physics of the wave coupling to the optical fiber and explains the different phenomena such as directional sensitivity and directional coupling of the wave. Applications of the different sensors in real SHM applications have also been discussed. Finally, the review identifies the encouraging trends and future areas where the field is expected to develop.

Shape reconstruction is growing as an important real-time monitoring strategy for applications that require rigorous control. Polymer optical fiber sensors (POF) have mechanical properties that allow the measurement of large curvatures, making them appropriate for shape sensing. They are also lightweight, compact and chemically stable, meaning they are easy to install and safer in risky environments. This paper presents a sensor system to detect angles in multiple planes using a POF-intensity-variation-based sensor and a procedure to detect the angular position in different planes. Simulations are performed to demonstrate the correlation between the sensor’s mechanical bending response and their optical response. Cyclic flexion experiments are performed at three test frequencies to obtain the sensitivities and the calibration curves of the sensor at different angular positions of the lateral section. A Fast Fourier Transform (FFT) analysis is tested as a method to estimate angular velocities using POF sensors. The experimental results show that the prototype had high repeatability since its sensitivity was similar using different test frequencies at the same lateral section position. The proposed approach proved itself feasible considering that all linear calibration curves presented a coefficient of determination (R2) higher than 0.9.

The focusing of light represents a key functionality, which can efficiently be achieved through wavefront shaping via metasurfaces (MSs). Remote light focusing requires interfacing these ultraflat photonic structures with optical fibers, which is hard to achieve due to fabrication limitations and challenging beam management. Herein, the successful interfacing of a focusing plasmonic metalens with a regular single‐mode step‐index fiber through modified electron beam lithography is demonstrated. Specifically, a plasmonic MS consisting of nanoslots is realized on the end face of a modified single‐mode fiber via planarization and e‐beam lithography. A key feature of the device is the introduction of a coreless glass section in between the fiber and MS, which allows for free beam expansion up to 48 μm to fully exploit the numerical aperture (NA) of the metalens. In agreement with simulations, a clear focus with a NA of about 0.3 is found in the experiments, confirming the successful realization of a plasmonic metalens‐enhanced single‐mode fiber. Due to its unique properties, this concept finds applications in a multitude of areas, examples of which include optical trapping, generation of sophisticated beam profiles, and boosting light coupling efficiencies.

The optical fiber grating sensors have strong potential for the detection of biological samples. However, a careful effort is still in demand to enhance the performance of existing grating sensors especially in biological sensing. Therefore, in this work, we have introduced a novel plus shaped cavity (PSC) in optical fiber model and used it for the detection of haemoglobin (Hb) refractive index (RI). The numerical analysis of designed model is done by the testing of single and double vertical slots cavity in optical fiber core structure. The testing of designed sensor model is done at the wavelength of 800 nm at which the RI of oxygenated and deoxygenated Hb is 1.392 and 1.389, respectively. The analysis of reported PSC sensor model is done in the wide range of Hb RI from 1.333 to 1.392. The tested range of RI corresponds to the Hb concentration from 0 to 140 gl-1. The obtained results states that for the tested range of RI, the autocorrelation coefficientt of R2 = 99.51 % is achieved. The analysis of projected work is done by using finite difference time domain (FDTD) method. The introduction of PSC can increase in sensitivity. In proposed PSC, the length and width of created slots are 1.8 μm and 1 μm, respectively, which is quite enough to observe the response of analytes RI. This can minimize the creation of multiple gratings required for observing the analyte response.

It is crucial to be time and resource-efficient when enabling and optimizing novel applications and functionalities of optical fibers, as well as accurate computation of the vectorial field components and the corresponding propagation constants of the guided modes in optical fibers. To address these needs, a novel full-vectorial fiber mode solver based on a discrete Hankel transform is introduced and validated here for the first time for rotationally symmetric fiber designs. It is shown that the effective refractive indices of the guided modes are computed with an absolute error of less than 10−4 with respect to analytical solutions of step-index and graded-index fiber designs. Computational speeds in the order of a few seconds allow to efficiently compute the relevant parameters, e.g., propagation constants and corresponding dispersion profiles, and to optimize fiber designs.

Optical fiber ball resonators based on single-mode fibers in the infrared range are an emerging technology for refractive index sensing and biosensing. These devices are easy and rapid to fabricate using a CO2 laser splicer and yield a very low finesse reflection spectrum with a quasi-random pattern. In addition, they can be functionalized for biosensing by using a thin-film sputtering method. A common problem of this type of device is that the spectral response is substantially unknown, and poorly correlated with the size and shape of the spherical device. In this work, we propose a detection method based on Karhunen−Loeve transform (KLT), applied to the undersampled spectrum measured by an optical backscatter reflectometer. We show that this method correctly detects the response of the ball resonator in any working condition, without prior knowledge of the sensor under interrogation. First, this method for refractive index sensing of a gold-coated resonator is applied, showing 1594 RIU−1 sensitivity, then, this concept is extended to a biofunctionalized ball resonator, detecting CD44 cancer biomarker concentration with a picomolar-level limit of detection (19.7 pM) and high specificity (30–41%).

In this in vitro experiment, the effect of 1.064 µm pulsed laser on both enamel- and dentin-dental tissues has been investigated. A total of fifty-five dental hard tissue samples were exposed to Nd:YAG laser that possesses a pulse width of 9 ns and 850 mJ of total energy. An optical fiber sensor was put behind the samples to measure the temperature instantaneously. A novel, to the best of our knowledge, fiber sensor has been proposed and used to measure the heat generated in dental hard tissues instantaneously after the application of laser irradiation on the tissue surface. This optical sensor exhibits a fast response time of about 1 ms and high sensitivity with about 1.975 nm/°C. The findings of this study in decreasing the probability of pulpal necrosis structure while handling the tooth, whether for ablation, welding, or tooth resurfacing purposes, may establish standards for dentists and laser manufacturers (healthcare professionals) that should be followed.

With the rapid increase in the use of optogenetics to investigate nervous systems, there is high demand for neural interfaces that can simultaneously perform optical stimulation and electrophysiological recording. However, high-magnitude stimulation artifacts have prevented experiments from being conducted at a desirably high temporal resolution. Here, a flexible polyimide-based neural probe with polyethylene glycol (PEG) packaged optical fiber and Pt-Black/PEDOT-GO (graphene oxide doped poly(3,4-ethylene-dioxythiophene)) modified microelectrodes was developed to reduce the stimulation artifacts that are induced by photoelectrochemical (PEC) and photovoltaic (PV) effects. The advantages of this design include quick and accurate implantation and high-resolution recording capacities. Firstly, electrochemical performance of the modified microelectrodes is significantly improved due to the large specific surface area of the GO layer. Secondly, good mechanical and electrochemical stability of the modified microelectrodes is obtained by using Pt-Black as bonding layer. Lastly, bench noise recordings revealed that PEC noise amplitude of the modified neural probes could be reduced to less than 50 µV and no PV noise was detected when compared to silicon-based neural probes. The results indicate that this device is a promising optogenetic tool for studying local neural circuits.

Functional nanocoatings have allowed hollow-core microstructured optical fibers (HC-MOFs) to be introduced into biosensing and photochemistry applications. However, common film characterization tools cannot evaluate the coating performance in situ. Here we report the all-optical noncontact characterization of the HC-MOF coating in real time. Self-assembled multilayers consisting of inversely charged polyelectrolytes (PEs) are deposited on the HC-MOF core capillary, and a linear spectral shift in the position of the fiber transmission minima with increasing the film thickness is observed as small as ∼ 1.5 − 6 n m per single PE bilayer. We exemplify the practical performance of our approach by registering an increase in the coating thickness from 6 ± 1 to 11 ± 1 n m per PE bilayer with increasing ionic strength in the PE solutions from 0.15 to 0.5 M NaCl. Additionally, we show real-time monitoring of pH-induced coating dissolving. Simplicity and high sensitivity make our approach a promising tool allowing noncontact analysis of the HC-MOF coating which is still challenging for other methods.

A compact microfluidic Raman detection system based on a single-ring negative-curvature hollow-core fiber is presented. The system can be used for in-line qualitative and quantitative analysis of biochemicals. Both efficient light coupling and continuous liquid injection into the hollow-core fiber were achieved by creating a small gap between a solid-core fiber and the hollow-core fiber, which were fixed within a low-cost ceramic ferrule. A coupling efficiency of over 50% from free-space excitation laser to the hollow core fiber was obtained through a 350 μm-long solid-core fiber. For proof-of-concept demonstration of bioprocessing monitoring, a series of ethanol and glucose aqueous solutions at different concentrations were used. The limit of detection achieved for the ethanol solutions with our system was ~0.04 vol.% (0.32 g/L). Such an all-fiber microfluidic device is robust, provides Raman measurements with high repeatability and reusability, and is particularly suitable for the in-line monitoring of bioprocesses.

At the present time, there are major concerns regarding global warming and the possible catastrophic influence of greenhouse gases on climate change has spurred the research community to investigate and develop new gas-sensing methods and devices for remote and continuous sensing. Furthermore, there are a myriad of workplaces, such as petrochemical and pharmacological industries, where reliable remote gas tests are needed so that operatives have a safe working environment. The authors have concentrated their efforts on optical fibre sensing of gases, as we became aware of their increasing range of applications. Optical fibre gas sensors are capable of remote sensing, working in various environments, and have the potential to outperform conventional metal oxide semiconductor (MOS) gas sensors. Researchers are studying a number of configurations and mechanisms to detect specific gases and ways to enhance their performances. Evidence is growing that optical fibre gas sensors are superior in a number of ways, and are likely to replace MOS gas sensors in some application areas. All sensors use a transducer to produce chemical selectivity by means of an overlay coating material that yields a binding reaction. A number of different structural designs have been, and are, under investigation. Examples include tilted Bragg gratings and long period gratings embedded in optical fibres, as well as surface plasmon resonance and intra-cavity absorption. The authors believe that a review of optical fibre gas sensing is now timely and appropriate, as it will assist current researchers and encourage research into new photonic methods and techniques.

This paper shows the results of the monitoring of the deformations of a tunnel, carried out using a distributed optical fiber strain sensor based on stimulated Brillouin scattering. The artificial tunnel of the national railway crosses the accumulation zone of an active landslide, the Varco d’Izzo earthflow, in the southern Italian Apennines. Severely damaged by the landslide movements, the tunnel was demolished and rebuilt in 1992 as a reinforced concrete box flanked by two deep sheet pile walls. In order to detect the onset of potentially dangerous strains of the tunnel structure and follow their time trend, the internal deformations of the tunnel are also monitored by a distributed fiber-optic strain sensor since 2016. The results of the monitoring activity show that the deformation profiles are characterized by strain peaks in correspondence of the structural joints. Furthermore, the elongation of the fiber strands crossing the joints is consistent with the data derived by other measurement systems. Experiments revealed an increase in the time rate of the fiber deformation in the first and last part of the monitoring period when the inclinometers of the area also recorded an acceleration in the landslide movements.

We detail a study of the techniques and sealing materials for optical fiber sensors used in dynamic environments with high pressure (&gt, 300 bar) and high temperature (&gt, 300 °C). The sealing techniques and materials are the key for the robustness of sensors in harsh dynamic environments, such as large combustion engines. The sealing materials and techniques studied in this work are high-temperature epoxies, metallic polymer, metallic solders, glass solder, cement, brazing and electroless nickel plating. Because obtaining high temperature simultaneously with high pressure is very difficult in the same chamber in the laboratory, we developed a new and simple method to test sealed fibers in these conditions in the laboratory. In addition, some sensors using the materials tested in the laboratory were also field tested in real thermoelectric combustion engines. The study also discusses the methods of fabrication and the cost−benefit ratio of each method.

[EN] Composites have added new dimensions to the design and construction of buildings and struc-tures. One of the wider spread composite applications in the construction industry is composite beams or pillars, which can be manufactured through pultrusion processes. These types of con-struction elements are usually used to withstand the weight of large loads, so their integrity must be guaranteed. Due to optical sensors¿ advantages over their electrical counterparts¿small sizes, low weight, non-conductive, and immunity to electromagnetic interference¿and FBGs having an outstanding position among optical fibre sensors¿due to their multiplexation capability and relatively easy monitoring¿in this study, we propose the integration of FBG sensors for the observation and analysis of the integrity of structures made with composite beams over time. The validation test results showed the successful embedding integration of FBG-based fibre optical sensors in an FRP pultrusion beam and strain transmission up to 7500 µ¿ from the composite test piece to the sensor. Additionally, we were able to anticipate the piece failure by the FBG spectrum deformation., This publication is partially supported by the I+D+i project SYNERGY PID2020-118310RBI00 funded by the MCIN/AEI/10.13039/501100011033; also, by the Generalitat Valenciana, the PROMETEO 2017/103 Research Excellency Award, and IDIFEDER/2020/032, as well as IDIFEDER/ 2021/050 GVA Infraestructura. D. Maldonado-Hurtado is supported by a scholarship PRE2018- 085654, funded by MCIN/AEI/10.13039/501100011033, and FSE invierte en tu futuro. J. Madrigal is supported by a scholarship PAID-01-18, funded by Universitat Politècnica de València.

A plug-and-play surface plasmon resonance (SPR) dual-parameter optical fiber biosensor is reported, in which Au film was firstly coated on the fiber surface for exciting SPR and the end half of the Au film was modified with Au nanoparticles to generate double SPR resonance valleys. For simultaneous detecting of glucose and cholesterol concentrations, modified P-mercaptophenylboronic acid (PMBA) and β-cyclodextrin (β-CD) were subsequently coated on the surface of sensor probe. Due to the cis-diol structure of glucose, it can interact with PMBA, leading to a red shift of one SPR resonant valley, whose maximum wavelength shift is 11.228 nm in the range of 0–1.7 mM glucose concentration. On the same time, the cholesterol molecules can realize the host-guest combination with β-CD, leading to a red shift of another SPR resonant valley, and the maximum wavelength shift is 18.893 nm in the cholesterol concentration range of 0–300 nM. The detection limits of the sensor to glucose and cholesterol are 0.00078 mM and 0.012 nM, respectively. The enhances the practical value of the dual-parameter sensor. Both theory and experiment results verify the feasibility of the “plug-and-play” sensor to measure the dual biomass of glucose and cholesterol with ultra-low detection limit and good selectivity. The proposed method provides a huge research value for the optical fiber sensor in multi-parameter measurement.

In a growing number of applications, fast and localized pressure measurement in aqueous media is desired. To perform such measurements, a custom-made single-mode fiber-optic probe hydrophone (FOPH) was designed and used to measure the pressure pulse generated by laser-induced breakdown (LIB) in water. The sensor enabled sub-nanosecond pressure rise time measurement. Both the rise time and the duration of the shockwave were found to be shorter in the direction perpendicular to the breakdown generating laser beam, compared to the shockwave observed in the parallel direction. Simultaneous high-frame-rate imaging was used to qualitatively validate the novel hydrophone data and to observe the shockwave evolution. The measurements were performed also on pressure pulses emitted during the generation of miniature ( [Formula: see text] diameter) laser-induced bubbles at very small distances (down to [Formula: see text]), further demonstrating the capabilities of the small-size sensor and the ability to measure locally. The results improve understanding of LIB shockwave characteristics dependence on laser pulse energy and duration.

Gold-coated tilted fiber Bragg gratings (TFBGs) have been highly studied over the last years, mainly for biosensing purposes. They present a comb-like spectrum of narrow-band cladding mode resonances that is often demodulated by tracking the change of a selected peak. In this paper, we report a twentyfold more sensitive demodulation method based on the intersection of the upper and lower envelopes of gold-coated TFBG spectra. This method has been successfully applied in biosensing experiments towards the detection of HER2 (Human Epidermal Growth Factor Receptor-2) proteins, a relevant biomarker for breast cancer. Practical improvements have also been implemented. First, a uniform FBG has been superimposed on the TFBG to reduce the read-out wavelength span to 10 nm instead of 70 nm while keeping the temperature-compensated measurements. Second, a micro-fluidic system has been implemented to smoothly deliver the samples to the sensor. These 3 originalities make this sensing platform even more attractive for use in practical applications., SCOPUS: ar.j, info:eu-repo/semantics/published

Significance: The highest absorption peaks of the main components of bone are in the mid-infrared region, making Er:YAG and CO2 lasers the most efficient lasers for cutting bone. Yet, studies of deep bone ablation in minimally invasive settings are very limited, as finding suitable materials for coupling high-power laser light with low attenuation beyond 2 μm is not trivial. Aim: The first aim of this study was to compare the performance of different optical fibers in terms of transmitting Er:YAG laser light with a 2.94-μm wavelength at high pulse energy close to 1 J. The second aim was to achieve deep bone ablation using the best-performing fiber, as determined by our experiments. Approach: In our study, various optical fibers with low attenuation (λ=2.94 μm) were used to couple the Er:YAG laser. The fibers were made of germanium oxide, sapphire, zirconium fluoride, and hollow-core silica, respectively. We compared the fibers in terms of transmission efficiency, resistance to high Er:YAG laser energy, and bending flexibility. The best-performing fiber was used to achieve deep bone ablation in a minimally invasive setting. To do this, we adapted the optimal settings for free-space deep bone ablation with an Er:YAG laser found in a previous study. Results: Three of the fibers endured energy per pulse as high as 820 mJ at a repetition rate of 10 Hz. The best-performing fiber, made of germanium oxide, provided higher transmission efficiency and greater bending flexibility than the other fibers. With an output energy of 370 mJ per pulse at 10 Hz repetition rate, we reached a cutting depth of 6.82±0.99 mm in sheep bone. Histology image analysis was performed on the bone tissue adjacent to the laser ablation crater; the images did not show any structural damage. Conclusions: The findings suggest that our prototype could be used in future generations of endoscopic devices for minimally invasive laserosteotomy.