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We report on our activities related to the development of surface enhanced Raman scattering (SERS) probes realized onto the optical fiber tip (OFT) through nanosphere lithography. In the first stage of our research, we adapted the nanosphere lithography to operate on the optical fiber tip, by assessing the process and demonstrating either the potentiality or the repeatability of the proposed nanopatterning approach. Successively, we investigated the ability of the manufactured structures on the fiber tip to act as SERS probes by measuring the SERS spectra in presence of a Biphenyl Thiol (BPT) monolayer. Firstly, we focused the attention on the samples shaped as closed packed array of nanospheres covered by gold. The analysis allowed us to identify the most promising SERS platform, exhibiting an Enhancement Factor (EF) of 4x10(5) and a SERS measurements variability lower than 10%. We addressed also the limitations related to the use of the same optical fiber for both illumination and light collection by selecting a commercial optical fiber exhibiting a suitable trade-off in terms of high excitation/collection efficiency and low silica background. Current activities are devoted to the investigation of other nanopatterns on the optical fiber tip (namely, Sparse Array of metallo-dielectric spheres) and the analysis of the probes response against different molecules.

In this paper we report on the engineering of repeatable surface enhanced Raman scattering (SERS) optical fiber sensor devices (optrodes), as realized through nanosphere lithography. The Lab-on-Fiber SERS optrode consists of polystyrene nanospheres in a close-packed arrays configuration covered by a thin film of gold on the optical fiber tip. The SERS surfaces were fabricated by using a nanosphere lithography approach that is already demonstrated as able to produce highly repeatable patterns on the fiber tip. In order to engineer and optimize the SERS probes, we first evaluated and compared the SERS performances in terms of Enhancement Factor (EF) pertaining to different patterns with different nanosphere diameters and gold thicknesses. To this aim, the EF of SERS surfaces with a pitch of 500, 750 and 1000 nm, and gold films of 20, 30 and 40 nm have been retrieved, adopting the SERS signal of a monolayer of biphenyl-4-thiol (BPT) as a reliable benchmark. The analysis allowed us to identify of the most promising SERS platform: for the samples with nanospheres diameter of 500 nm and gold thickness of 30 nm, we measured values of EF of 4 × 105, which is comparable with state-of-the-art SERS EF achievable with highly performing colloidal gold nanoparticles. The reproducibility of the SERS enhancement was thoroughly evaluated. In particular, the SERS intensity revealed intra-sample (i.e., between different spatial regions of a selected substrate) and inter-sample (i.e., between regions of different substrates) repeatability, with a relative standard deviation lower than 9 and 15%, respectively. Finally, in order to determine the most suitable optical fiber probe, in terms of excitation/collection efficiency and Raman background, we selected several commercially available optical fibers and tested them with a BPT solution used as benchmark. A fiber probe with a pure silica core of 200 µm diameter and high numerical aperture (i.e., 0.5) was found to be the most promising fiber platform, providing the best trade-off between high excitation/collection efficiency and low background. This work, thus, poses the basis for realizing reproducible and engineered Lab-on-Fiber SERS optrodes for in-situ trace detection directed toward highly advanced in vivo sensing.

We report on the engineering of repeatable surface enhanced Raman scattering (SERS) optrodes realized through nanosphere lithography on optical fiber (Figure 1). In particular, the Lab-on-Fiber SERS optrode consists of polystyrene nanospheres in close-packed arrays (CPA) configuration covered by a thin film of gold onto the optical fiber tip. The SERS surfaces were fabricated by using a nanosphere lithography approach that already demonstrated to be able to produce highly repeatable patterns on the fiber tip [1]. Starting from the promising pristine results, in order to engineer and optimize the SERS probes, we first evaluated and compared the SERS performances in terms of Enhancement Factor (EF) pertaining to different patterns with different nanospheres diameters and gold thicknesses. To this aim, the EF of SERS surfaces with a pitch of 500, 750 and 1000 nm, and gold films of 20, 30 and 40 nm have been retrieved, adopting the SERS signal of a monolayer of biphenyl-4-thiol (BPT) as a reliable benchmark (Figure 2). The analysis allowed us the identification of the most promising SERS platform: for the samples with nanospheres diameter of 500 nm and gold thickness of 30 nm, we measured values of EF of 4×105, which is comparable with state-of-the-art SERS EF achievable with highly performing colloidal gold nanoparticles [2]. The reproducibility of the SERS enhancement was thoroughly evaluated. Finally, in order to determine the most suitable optical fiber probe, in terms of excitation/collection efficiency and Raman background, we selected several commercially available optical fibers and tested them towards a BPT solution used as benchmark. A fiber probe with pure silica core of 200 µm diameter and high numerical aperture (i.e. 0.5) was found to be the most promising fiber platform providing the best trade-off between high excitation/collection efficiency and low background (Figure 3). Ongoing activities are devoted to use our Lab-on-Fibre SERS optrodes for cancer cell identification with the ambitious aim to achieve a highly advanced in-vivo sensor.

We present a fiber optic magnetic field sensor conceived for magnetic resonance imaging (MRI) applications. The sensor is based on the integration of fiber optic strain sensors (fiber Bragg gratings—FBGs) with a sensing material (Terfenol-D). The response of an FBG integrated with a block of Terfenol-D was preliminarily investigated by taking into account the dependence of the Terfenol-D magnetostrictive response on both the longitudinal and transversal magnetic fields, with different preloads. Based on the performed characterizations, a triaxial magnetic field sensor was designed, characterized, and fabricated. An algorithm enabling the demodulation of the magnetic field from the readout of the three FBGs was also implemented, by taking into account the interdependence among the different sensor responses. Experimental results demonstrate the ability of the triaxial sensor to measure the magnetic field. Performance assessment and critical analysis are reported as well, elucidating both the abilities and limitations of the implemented sensing configuration. Finally, as proof of principle, a sensing system constituted of 20 triaxial sensors has been fabricated and used to map the magnetic field strength distribution in an MRI diagnostic centre.

This paper reports on the assessment of a simple and economical self-assembly methodology to obtain reproducible infstrates onto the optical fiber tip for surface-enhanced Raman spectroscopy (SERS) applications. The method relies on the use of the nanosphere lithography of the optical fiber end facet. A careful analysis has been carried out to investigate the capability of the proposed procedure to realize repeatable pattern on the optical fiber tip. Finally, we demonstrate the effective application of the patterned OFTs as SERS nanoprobes. © 2017 SPIE.

We demonstrate the ability of Fiber Bragg Gratings (FBGs) sensors to protect large areas from unauthorized activities in railway scenarios such as stations or tunnels. We report on the technological strategy adopted to protect a specific depot, representative of a common scenario for security applications in the railway environment. One of the concerns in the protection of a railway area centers on the presence of rail-tracks, which cannot be obstructed with physical barriers. We propose an integrated optical fiber system composed of FBG strain sensors that can detect human intrusion for protection of the perimeter combined with FBG accelerometer sensors for protection of rail-track access. Several trials were carried out in indoor and outdoor environments. The results demonstrate that FBG strain sensors bonded under a ribbed rubber mat enable the detection of intruder break-in via the pressure induced on the mat, whereas the FBG accelerometers installed under the rails enable the detection of intruders walking close to the railroad tracks via the acoustic surface waves generated by footsteps. Based on a single enabling technology, this integrated system represents a valuable intrusion detection system for railway security and could be integrated with other sensing functionalities in the railway field using fiber optic technology.

In this paper, we report a fiber-optic triaxial magnetic field sensor, based on Fiber Bragg Gratings (FBGs) integrated with giant magnetostrictive material, the Terfenol-D. The realized sensor has been designed and engineered for Magnetic Resonance Imaging (MRI) applications. A full magneto-optical characterization of the triaxial sensing probe has been carried out, providing the complex relationship among the FBGs wavelength shift and the applied magnetostatic field vector. Finally, the developed fiber optic sensors have been arranged in a sensor network composed of 20 triaxial sensors for mapping the magnetic field distribution in a MRI-room at a diagnostic center in Naples (SDN), equipped with Positron emission tomography/magnetic resonance (PET/MR) instrumentation. Experimental results reveal that the proposed sensor network can be efficiently used in MRI centers for performing quality assurance tests, paving the way for novel integrated tools to measure the magnetic dose accumulated day by day by MRI operators.

In this work, we report a straightforward and cost-effective fabrication route for the development of nano-patterned optical fiber tips. The technique is based on self-assembling polystyrene microspheres at the air/water interface and on their successive transferring on the fiber tip of single mode optical fiber. By applying to the fiber further treatments like particle size reduction, metal coating and sphere removal, different periodic structures have been conveniently realized. The morphological analysis reveals indeed the successful creation on the optical fiber tip of regular metallic-dielectric spheres' arrays as well as metallic patterns with dimensional features down to a submicron scale. Finally, as proof of concept, we demonstrated the capability of the realized patterns to work as efficient Surface Enhanced Raman Spectroscopy (SERS) fiber probes. © 2016 SPIE.

We report on a method for integrating sub-wavelength resonant structures on top of optical fiber tip. Our fabrication technique is based on direct milling of the glass on the fiber facet by means of focused ion beam. The patterned fiber tip acts as a structured template for successive depositions of any responsive or functional overlay. The proposed method is validated by depositing on the patterned fiber a high refractive index material layer, to obtain a ‘double-layer’ photonic crystal slab supporting guided resonances, appearing as peaks in the reflection spectrum. Morphological and optical characterizations are performed to investigate the effects of the fabrication process. Our results show how undesired effects, intrinsic to the fabrication procedure should be taken into account in order to guarantee a successful development of the device. Moreover, to demonstrate the flexibility of our approach and the possibility to engineering the resonances, a thin layer of gold is also deposited on the fiber tip, giving rise to a hybrid photonic-plasmonic structure with a complementary spectral response and different optical field distribution at the resonant wavelengths. Overall, this work represents a significant step forward the consolidation of Lab-on-Fiber Technology.

The integration of microfluidics and photonic biosensors has allowed achievement of several laboratory functions in a single chip, leading to the development of photonic lab-on-a-chip technology. Although a lot of progress has been made to implement such sensors in small and easy-to-use systems, many applications such as point-of-care diagnostics and in vivo biosensing still require a sensor probe able to perform measurements at precise locations that are often hard to reach. The intrinsic property of optical fibers to conduct light to a remote location makes them an ideal platform to meet this demand. The motivation to combine the good performance of photonic biosensors on chips with the unique advantages of optical fibers has thus led to the development of the so-called lab-on-fiber technology. This emerging technology envisages the integration of functionalized materials on micro- and nano-scales (i.e. the labs) with optical fibers to realize miniaturized and advanced all-in-fiber probes, especially useful for (but not limited to) label-free chemical and biological applications. This review presents a broad overview of lab-on-fiber biosensors, with particular reference to lab-on-tip platforms, where the labs are integrated on the optical fiber facet. Light-matter interaction on the fiber tip is achieved through the integration of thin layers of nanoparticles or nanostructures supporting resonant modes, both plasmonic and photonic, highly sensitive to local modifications of the surrounding environment. According to the physical principle that is exploited, different configurations - such as localized plasmon resonance probes, surface enhanced Raman scattering probes and photonic probes - are classified, while various applications are presented in context throughout. For each device, the surface chemistry and the related functionalization protocols are reviewed. Moreover, the implementation strategies and fabrication processes, either based on bottom-up or top-down approaches, are discussed. In conclusion we highlight some of the further development opportunities, including lab-in-a-needle technology, which could have a direct and disruptive impact in localized cancer treatment applications.

In this work, we report a fabrication route for self-assembling periodic patterns on optical fiber tips. The technique is based on self-assembling polystyrene microspheres at the air/water interface and on successive transferring of the monolayer colloidal crystal on the fiber tip. By applying to the fiber further treatments like particle size reduction, metal coating and sphere removal, different periodic structures are conveniently realized. The results obtained indicate that self-assembly technique affords opportunity to create on the optical fiber tip dielectric and metallic-dielectric spheres' arrays with a feature size down to a submicron scale or metallic patterns with a few hundred nanometers at low fabrication costs. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

This paper reports a simple and economical method for the fabrication of nanopatterned optical fiber nanotips. The proposed patterning approach relies on the use of the nanosphere lithography of the optical fiber end facet. Polystyrene (PS) nanospheres are initially self-assembled in a hexagonal array on the surface of water. The created pattern is then transferred onto an optical fiber tip (OFT). The PS monolayer colloidal crystal on the OFT is the basic building block that is used to obtain different periodic structures by applying further treatment to the fiber, such as metal coating, nanosphere size reduction and sphere removal. Ordered dielectric and metallo-dielectric sphere arrays, metallic nanoisland arrays and hole-patterned metallic films with feature sizes down to the submicron scale are achievable using this approach. Furthermore, the sizes and shapes of these periodic structures can be tailored by altering the fabrication conditions. The results indicate that the proposed self-assembly approach is a valuable route for the development of highly repeatable metallo-dielectric periodic patterns on OFTs with a high degree of order and low fabrication cost. The method can be easily extended to simultaneously produce multiple fibers, opening a new route to the development of fiber-optic nanoprobes. Finally, we demonstrate the effective application of the patterned OFTs as surface-enhanced Raman spectroscopy nanoprobes.

The "lab-on-fiber" technology has been recently proposed as a valuable route for the realization of novel and highly functionalized technological platforms completely integrated in a single optical fiber in communication and sensing applications. As a follow-up of the proposed technological approach, here, we present recent results on the fabrication of metallo-dielectric structures on the optical fiber tip by using a self-assembly technique. Our studies aim to attain advanced nanostructured sensors by exploiting easy and low-cost fabrication processes suitable to be employed in massive production of technologically advanced devices. The pursued approach basically consists in the preliminary preparation of a patterned polymeric film by the breath figure technique, directly on the optical fiber tip, and in the successive metal deposition by evaporation. The experimental results demonstrate the successful creation of a metallo-dielectric honeycomb pattern on the optical fiber tip. The sensing properties of the optical fiber probes have been successfully explored in terms of sensitivity to the surrounding refractive index changes demonstrating their potentialities for chemical and biological sensing applications. © 2014 Springer International Publishing Switzerland.

We propose a novel fabrication process to realize optical sensing probes based on metal-dielectric crystals self-assembled on an optical fiber tip. The breath figure methodology has been adapted to work directly on nonconventional substrates, such as optical fibers, enabling the formation of regular and ordered metallo-dielectric crystals on optical fiber tips. Accurate morphological characterization was carried out to qualify the fabrication process. The reported results indicate that the proposed fabrication technique provides a method for rapid and cost-effective prototyping of photonic-plasmonic nanoprobes for sensing applications. To achieve this goal, we develop a technological platform via the addition of polymer-metal crystals onto the tip of a standard single optical fiber, which is able to support surface plasmon resonances in the near-infrared. A dedicated numerical tool was developed to study and analyze arbitrary subwavelength structures integrated on the optical fiber tip by taking into account finite-size effects. The numerical results are in good agreement with the observed experimental spectra and reveal that the fabricated sensing probes act as structured interferometers that are assisted by surface plasmon excitations at the metallo-dielectric interfaces. To prove the sensing capability of the proposed platform, refractive index measurements were carried out, revealing a sensitivity of up to 2300 nm/RIU, outperforming most plasmonic probes synthesized on optical fiber tips. The achieved performances, obtained using very small active areas, demonstrate the effectiveness of these self-assembled fiber-optic probes for label-free chemical and biological sensing applications.

Recently, great efforts have been carried out to design optimized metallic nano-grating back-reflectors to improve the light absorption in thin film solar cells. In this paper, is introduced a feasibility study on the prototyping of patterned substrate for solar cell fabrication. In particular, is demonstrated that the Focused Ion Beam lithography not affect the electric performances of the realized cell, giving us the opportunity to use this lithography technique for prototyping each kind of substrate for solar cell fabrication. © 2014 IEEE.

We present recent results on the fabrication of metallo-dielectric structures on the optical fiber tip by using a self-assembly technique. Our studies aim to attain advanced nanostructured sensors by exploiting easy and low cost fabrication processes suitable to be employed in massive production of technologically advanced devices in the roadmap of the Lab on Fiber Technology. The pursued approach basically consists in the preliminary preparation of a patterned polymeric film by the breath figure technique, directly on the optical fiber tip, and in the successive metal deposition by evaporation. The experimental results demonstrate the successful creation of a metallo-dielectric honeycomb pattern on the optical fiber tip. The experimental spectral features are in good agreement with the numerical analysis, elucidating the photonic and plasmonic interactions occurring in the Lab onto the optical fiber tip. The sensing properties of the optical fiber probes have been successfully explored in terms of sensitivity to the surrounding refractive index changes demonstrating their potentialities for chemical and biological sensing applications.

The “Lab on Fiber” technology has been recently proposed as a valuable route for the realization of novel and highly functionalized technological platforms completely integrated in a single optical fiber in communication and sensing applications. As a follow up of the proposed technological approach, here, we present recent results on the fabrication of metallo-dielectric structures on the optical fiber tip by using a self-assembly technique. Our studies aim to attain advanced nanostructured sensors by exploiting easy and low cost fabrication processes suitable to be employed in massive production of technologically advanced devices. The pursued approach basically consists in the preliminary preparation of a patterned polymeric film by the breath figure technique, directly on the optical fiber tip, and in the successive metal deposition by evaporation. The experimental results demonstrate the successful creation of a metallodielectric honeycomb pattern on the optical fiber tip. The experimental spectral features are in good agreement with the numerical analysis, elucidating the photonic and plasmonic interactions occurring in the Lab onto the optical fiber tip. The sensing properties of the optical fiber probes have been successfully explored in terms of sensitivity to the surrounding refractive index changes demonstrating their potentialities for chemical and biological sensing applications.

In this chapter, we report on recent numerical and experimental results obtained with Fiber Bragg Grating (FBG) hydrophones for underwater acoustic detection. The optical hydrophones under investigation consist of FBGs coated with ring-shaped polymers of different size. Via full-wave numerical simulations, we study the complex opto-acousto-mechanical interaction among an incident acoustic wave traveling in water, the optical fiber surrounded by the ring shaped coating, and the FBG inscribed the fiber. Our results fully characterize the opto-acoustic response of the optical hydrophone, and highlight the key role played by the coating in enhancing significantly its sensitivity, over the whole acoustic wave range of interest (up to 30 kHz) by comparison with a standard uncoated configuration. The coating material was selected and designed in order to provide mechanical amplification, via choice of its acoustic-mechanical properties. Our underwater acoustic measurements reveal the resonant behavior of these optical hydrophones, as well as its dependence on the coating size. By comparison with uncoated FBGs, responsivity enhancements were found, demonstrating the effectiveness of polymeric coating in tailoring the acoustic response of FBG based hydrophones.

In this work, we report the preliminary results on the fabrication of metallo-dielectric nanostructures on the optical fiber tip by using a simple and low cost self-assembly approach. The fabrication process relies on the breath figure technique here adapted to operate on unconventional substrates as the case of single mode optical fibers. The experimental results demonstrate the successful creation of a honeycomb pattern on the optical fiber tip and the feasibility of the proposed approach in the roadmap of "Lab on fiber" technology development. Further work is currently running aimed to the assessment the presented fabrication procedures in order to attain advanced optical fiber sensing probes with high fabrication throughput by exploiting a low cost technology. © (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

In the recent years, a new concept is emerging in the scientific community dealing with the possibility to use optical fibers as platform to develop all-in-fiber multimaterial and multifunctional optical devices and systems (Abouraddy et al., 2007). The key feature of these new optoelectronic devices relies on the proper integration of specific materials, such as conductors, semiconductor and insulator, into the same optical fiber in order to attain advanced functionalities within a single optical fiber. A promising building block to realize these multifunctional optoelectronic devices are the Microstructured Optical Fibers (MOFs) which, being composed by a periodic distribution of micrometric air-holes running uniformly along the fiber length (Knight et al., 2003), offer an high degree of freedom in their fabrication and at the same time several opportunities of integration with specific materials. Also by manipulating the properties of the in-fiber integrated materials, the guiding features of the MOF itself can be properly changed in order to develop new tunable photonic devices (Domachuk et al. 2004; Larsen et al. 2003; Huang et al. 2004) as well as optical fiber sensors (Benabid et al. 2005; Matejec et al. 2006). Single Walled Carbon Nanotubes (SWCNTs) constitute a very promising material for multimaterial and multifunctional photonic devices in light of their unique electrical and mechanical properties (Dresselhaus et al. 2001). Furthermore, the opto-chemical sensing properties of carbon nanotubes, deposited onto singlemode standard optical fiber (SOF) configured in buffered and not buffered reflectometric configurations, have been demonstrated to be suitable (Penza et al. 2004; Penza et al. 2005 ; Consales et al. 2006; Consales et al. 2007) to perform chemical detection of volatile organic compounds (VOCs) at room temperature. 26

In this letter, a Photonic True Time Delay (PTTD) unit for phased array antennas is experimentally demon- strated. The PTTD unit, employing a single wavelength laser source, exploits the distributed photonic bandgap offered by a Linearly Chirped Fiber Bragg Grating (LCFBG) to attain different time delays by properly actuating the physical and geometrical features of the LCFBG through temperature changes. The time delay response of the TTD unit has been measured experimentally revealing multiband operation capability (S, C, X and Ku bands) with ps time delay resolution and a maximum dynamic range of 250ps. The time steering demonstration has been performed by characterizing in the Ku band an array prototype within a Near Field range.

In this work, we report on the investigation of in-fiber photonic devices based on microstructured chirped fiber Bragg gratings (CFBGs) for sensing applications. The basic device here analyzed consists in a CFBG with single or multiple defects obtained by a deep and localized stripping of the cladding layer along the grating structure. The effect of each local thinning along the grating length, properly exploited, basically enables the formation of one pass-band channel within the pristine grating bandwidth and correspondently in one stop-band out of the pristine grating bandwidth. In addition, due to spatial encoding in chirped gratings, each channel spectral position exclusively depends on the features of its own defect (length, depth of the defect and surrounding refractive index) in a well defined location along the grating. Thus, the spectral properties of each channel are not affected by defects located elsewhere along the grating structure, enabling the possibility to develop independent multipoint sensors by exploiting a single grating device.

In this work, we report on the integration of Hollow-core Optical Fibers (HOF) and Single Walled Carbon NanoTubes (SWCNTs) in order to obtain new functionalized devices by means of the modification of the photonic bandgap (PBG) characterizing the HOF itself. The samples were obtained by coating and partially filling by SWCNTs the termination of HOFs. The infiltration of SWCNTs inside the HOF holes has been accomplished by means of the Langmuir-Blodgett technique. Far field transmission characterizations have been carried out at 1550nm in order to study the influence of the carbon nanotubes within the HOF holes on the HOF PBG. Finally, in light of the sensing features of the SWCNTs, the realized samples have been employed as opto-chemical sensors for volatile organic compounds (VOCs) detection and their sensing capability has been proved by their exposure to VOCs traces. Experimental results demonstrate the success of the SWCNTs partial filling within the HOF holes, the influence of the deposition parameters on the HOF PBG and sensing performances as well as the sensor capability to perform VOCs detection with a good sensitivity and fast response times.

In this work, a fiber optic multifunction sensing system is presented. Fiber Bragg grating (FBG) technology is integrated with a thin film refractometric system in order to retrieve simultaneous measurements of temperature and ammonia concentration in water. The sensing probe is fabricated by depositing a tin dioxide (SnO2) layer on the distal end of a single mode standard optical fiber (SOF) including a fiber Bragg grating. Experimental results are shown, demonstrating the capability of the proposed sensor to perform chemical detection of ammonia in the range of sub-ppm with fast time response and good desorption properties

In this work, preliminary experimental results on the capability of a Metal Oxides (MOXs) based optical sensor to perform ammonia detection in water environments, at room temperature, are presented. Electro-spray pyrolisis technique has been used to deposit the SnO2 films on the distal end of standard Silica Optical Fibers (SOFs). Reflection spectra of the sensing probes have been measured in the range 1520-1620nm by using a tunable laser and an optical spectrum analyzer. Single wavelength reflectance measurements have been carried out to test the sensing performances for ammonia detection in the range 4-20 ppm. High sensitivity to the target analyte and fast response times have been observed. From the results obtained, a Limit Of Detection (LOD) as low as sub-ppm has been achieved.

The "lab-on-fiber" concept envisions novel and highly functionalized technological platforms completely integrated in a single optical fiber that would allow the development of advanced devices, components and sub-systems to be incorporated in modern optical systems for communication and sensing applications. The realization of integrated optical fiber devices requires that several structures and materials at nano- and micro-scale are constructed, embedded and connected all together to provide the necessary physical connections and light-matter interactions. This paper reviews the strategies, the main achievements and related devices in the lab-on-fiber roadmap discussing perspectives and challenges that lie ahead.