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In this paper we present an exploratory study on the understanding of reality among scientists. The nature of reality has been a conundrum for generations of theologians, philosophers, and scientists as well as the lay public. It also appears as a scientific problem in various disciplines, from physics to psychiatry and neuroscience. For the purpose of our study, we employed Chamber REST (Restricted Environmental Stimulation), which has been known to produce substantial perceptual effects such as visual or auditory pseudo-hallucinations. We hypothesized that such experiences could alter basic underlying metaphysical beliefs which our subject-scientists hold about reality. We conclude that the technique showed the potential to induce such changes, but the outcome is also probably dependent on their pre-existing views gained through previous experiences, such as for example altered states of consciousness. Also, the effects of Chamber REST seem to be in this respect comparable to psychedelic sessions.

We have addressed the challenge to carry out the angular tilt stabilization of a laser guiding mirror which is intended to route a laser beam with a high energy density. Such an application requires good angular accuracy as well as large operating range, long term stability and absolute positioning. We have designed an instrument for such a high precision angular tilt measurement based on a triangulation method where a laser beam with Gaussian profile is reflected off the stabilized mirror and detected by an image sensor. As the angular deflection of the mirror causes a change of the beam spot position, the principal task is to measure the position on the image chip surface. We have employed a numerical analysis of the Gaussian intensity pattern which uses the nonlinear regression algorithm. The feasibility and performance of the method were tested by numeric modeling as well as experimentally. The experimental results indicate that the assembled instrument achieves a measurement error of 0.13 microradian in the range +-0.65 degrees over the period of one hour. This corresponds to the dynamic range of 1:170 000., 7 pages, 4 figures; SPIE Photonics Europe, 2014, Brussels, Belgium

Roosts provide bats with place for daytime sheltering, protection from weather and predators, mating, and social interaction. Movements between multiple roosts are often necessary, either due to limited roost life, changes in roost conditions or demands at different times of the year. Information transfer is an important contributor to day-roosting behaviour and typically exhibits non-random social assortment dynamics. Some individuals appear to explore and share roost discoveries more often than others, though it remains unclear whether associations are stronger between close relatives than less related individuals. In the present study, network analysis, in combination with genetic and spatial data, was used to explore the roosting behaviour of Egyptian fruit bats (Rousettus aegyptiacus) within an isolated deme. Our results showed that the roosts had distinct core-periphery structure. The core of the winter roost network was represented by only two roosts, while in spring, the season of food scarcity, the core was represented by multiple roosts, suggesting their potential role as centres, where information about roosts and foraging sites is exchanged. We found no relationship between relatedness and roost sharing over two seasons. These results provide strong support that Egyptian fruit bats do not roost preferentially with relatives, in contrast to many animal populations where individuals preferentially associate with kin.

In the paper, we analyze several key philosophical approaches to objective knowledge (Descartes, Kant), which we described as “speculative”, that is theoretical and independent of experience. Our interpretation is based on the argument that the demarcation between speculative philosophy and empirical science (which is at the same time the boundary of objective knowledge) has been gradually reduced and that philosophy has been naturalized. We claim that Popper’s transcendental thesis was extended by Quine and his appeal to the naturalization of philosophy, and Bloor accepted naturalism as one of the premises for his sociology of scientific knowledge. The culmination of this tendency is in empirical and experimental philosophy. In conclusion, we will introduce experimental philosophy, which has developed significantly in recent years, as one of the ways how to approach the question of “objective knowledge” by combining speculative approaches and empirically acquired data.

Trapped ions, as one of the pillars of progress in frequency metrology and quantum optics, require a complex experimental environment with well-defined conditions. We present that a feature called dark resonance, provided by the trapped ion itself, can be used as a versatile sensor for enhanced in-situ analysis of interacting fields. The dark resonance is formed in the lambda-type energy level scheme of a laser cooled 40Ca+ ion and corresponds to a fluorescence quenching. The method uses an analysis of the detection times of photons emitted from the upper energy level, which is excited via two optical dipole transitions. The two excitation lasers are phase locked to an optical frequency comb to reduce their linewidths and for precise control of their optical frequencies within the dark resonance. The amplitudes of interacting fields are obtained using the Fourier transform of the ion fluorescence or photon correlation measurements. This paper shows that the method can be applied for sensing of electric, magnetic and electromagnetic fields. Firstly, we present the potential for frequency analysis of the secular motion of a few-ion Coulomb crystal, which corresponds to the axial static electric field of a linear ion trap. Secondly, we demonstrate the optical frequency analysis of the employed lasers driving the two transitions. In the last case we show the analysis of an alternating magnetic field at the position of single ion.

Liquid crystal microdroplets with readily adjustable optical properties have attracted considerable attention for building reconfigurable optofluidic microsystems for sensing, imaging, and light routing applications. In this quest, development of active optical microcavities serving as versatile integrated sources of coherent light and ultra-sensitive environmental sensors has played a prominent role. Here, we study transportable optofluidic microlasers reversibly tunable by an external electric field, which are based on fluorophore-doped emulsion droplets of radial nematic liquid crystals manipulated by optical tweezers in microfluidic chips with embedded liquid electrodes. Full transparency of the electrodes formed by a concentrated electrolyte solution allows for applying an electric field to the optically trapped droplets without undesired heating caused by light absorption. Taking advantage of independent, precise control over the electric and thermal stimulation of the lasing liquid crystal droplets, we characterize their spectral tuning response at various optical trapping powers and study their relaxation upon a sudden decrease in the trapping power. Finally, we demonstrate that sufficiently strong applied electric fields can induce fully reversible phase transitions in the trapped droplets even below the bulk melting temperature of the used liquid crystal. Our observations indicate viability of creating electrically tunable, optically transported microlasers that can be prepared on-demand and operated within microfluidic chips to implement integrated microphotonic or sensing systems.

We propose a novel methodology to estimate parameters characterizing a weakly nonlinear Duffing oscillator represented by an optically levitating nanoparticle. The method is based on averaging recorded trajectories with defined initial positions in the phase space of nanoparticle position and momentum and allows us to study the transient dynamics of the nonlinear system. This technique provides us with the parameters of a levitated nanoparticle such as eigenfrequency, damping, coefficient of nonlinearity and effective temperature directly from the recorded transient particle motion without any need for external driving or modification of an experimental system. Comparison of this innovative approach with a commonly used method based on fitting the power spectrum density profile shows that the proposed complementary method is applicable even at lower pressures where the nonlinearity starts to play a significant role and thus the power spectrum density method predicts steady state parameters. The technique is applicable also at low temperatures and extendable to recent quantum experiments. The proposed method is applied on experimental data and its validity for one-dimensional and three-dimensional motion of a levitated nanoparticle is verified by extensive numerical simulations.

Animals are faced with a range of ecological constraints that shape their behavioural decisions. Habitat features that affect resource abundance will also have an impact, especially as regards spatial distribution, which will in turn affect associations between the animals. Here we utilised a network approach, using spatial and genetic data, to describe patterns in use of space (foraging sites) by free-ranging Egyptian fruit bats (Rousettus aegyptiacus) at the Dakhla Oasis in Egypt. We observed a decrease in home range size during spring, when food availability was lowest, which was reflected by differences in space sharing networks. Our data showed that when food was abundant, space sharing networks were less connected and more related individuals shared more foraging sites. In comparison, when food was scarce the bats had few possibilities to decide where and with whom to forage. Overall, both networks had high mean degree, suggesting communal knowledge of predictable food distribution.

In this article we describe prototype designs and tests for low‐cost rotational medium‐ and strong‐motion seismometers using three types of proof mass (two liquid and one solid) and a number of transducer configurations. This article describes the third set of designs and tests in our development program. The details of our results for most of these are in the Ⓔ electronic supplement to this article, whereas here we concentrate on three of the most promising and representative design combinations. Most of our results pertain to sensors with water or silicon oil as the proof mass, though we also tested a torsion‐bar design with a solid proof mass. We find that most mass–transducer combinations lead to output proportional to rotational acceleration, with varying degrees of fidelity. Most combinations we tested can be dismissed from further development for reasons of performance or inconvenience during analysis of acceleration response (compare with Ⓔ electronic supplement). In this article, we describe three of the more promising combinations, one each for the three types of response functions we measured. Of these three, one mass–transducer combination in particular (a hinged sensing element and capacitive transduction) has output voltage closely proportional to rotational displacement (angle) over a wide frequency range; such displacement proportionality obviates two of the integration steps normally required to solve for continuum single‐point motions or correct for tilt‐induced errors in horizontal translational sensors. Thus, although we illustrate two other designs of some promise, we propose a new design that follows this displacement‐proportional path while increasing the device’s sensitivity to on‐axis rotations, improving its manufacturing ease and lowering its sensitivity to translational motions. Online Material: Results and related material for mass–transceiver combinations, drawings and photographs of liquid proof masses, amplitude and phase transfer functions, clip and linearity tests, and noise plots.

V uvodni casti zrekapitulujeme v hrubých obrysech Popperovu teorii demarkace v navaznosti na jeho dalsi teze týkajici se kritiky induktivnich postupů, ulohy metafyziky ve vědě a falzifikaci. Dilo videňskeho filozofa vyvolalo znacne množstvi reakci, jejichž spektrum sahalo od dilcich modifikaci Popperových myslenek jeho žaky, přes navrhy nových teorii jim inspirovaných, až po zasadni kritiku. Hlavni směry teto kritiky nacrtneme (bez naroku na uplnost) v dalsi casti statě. Polemizujeme předevsim s jednostranným odmitnutim indukce a pokousime se zde rehabilitovat některe induktivni postupy. Nasledně upozornime na nedostatky Popperova pojeti falzifikace i na problemy použitelnosti jeho demarkacniho kriteria na typických přikladech ze sfery metafyziky a "pseudovědy" (psychoanalýza, astrologie). Zavěr věnujeme diskuzi o uloze indukce a dedukce ve vědě, posouzeni užitecnosti Popperových teorii ve vztahu k soucasne vědě.

We studied ranging and feeding behavior of Cypriot fruit bats during the summer and winter, which are critical periods with limited food supply and adverse conditions. Seasonal changes in ranging behavior were characterized by a steep increase in the size of core feeding areas and home ranges from summer to winter. Males and females did not differ in the size of summer and winter core areas and home ranges, but they differed in the distance they traveled to summer feeding sites. Summer food consisted of fruits of Ficus carica and flowers of Agave americana. Winter food consisted of dates, fruits of Melia azedarach, Citrus reticulata, C. limon, Myrtus communis, and the flowers of Eucalyptus spp. Males and females differed as to the proportion of time they spent feeding on different food types, which may be explained by sexual differences related to food quality requirements. Summer foraging activity tended to be in areas with water bodies and larger fruit orchards. Winter foraging activity occurred more in areas with larger fruit orchards, a higher number of citrus plantations and date palms, typically located in built-up areas. The body condition of the bats was worse during the summer, which we assume was the result of their more limited diet during this period, making summer a more stressful period for them than winter. Active conservation management of Cypriot fruit bats should include the construction of artificial water sources in the vicinity of fruit orchards, but also controversial practices such as supporting the occurrence of particular nonnative plant species, thereby enhancing food availability in critical times of the year.

We report on a traceable calibration system for a 3500mm-long console that carries a measurement system for inspecting the diameter of a circular reactor chassis. The system uses two single-pass laser interferometers with homodyne fringe detection for measurement in two degrees of freedom. The hybrid FPGA-microcontroller control module carries out the fringe detection together with the application-specific scale linearization approach and the compensation of environmental influences such as thermal elongation and the refractive index of air fluctuations. We demonstrated the system feasibility with an accuracy of a few microns and translation velocity higher than 0:1 metre per second., Comment: CPS 2018, Lednice, CZ, September 2018 7 pages, 8 figures

Since the early 20th century underdetermination has been one of the most contentious problems in the philosophy of science. In this article I relate the underdetermination problem to models in biology and defend two main lines of argument: First, the use of models in this discipline lends strong support to the underdetermination thesis. Second, models and theories in biology are not determined strictly by the logic of representation of the studied phenomena, but also by other constraints such as research traditions, backgrounds of the scientists, aims of the research and available technology. Convincing evidence for the existence of underdetermination in biology, where models abound, comes both from the fact that for a natural phenomenon we can create a number of candidate models but also from the fact that we do not have a universal rule that would adjudicate among them. This all makes a strong case for the general validity of underdetermination thesis.

Book review:Ippoliti, Emiliano, Sterpetti, Fabio, Nickles Thomas (editors): Models and Inferences in Science (Switzerland: Springer International Publishing, 2016, 256 p.)

The satellite tracking of animal individuals remains a signiucant source of knowledge in the area of zoology. The greatest limitation is the size and weight of the satellite position loggers that prevents the usage of satellite telemetry on three-fourths of mammal and bird species. We present an architecture and design of a miniaturized GPS logger with the weight below ten grams that would be suitable for the studies targeting demanding study groups such as the only European flying fox. Our design combines the GPS logging with traditional telemetry signaling, typically used for manual radio tracking, allows for radio-transmitted position data retrieval and the 2–3 days of battery life. The performance has been verified within a field testing.

This paper focuses on major issues related to data reliability and MOBNET network performance in the AlpArray seismic experiments, in which twenty temporary broad-band stations of the Czech MOBNET pool of mobile stations have been involved. Currently used high-resolution scientific methods require high-quality data recorded for a sufficiently long time interval at observatories and during full time of operation of temporary stations. In this paper we present both new hardware and software tools that help to assure the high-quality standard of broad-band seismic data. Special attention is paid to issues like a detection of sensor mis-orientation, timing problems, exchange of record components and/or their polarity reversal, sensor mass centring, or anomalous channel amplitudes due to, e.g., imperfect gain. Thorough data-quality control should represent an integral constituent of seismic data recording, pre-processing and archiving, especially for data from temporary stations in passive seismic experiments. Large international seismic experiments require enormous efforts of scientists from different countries and institutions to gather hundreds of stations to be deployed in the field during a limited time period. In this paper, we demonstrate beneficial effects of the procedures we have developed for having a sufficiently large set of high-quality and reliable data from each group participating in field experiments.

We collected and analyzed data on the annual course of reproduction of the Egyptian fruit bat (Rousettus aegyptiacus) in 2 climatically distinct areas, the Mediterranean and the Egyptian desert, located at the northern limits of the species' distribution. In both regions, reproductive seasonality was characterized by distinct bimodality in birth timing regardless of climatic differences. A low incidence of simultaneous pregnancy and lactation indicated that both seasonal bimodal polyestry with and without postpartum estrus may occur in both regions, with a possibly lower incidence of postpartum estrus in females from the Mediterranean population. Observed shifts in birth timing between the Mediterranean and the desert study area corresponded to regional differences in fruiting phenology of major dietary plants. The male reproductive cycle was synchronized with that of females. The period of testicular recrudescence occurred during the peak pregnancy period. Because testis size was related to body...

We describe the production of substrate-borne vibrations in a subterranean mole rat of the genus Tachyoryctes for the first time. These signals with a supposed communication function were recorded using two approaches. Firstly, we recorded the production of spontaneous substrate-borne vibrations of individual test animals in artificial tunnels simulating a mole rat burrow system. Secondly, we recorded substrate-borne vibrations in individuals with interconnected home systems divided by a barrier. We found that Tachyoryctes produces these seismic signals by striking its head against the ceiling of the tunnel. Two types of seismic signals differing in physical parameters were identified. A slow signal (inter-pulse distance 0.12 s, inter-bout distance 3.89 s, number of pulses within each bout 9.53) was produced in both experiments, whereas a fast signal (inter-pulse distance 0.05 s, inter-bout distance 18.44 s, number of pulses within each bout 22.54) was produced mainly in close proximity to another individual. Our results indicate that fast signals are probably individually specific, because the success rate of classification according to discriminant function analysis was 70.4 % for the three tested individuals.

V nasledujicim textu nejprve zařadime Kantovo dilo do kontextu osvicenske filosofie a přibližime jeho nahled na některe otazky tehdejsi metafyziky a přirodni filosofie. Pote se zaměřime zejmena na Kantovu sveraznou koncepci prostoru a casu v ramci transcendentalni estetiky a transcendentalni logiky, kterou Kant systematicky představil v Kritice cisteho rozumu . Nasledně přezkoumame hlavni namitky, ktere filosofove i vědci vůci teto koncepci vznesli. To nam pak bude odrazovým můstkem k zavěrecne debatě o vztahu fyzikalnich pojmů a teorii k metafyzice.

We present an investigation of iodine cell purity and influence of contaminations upon frequency shifts of iodine-stabilized frequency-doubled Nd : YAG lasers. The study combines measurements of laser-induced fluorescence and evaluation through the Stern–Volmer formula, with direct measurement of frequency shifts referenced by means of an optical comb to a radiofrequency clock etalon. These indirect and direct approaches are compared and provide feedback on the cell manufacturing procedure. Significant improvement of the apparatus for the measurement of induced fluorescence is reported, leading to better repeatability of the results. The ultimate precision that can be achieved in measurements of the absolute frequency of a stabilized laser is discussed in terms of the cell quality. (Some figures in this article are in colour only in the electronic version)

Research on high-resolution tomography, three-dimensional anisotropy modelled from shear-wave splitting and P-residual analysis, as well as receiver function interpretation, are in progress with the aim to image the crust and uppermost mantle velocities in the Bohemian Massif. Structure of the deep lithosphere and location of boundaries of mantle domains will be compared with tectonics of the crust and limits of terranes derived by geologic and palaeomagnetic methods.

We present a current controller which satisfies the highest protection criteria of semiconductor lasers notorious for their great sensitivity to damage caused by induced electromagnetic interference. The core current source is supplied by linear isolating converter providing ripple free voltage. It is galvanically isolated, double shielded and current sense as well as current modulation are coupled via linear optocouplers. The current controller in this configuration makes safe operation of semiconductor lasers in laboratory conditions possible.

An international comparison of eight 127I2-stabilized semiconductor laser systems (DLs) has been carried out. Five of the DLs were extended-cavity lasers (ECLs) using extra-cavity saturation spectroscopy; another was a microlens-mounted diode modified to have weak optical feedback, stabilized using the same technique; the seventh ECL was stabilized using frequency-modulated spectroscopy. The final DL was a simple laser diode at 635 nm locked with a digital system on a linear absorption of iodine. The P(33) 6-3 transition of iodine was first used to compare the first seven DLs with a He-Ne laser stabilized on the R(127) 11-5 transition of iodine. The relative frequency stability of these lasers was between 5 parts in 1011 and 7 parts in 1012 for a sampling time of 1 s, with the best results less than 2 parts in 1013 over 1000 s. The frequency repeatability measured during one week was of the order of a few tens of kilohertz. This large fluctuation was caused by poor adjustment of the electronic offset of two of the lasers. For the well-corrected lasers, the repeatability was within a few kilohertz. A study of stabilization on the strong absorption group of transitions R(60) 8-4, R(125) 9-4 and P(54) 8-4, located about -12 GHz from the R(127) 11-5 transition, was also carried out. For the first time, a short-term frequency stability better than that of the classical He-Ne laser around 633 nm has been achieved with a relative frequency stability of 4 parts in 1012 for 1 s.

We present the first results of a comparison of deep lithosphere structure of three Variscan massifs - the Armorican Massif, French Massif Central and Bohemian Massif, as revealed by recent tomographic studies of seismic anisotropy. The data originate from several field measurements made in temporary arrays of stations equipped with both short-period and broadband seismometers with digital recording. The study is based on teleseismic body waves and a joint inversion of anisotropic data (P-residual spheres, the fast shear-wave polarizations and split times) and demonstrates that the three Variscan massifs appear to consist of at least two parts with different orientation of large-scale fabric derived from seismic anisotropy. The boundaries of anisotropic lithospheric domains are related to prominent tectonic features recognised on the surface as sutures, shear zones or transfer fault zones, as well as grabens, thus indicating that some of them extend deep through the entire lithosphere.

The local network of digital seismic stations WEBNET monitors the seismic activitv of practically the whole region of Western Bohemia/Vogtland swarms. The network consists of ten short-period stations and one very broadband station. The paper describes the configuration of the network, instrumental equipment and the basic parameters of the stations. The method of and formula for computing the local magnitudes from the WEBNET and KRASLICE seismograms are also given. Based on continuous WEBNET observations in the period 1995-1999, we were able to improve the model of temporal and spatial energy release in the region, the principal characteristics of which are summarised in the paper. Apart from direct P and S waves, the WEBNET seismograms also contain other significant P- and S-type waves, provisionally interpreted as reflected PxP, SxS and SxP waves. The fundamental characteristics of these waves are given in the paper, and tentative mechanisms of their origination are discussed. The large residua in the travel times of the P and S waves, and the discrepancies in the seismograms recorded at stations located east of the principal focal zone are pointed out.

Although the laser interferometry represents the most precise class of techniques in the field of precise measurement of geometrical quantities, its wide use in measurement systems is still accompanied by many unresolved challenges. One of these challenges is the complexity of underlying optical systems. We present a novel approach to the interference phase detection - fringe subdivision - in the homodyne laser interferometry that aims at reduction of the optical complexity while the resolution is preserved. Our method employs a series of computational steps to infer a pair of signals in quadrature that allows to determine the interference phase with a sub-nanometre resolution from an interference signal from a non-polarising interferometer sampled by a single photodetector. The complexity trade-off is the use of laser beam with frequency modulation capability. The method was experimentally evaluated on a Michelson interferometer-based free-space setup and its performance has been compared to a traditional homodyne detection method. The results indicate the method is a feasible al­ ternative for the traditional homodyne detection since it performs with comparable accuracy (< 0.5nm standard deviation), especially where the optical setup complexity is principal issue and the modulation of laser beam is not a heavy burden, for instance in multi-axis measurement systems or laser diode based systems.

The radio telemetry is a well-known technique used within zoological research to exploit the behaviour of animal species. A usage of GPS for a frequent and precise position recording gives interesting possibility for a further enhancement of this method. We present our proposal of an architecture and design concepts of telemetry transmitter with GPS module, called GTAG, that is suited for study of the Egyptian fruit bat (Rousettus aegyptiacus). The model group we study set particular constrains, especially the weight limit (9 g) and prevention of any power resources recharging technique. We discuss the aspect of physical realization and the energyconsumption issues. We have developed a reference implementation that has been already deployed during telemetry sessions and we evaluate the experience and compare the estimated performance of our device to a real data.

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The depth of penetration is probably the most important factor that influences the quality of a laser weld. The depth strongly depends on the focus of the welding beam. The sublimating material forms plasma vapors, that act as a lens and defocus the laser beam. Our contribution presents a method to compensate this phenomenon using an adaptive mirror - a mirror with flexible surface that can adjust the shape of the welding beam. The mirror is regulated by a feedback control loop so that the focus of the laser beam and the penetration depth remain in an optimal range. Since the only possibility to state the penetration depth is to monitor outer effects to estimate desired parameters. a sensor unit is used to monitor the optical emissions of the plasma vapors and the measured data are inputs to an algorithm that estimates the penetration depth. We have done several experiments that study the relation of the adaptive mirror focus and the laser beam shape and how it influences the penetration depth. The estimation results are compared with material samples from test welds. On the basis of these experiments, a preliminary version of a control system was developed and a tested. The tests has shown that the implementation of the control system has positive influence on the quality of the resulting weld.

We describe in this paper a pilot experiment of a white-light fringe analysis with a low-cost color CCD camera. The used detection technique employs the phase-crossing algorithm which identifies the zero optical path difference as the point where the phase difference between the red, green and blue part of the white-light interference fringe becomes equal to zero. An experimental arrangement is based on superluminescent LED diode. The experimental setup is designed to be a crucial part of the complex system for automatic contactless diagnostic and calibration of gauge blocks.

Frequency doubled Nd:YAG lasers are often the option with stabilization to the saturated absorption in molecular iodine featuring good signal-to-noise ratio at the 532 nm. Purity of iodine in the absorption cell is one of the most important factor how to achieve results in optical frequencies corresponding to theoretical values. We present results of measurement of purity of sets of iodine cells made at our institute. The purity was tested by improved method based on measurement of induced fluorescence and evaluation by the Stern-Volmer formula. Frequency-doubled Nd:YAG lasers stabilized with these cells were compared to evaluate their frequency shifts. The absolute frequencies of selected iodine hyperfine transitions were measured in direct laser frequency comparison with the reproducibility well below the kHz level. The results indicating the iodine cell purity are presented with relation to the absolute frequency shifts. This not only highlights the influence of iodine cell quality onto the stability and absolute frequency of lasers etalons but also shows the way towards improvements of the iodine cell manufacturing technology.

We present methods of improvement of wavelength stability and tuneability of semiconductor laser diodes in fiber laser interferometers by fiber Bragg gratings (FBGs). We developed simulation method to calculation of arbitrary fiber grating (apodized, chirp etc.) with high precision by combination of methods based on layered dielectric media (LDM) and transfer matrix. On the basis of our simulations and measurements of the commercially available fiber gratings we designed a special 100 mm long fiber Bragg grating with apodization. We expect the application of the FBG to improvement of the linewidth and mode-hop free tuning range of semiconductor lasers at the wavelength 760 nm to increase resolution of fiber laser interferometer based on these diodes. We built the absolute fiber laser interferometer with Vertical Cavity Surface Emitting Laser (VCSEL) to easy employ FBG to stabilize wavelength and control the tuning range. First set up is presented.