scholarly journals Акустооптические модуляторы с расширенной частотной полосой для волоконно-оптических линий

2021 ◽  
Vol 91 (6) ◽  
pp. 1021
Author(s):  
В.М. Епихин ◽  
А.В. Рябинин
Keyword(s):  
Optical Fibers ◽  
Frequency Band ◽  
Switching Time ◽  
Optical Loss ◽  
Single Mode ◽  
Operating Mode ◽  
Center Frequency ◽  
Frequency Shifter ◽  
Focused Beam ◽  
Good Agreement

A modulator-frequency shifter with single-mode optical fibers for a radiation wavelength of 1064 nm has been developed and manufactured. The light beam was focused in the center of the sound column. Modulator switching time ≃ 18 ns. Operating mode: pulse, continuous. Total optical loss at center frequency: -3.2 dB. An expression for the frequency band of reception of the modulator is obtained. The estimates are in good agreement with the experimental data ≃ 40 MHz. It is shown that the use of a scheme with a focused beam makes it possible to implement a modulator with a minimum switching time ≃ (2-3) ns and a receiving frequency band ≃ (200-300) MHz.

scholarly journals Dependence of optical attenuation on radiation wavelength and waveguide geometry in copper-coated optical fibers

2020 ◽  
Vol 238 ◽  
pp. 11013
Author(s):  
Pavel Cherpak ◽  
Renat Shaidullin ◽  
Oleg Ryabushkin
Keyword(s):  
Optical Fibers ◽  
Near Infrared ◽  
Optical Loss ◽  
Single Mode ◽  
Optical Losses ◽  
Radiation Losses ◽  
Optical Attenuation ◽  
Novel Approach ◽  
Laser Sources

We demonstrate a novel approach to the determination of optical loss coefficients in metal-coated fibers in a 0.4-1.9 μm wavelength range. It is based on measuring the change of temperature-dependent electrical resistance of the metal coating caused by laser radiation transmitted through the fiber. A number of single-mode and multimode metallized fibers were investigated using several laser sources operating in visible and near infrared ranges. The spectral dependencies of optical losses of copper-coated fibers were experimentally obtained. The region that corresponds to the minimum optical losses is located near 1 μm wavelength. The increase of radiation losses in 1.5-1.9 μm region is much steeper compared to polymer-coated fibers.

scholarly journals Acousto-optic modulators/frequency shifters with single-mode optic fibers

2021 ◽  
Vol 2127 (1) ◽  
pp. 012037
Author(s):  
V M Epikhin ◽  
M M Mazur ◽  
A V Ryabinin ◽  
P V Kamaushkin ◽  
L I Mazur
Keyword(s):  
Single Crystal ◽  
Light Beam ◽  
Optical Fibers ◽  
Switching Time ◽  
Electrical Breakdown ◽  
Single Mode ◽  
Double Crystal ◽  
Emission Frequency ◽  
Beam Focusing ◽  
Optic Fibers

Abstract Acousto-optic modulators/frequency shifters based on TeO2 crystals with single-mode optical fibers supporting and not supporting polarization for collimated and focused light beams at radiation wavelengths of 785, 1064, 1550 nm have been developed, produced and experimentally investigated. The mechanisms of formation and methods of expanding the working band of the modulator are determined. A double-crystal acousto-optic laser emission frequency shifter with an working bandwidth of ≈40 MHz has been created. Single-crystal modulators based on collimated beams with a frequency band of ≈10 MHz are considered. A single-crystal modulator with a focused light beam with a switching time of ≈ 18 ns and an extended reception band of ≈ 40 MHz is investigated. It is shown that a light beam focusing makes it possible to implement a modulator with a minimum switching time of ≈ (2-3) ns. This value is limited by electrical breakdown of the ultrasonic wave transmitter.

scholarly journals Bend loss fiber optics design based on sinusoidal and ellipse configurations

2021 ◽  
Vol 51 (3) ◽  
Author(s):  
Noor Azie Azura Mohd Arif ◽  
Dilla Durhya Burhanuddin ◽  
Sahbudin Shaari ◽  
Abang Annuar Ehsan
Keyword(s):  
Fiber Optics ◽  
Optical Fibers ◽  
Optical Loss ◽  
Single Mode ◽  
Fiber Optic Sensor ◽  
Curvature Radius ◽  
Sensor Applications ◽  
Bending Loss ◽  
Bending Radius ◽  
Bending Sensor

Bending losses in optical fibers comprise one of the extrinsic attenuations that contribute to optical loss and they are essential for optical fiber bending sensor applications. This work investigated the optical loss in a standard single-mode step-index fiber optics due to fiber bending at 1550 nm wavelength. Variations in macro-bending loss with curvature radius and turn number have been measured. Curvature radius and turn number are examined for sinusoidal and elliptical shaped bending configurations. It has been found that the loss increases as the bending radius and number of turns increase. The result also showed that elliptical shaped bending configuration produced more loss in contrast to that of sinusoidal shaped at bending angles of 180° and 360°. The study on the macro-bending loss in terms of curvature radius and turn number for both elliptical and sinusoidal shaped bending configurations is beneficial for future fiber optic sensor applications.

scholarly journals 2D materials coated on etched optical fibers as humidity sensor

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Erfan Owji ◽  
Hossein Mokhtari ◽  
Fatemeh Ostovari ◽  
Behnam Darazereshki ◽  
Nazanin Shakiba
Keyword(s):  
Graphene Oxide ◽  
Optical Fibers ◽  
Humidity Sensor ◽  
2D Materials ◽  
Optical Loss ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Test Set ◽  
Humidity Sensing ◽  
Molybdenum Diselenide

AbstractIn this investigation, etched-fibers are coated by 2D layers such as Molybdenum disulfide (MoS2), Molybdenum diselenide (MoSe2) and composition of graphene and graphene oxide (G/GO) to modify humidity sensing. The relative differentiation of attenuations (RDA) in presence of relative humidity (RH) is measured by Optical Loss Test Set at two standard-wavelengths-telecommunication (1310 nm and 1550 nm). Results show that the etched single-mode fiber (ESMF) coated with G/GO has relatively high and one by one function for RDA versus RH (more than 30%). Also, its sensitivity and variance are reasonable. The MoSe2 based sensor is applicable at humidity below 30% because of higher RDA. However, it is not useful at humidity more than 30% due to the absence of one by one function for RDA versus RH. Besides, ESMF coated with MoS2 has indistinctive behavior and is not useful as a humidity sensor.

Intensification of Spontaneous Raman Spectra by Use of Liquid Core Optical Fibers

1972 ◽  
Vol 26 (6) ◽  
pp. 585-589 ◽  
Author(s):  
G. E. Walrafen ◽  
J. Stone
Keyword(s):  
Fiber Optics ◽  
Raman Spectra ◽  
Optical Fibers ◽  
Laser Power ◽  
Liquid Core ◽  
Fused Quartz ◽  
Ion Laser ◽  
Argon Ion ◽  
Focused Beam ◽  
Good Agreement

Intense spontaneous Raman radiation has been obtained from C6H6 and C2CI4 by passing the focused beam from an argon ion laser (4880 Å, 5 to 250 mW) through filled hollow fused quartz optical fibers having core diameters of ∼75 µm and lengths from 10 to 25 meters. Spectral intensifications by factors of ∼102 to 103 compared to conventional sample techniques have been obtained with the fiber optics method. Raman spectra were recorded with a Cary model 81 spectrophotometer by collecting the divergent radiation emitted from the end of the optical fiber at the focus of the “image slicer.” However, the intensification method is general and may be employed with any double or triple monochromator by placing the fiber end near the entrance slit. For C6H6 at least 33 Raman components were observed in the 3300 > A Δ ν̄ > 1650 cm−1 region including shifts due to overtones and combinations, by using a slit-width of 2 cm−1 with a 15 m fiber length and a laser power of ∼130 mW. The Raman spectra from C6H6 were found to be in good agreement with those recently reported by Schrötter and Bofilias. For C2CI4 intense spectra were also obtained using 2 cm−1 slit-widths with fiber lengths of 25 m and power levels to 250 mW. These spectra augment those obtained earlier by Wittek and indicate five newly observed Raman and infrared coincidences that in several cases may result from the breakdown of D2h selection rules. Details of the fiber optics Raman technique are described.

Design Considerations in Reduced-Diameter Single-Mode Optical Fibers

2002 ◽  
Author(s):  
Wilson K. Chiu ◽  
Gregory H. Ames ◽  
Marilyn J. Berliner
Keyword(s):  
Optical Fibers ◽  
Single Mode ◽  
Design Considerations

scholarly journals Sensing, Actuation, and Control of the SmartX Prototype Morphing Wing in the Wind Tunnel

Actuators ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 107
Author(s):  
Nakash Nazeer ◽  
Xuerui Wang ◽  
Roger M. Groves
Keyword(s):  
Wind Tunnel ◽  
Optical Fibers ◽  
Fiber Optic ◽  
Experimental Testing ◽  
Single Mode ◽  
Fiber Optic Sensor ◽  
Sensor Data ◽  
Random Errors ◽  
Morphing Wing ◽  
Actuator Dynamics

This paper presents a study on trailing edge deflection estimation for the SmartX camber morphing wing demonstrator. This demonstrator integrates the technologies of smart sensing, smart actuation and smart controls using a six module distributed morphing concept. The morphing sequence is brought about by two actuators present at both ends of each of the morphing modules. The deflection estimation is carried out by interrogating optical fibers that are bonded on to the wing’s inner surface. A novel application is demonstrated using this method that utilizes the least amount of sensors for load monitoring purposes. The fiber optic sensor data is used to measure the deflections of the modules in the wind tunnel using a multi-modal fiber optic sensing approach and is compared to the deflections estimated by the actuators. Each module is probed by single-mode optical fibers that contain just four grating sensors and consider both bending and torsional deformations. The fiber optic method in this work combines the principles of hybrid interferometry and FBG spectral sensing. The analysis involves an initial calibration procedure outside the wind tunnel followed by experimental testing in the wind tunnel. This method is shown to experimentally achieve an accuracy of 2.8 mm deflection with an error of 9%. The error sources, including actuator dynamics, random errors, and nonlinear mechanical backlash, are identified and discussed.

scholarly journals Design and analysis of a fiber-optic sensing system for shape reconstruction of a minimally invasive surgical needle

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aizhan Issatayeva ◽  
Aida Amantayeva ◽  
Wilfried Blanc ◽  
Daniele Tosi ◽  
Carlo Molardi
Keyword(s):  
Performance Analysis ◽  
Minimally Invasive ◽  
Optical Fibers ◽  
Single Mode ◽  
Spectral Shift ◽  
Shape Reconstruction ◽  
Minimally Invasive Surgical ◽  
Working Principle ◽  
Doped Fibers ◽  
Distributed Measurement

AbstractThis paper presents the performance analysis of the system for real-time reconstruction of the shape of the rigid medical needle used for minimally invasive surgeries. The system is based on four optical fibers glued along the needle at 90 degrees from each other to measure distributed strain along the needle from four different sides. The distributed measurement is achieved by the interrogator which detects the light scattered from each section of the fiber connected to it and calculates the strain exposed to the fiber from the spectral shift of that backscattered light. This working principle has a limitation of discriminating only a single fiber because of the overlap of backscattering light from several fibers. In order to use four sensing fibers, the Scattering-Level Multiplexing (SLMux) methodology is applied. SLMux is based on fibers with different scattering levels: standard single-mode fibers (SMF) and MgO-nanoparticles doped fibers with a 35–40 dB higher scattering power. Doped fibers are used as sensing fibers and SMFs are used to spatially separate one sensing fiber from another by selecting appropriate lengths of SMFs. The system with four fibers allows obtaining two pairs of opposite fibers used to reconstruct the needle shape along two perpendicular axes. The performance analysis is conducted by moving the needle tip from 0 to 1 cm by 0.1 cm to four main directions (corresponding to the locations of fibers) and to four intermediate directions (between neighboring fibers). The system accuracy for small bending (0.1–0.5 cm) is 90$$\%$$ % and for large bending (0.6–1 cm) is approximately 92$$\%$$ % .

Dispersion properties of single-mode optical fibers in telecommunication region: poly (methyl methacrylate) (PMMA) versus silica

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Hassan Pakarzadeh ◽  
Seyed Mostafa Rezaei ◽  
Mostafa Taghizadeh ◽  
Forough Bozorgzadeh
Keyword(s):  
Methyl Methacrylate ◽  
Optical Fibers ◽  
Spectral Range ◽  
Structural Parameters ◽  
Practical Importance ◽  
Single Mode ◽  
Dispersion Characteristics ◽  
Poly Methyl Methacrylate ◽  
Dispersion Wavelength ◽  
Zero Dispersion Wavelength

AbstractIn this paper, the dispersion characteristics of two standard single-mode optical fibers (SMFs), fabricated with silica and poly (methyl methacrylate) (PMMA) are studied in telecommunication spectral regions. The effect of structural parameters, such as the radius of the fiber core and the relative core-cladding index difference, is numerically investigated. It is found that over whole spectral range, the PMMA-based SMF shows lower dispersion than the silica SMF. Also, the zero-dispersion wavelength (ZDW) of PMMA-based SMF is longer than that of silica fiber. The results may be of practical importance for the telecommunication applications.

Sign in / Sign up

Export Citation Format

Share Document