Acousto-optic modulators/frequency shifters with single-mode 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.

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Акустооптические модуляторы с расширенной частотной полосой для волоконно-оптических линий

Журнал технической физики ◽

10.21883/jtf.2021.06.50874.330-20 ◽

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.

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Cell Density Detector Based on Light Beam Focusing

Micromachines ◽

10.3390/mi9110592 ◽

2018 ◽

Vol 9 (11) ◽

pp. 592 ◽

Cited By ~ 2

Author(s):

Aoqun Jian ◽

Huiming Li ◽

Yixia Zhang ◽

Qianqian Duan ◽

Qianwu Zhang ◽

...

Keyword(s):

Light Beam ◽

Optical Fibers ◽

Low Cost ◽

Adherent Cells ◽

Detection Range ◽

Beam Focusing ◽

Convex Lens ◽

A Cell ◽

Cell Counter ◽

Collimating Lens

Although the lab-on-a-chip system has been successfully applied in a wide variety of fields, the goal of achieving a cell counter with simple operation, low cost, and high accuracy still attracts continuous research efforts. In this paper, the authors explore a cell counter based on light beam focusing to measure the density of adherent cells. In this sensor, the light emitted from the optical fibers is collimated by the collimating lens formed in polydimethylsiloxane (PDMS). The uniformly attached adherent cells act as a convex lens, focusing the collimated light propagated through them. The intensity of the focused light indicates the density of the adherent cells. For Hela cells, a detection limit of 8.3 × 104 cells/mL with a detection range from 0.1 × 106 cells/mL to 1.0 × 106 cells/mL is achieved. This sensor is particularly useful for drug screening, cell pathology analysis, and cancer pre-diagnosis.

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Phase Sensitivity of Conventional Single-Mode, PANDA, and Holey Optical Fibers: A Comparison Study

10.21236/ada408460 ◽

2002 ◽

Author(s):

Wilson K. Chiu ◽

Jason M. Maguire ◽

Marilyn J. Berliner

Keyword(s):

Optical Fibers ◽

Single Mode ◽

Phase Sensitivity ◽

Comparison Study

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Design Considerations in Reduced-Diameter Single-Mode Optical Fibers

10.21236/ada633188 ◽

2002 ◽

Author(s):

Wilson K. Chiu ◽

Gregory H. Ames ◽

Marilyn J. Berliner

Keyword(s):

Optical Fibers ◽

Single Mode ◽

Design Considerations

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

Actuators ◽

10.3390/act10060107 ◽

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.

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

Scientific Reports ◽

10.1038/s41598-021-88117-7 ◽

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$$\%$$ % .

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

Journal of Optical Communications ◽

10.1515/joc-2020-0172 ◽

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.

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