Wyniki wyszukiwania - BazTech

1

Radio-over-fibre for generation and transmission 32-tupling frequency optical millimeter wave with polarization modulators

Chen Xinqiao, Dai Siyuan, Liu Xiaorui, Chen Xu, Li Zhihan

Optica Applicata

|

2024

|

Vol. 54, nr 1

51--67

EN

A novel structure to generate 32-tupling frequency millimeter-wave (MMW) signal using polarization modulators (PolM) is proposed. The ±16th order sidebands are generated by the 16th order sidebands generator which is mainly constructed by six PolMs and beat in a photodetector for generating the 32-tupling frequency MMW. The optical sideband suppression ratio (OSSR) of the generated ±16th order sidebands are 29.89 and 29.7 dB from theoretical analysis and simulation. The radio frequency (RF) spurious suppression ratio (RFSSR) of the obtained 32-tupling frequency MMW are 23.88 and 23.32 dB from theoretical analysis and simulation. A radio over fiber (ROF) system to transmit the generated 32-tupling frequency MMW is built. In the center station, the +16th order sideband from the ±16th order sideband generator is filtered out by a filter, after the downlink data is modulated on it. It is recombined with –16th order sideband and transmitted to the based station over fiber. In the based station, a part of –16th order sideband is reflected by a fiber Bragg grating (FBG), and the uplink data is modulated on it and transmitted to the center station over fiber. The signal emerging from the FBG is injected into the photodetector and the 32-tupling frequency MMW with downlink data is generated. The simulation results show that for the transmission fiber length 30 km, the bit-error-rate (BER) is less than 10–9, the power cost of the uplink and downlink is less than 0.44 and 0.5 dB, respectively.

2

Design of a photonic unitary neural network based on MZI arrays

Zhang Ye, Wang Ruiting, Zhang Yejin, Su Yanmei, Wang Pengfei, Luo Guangzhen, Zhou Xuliang, Pan Jiaoqing

Optica Applicata

|

2024

|

Vol. 54, nr 1

5--13

EN

In recent years, optical neural networks have attracted widespread attention, due to their advantages of high speed, high parallelism, high bandwidth, and low power consumption. Photonic unitary neural network is a kind of neural networks that utilize the principles of unitary matrices and photonics to perform computations. In this paper, we design a photonic unitary neural network based on Mach–Zehnder interferometer arrays. The results show that the network has a good performance on both triangular and circular binary classification datasets, where most of the data points are correctly classified. The accuracies achieve 97% and 95% for triangular and circular datasets, with the loss function values of 0.023 and 0.046, respectively.

3

A MZI-based optical neural network for image classification

Zhang Ye, Zhang Saining, Zhang Danni, Wang Ruiting, Su Yanmei, Yi Junkai, Wang Pengfei, Luo Guangzhen, Zhou Xuliang, Pan Jiaoqing

Optica Applicata

|

2024

|

Vol. 54, nr 1

97--104

EN

In recent years, with the expansion of information, artificial intelligence technology has been developed and used in various fields. Among them, optical neural network provides a new type of special neural network accelerator chip solution, which has the advantages of high speed, high bandwidth, and low power consumption. In this paper, we construct an optical neural network based on Mach–Zehnder interferometer. The experimental results on the image classification of MNIST handwritten digitals show that the optical neural network has high accuracy, fast convergence and good scalability.

4

Vibration sensing with the optical fibre Mach-Zehnder interferometer

Kurzych Anna T., Jaroszewicz Leszek R.

Opto-Electronics Review

|

2023

|

Vol. 31, No. 4

art. no. e148992

EN

Vibration is a ubiquitous phenomenon that occurs in everyday life and people are exposed to it almost all the time. Most often, vibration is measured using electromechanical devices such as piezoelectric, piezoresistive, or capacitive accelerometers. However, attention should be paid to the limitations of such vibration sensors. They cannot operate in the presence of strong electromagnetic fields. Measurements with electromechanical devices require physical contact between the sensor and the vibrating object, which is not always possible due to the design of the sensor and device. The possibility of a non-contact vibration measurement in harsh environments is provided by the technology of interferometric fibre optic sensors. This paper reports the principle of operation, design aspects, experimentation, and performance of a Mach-Zehnder interferometric setup for the measurement of vibration frequency. There are different sensing arms implemented in the interferometer: single-mode, polarization-maintaining, and tapered optical fibre. The paper emphasises the simplicity of the set-up structure and the detection capabilities based on the interferometric sensing giving the possibility of constructing a commercial vibration sensor for all industry demands.

5

In-fiber Mach–Zehnder interferometer based on polarization-maintaining fiber for displacement and temperature sensing

Cheng Jun-Ni, Jiang Xiao-Yan

Optica Applicata

|

2023

|

Vol. 53, nr 1

21--33

EN

A displacement sensor based on polarization-maintaining fiber has been proposed and proved in experiment. The polarization-maintaining fiber (PMF) is sandwiched with two graded-index multimode fibers (GI MMF), which form the Mach–Zehnder interferometer (MZI) sensor. Graded-index multimode fiber serve as an optical coupler for modes conversion. The results show that with the increase of displacement, the spectrum moves to the long wavelength direction, but when temperature increases, the spectrum has a red shift, which means that the displacement and temperature can be measured separately according to the wavelength drift direction. The sensor consists of 4 mm GI MMF and 14 mm PMF, which can exhibit the displacement sensitivity of –9.275 pm/μm in the range of 0–600 μm. In addition, temperature will also affect the sensitivity of displacement measurement, so the sensitivity of the sensor to temperature is also measured. The results show that the selected monitoring dip provides a better temperature sensitivity of 33.605 pm/°C in the range of 35–75°C. The sensor is easy to fabricate and does not has any functional coating, which make it become a good candidate in the industrial field.

6

Effect of various overlap distance in waist enlarged tapers in Mach zehnder interferometer fiber optic sensor for liquid temperature monitoring

Razak Hanim Abdul, Abdul Ghafar Ahmad Mubasyir, Haroon Hazura, Idris Siti Khadijah, Mohd Zain Anis Suhaila, Salehuddin Fauziyah, Abdul Rahim Hazli Rafis

Przegląd Elektrotechniczny

|

2022

|

R. 98, nr 4

77--80

EN

A fiber optic sensor (FOS) based on the Mach-Zehnder interferometer (MZI) suitable for monitoring the liquid temperature is proposed and demonstrated. The sensor head was formed by a single mode–multimode–single mode (SMS) fiber structure through arc fusion splicing. The intermodal interference is achieved by two waist- enlarged tapers (WET) at the coupling points of the multimode fiber (MMF) and single mode fibers (SMF). The sensitivity of the sensor was determined based on the overlap distance for waist enlargement, tested in different temperatures of liquid. Five different overlap distances set in the conventional fiber splicer were 30 µm, 60 µm, 90 µm, 120 µm and 150 µm. The highest sensitivity of 0.0984 nm/℃ was produced by the SMS sensor with overlap distance of 150 µm. Such easily fabricated, cost-effective and temperature-immune fiber interferometer could be used for high temperature sensing applications. Manipulation of the overlap distance contributes to the advancement of the device.

PL

Zaproponowano i zademonstrowano czujnik światłowodowy (FOS) oparty na interferometrze Mach-Zehnder (MZI) odpowiedni do monitorowania temperatury cieczy. Głowica czujnika została utworzona przez strukturę włókna jednomodowego-wielomodowego-jednomodowego (SMS) poprzez spawanie łukowe. Intermodalność intermodalna jest uzyskiwana dzięki dwóm zwężeniom powiększonym w talii (WET) w punktach łączenia włókien wielomodowych (MMF) i jednomodowych (SMF). Czułość czujnika została określona na podstawie odległości zakładki dla powiększenia talii, badanej w różnych temperaturach cieczy. Pięć różnych odległości nakładania ustawionych w konwencjonalnej spawarce włókien wynosiło 30 µm, 60 µm, 90 µm, 120 µm i 150 µm. Największą czułość 0,0984 nm/℃ uzyskał czujnik SMS z odległością nakładania 150 µm. Taki łatwy w produkcji, opłacalny i odporny na temperaturę interferometr światłowodowy może być używany w aplikacjach z czujnikami wysokiej temperatury. Manipulacja odległością nakładania się przyczynia się do postępu urządzenia.

7

Phase coding of information in the optical fibre sensor

Życzkowski M., Karol M., Pałka N.

Opto-Electronics Review

|

2020

|

Vol. 28, No. 1

1--7

EN

Determining the dependence of phase difference modulations between light pulses in a modified Mach-Zehnder interferometer was used to develop an optical system coding the information and working as an eavesdropping sensor for an optical fibre information exchange system. The basic challenge in the system development is to maintain stable operation in changing environmental conditions, as well as to ensure optimal parameters of the phase modulator. The system was tested for various many-kilometer long transmission lines of single-mode fibres. The research was focused on achieving the normative Bit Error Rate for the system in the 100 Mbit/s range (STM-1). Such a system can be used in commercial applications for the code key secure transmission in the physical layer of the link.

8

Pulsed interferometric optical fibre sensor detecting wiretapping in long transmission lines

Życzkowski M., Karol M.

Opto-Electronics Review

|

2018

|

Vol. 26, No. 2

183--187

EN

A modiﬁed optical ﬁbre based Mach-Zehnder interferometer was applied as a sensor to detect wiretapping in long transmission optical ﬁbre lines. The signal consisting of short pulses (around 1 ns) was launched to the input of the interferometer based on the polarization maintaining ﬁbres and polarization elements. When the sensing line was undisturbed, detectors registered only a single pulse. The additional two side pulses appear, if the wiretapping attempt took place. For robust detection of any alarm situation we proposed two-criteria algorithm to minimize false alarm rate. Moreover, slow environmental ﬂuctuations were continuously monitored and compensated by polarization controllers. We measured frequency characteristics of the sensor and performed a hundred wiretapping attempts, which proved high performance of the sensor.

9

Application of the Mach-Zehnder interferometer to measure the quadratic electro-optic effect in nonpolar liquids

Ledzion R., Górski P., Kubiak K., Kucharczyk W.

Scientific Bulletin. Physics / Lodz University of Technology

|

2015

|

Vol. 36

55--61

EN

A modification of Mach-Zehnder interferometer is proposed. It is shown that by introducing an additional time dependent phase shift in one of the interferometer arms, its sensitivity may be significantly increased. The method is applied to measure the quadratic electrooptic effect in transformer oil.

PL

Zaproponowano metodę pomiaru kwadratowego efektu elektrooptycznego w cieczach przy wykorzystaniu interferometru Macha-Zehndera. Pokazano, że dodatkowa modulacja fazy w jednym z ramion interferometru znacząco zwiększa czułość pomiaru. Metodę zastosowano do pomiaru składowych tensora kwadratowego efektu elektrooptycznego w oleju transformatorowym.

10

Interference effect in a dual microresonator-coupled Mach-Zehnder interferometer

Lu Y., Huang X., Fu X., Wen W., Yao J.

Optica Applicata

|

2012

|

Vol. 42, nr 1

23-29

EN

We present a theoretical study of interference effect in a Mach-Zehnder interferometer in which two microresonators are side coupled to both arms of the interferometer. The results show that sharp asymmetric Fano resonance, coupled resonator induced transparency and absorption effects can be created in such a structure. We demonstrate that these effects arise from interference between a resonance mode and a continuing propagating mode with asymmetric phase difference, destructive interference between two overcoupled resonance modes, and constructive interference between an overcoupled resonance mode and an undercoupled mode or a continuing propagating mode with symmetric phase differences, respectively. These effects may offer a better understanding of the analogous effects in atomic medium and also make optical resonators a potential device to utilize these effects.

11

Pomiar czułości włókien mikrostruturalnych przy wykorzystaniu interferometru Macha-Zehndera

Murawski M., Szymański M., Hołdyński Z., Tenderenda T., Ostrowski T., Pawlik K., Łukowski A., Krisch H., Marć P., Jaroszewicz L., R., Nasiłowski T.

Elektronika : konstrukcje, technologie, zastosowania

|

2012

|

Vol. 53, nr 11

52-54

PL

Właściwości włókien mikrostrukutralnych takie jak: jednomodowe prowadzenie światła w szerokim zakresie spektralnym (od ultrafioletu do podczerwieni), bardzo wysoka dwójłomność, bardzo duże lub bardzo małe pole modu są przedmiotem badań wielu zespołów naukowych na świecie. Właściwości te wynikają przede wszystkim z rozmiaru, kształtu oraz lokalizacji otworów powietrznych w strukturze włókna mikrostrukturalnego. Zmiana tych parametrów pozwala na zastosowania takich włókien do różnych aplikacji. Sprawia to rosnące zainteresowanie włóknami mikrostrukturalnymi które widoczne jest w powstających czujnikach opartych na ich bazie - m. in. Czujniki interferometryczne do detekcji rozmaitych parametrów fizycznych. Jednym z takich czujników jest światłowodowy interferometr Macha-Zehndera wykorzystujący jako gałąź czujnikową włókno mikrostrukturalne. Interferometr ten jest jednym z układów który nie został opisany w fachowej literaturze. Czujnik zbudowany w oparciu o taki interferometr może być użyty do pomiarów wibracji, dynamicznego lub statycznego nacisku, rozciągania lub skręcania. W pracy tej przedstawione zostało porównanie czułości temperaturowej oraz mechanicznej włókien mikrostrukturalnych ze standardowymi włóknami jednomodowymi. Do tego celu wykorzystaliśmy interferometr Macha- Zehndera z wymiennym ramieniem czujnikowym. Zastosowanie takiego rozwiązania pozwoliło na zbadanie wielu światłowodów w jednym układzie pomiarowym. Czułość temperaturowa jest najistotniejszym czynnikiem przy projektowaniu czujników. Włókna mikrostrukturalne zbudowane są z czystego szkła krzemiankowego z heksagonalną macierzą otworów powietrznych co powoduje brak naprężeń termicznych pomiędzy płaszczem a rdzeniem jak w przypadku włókien z domieszkowanym rdzeniem.

EN

Microstructured fibres (MSFs) reveal unique properties including endlessly single-mode operation from ultraviolet to infrared wavelengths, very high birefringence or nonlinearity, very large or very small effective mode field area, and many others. The size, shape and the location of the air holes allow for tailoring MSF parameters in a very wide range, way beyond the classical fibres, what opens up the possibilities for various applications. Due to their advantages MSFs obtain growing attention for their perspectives in sensing applications. Different MSF sensors have already been investigated, including interferometrie transducers for diverse physical parameters. Until now, there have not been any publications reporting on the sensing applications of MSF Mach-Zehnder interferometers, targeting the mechanical measurements of vibrations, dynamic or static pressure, strain, bending and lateral force. Moreover, a critical feature opening the prospective of optical fibre transducer to successfully accomplish a particular sensing task remains its cross-sensitivity to temperature. Studied MSF is made of pure silica glass in the entire cross-section with a hexagonal structure of the holes. Consequently, there is no thermal stress induced by the difference in thermal expansion coefficients between the doped core region and the pure silica glass cladding, in contrast to standard fibres.

12

Temperatures of Titan and Mars-like plasmas measured by laser interferometry

Menecier S., Legros L., Vacher D., Cerqueira N., Andre P.

Journal of Technical Physics

|

2009

|

Vol. 50, no 3

199-212

EN

This paper presents measurements of temperature profiles of Mars and Titan-like plasmas created with an Inductively Coupled Plasma torch, using a Mach-Zehnder interferometer. Acquired interfero-grams were treated using Fast Fourier Transform and Abel inversion to obtain the radial distribution of the plasma index refraction. Temperature profiles were then obtained from the Gladstone-Dale relation, taking in account the plasma composition versus temperature.

13

Experimental Study of Simultanoeus Transmission of a Light Wave and an Ultrasonic Wave in an Optical Fiber with the use of a Mach-Zehnder Interferometer

Muc S., Gudra T., Bereś-Pawlik E.

Archives of Acoustics

|

2009

|

Vol. 34, No. 4

697-714

EN

The possibility of acoustic wave propagation in optical waveguides creates new prospects for the simultaneous use of a light wave and an ultrasonic wave in, for instance, medicine for cutting biological tissues with a surgical ultrasonic laser knife. A Mach–Zehnder optical waveguide interferometer was used in the experimental studies of simultaneous transmission of those two wave types. If ultrasonic vibrations are delivered to one of the interferometer arms, a light modulation effect is produced. This paper presents measurement results for different methods of delivering ultrasonic waves to the optical fiber, i.e. using radial vibrations of a piezoelectric disk or longitudinal vibrations generated by a sandwich ultrasonic transducer with a velocity transformer.

14

Direct measurement of group dispersion of optical components using white-light spectral interferometry

Chlebus R., Hlubina P., Ciprian D.

Opto-Electronics Review

|

2007

|

Vol. 15, No. 3

144-148

EN

We present a simple white-light spectral interferometric technique employing a low-resolution spectrometer for a direct measurement of the group dispersion of optical components over a wide wavelength range. The technique utilizes an unbalanced Mach-Zehnder interferometer with a component under test inserted in one arm and the other arm with adjustable path length. We record a series of spectral interferograms to measure the equalization wavelength as a function of the path length difference. We measure the absolute group refractive index as a function of wavelength for a quartz crystal of known thickness and the relative one for optical fiber. In the latter case we use a microscope objective in front and a lens behind the fiber and subtract their group dispersion, which is measured by a technique of tandem interferometry including also a Michelson interferometer.

15

Cost-effective method for generating >20 GHz pulse trains using actively mode locking fiber ring laser

Kim Sun-Jong, Park Chang-Soo

Optica Applicata

|

2004

|

Vol. 34, nr 1

17-24

EN

This study proposes a simple method to generate high-speed pulse of more than 20 GHz. Its cost performance ratio in an actively rational harmonic mode locking scheme is maximized when the multiplication factor p = 4 and 6. The operation is based on a relatively simple structure using the optical Mach–Zehnder modulator (MZM) biased at the minimum transmission peak and optical filtering via a Mach–Zehnder interferometer (MZI) comb filter. Stable and amplitude-equalized pulse trains with a repetition rate of ~20.345 GHz are successfully demonstrated.

16

Multimode interference structures : new way of passive elements technology for photonics

Błahut M., Opilski A.

Opto-Electronics Review

|

2001

|

Vol. 9, No. 3

293-300

EN

The aim of this work is presentation of principles of work and properties of multimode interference (MMI) structures and their basic applications in optoelectronic circuits. We discuss the principles of simple, mirrored and multiple images formation paying attention to imaging quality, tolerance, losses, and power division in output signals. On the base of it, MMI applications in integrated optic systems - in splitters and couplers NxM technology, modulators and switches in Mach-Zehnder configuration and multiplexers are considered. The possibility of MMI production in gradient-index wavequides made by ion exchange in glass is also presented.