Two wavelength frequency transfer over an optical fiber link

In this paper we present the theory and the experimental setup used to transfer a standard frequency, to synchronize two clocks linked by an optical fiber. In order to verify the accuracy on frequency transfer over fiber link, we prepared an experiment that allows testing the performance of the setup for a variable set of environmental conditions, namely associated to temperature and vibration variations. The experimental setup shows the fiber optic link between one laboratory, where the standard frequency is generated, and another laboratory, where the equipment for simulating temperatures and vibrations are installed. The standard frequency, traceable to UTC(IPQ), is used to modulate two lasers with different wavelength,, injected in the optical fiber. At the end of the optical fiber the signals will be out of phase due to the inherent chromatic dispersion, which is also dependent on the temperature of the propagation media. Measuring the phase variations, caused by temperature gradients in the fiber, we can compensate the frequency transfer and synchronize the clocks. Evaluating all uncertainty components in this model, allows the metrological characterization of the synchronization and obtain the associated uncertainty of this quantity.

Download Full-text

Field Trial of Stable Radio Frequency Transfer System in 100 km Metropolitan Optical Fiber Link

2020 Joint Conference of the IEEE International Frequency Control Symposium and International Symposium on Applications of Ferroelectrics (IFCS-ISAF) ◽

10.1109/ifcs-isaf41089.2020.9234918 ◽

2020 ◽

Author(s):

Chenxia Liu ◽

Shujin Zhou ◽

Zhuoze Zhao ◽

Hao Gao ◽

Jinting Cong ◽

...

Keyword(s):

Optical Fiber ◽

Radio Frequency ◽

Field Trial ◽

Transfer System ◽

Fiber Link ◽

Frequency Transfer

Download Full-text

Adaptive Noise Cancellation of an Analog Fiber Optic Link

10.32920/ryerson.14652360 ◽

2021 ◽

Author(s):

Mohammad Nazrul Islam

Keyword(s):

Optical Fiber ◽

Fiber Optic ◽

Signal To Noise Ratio ◽

Optical Power ◽

Noise Cancellation ◽

Adaptive Noise Cancellation ◽

Fiber Link ◽

The Mean ◽

Simulation Results ◽

Adaptive Noise

There are three dominant noise mechanisms in an analog optical fiber link. These are shot noise that is proportional to the mean optical power, relative intensity noise (RIN) that is proportional to the square of the instanteaneous optical power. This report describes an adaptive noise cancellation of these dominant noise processes that persist an analog optical fiber link. The performance of an analog optical fiber link is analyzed by taking the effects of these noise processes. Analytical and simulation results show that some improvement in signal to noise ratio (SNR) and this filter is effective to remove noise adaptively from the optical fiber link.

Download Full-text

Stabilized Radio Frequency Transfer via 100 km Urban Optical Fiber Link Using Passive Compensation Method

IEEE Access ◽

10.1109/access.2019.2930554 ◽

2019 ◽

Vol 7 ◽

pp. 97487-97491 ◽

Cited By ~ 1

Author(s):

Chenxia Liu ◽

Shujin Zhou ◽

Jianming Shang ◽

Zhuoze Zhao ◽

Hao Gao ◽

...

Keyword(s):

Optical Fiber ◽

Radio Frequency ◽

Compensation Method ◽

Fiber Link ◽

Frequency Transfer ◽

Passive Compensation

Download Full-text

Preparation and Characterization of Microsphere ZnO ALD Coating Dedicated for the Fiber-Optic Refractive Index Sensor

Nanomaterials ◽

10.3390/nano9020306 ◽

2019 ◽

Vol 9 (2) ◽

pp. 306 ◽

Cited By ~ 7

Author(s):

Paulina Listewnik ◽

Marzena Hirsch ◽

Przemysław Struk ◽

Matthieu Weber ◽

Mikhael Bechelany ◽

...

Keyword(s):

Refractive Index ◽

Optical Fiber ◽

Fiber Optic ◽

Single Mode ◽

Atomic Layer ◽

Fiber Optic Sensor ◽

Refractive Index Sensor ◽

Layer Deposition ◽

Fabry Perot

We report the fabrication of a novel fiber-optic sensor device, based on the use of a microsphere conformally coated with a thin layer of zinc oxide (ZnO) by atomic layer deposition (ALD), and its use as a refractive index sensor. The microsphere was prepared on the tip of a single-mode optical fiber, on which a conformal ZnO thin film of 200 nm was deposited using an ALD process based on diethyl zinc (DEZ) and water at 100 °C. The modified fiber-optic microsphere was examined using scanning electron microscopy and Raman spectroscopy. Theoretical modeling has been carried out to assess the structure performance, and the performed experimental measurements carried out confirmed the enhanced sensing abilities when the microsphere was coated with a ZnO layer. The fabricated refractive index sensor was operating in a reflective mode of a Fabry–Pérot configuration, using a low coherent measurement system. The application of the ALD ZnO coating enabled for a better measurement of the refractive index of samples in the range of the refractive index allowed by the optical fiber. The proof-of-concept results presented in this work open prospects for the sensing community and will promote the use of fiber-optic sensing technologies.

Download Full-text

Integrated Fiber Optic Sensors For Nondestructive Characterization Of Concrete Structures

MRS Proceedings ◽

10.1557/proc-503-107 ◽

1997 ◽

Vol 503 ◽

Author(s):

F. Ansari

Keyword(s):

Optical Fiber ◽

Optical Fibers ◽

Fiber Optic ◽

Optical Fiber Sensor ◽

Fiber Optic Sensors ◽

Fiber Sensors ◽

Fully Integrated ◽

Integrated Optical ◽

Concrete Elements

ABSTRACTIt is possible to monitor the initiation and progress of various mechanical or environmentally induced perturbations in concrete elements by way of fully integrated optical fiber sensors. Geometric adaptability and ease by which optical fibers can be embedded within concrete elements has led to the development of a number of innovative applications for concrete elements. This article is intended for a brief introduction into the theories, principles, and applications of fiber optic sensors as they pertain to applications in concrete.. However, due to the fact that the transduction mechanism in optical fibers is invariant of the materials employed, the principles introduced here also correspond to other structural materials. The only application related differences among various materials pertain to sensitivity and choice of optical fiber sensor types.

Download Full-text

Influence of Fiber Properties on Harmonic and Intermodulation Distortions of Semiconductor Lasers

Journal of Engineering Research and Reports ◽

10.9734/jerr/2021/v20i717342 ◽

2021 ◽

pp. 56-67

Author(s):

Moustafa Ahmed ◽

Yas Al-Hadeethi ◽

Ghodran Alghamdi

Keyword(s):

Optical Fiber ◽

Semiconductor Lasers ◽

Modulation Depth ◽

Chromatic Dispersion ◽

Harmonic Distortion ◽

Intermodulation Distortion ◽

Signal Distortion ◽

Laser Signal ◽

Fiber Link ◽

Intermodulation Distortions

This paper introduces modeling and simulation of the harmonic and intermodulation distortions of semiconductor laser radiating an optical fiber link. The study is based on the rate equation model of semiconductor lasers excited by injection current with two sinusoidal tones separated by a radio frequency. The modulated laser signal is modeled in both the time and frequency domains. The laser signal distortions include the 2nd and 3rd harmonic distortion (2HD and 3HD), and the third-order intermodulation distortion IMD3. The laser is assumed to be modulated around its relaxation frequency. Influence of the modulation depth on the signal distortion is investigated when the laser is free running and when it is radiating a fiber link. In the latter case, influences of the attenuation and chromatic dispersion on the signal dispersion are elucidated when the fiber length increases up to 10 km. The results show that the fiber attenuation does not affect the signal distortion, whereas the chromatic dispersion affects both the harmonic distortions and intermodulation distortion. Sending the laser signal down an optical fiber of length ~ 5km can help in minimizing 2HD which is the dominant harmonic distortion of the modulated signal. This range of optical fiber is also characterized with intermodulation distortion less than 0dBc.

Download Full-text