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A helical long-period grating (HLPG) was written in a polarization maintaining fiber (PMF) with CO2 laser. The twist characteristics of individual and cascaded PMF-HLPG were investigated experimentally. It was found that PMF-HLPG behaved differently with a different light input. When a polarized light was launched into the cascaded PMF-HLPGs with opposite helical direction, a high twist sensitivity...
In order to reduce the false matching rate and matching time, an improved algorithm based on RANSAC-SIFT was proposed. The feature points were extracted by SIFT algorithm firstly. Then most of the mismatching points were eliminated according to the constraints that matching distances tend to be consistent. Finally the remaining points were regarded as pre matching points for achieve fine matching...
In this paper, characteristics of high-order linearly chirped waveguide Bragg gratings (LCWBGs) are studied. The influence of saturation coefficient and grating order on the reflection spectrum (central wavelength, chirp coefficient, maximum reflectivity and total reflection bandwidth) of high-order LCWBGs is analyzed. LCWBGs with different grating orders have different optimal saturation coefficients...
The Optical transmission characteristics of microfiber coupler in micron dimension were analyzed. The optical field distribution between two fibers was gotten by numerical simulation with beam propagation method, and then the variation of the output light power of the coupler with different length is obtained. Based on the experimental platform for the production of microfiber coupler, the energy...
A narrow pulse driver circuit was studied in this paper. we proposed and demonstrated a method combining the analog circuit and the digital circuit. By analyzing the working principle of transistor, we selected the HEMT transistor as a high-speed switch. It can supply voltage pulse or current pulse according to different applications. The generation of trigger signal, controls of the pulse width and...
Single event effect susceptibility of industrial MCUs and key drive chips of several commercial transceivers are studied based on heavy ions and pulse laser methods. Based on the testing results, the performance of receive chips are better than transmit chips or transceiver chips, and the threshold values of transmit chips or transceiver chips are between 30 and 37MeV.cm2/mg. However, the MCUs are...
The mission analysis for tracking ships are one of the most import works for sea based spacecraft tracking and control. Many constraints such as access interval, tracking site maritime condition, coverage and antenna pattern have to be considered in the analysis. In the past mission analyses, antenna patterns of spacecraft transceivers were commonly simplified as the parameter half cone. However,...
The long-distance ultraviolet communication has to take the influence of atmosphere turbulence into consideration. This paper proposed a new turbulent channel combined with single scattering model for ultraviolet communication, where the variation of refractive-index structure parameter is introduced. The calculating results of new model is closer to the experimental results compared to that of the...
We report on the demonstration of a 418 W high power random fiber laser, which is the highest power to the best of our knowledge. The random laser is a half-open cavity based on 130 meters long passive fiber with core diameter of 20 μm. It is pumped by 1070 nm Yb-doped fiber laser. The central wavelength of 1st order random laser is 1120 nm. The output power, spectral, and temporal characters are...
In this paper, wavelength division multiplexing and space division multiplexing (WDM-SDM) passive optical access network employing multi-core fiber (MCF) and self-homodyne detection is proposed. 4×56-Gb/s PDM-16QAM-OFDM transmission is realized over 10-km 7-core fiber with simplified digital signal processing.
In this paper, a 60cm free-space optical card-to-card wavelength division multiplexing (WDM) transmission architecture using OFDM modulation and coherent detection is proposed and demonstrated, which can offer flexibility and high speed transmission simultaneously. The experimental results show that the net data rate is up to 106.9Gb/s and the receiver sensitivity is −34dBm at the BER threshold of...
We compared the performance of the asymmetric and direct current bias limiting optical orthogonal frequency division multiplexing (ADO-OFDM), asymmetric limiting optical orthogonal frequency division multiplexing (ACO-OFDM), and the direct current bias limiting optical orthogonal frequency division multiplexing (DCO-OFDM) in visible light communication (VLC) systems. We optimize the power ratio between...
The sensing performance in Brillouin-based distributed fiber sensors is ultimately depends on the signal-to-noise ratio (SNR) of the received signal. In order to enhance the SNR, thus improve the sensing performance, several wavelength diversity techniques have been proposed. This paper presents the current wavelength diversity techniques employed in both Brillouin optical time-domain reflectometry...
Ballistocardiography (BCG) is a non-invasive method for measuring the reaction force of the human body to the ejection of blood at each cardiac cycle. It is now being the subject of renewed research interest due to recent technological advancement in the field of sensors. In this paper, we summarize our work on BCG with optical fiber sensors for various applications in the past 6 years. These include...
Ballistocardiography (BCG) is a non-invasive method for measuring the reaction force of the human body to the ejection of blood at each cardiac cycle. It is now being the subject of renewed research interest due to recent technological advancement in the field of sensors. In this paper, we summarize our work on BCG with optical fiber sensors for various applications in the past 6 years. These include...
The growing data traffic in the local area networks (LAN) is driving development of the cost-effective transmission systems. In this paper, we investigate the influence of a semiconductor optical amplifier (SOA) on the transmission system of 60 km standard single-mode fiber (SSMF) in the 1310 nm wavelength-division-multiplexed (WDM) system. We investigate the SOA performance and analyze the receiver...
Because of its high transmission rate, Time and Wavelength Division Multiplexed Passive Optical Network (TWDM-PON) has become a particular research topic. Due to the wavelength flexibility and multiple user's access, it becomes necessary and imperative to consider the fairness between all the Optical Network Units (ONUs) so that we can improve the quality of service of the users. This fairness includes...
In Ethernet passive optical network (EPON), the distance between optical network units (ONUs) and optical line terminal (OLTs) is in a large range of changes. Only dividing ONUs into a network according to locations will influence the user's QoS. In view of this situation, this paper puts forward a planning strategy of ONUs clustering. We first consider the economy, network delay and network reliability,...
In ethernet passive optical network (EPON), the distance between optical network units (ONUs) and optical line terminal (OLTs) is in a large range of changes. Only dividing ONUs into a network according to locations will influence the user's QoS. In view of this situation, this paper puts forward a planning strategy of ONUs clustering. We first consider the economy, network delay and network reliability,...
Weight distribution of code is very important for error correction in the use of Turbo coding program in optical fiber communication. Input sequence need to pass convolutional encoder, Therefore, it is necessary that the weight of the output should be kept as large as possible. Although the interleaver can help to improve the output code weight, the higher the complexity of interleaving, the iterative...
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