In this paper we perform an optimization of Brillouin optical time-domain analysis (BOTDA) sensors for achieving high resolution over long sensing ranges using distributed Raman amplification. By employing an optimized first-order bi-directional Raman amplification scheme and combining high-power fiber-Raman lasers and Fabry-Pérot lasers with low relative-intensity-noise (RIN), we demonstrate d...

In this Letter, we combine the use of optical preamplification at the receiver and optical pulse coding techniques with an optimized modulation format to effectively extend the sensing range of Brillouin optical time-domain analysis (BOTDA) sensors. Combining a return-to-zero modulation format with 25% duty cycle and linear gain preamplification allows for temperature and strain measurements ov...

در این مقاله یک مدل ریاضی برای مسئله سیستم تولیدی همکارانه ساخت بر اساس سفارش با رعایت انصاف تخصیص بار‌های تولید طراحی شده است. اهداف اصلی مدل، کمینه‌سازی هزینه‌‌های کل و حداکثر استفاده از منابع به‌منظور عادلانه شرایط عدم­قطعیت کنترل پارامتر‌های غیرقطعی روش برنامه‌ریزی فازی ‌شده نتایج نشان می‌دهد افزایش نرخ عدم‌قطعیت، می­یابد. ازآنجاکه ظرفیت کارخانه‌ها ثابت است، مقدار تقاضا، هر کارخانه نیز می­ی...

This paper presents a thorough study of the different sources of noise affecting Brillouin optical time-domain analyzers (BOTDA), providing a deep insight into the understanding of the fundamental limitations of this kind of sensors. Analytical and experimental results indicate that the noise source ultimately fixing the sensor performance depends basically on the fiber length and the input pum...

ABSTRACT We propose and experimentally demonstrate the highest-resolution BOTDA system ever reported using Brillouin dynamic grating in a polarization-maintaining fiber (PMF). Acoustic waves containing the information of local Brillouin frequency are generated by a long pump pulse in one polarization, and read out by a short probe pulse in the orthogonal polarization at a clearly distinct optic...

A novel scheme is proposed to extend the sensing range of Brillouin optical time-domain analyzers (BOTDA). Specially-designed erbium doped fiber amplifier (EDFA) repeaters are located every 65km fiber along the sensing cable to achieve a total sensing length of 325km, corresponding to a 650km loop. At the end of the sensing fibre, we experimentally demonstrated a measurement repeatability of 2°...

A frequency-sweep-free method for distributed Brillouin sensing is proposed, having the potential for fast dynamic strain measurements. In this reported implementation of the method, multiple probe waves with carefully chosen optical frequencies simultaneously propagate in the fiber against an equal number of sequentially-launched, short pump pulses of matching frequencies, where each of pump-p...

We evaluate the Brillouin frequency shift (BFS) determination error when utilizing the Brillouin phase spectrum (BPS) instead of the Brillouin gain spectrum (BGS) in BOTDA systems. Systems based on the BPS perform the determination of the BFS through a linear fit around the zero de-phase frequency region. An analytical expression of the error obtained in the BFS determination as a function of t...

In this paper, a standard test method of evaluating the measurement performance of distributed sensors such as Brillouin scattering based fiber optic sensors (FOSs) and other long gauge sensors for monitoring cracks is proposed. The performance evaluation of two types of Brillouin scattering based DFOSs named as BOTDR(Brillouin Optical Time Domain Reflectometry) and PPP-BOTDA (Pulse Pre-Pump Br...