本文選題：布里淵散射　切入點(diǎn)：外差檢測(cè)　出處：《紅外與激光工程》2017年11期

【摘要】：針對(duì)傳統(tǒng)單脈沖布里淵光時(shí)域反射系統(tǒng)信號(hào)微弱、性能提升受限的問題,提出了一種雪崩光電二極管(APD)檢測(cè)器本地外差檢測(cè)的格雷(Golay)編碼布里淵光時(shí)域反射系統(tǒng)。分析了Golay碼應(yīng)用于該系統(tǒng)的編解碼原理及系統(tǒng)外差檢測(cè)原理,討論了光纖受激布里淵散射閾值對(duì)編碼系統(tǒng)平均入纖功率的限制,推導(dǎo)了系統(tǒng)信噪比的數(shù)學(xué)表達(dá)式,研究系統(tǒng)信噪比與APD倍增因子、編碼長(zhǎng)度的關(guān)系,分別得到了APD最佳倍增因子和系統(tǒng)最佳編碼長(zhǎng)度的表達(dá)式。MATLAB仿真結(jié)果表明,選用帶寬為500 MHz的APD光電檢測(cè)器和峰值功率50 m W、脈沖寬度100 ns的入纖脈沖時(shí),系統(tǒng)APD倍增因子和編碼長(zhǎng)度均存在最佳值,系統(tǒng)最佳編碼長(zhǎng)度的確定不僅依賴于系統(tǒng)的散粒噪聲和熱噪聲功率,還由光纖受激布里淵散射閾值共同決定。經(jīng)優(yōu)化計(jì)算得,該系統(tǒng)的APD最佳倍增因子為5,最佳編碼長(zhǎng)度為128位時(shí),在25 km光纖末端的系統(tǒng)信噪比比傳統(tǒng)單脈沖系統(tǒng)提高了26.42 d B,溫度和應(yīng)變分辨率分別達(dá)到了1.60℃和35.48。
[Abstract]:The traditional single pulse Brillouin optical time domain reflectance system is weak and limited in performance improvement. In this paper, a Brillouin optical time domain reflectance system for local heterodyne detection of avalanche photodiode detector is presented. The encoding and decoding principle of Golay code applied to the system and the principle of system heterodyne detection are analyzed. This paper discusses the limitation of the threshold of stimulated Brillouin scattering on the average incoming power of the coding system, deduces the mathematical expression of the signal-to-noise ratio of the system, and studies the relationship between the SNR of the system and the multiplying factor of APD and the encoding length. The expressions of the optimal multiplication factor of APD and the optimal coding length of the system are obtained respectively. The simulation results show that the APD photodetector with a bandwidth of 500 MHz and the input pulse with a peak power of 50 MW and a pulse width of 100ns are selected. The APD multiplication factor and coding length of the system have the best values. The determination of the optimal coding length of the system depends not only on the power of shot noise and thermal noise of the system, but also on the threshold of stimulated Brillouin scattering of optical fiber. When the optimal APD multiplication factor is 5 and the optimal coding length is 128-bit, the SNR of the 25km fiber end is 26.42 dB higher than that of the traditional monopulse system. The temperature and strain resolution are 1.60 鈩，

本文編號(hào)：1694398