Details

Autor(en) / Beteiligte

• Hao Yun-qi
• Ye Qing
• Pan Zheng-qing
• Cai Hai-wen
• Qu Rong-hui

Titel

Analysis of bandwidth-reduced local oscillator in Brillouin optical time domain reflectometry

Ist Teil von

• 2011 Asia Communications and Photonics Conference and Exhibition (ACP), 2011, p.1-7

Ort / Verlag

IEEE

Erscheinungsjahr

2011

Quelle

IEEE/IET Electronic Library

Beschreibungen/Notizen

• A local oscillator for coherent detection of backward Brillouin scattering in Brillouin optical time domain reflectometry (BOTDR) has been analyzed. A ring Brillouin fiber laser, whose Brillouin gain media is 70m high-nonlinear-fiber (HNLF), is used as local oscillator of coherent detection. The BFL operates at 1549.06nm red-shifted 0.084nm from the pump laser. As to Brillouin light, The detection frequency is reduced from ~11GHz of direct detection to ~420MHz of heterodyne detection in this paper. Self-lasing cavity-modes of BFL impose the "burr" intervalled at 2.5MHz on the frequency domain analysis of the beat-frequency siganl. Signal-to-noise ratio (SNR) of beat-frequency signal decreases greatly, resulting to Lorentzian fitting with error. By adjusting variable optical attenuator (VOA) to increase the cavity loss in the fiber ring cavity, the self-lasing cavity-modes will be eliminated and a stable Brillouin laser will be obtained. The frequency estimation accuracy is improved greatly.