Laser Institute of Shandong Academy of Science

Yanbin Wu

Jiasheng Ni

Chen Wang

Chang Li

Chang Wang

Ying Shang

Bing Cao

Sheng Huang

Yingying Wang

Wenan Zhao

An EHz ultrafast modulated pulse scanning laser and a distributed fiber sensing system. A plurality of phase-shift gratings are engraved on a doped fiber, the phase-shift gratings having different central window wavelengths and a wavelength interval between the adjacent central window wavelengths being a preset fixed value. When a pump light emitted by a pump laser source is coupled by a wavelength division multiplexer and enters the doped fiber, a single-mode narrow-linewidth laser light having multiple wavelengths with a wavelength interval being a preset fixed value can be generated, by using the phase-shift gratings graved on the doped fiber. The ultrafast modulation is completed by using a time-domain control method based on an EOM. An internally frequency converted pulse light formed by splicing pulse lights whose frequencies linearly increase is obtained, thus forming the EHz ultrafast modulation of a distributed feedback fiber laser. In this way, a coherence length of an output laser light is increased while a frequency of the laser light is remained.

EHz ultrafast modulated pulse scanning laser and distributed fiber sensing system

A high-performance distributed fiber sensing system based on EHz ultrafast pulse scanning. During testing of a disturbance signal, an internally frequency converted pulse light emitted by an EHz ultrafast pulse scanning laser enters a sensing fiber after passing through a circulator, and a backward Rayleigh scattering signal transmitted by the sensing fiber enters an unbalanced Michelson interferometer after passing through a coupler. By designing an arm length difference between two interference arms, interferences sequentially occur for the backward Rayleigh scattering light at a position where lengths of two adjacent arms differ. A signal received after passing through the unbalanced Michelson interferometer includes a phase difference signal caused by an external disturbance signal in the sensing fiber. Finally, variations of the phase difference signal over time are demodulated by using a phase demodulation unit, so that a dynamic measurement of the disturbance signal in the sensing fiber may be performed.

High-performance distributed fiber sensing system based on EHz ultrafast pulse scanning

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Jinan, China

Yanbin Wu