We propose and experimentally demonstrate the use of cyclic pulse coding to improve the performance of hybrid Raman/fiber Bragg grating (FBG) fiber-optic sensors, for simultaneous measurement of distributed static temperature and discrete dynamic strain over the same sensing fiber. Effective noise reduction is achieved in both Raman optical time-domain reflectometry and dynamic interrogation of time-division-multiplexed fiber FBG sensors, enhancing the sensing range resolution and providing real-time point dynamic strain measurement capabilities. The highly integrated sensor scheme employs broadband apodized low-reflectivity FBGs, a single narrowband optical source, and a shared receiver block.
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http://dx.doi.org/10.1364/OL.38.000471 | DOI Listing |
By focusing on a typical emitting wavelength of 1120 nm as an example, we present the first, to the best of our knowledge, demonstration of a high-efficiency, narrow-linewidth kilowatt-level all-fiber amplifier based on hybrid ytterbium-Raman (Yb-Raman) gains. Notably, two temporally stable, phase-modulated single-frequency lasers operating at 1064 nm and 1120 nm, respectively, were applied in the fiber amplifier, to simultaneously alleviate the spectral broadening of the 1120 nm signal laser and suppress the stimulated Brillouin scattering effect. An over 1 kW narrow-linewidth 1120 nm signal laser was obtained with slope efficiency of ${\sim}{77}\% $∼77% and beam quality of ${\rm M}_x^2\sim {1.
View Article and Find Full Text PDFIn this paper, the spectral evolution properties and gain dynamics in hybrid rare-earth-Raman fiber amplifiers (H-RFAs) are demonstrated theoretically. Spectral broadening mechanisms and design strategies are given for H-RFAs based on two different types of pump schemes for generating the pump laser of Raman gain. As for the diode-pumped scheme, only a temporal stable pump laser of Raman gain is required to achieve the narrow-linewidth operation of an ultimate Raman fiber laser.
View Article and Find Full Text PDFActively mode locked Raman lasing in a ring PM-fiber cavity pumped by a linearly polarized Yb-doped fiber laser is studied. At co-propagating pumping, a stochastic pulse with duration defined by the AOM switching time (~15 ns) is generated with the round-trip period. At counter-propagating pumping, one or several sub-ns pulses (within the AOM switching envelope) are formed.
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August 2013
Wireless and Photonics Networks Research Center, Faculty of Engineering, Universiti Putra Malaysia 43400 UPM Serdang, Selangor, Malaysia.
We demonstrate a tunable multi-wavelength Brillouin-Raman fiber laser with 20 GHz wavelength spacing. The setup is arranged in a linear cavity by employing 7.2 and 11 km dispersion compensating fibers (DCF) in addition to a 30 cm Bismuth-oxide erbium doped fiber.
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February 2013
Scuola Superiore Sant’Anna, via G. Moruzzi 1, Pisa 56124, Italy.
We propose and experimentally demonstrate the use of cyclic pulse coding to improve the performance of hybrid Raman/fiber Bragg grating (FBG) fiber-optic sensors, for simultaneous measurement of distributed static temperature and discrete dynamic strain over the same sensing fiber. Effective noise reduction is achieved in both Raman optical time-domain reflectometry and dynamic interrogation of time-division-multiplexed fiber FBG sensors, enhancing the sensing range resolution and providing real-time point dynamic strain measurement capabilities. The highly integrated sensor scheme employs broadband apodized low-reflectivity FBGs, a single narrowband optical source, and a shared receiver block.
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