Random Fiber Laser Based On Distributed Chirped Grating Feedback

Random lasers have been rapidly developed because of their dramatically different lasing mechanism from conventional lasers and potential applications in lighting,imaging and sensing.As the development of the materials of the medium,silicon fiber becomes the most popular medium to provide for laser because the one-dimensional geometry of optical fibers supplies more efficiency gains for lasers.In recent years,more and more random fiber lasers are investigated and studied.However,most of the random fiber lasers gain feedback in a long lengh fiber and requiring high pump power.Thus,achieving a low-threshold random fiber laser with short length is one of the trends in the development of random fiber laser.In this paper,we demonstrate a random fiber laser based on Single mode/Er-doped fiber with randomly spaced chirp gratings for the first time.The chirped gratings were fabricated by using a frequency-doubled Argon laser at 244 nm and a chirped phase mask.In order to increase the randomness in light feedback,every two adjacent chirped gratings have inverse chirp rate.Finally,a grating array with 16 chirped gratings in the Er-doped fiber and three grating arrays with 10/20/30 in the single-mode fiber fiber fiber were achieved.A random fiber laser based on randomly spaced chirped gratings is proposed.Random distributed feedback is effectively realized through the chirped gratings.A 980-nm laser diode was employed to pump the chirped-grating array through a 980/1550 nm wavelength division multiplexer(WDM).Finally,laser output was achieved with a pump threshold of 36 mW via the combination of gain provided in EDF and random distributed feedback obtained through light localization effect.Laser performance was studied as a function of pump power and time.A random fiber laser based on an Er-doped fiber with randomly spaced chirped gratings is proposed.Random distributed feedback is effectively realized through the chirped gratings,which are fabricated in a 1-m-long Er-doped fiber with a random separation ranging from 30 to 100 mm by using a UV laser.A 980-nm laser diode was employed to pump the chirped-grating array through a 980/1550 nm wavelength division multiplexer(WDM).Random lasing oscillation is achieved via the combination of gain provided in EDF and random distributed feedback obtained through light localization effect.The multi-wavelength output was generated above the pump threshold of 15 mW.The slope efficiency of the random fiber laser is 1.9%.Laser performance was studied as a function of pump power and time.