Search results for "Distributed feedback laser"
showing 10 items of 40 documents
All-fiber actively Q-switched Yb-doped laser
2006
Abstract An all-fiber actively Q-switched Yb-doped laser is presented. Q-switching is performed by modulating a fiber Bragg grating via a magnetostrictive rod which is fixed to the fiber at the position of the grating. By exposing the rod to a changing magnetic field, the rod is stretched and relaxed causing the Bragg wavelength of the grating to shift and thereby changes the Q-factor of the cavity. Using Yb-doped fiber, pulses at 1052 nm are obtained at repetition rates from 1 to 200 kHz. At 75 kHz, 0.5 μJ pulses with peak powers of 3 W can be produced when 180 mW of pump power is applied. To the knowledge of the authors, this is the first all-fiber actively Q-switched Yb-doped laser prese…
Fiber Ring Laser Operated by Dynamic Local Phase Shifting of a Chirped Grating
2009
An ultranarrow linewidth erbium-doped fiber ring laser is presented. It is based on the filtering properties of a phase-shifted chirped fiber Bragg grating, which is inserted inside the cavity of the laser. A dynamic control of the phase shifting, which is induced by a magnetostrictive transducer, permits both tunable continuous-wave and actively Q-switched operation. The use of a chirped grating overcomes the limitations imposed by the narrow spectra of uniform gratings observed in previously reported ring lasers based on intracavity transmission filters.
Q-switched all-fibre laser using a fibre-optic resonant acousto-optic modulator
2007
Abstract We report an actively Q-switched all-fibre laser using a fibre-optic resonant acousto-optic modulator as Q-switching element. The modulator consists of a short-length fibre Bragg grating modulated by a standing longitudinal elastic wave, being the grating length much shorter than the acoustic wavelength. Q-switch pulses were successfully obtained from an Er3+-doped fibre laser at repetition rates of 18 and 37 kHz.
Tunable narrowband fiber laser with feedback based on whispering gallery mode resonances of a cylindrical microresonator.
2013
Narrowband filtering based on whispering gallery modes of a slightly tapered cylindrical optical microresonator was used to implement a tunable narrowband erbium-doped fiber laser. The laser can be set to emit a single longitudinal cavity mode (single frequency), although the laser cavity is a few meters long. In the single-frequency regime the laser can emit a maximum power of 0.380 mW with a linewidth <35 kHz and a signal-to-noise ratio exceeding 50 dB. Tunability is achieved by sliding the excitation point along the microcylinder. A tuning range of 1.16 nm is demonstrated.
Generation of Bound States of Three Ultrashort Pulses With a Passively Mode-Locked High-Power Yb-Doped Double-Clad Fiber Laser
2004
We report the generation of high-power ultrashort bound states of three pulses in an ytterbium-doped double-clad fiber laser. The laser is mode-locked through nonlinear polarization rotation technique in a unidirectional cavity configuration. A pair of diffraction grating is incorporated in the cavity to compensate for the normal dispersion of the fiber. The laser generates chirped bound states of three pulses with either equal or different time separations, with more than 500-pJ energy per pulse. These pulses are subsequently compressed to 100 fs with a compression factor of more than 40.
Actively Q-switched DFB fiber laser for Brillouin sensor applications
2009
Q-switching of distributed feedback (DFB) fiber lasers permits to achieve high peak powers, preserving an ultra narrow linewidth [1,2]. The development of a new in-line acousto-optic modulator based on a magnetostrictive actuator, instead of a piezoelectric-based device, permits an efficient excitation of elastic pulses propagating along the optical fiber and an easy access to both emission outputs of the laser. The repetition rate can be continuously adjusted, as well as the amplitude of the elastic pulses. The interaction of these elastic pulses with a fiber Bragg grating written in an erbium-doped fiber permits an actively Q-switched operation of the DFB fiber laser [3]. The birefringenc…
Single- to three-wavelength switchable ytterbium-doped fiber laser based on intracavity induced loss by a long-period holey fiber grating
2011
In this paper, we propose and demonstrate a versatile and simple single-, dual- and three-wavelength switchable ytterbium-doped fiber laser using the intracavity induced-loss generated by a mechanically induced long-period grating (MLPFG) in a holey fiber. The laser net gain in the cavity is reshaped through the MLPFG by adjusting the twist rate and the pressure of the holey fiber in the long-period grating. In this way, the twist response of the MLPFG enables the laser to switch between the single-, dual-, and three-wavelength operations and the tuning of the simultaneous two- and three-wavelengths. These results are of great interest in the design of flexible multiwavelength sources with …
Diode-pumped self-Q-switched erbium-doped all-fibre laser
2004
A diode-pumped self-Q-switched erbium-doped fibre laser is developed and studied. The laser has an all-fibre configuration containing a piece of an active heavily erbium-doped fibre and two fibre Bragg grating mirrors and does not require any additional intracavity elements to obtain short pulses. Analysis of the laser operation suggests that the most probable mechanism of passive Q-switching of the laser cavity is absorption from the excited state of erbium resulting in the thermally induced nonlinear change in the refractive index in the erbium-doped fibre.
Smart Q-switching for single-pulse generation in an erbium-doped fiber laser
2012
In this paper, we report an active Q-switching of an erbium-doped fiber laser with special modulation functions and novel laser geometry. We experimentally demonstrate that using such a smart Q-switch approach, Q-switch ripple-free pulses with Gaussian-like shape and 17.3 ns width can be easily obtained. The idea behind the smart Q-switch is to suppress one of two laser waves contra-propagating along the fiber cavity, which arises after Q-cell opening, and to eliminate the minor sub-pulses.
Enhanced Q-switched distributed feedback fiber laser based on acoustic pulses
2009
An acoustically Q-switched distributed feedback fiber laser with enhanced performance is presented. It is based on an FBG written in an erbium doped fiber, in which a dynamic defect is introduced by means of a short acoustic pulse. The performance of the laser depends on the reflectivity of the grating. In this work, we present two different Q-switched distributed feedback fiber lasers realized with active gratings of different reflectivities. Both lasers are characterized at different pump powers and repetition rates. It is shown that the performance of the laser based on the weaker grating was significantly improved with respect to the laser based on the stronger grating. In terms of peak…