Contexts in source publication

Context 1
... controller helps to fix optimal polarization direction. That increases measurement accuracy. By changing the optical path delay time the interferometer can automatically fit the frequency transfer function to a particular carrier frequency of optical signal. The frequency transfer function of the Mach-Zehnder fiber interferometer is shown in Fig. 3. As can be seen, it is a sinusoidal function and its period is called a free spectral range (FSR). The optical signal frequency (chirp) variation should be lower than FSR/4=35 GHz. The frequency transfer function can be arbitrarily shifted with respect to the optical signal carrier frequency. And thus, during the first phase the ...
Context 2
... signal frequency (chirp) variation should be lower than FSR/4=35 GHz. The frequency transfer function can be arbitrarily shifted with respect to the optical signal carrier frequency. And thus, during the first phase the frequency transfer function is shifted to the carrier frequency at the point "A", during the second phase -at the point "B" Fig. ...
Context 3
... most precise match of experimental and simulation results for all investigated lasers with different characteristics was obtained. The mismatch of analyzed laser parameters does not exceed the limit of 10%. No. DFB laser The most precise match of laser characteristics was obtained for the laser with the characteristics shown in Fig. 13a (chirp and density of electrons; the chirp is proportional to the carrier density (Henry, 1982)) and Fig. 13b (optical power pulse ...
Context 4
... different characteristics was obtained. The mismatch of analyzed laser parameters does not exceed the limit of 10%. No. DFB laser The most precise match of laser characteristics was obtained for the laser with the characteristics shown in Fig. 13a (chirp and density of electrons; the chirp is proportional to the carrier density (Henry, 1982)) and Fig. 13b (optical power pulse ...

Citations

... In the following we consider chirp effects [20][21][22] as a full contribution to the search of proper seed conditions to optimize the output performance, in combination with LMF. They must be discriminated, to determine an effective value of the Brillouin gain as a function of this combination. ...
Article
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We present a comprehensive analysis of the technique of Longitudinal-Mode-Filling (LMF) to reduce Stimulated Brillouin Scattering (SBS) limitations in Ytterbium Doped Fibre Amplifiers (YDFA), for the generation of nanosecond, temporally shaped pulses. A basic Master-Oscillator-Power-Amplifier (MOPA) system, comprising an output YDFA with 10µm-core active fibre, is experienced for benchmarking purposes. Input pulse-shaping is operated thanks to direct current modulation in highly multimode laser-diode seeds, either based on the use of Distributed Feed-Back (DFB) or of a Fibre Bragg Grating (FBG). These seeds enable wavelength control. We verify the effectiveness of the combination of LMF, with appropriate mode spacing, in combination with natural chirp effects from the seed to control the SBS threshold in a broad range of output energies, from a few to some tens of µJ. These variations are discussed versus all the parameters of the laser system. In accordance with the proposal of a couple of basic principles and with the addition of gain saturation effects along the active fibre, we develop a full-vectorial numerical model. Fine fits between experimental results and theoretical expectations are demonstrated. The only limitation of the technique arises from broadband beating noise, which is analysed thanks to a simplified, but fully representative description to discuss the signal-to-noise ratio of the amplified pulses. This provides efficient tools for application to the design of robust and cost-effective MOPAs, aiming to the generation of finely shaped and energetic nanosecond pulses without the need for any additional electro-optics.