排序方式: 共有26条查询结果,搜索用时 15 毫秒
1.
O. Pottiez Author Vitae B. Ibarra-Escamilla Author Vitae Author Vitae R. Grajales-Coutiño Author Vitae Author Vitae 《Optics & Laser Technology》2010,42(2):403-408
In this paper we study theoretically and experimentally a wavelength-tuneable Sagnac birefringence filter. The device is a Sagnac interferometer including a symmetric fibre coupler and a length of high-birefringence fibre in the loop. A wave retarder is inserted at each end of the birefringent fibre for absolute wavelength tuning. We show theoretically that wavelength tuning through wave plate orientation ensuring constant amplitude of the filtering function is possible only if a minimum of two wave retarders are included in the setup. The position of the transmission peaks then varies linearly with the angle of one of the retarders and can be adjusted over one entire channel spacing. This happens only when a quarter-wave retarder and a half-wave retarder are used, if the former is oriented at 45° with respect to the fibre birefringence axes, while the orientation of the latter serves as the adjustment parameter. The theoretical predictions are confirmed by the experimental results. 相似文献
2.
J.C. Hernandez-Garcia O. Pottiez J.M. Estudillo-Ayala R. Rojas-Laguna 《Optics Communications》2012,285(7):1915-1919
This paper covers a numerical analysis of supercontinuum spectrum generation in a piece of standard fiber by using as the pump noise-like pulses produced by a passively mode-locked fiber laser. An experimental study was also carried out, yielding results that support the numerical results. In the numerical study we estimated that the spectral extension of the generated supercontinuum reaches ~ 1000 nm, and that it presents a high flatness over a region of ~ 220 nm (1630 nm-1850 nm) when we use as the pump noise-like pulses with a wide optical bandwidth (~ 50 nm) and a peak power of ~ 2 kW. Experimentally, the output signal spectrum extends from ~ 1530 nm to at least 1750 nm and presents a high flatness over a region of 1640 nm to 1750 nm for the same value of numerical input power, 1750 nm being the upper limit of the optical spectrum analyzer. The numerical analysis presented here is thus an essential part to overcome the severe limitation in measuring capabilities and to understand the phenomena of supercontinuum generation, which is mainly related to Raman self-frequency shift. Finally, this work demonstrates the potential of noise-like pulses from a passively mode-locked fiber laser for broadband spectrum generation. 相似文献
3.
Tunable dual-wavelength fiber laser based on a polarization-maintaining fiber Bragg grating and a Hi-Bi fiber optical loop mirror 总被引:1,自引:0,他引:1
R. I. Álvarez-Tamayo M. Durán-Sánchez O. Pottiez E. A. Kuzin B. Ibarra-Escamilla 《Laser Physics》2011,21(11):1932-1935
We demonstrate experimentally the operation of a linear cavity dual-wavelength fiber laser using a polarization maintaining
fiber Bragg grating (PM-FBG) as an end mirror that defines two closely spaced laser emission lines. The PM-FBG is also used
to tune the laser wavelengths. The total tuning range is ∼8 nm. The laser operates in a stable dual-wavelength mode for an
appropriate adjustment of the cavity losses for the generated wavelengths. The high birefringence (Hi-Bi) fiber optical loop
mirror (FOLM) is used as a tunable spectral filter to adjust the losses. The FOLM adjustment was performed by the temperature
control of the Hi-Bi fiber. 相似文献
4.
Stabilization of an actively mode-locked fiber laser in the frequency-doubling rational-harmonic mode-locking regime is demonstrated experimentally for the first time to the authors' knowledge. The stabilization is achieved by a method based on minimization of the average optical power at the second output of a dual-output Mach-Zehnder modulator used as a mode locker. This method produces long-term stable operation of the laser with ~35-dB suppression of the pulse-to-pulse amplitude fluctuation caused by rational-harmonic frequency doubling. 相似文献
5.
B. Ibarra-Escamilla O. Pottiez R. Zhou Q. Zhan P. E. Powers E. A. Kuzin J. W. Haus 《Laser Physics》2011,21(11):1936-1940
We experimentally demonstrated a stable, wavelength-tunable fiber laser using a polarization-maintaining, double-clad Er:Yb
doped fiber amplifier in the cavity. The output wavelength is tunable over the range from 1535 to 1567 nm using a fixed grating
and the dichroic mirror placed on a rotational mount; under rotation of the dichroic mirror the tuning ratio of 50 nm/deg
was found. We studied the wavelength tuning range dependence on the amplifier fiber length and achieved a maximal output power
of 850 mW. This configuration can be Q-switched for high peak power and its narrow bandwidth is suitable for nonlinear optics
applications, such as parametric teraherthz generator. 相似文献
6.
M. Durán-Sánchez A. Flores-Rosas R. I. álvarez-Tamayo E. A. Kuzin O. Pottiez M. Bello-Jimenez B. Ibarra-Escamilla 《Laser Physics》2010,20(5):1270-1273
We experimentally demonstrate a fine adjustment of cavity loss by Sagnac loop for a dual wave-length generation. The single
or dual wavelengths are obtained by controlling the losses on both cavities through a fiber optical loop mirror (FOLM). Wavelength
separation on the dual laser is 0.98 nm. The dual or single wavelength is obtained by changes in temperature in the order
of 10−1°C around the maximum in the FOLM. Also, we investigate energy fluctuations on signal level saturation effect in the cavity
through different pumping power that act on the EDF, where we note that from the 60-mW pumping begins to generate dual-wavelength
and 80-mW stabilizes. 相似文献
7.
We demonstrate theoretically and experimentally that efficient signal shaping operation can be obtained at moderate power by using the transmission characteristic of a power-symmetric nonlinear optical loop mirror (NOLM) including highly twisted fibre and operating through nonlinear polarisation rotation, when the circular polarisation state orthogonal to the input polarisation is selected at the NOLM output. By adjusting the angle of the quarter-wave retarder inserted in the loop, the phase bias of the transfer characteristic can be adjusted precisely to enable proper signal shaping for moderate values of input power, remaining well below switching power. The tolerance of the procedure to deviations of the input polarisation from the ideal circular case is investigated numerically. We demonstrate experimentally the capabilities of this setup for both power equalisation and extinction ratio enhancement. Finally, we show that this setup is also useful to shape ultrashort optical pulses from the relaxation oscillations of a DFB semiconductor laser. In comparison with other NOLM-based techniques, the proposed approach allows to reduce by a factor of 8-10 the peak power required for pulse shaping, for the same fibre length and Kerr coefficient. 相似文献
8.
We demonstrate theoretically, experimentally and numerically that a steep all-optical transfer characteristic can be obtained from a power-symmetric NOLM, including a quarter wave retarder and highly twisted fibre, followed by a polarizer. We first develop a theoretical analysis to show that, if the input polarisation is chosen linear, then for a correct choice of the wave plate and input polarisation angles the transmission grows from zero with a 4 dB/dB slope as power is increased, two times faster than can be obtained with a NOLM alone. An experimental study is then realised, which supports the theoretical results. Steep switching is demonstrated for reasonably low peak power levels that do not exceed 8 W, less than one third of the NOLM critical power. In addition, using the same setup we demonstrate the possibility to obtain a sinusoidal transmission characteristic that cancels out for a particular nonzero value of input power, which can be easily adjusted simply through rotation of the wave plate and output polarizer. This setup would be very useful in the frame of optical pulse shaping and signal processing applications, among others. 相似文献
9.
10.
Properties of the pulse train generated by repetition-rate-doubling rational-harmonic actively mode-locked Er-doped fiber lasers 总被引:1,自引:0,他引:1
We demonstrate for the first time to our knowledge, experimentally and theoretically, that the pulse-to-pulse amplitude fluctuations that occur in pulse trains generated by actively mode-locked Er-doped fiber lasers in a repetition-rate-doubling rational-harmonic mode-locking regime are completely eliminated when the modulation frequency is properly tuned. Irregularity of the pulse position in the train was found to be the only drawback of this regime. One could reduce the irregularity to a value acceptable for applications by increasing the bandwidth of the optical filter installed in the laser cavity. 相似文献