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241.
H. Ahmad A. Z. Zulkifli F. D. Muhammad M. Z. Zulkifli K. Thambiratnam S. W. Harun 《Applied physics. B, Lasers and optics》2014,115(3):407-412
A passively mode-locked, bismuth–erbium-co-doped fiber (Bi-EDF) with a pulse width of 460 fs is proposed and demonstrated. A highly doped, 180-cm Bi-EDF with an erbium concentration of 3,250 ppm/wt and an absorption rate of 133 dB/m at 1,530 nm serves as the gain medium. The cavity is 11.6 m long with an overall group velocity dispersion of +0.063 ps2. The output pulses have a repetition rate, average output power, pulse energy and peak power of 11.18 MHz, 5 mW, 448 pJ and 1 kW, respectively. The system has a high beam quality and a narrow pulse width output in the L-band region. 相似文献
242.
Özlem Öksüzer Harun Karsli Fatma Taşdelen Yeşildal 《Numerical Functional Analysis & Optimization》2016,37(5):583-602
This article studies the variation detracting property and rate of approximation of the Bernstein-Stancu polynomials in the space of functions of bounded variation with respect to the variation seminorm. Moreover, we will present Voronovskaya-type theorems for Bernstein-Stancu polynomials Bn, α, βf and for the first derivative of these polynomials. Finally we include some graphical examples. 相似文献
243.
The phase diagram of symmetric ternary blends of diblock copolymers and homopolymers in thin films was determined as a function of increasing volume fraction of homopolymer (phi(H)) and was similar to that for these materials in the bulk. Blends with compositions in the lamellar region of the diagram (phi(H)< or =0.4) could be directed to assemble into ordered lamellar arrays on chemically striped surfaces if the characteristic blend dimension (L(B)) and the period of the stripes (L(S)) were commensurate such that L(S)=L(B)+/-0.10L(B). Blends with compositions in the microemulsion region of the diagram (phi(H) approximately 0.6) assembled into defect-free lamellar phases on patterned surfaces with L(S)> or =L(B), but formed coexisting lamellar (with period L(S)) and homopolymer-rich phases when L(S)相似文献
244.
N. S. Shahabuddin H. Mohamad M. A. Mahdi Z. Yusoff H. Ahmad S. W. Harun 《Laser Physics》2012,22(1):212-215
A simple multi-wavelength source is demonstrated based on spectral slicing of supercontinuum (SC) light using a Sagnac loop
mirror. A mode locked fiber laser with pulse width of 800 fs is employed to generate the SC in photonic crystal fiber (PCF).
The SC light extending from 1200 nm up to the wavelength region above 1750 nm is obtained at the amplified pulse pump power
of 30 dBm. By slicing the SC with a loop mirror, a multiwavelength comb spectrum is obtained with different channel spacing
for different operating wavelength region. Spacings of 1.5, 2.3, and 2.9 nm are shown at wavelength regions of 1220, 1450,
and 1730 nm, respectively. It is also observed that the signal to noise ratio (SNR) increases from 15 to 20 dB as the operating
wavelength increases from 1220 to 1730 nm region. 相似文献
245.
Stable double spacing multiwavelength Brillouin-Erbium doped fiber laser based on highly nonlinear fiber 总被引:1,自引:0,他引:1
A double frequency spaced multiwavelength Brillouin-Erbium doped fiber laser (BEDFL) with figure-of-eight cavity have been
successfully developed and tested. Double frequency spacing is achieved by using a piece of 2 km of highly nonlinear fiber
(HNLF) as a gain medium. Figure-of-eight configuration removes the odd order Stokes signals via a four-port circulator. Fifteen
Stokes channels are simultaneously generated with a spacing of 0.154 nm that is around 20 GHz, when the Brillouin pump and
980 nm pump powers are fixed at the optimized values of 6 dBm and 40 mW, respectively. Fourteen anti stoke channels are also
obtained, which are generated through four wave mixing (FWM) process in the laser cavity. The output is smooth triangular
comb. The BEFL can also be tuned from 1526.5 to 1567.5 nm. 相似文献
246.
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