共查询到20条相似文献,搜索用时 531 毫秒
1.
R. Caponi E. Ciaramella E. Riccardi M. Schiano T. Tambosso G. Zaffiro 《Fiber and Integrated Optics》2000,19(4):295-309
Polarization mode dispersion of chirped Bragg gratings is analyzed in terms of key birefringence phenomena and impact on telecommunication systems performance. The influence on polarization mode dispersion (PMD) of fiber birefringence, grating chromatic dispersion, and ripples of the group delay curve is pointed out. Polarization mode dispersion influence on systems performance is investigated by numerical simulations and transmission experiments at 10 Gbit/s. The deterministic nature of Bragg gratings PMD determines a moderate, upper-limited system penalty for a transmission line employing a single compensating device. However, in the case of broadband components, a non-negligible PMD penalty may be observed due to the difficulty of controlling accurately the group delay linearity. 相似文献
2.
R. Caponi E. Ciaramella E. Riccardi M. Schiano T. Tambosso G. Zaffiro 《Fiber and Integrated Optics》2013,32(4):295-309
Polarization mode dispersion of chirped Bragg gratings is analyzed in terms of key birefringence phenomena and impact on telecommunication systems performance. The influence on polarization mode dispersion (PMD) of fiber birefringence, grating chromatic dispersion, and ripples of the group delay curve is pointed out. Polarization mode dispersion influence on systems performance is investigated by numerical simulations and transmission experiments at 10 Gbit/s. The deterministic nature of Bragg gratings PMD determines a moderate, upper-limited system penalty for a transmission line employing a single compensating device. However, in the case of broadband components, a non-negligible PMD penalty may be observed due to the difficulty of controlling accurately the group delay linearity. 相似文献
3.
Ilda Abe Rafael E. de Ges Jos L. Fabris Hypolito J. Kalinowski Mrcia Müller Meire C. Fugihara Rosane Falate Barbara W. Diesel Ricardo C. Kamikawachi Carmen L. Barbosa 《Optics and Lasers in Engineering》2003,39(5-6):537-548
In this work, we report production and modelling of both Bragg gratings and rocking filters in high birefringence fibre optics. Bragg gratings are produced by UV (257.0 nm) external interferometric exposition of a frequency-doubled Ar+ ion laser, whereas for rocking filters formation the visible Ar+ ion laser lines in 488.0 and 514.5 nm are used in an internal method. The spectral characteristics due to the birefringence properties are studied through numerical methods and experimental techniques. The spectral responsivity of the structures under temperature changes and stress application is presented. 相似文献
4.
J. Castrellon-Uribe C. Cuevas-Arteaga A. Trujillo-Estrada 《Optics and Lasers in Engineering》2008,46(6):469-476
We report a method based on the power ratio of transmittance for monitoring the corrosion rate in stainless steel 304L immersed in an aqueous solution of lithium bromide at 50 wt%, at 70 °C. The optical transmittance measured in the solution contaminated with corrosion oxides at different times of exposure is related to the physical degradation of the stainless steel samples. Lasers at 532 and 632 nm were utilized for monitoring the accumulation of corrosion oxides dissolved in the lithium bromide solution of the metallic samples for 480 h. The change in the optical power of transmittance was 13 μW/480 h measured at 532 nm and 3.6 μW/480 h at 632 nm. The variation of the power ratio for 532 nm was from 0.01 to 0.24, and for 632 nm, from 0.01×10−3 to 15.61×10−3; this is proportional to an accumulated corrosion rate of [0.0142×10−3–0.552×10−3 g/cm2] for an exposure time of 432 h. 相似文献
5.
Ral Valle Simon Frdrick Karen Asatryan Michel Fischer Tigran Galstian 《Optics Communications》2004,230(4-6):301-307
Real-time study of the formation of Bragg gratings in monolayer As2S3 ridge waveguides is presented. A transverse holographic method is used to record such gratings. The periodic photodarkening of the layer leads to the formation of a Bragg grating with resonant wavelength 1.55 μm. The experiment allowed to control in situ the grating parameters such as the reflectivity, the resonant wavelength (between 1500 and 1630 nm) and the bandpass at −3 dB. 相似文献
6.
Q. Zhao J.Q. Pan J. Zhang B.X. Li F. Zhou B.J. Wang L.F. Wang J. Bian L.J. Zhao W. Wang 《Optics Communications》2006,260(2):666-669
A strained InGaAsP-InP multiple-quantum-well DFB laser monolithically integrated with electroabsorption modulator by ultra-low-pressure (22 mbar) selective-area-growth is presented. The integrated chip exhibits superior characteristics, such as low threshold current of 19 mA, single-mode operation around 1550 nm range with side-mode suppression ratio over 40 dB, and larger than 16 dB extinction ratio when coupled into a single-mode fiber. More than 10 GHz modulation bandwidth is also achieved. After packaged in a compact module, the device successfully performs 10-Gb/s NRZ transmission experiments through 53.3 km of standard fiber with 8.7 dB dynamic extinction ratio. A receiver sensitivity of −18.9 dBm at bit-error-rate of 10−10 is confirmed. 相似文献
7.
Via a cascaded structure, the peak-to-trough ratio is considerably improved for sampled fiber Bragg gratings (SFBGs) based on multiple-phase-shift (MPS) technique. This cascaded filter is composed of two identical SFBGs which are inserted with the increasing or decreasing arrangement of phase shifts. With this inverse arrangement of MPS in grating design, the phase fluctuation of individual SFBG can be compensated, and as a result an excellent phase matching condition is realized. In this way, the peak-to- trough ratio in reflection spectra is improved from 6 to 12 dB when multiplication factor m = 4, and from 5dBto 10dBwhenm=8. 相似文献
8.
Jinhui Wang Gongqiang Liu Gang Ni Youwei Du 《Journal of magnetism and magnetic materials》2004,280(2-3):316-321
Reversible and irreversible domain wall (DW) motions have been investigated in La0.7Sr0.3MnO3 ceramic samples using frequency-response complex permeability with various amplitudes of AC field. We also examine the effects of temperature in the range from 293 to 368 K and transverse DC magnetic field with a maximum of 4.40×105 A/m on the real part of permeability (μ′). Two relaxations corresponding to reversible wall motions and domain rotations occur in low and high frequency regions, respectively. The irreversible DW displacements can be activated as the amplitude larger than the pinning field of 3 A/m, leading to an increase in μ′. The μ′ obeys a Rayleigh law at the temperature below 343 K or under DC field of less than 4.22×104 A/m. The Rayleigh constant η increases from 5.45×10−2 to 1.54×10−1 (A/m)−1 as the temperature rises from 293 to 343 K, and η decreases from 5.58×10−2 to 3.67×10−2 (A/m)−1 with increasing DC field from 1.99×103 to 4.22×104 A/m. 相似文献
9.
The third-order nonlinear optical response of a triphenylmethane dye (Acid blue 7) was studied using the Z-scan technique with a continuous-wave He–Ne laser radiation at 633 nm. The magnitude and sign of the third-order nonlinear refractive index n2 of aqueous solution of Acid blue 7 dye were determined; the negative sign indicates a self-defocusing optical nonlinearity in the sample studied. The negative nonlinear refractive index n2 and nonlinear absorption coefficient β were estimated to be −1.88 × 10−7 cm2/W and −3.08 × 10−3 cm/W, respectively, corresponding to Re(χ(3)) = −8.35 × 10−6 esu, and Im(χ(3)) = −6.88 × 10−7 esu. The experimental results show that Acid blue 7 dye have potential applications in nonlinear optics. 相似文献
10.
R.A. Ganeev M. Baba A.I. Ryasnyansky M. Suzuki H. Kuroda 《Optics Communications》2004,240(4-6):437-448
The optical, structural, and nonlinear optical properties of silver nanoparticles prepared by laser ablation in various liquids were investigated at 397.5, 532, and 795 nm. The TEM and spectral measurements have shown temporal dynamics of size distribution of Ag nanoparticles in solutions. The thermal-induced self-defocusing dominated in the case of high pulse repetition rate as well as in the case of nanosecond pulses. In the case of low pulse repetition rate, the self-focusing (γ = 3 × 10−13 cm2 W−1) and saturated absorption (β = −1.5 × 10−9 cm W−1) of picosecond and femtosecond radiation were observed in these colloidal solutions. The nonlinear susceptibility of Ag nanoparticles ablated in water was measured to be 5 × 10−8 esu (at λ = 397.5 nm). 相似文献
11.
We experimentally demonstrate a wavelength-spacing tunable multiwavelength erbium-doped fiber laser based on degenerate four-wave mixing in a dispersion-shifted fiber incorporating multiple-fiber Bragg gratings. We have achieved stable operation of the multiwavelength erbium-doped fiber laser, which has 0.8 nm spacing ten-channel lasing wavelengths and a high extinction ratio of more than approximately 45 dB, at room temperature. The output power of the multiwavelength erbium-doped fiber laser is stable, so the peak fluctuation is less than approximately 0.2 dB. By changing the properties such as loss and polarization state of multiple fiber Bragg grating cavities, we can exercise flexible control of the wavelength spacing of the multiwavelength output. We can also obtain switchable multiwavelength lasing operation by elimination of the effects of alternate single-fiber Bragg gratings. 相似文献
12.
The circular polarization of the 482 keV γ-radiation of 181Ta and the 343 keV γ-radiation of 175Lu was measured with a Compton polarimeter. Spurious effects arising from higher order contributions of quantum electrodynamics to the Compton scattering cross section were discovered. The results for the polarization are P = − (4.1±1.3)10−6 for 181Ta and P = − (1.5±6.0)10−6 for 175Lu. These values are corrected for instrument asymmetries, bremsstrahlung and intensity of other lines. 相似文献
13.
Balram Tripathi F. Singh D.K. Avasthi D. Das Y.K. Vijay 《Physica B: Condensed Matter》2007,400(1-2):70-76
Mn2+-doped CdS nanocrystals have been synthesized by adopting an aqueous solution precipitation method. These nanocrystals have been studied using X-ray diffraction (XRD), X-ray fluorescence (XRF), optical absorbance, photoluminescence (PL), DC electrical conductivity measurements and positron annihilation lifetime spectroscopy (PALS). The system has been found to be in the hexagonal phase. PL spectra have been studied on most prominent exciton peaks within the wavelength range (586–731 nm). The emission intensity is found to increase on increasing Mn2+ ion concentration (0–5%). Electrical conductivity lies within 0.819×10−6 to 1.69×10−6 Ω−1 m−1 and the system shows power law dependence for n=3–3.77. The Cd vacancies concentration has been found to decrease on increasing Mn%. 相似文献
14.
This paper proposes a performance-enhanced code-division-multiple-access (CDMA) system using modified pseudorandom noise (PN) coded fiber Bragg gratings (FBGs) with a bipolar optical CDMA encoder/decoder. The data were encoded either by a unipolar signature sequence of modified PN code or by its complement, depending on whether the data bit was ‘1’ or ‘0’. Numerical simulation confirmed that bit error rate (BER) performance largely improved due to the increased decision margin at the receiver. Furthermore, at the BER of 10−9, the tolerance of spectral power distortion in the optical source appeared to be nearly twice that of conventional optical CDMA systems. 相似文献
15.
The generation of coherent optical subcarriers based on a concatenated dual-drive Mach-Zehnder intensity modulator(IM) and two phase modulators(PMs) is proposed and experimentally demonstrated.The modulation index and DC bias of PM+IM modulation are theoretically investigated.Theoretical analysis and numerical study are also carried out to examine the proposed scheme.We use 25-GHz RF synchronous sinusoidal signals to drive cascaded two-stage PMs and IM,through which we generate 28 subcarriers with peak power fluctuations less than 4 dB.The measured tone-to-noise ratio of the subcarrier is higher than 40 dB.The experimental results show that for 100-Gb/s polarization multiplexing QPSK signal,the receiver sensitivity of the back-to-back signal is -28.6 dBm,and the power penalty is lower than 1 dB after 100-km transmission at the BER of 1×10-9. 相似文献
16.
Yi-Lin Yu Edvin Skaljo Hoa Le Minh Zabih Ghassemlooy 《Fiber and Integrated Optics》2013,32(5-6):383-394
AbstractThis article presents a novel bidirectional wavelength reconfigurable optical network utilizing a remotely pumped erbium-doped fiber amplifier and tunable fiber Bragg gratings. The system is experimentally demonstrated at a 10-Gb/s per channel over 20-km fiber span that verifies the metro-network range system performance. The achieved power penalty is less than 1 dB when compared to the back-to-back transmission link. An example of practical application where the proposed module is used as an add/drop multiplexer and a remote node in the bidirectional wavelength division multiplexing passive optical network system is described. 相似文献
17.
线性啁啾光纤Bragg光栅的实验研究 总被引:2,自引:2,他引:0
本文给出了142mm长相位掩模板和扩束技术研制的色散补偿线性啁啾Bragg光纤光栅(CFBG)的反射谱特性及传输实验结果,本实验研制的线性啁啾Bragg光纤光栅样品带宽为0.56~0.92mm.可实现对普通光纤色散补偿100km以上,色散代价小于1.5dB. 相似文献
18.
B. Aas E. Bleszynski M. Bleszynski M. Hajisaeid G. J. Igo F. Irom G. Pauletta A. Rahbar A. T. M. WangC. F. Amann T. A. Carey W. D. Cornelius J. B. McClellandM. Barlett G. W. HoffmannM. Gazzaly 《Nuclear Physics A》1986,460(4):675-698
Measurements for the elastic and inelastic scattering of 500 MeV protons from 40Ca and 208Pb at small momentum transfers are reported. The induced proton polarization P and the spin rotation parameter Q were measured for the elastic scattering. The spin rotation parameters DSS′, DSL′, DLL′, dLS′ and the induced polarization P were measured for transitions to the 3−(3.37 MeV) and 5−(4.48 MeV) states in 40Ca and the 3−(2.61 MeV) state in 208Pb. Comparisons of the data with the theoretical calculations were carried out in the framework of nonrelativistic and relativistic approaches. We extracted the spin-up and spin-down channels for the elastic scattering cross sections and found that predictions of the relativistic and nonrelativistic approaches agree well with the spin-up channel data and differ considerably in the spin-down channel. 相似文献
19.
The betaspectra of 12B and 12N have been measured with a NaI crystal as spectrometer. Assuming a shape correction factor 1 + aW + bW2 and b− = 1.106 × 10−4 MeV−2, b+ = −1.397 × 10−4 MeV−2, the spectra yield a− = (+0.91 ± 0.11) × 10−2 MeV−1 and a+ = (−0.07 ± 0.09) × 10−2 MeV−. the a− − a+ = (+0.98 ± 0.09) × 10−2 MeV−1 is in agreement with the weak magnetism prediction. 相似文献
20.
Study on the 4×10 Gb/s,400 km dispersion compensation by chirped optical fiber grating 总被引:1,自引:0,他引:1
In this paper, the dispersion compensation for 4×10 Gb/s, 400 km G.652 fiber by chirped optical fiberBragg grating (FBG)is introduced.For the first time,we have measured and compensated the polarizationmode dispersion(PMD)of FBG, which in each channel is less than 1.1 ps.When the bit crror rate(BER)is 10~(-10)and the bit error is zero, the transmission power penalty of each channel is less than 2 dB, andthe best, result is negative which means that the receiver sensitivity is increased after transmission. 相似文献