共查询到20条相似文献,搜索用时 15 毫秒
1.
P.D. Dragic 《Photonics Technology Letters, IEEE》2005,17(8):1629-1631
We present a model for the injection seeding of a fiber ring laser. Agreement between theory and experiment is found to be excellent. An injection-seeded fiber laser is attractive for lidar applications requiring narrow linewidth and highly stable peak output wavelength. 相似文献
2.
介绍光纤的概念及其种类,光纤损耗和传输优点,并应用matlab软件数值模拟了单模光纤模场的分布特性,结论为光纤器件的制作提供参考. 相似文献
3.
A.K. Srivastava J.L. Zyskind J.D. Evankow J.W. Sulhoff Y. Sun M.A. Mills 《Photonics Technology Letters, IEEE》1997,9(12):1576-1577
A two-stage erbium-doped fiber amplifier (EDFA) with extremely flat gain (/spl plusmn/0.1 dB) over 17-nm bandwidth is demonstrated. The gain flatness is achieved by incorporating samarium-doped fiber in the mid section of the amplifier. 相似文献
4.
Modeling of gain in erbium-doped fiber amplifiers 总被引:3,自引:0,他引:3
Saleh A.A.M. Jopson R.M. Evankow J.D. Aspell J. 《Photonics Technology Letters, IEEE》1990,2(10):714-717
An analytic method is described for fully characterizing the gain of an erbium-doped fiber amplifier (EDFA) that is based on easily measured monochromatic absorption data. The analytic expressions presented, which involve the solution of one transcendental equation, can predict signal gains and pump absorptions in an amplifier containing an arbitrary number of pumps and signals from arbitrary directions. The gain of an amplifier was measured over a range of more than 20 dB in both pump and signal powers. The measured theoretical results agreed to within 0.5 dB. Although the results described apply explicitly to EDFAs pumped in the 1480-nm region, they are also applicable to EDFAs pumped in the 980-nm region. The method is valid whenever the gain saturation by amplified spontaneous-emission noise can be neglected, which is typically the case for amplifiers with less than about 20 dB of gain 相似文献
5.
AC and DC gain tilt of erbium-doped fiber amplifiers 总被引:1,自引:0,他引:1
AC gain tilt and DC gain tilt are defined as the variable gain of an erbium-doped fiber amplifier (EDFA) with input laser wavelength chirp due to modulation, and with different static laser unmodulated wavelengths of no modulation. This paper proposes a novel experimental setup for measuring AC gain tilt. This paper also clarifies experimentally and theoretically the dependency of the AC gain tilt on the input light modulation frequency from near DC to high frequency. The measured AC gain tilt values at high frequency resemble the measured spontaneous gain tilt values for input wavelengths from 1530 to 1580 nm. The influence of the AC gain tilt effect on AM-SCM video transmission systems is evaluated 相似文献
6.
Boothroyd S.A. Skirtach A. Les Chan Akmaloni A. 《Quantum Electronics, IEEE Journal of》1999,35(1):39-46
Experimental and theoretical results for nonlinear wave mixing in a pumped erbium-doped fiber are presented where a fast phase transient is applied to one of the beams. The ratio of the imaginary part to the real part of the complex nonlinear refractive index is determined from the initial phase of the beam coupling. The fast phase transient is applied for the first time to measure the response time of index gratings in a nonlinear device. We show that the grating lifetime depends on both the pump and amplified signal beams and that the nonlinear index change occurs with a time constant of the order of 100 μs for CW conditions in a highly doped fiber 相似文献
7.
E. Desurvire M. Zirngibl H.M. Presby D. DiGiovanni 《Photonics Technology Letters, IEEE》1991,3(5):453-455
Dynamic compensation of low-frequency gain fluctuations in saturated erbium-doped fiber amplifiers is demonstrated. This compensation, based on a simple feedback-loop scheme makes it possible to reduce transient gain fluctuations efficiently across the whole amplifier bandwidth using only a low-power optical feedback signal. Such an, automatic gain control technique could be applied to suppress data packet interference due to traffic bursts in multiple-access networks, as well as in the implementation of long-haul fiber systems using erbium fiber amplifiers.<> 相似文献
8.
Nilsson J. Yun S.Y. Hwang S.T. Kim J.M. Kim S.J. 《Photonics Technology Letters, IEEE》1998,10(11):1551-1553
We use for what we believe is the first time narrow-band end-reflectors to reduce losses through short-wavelength amplified stimulated emission (ASE) in silica-based erbium-doped fiber amplifiers operating at wavelengths above 1570 mm. The end-reflectors feed a small fraction of the ASE, up to a few tenths of a milliwatt, back into the amplifying fiber. The reflected ASE compresses the short-wavelength gain and thus reduces the ASE-losses, from, e,g., 50 mW for a launched pump power of 110 mW at 980 nm without end-reflector to 10 mW with an optimized end-reflector. We investigate possible improvements of gain (around 5 dB) and output power (up to 17 mW), and the influence of the amount and wavelength of the feedback 相似文献
9.
The gain dynamics in erbium-doped fibers (EDFs) with various numerical apertures (NAs) and cutoff wavelengths used in amplifiers employed in wavelength-division-multiplexing (WDM) networks is investigated by using the time-dependent amplifier model. The calculation shows that the transient response at a time immediately after some channels have been dropped depends on the cutoff wavelength, and the cutoff wavelength for the highest transient response is independent of NA. The calculation also shows that the transient response for a constant cutoff wavelength increases with an increase in NA. Experimental results for the transient response of EDFs with similar NAs and different cutoff wavelengths agree with the calculated results for various input signal powers, input signal power changes, and surviving channel wavelengths when there is no influence of neglection of amplified spontaneous emission and EDF background loss on the calculation. 相似文献
10.
Analysis of AC gain tilt in erbium-doped fiber amplifiers 总被引:1,自引:0,他引:1
J. Nilsson Y.W. Lee S.J. Kim S.H. Lee W.H. Choe 《Photonics Technology Letters, IEEE》1996,8(4):515-517
We analyze theoretically and experimentally the dependence of AC gain tilt variations on gain variations in homogeneously broadened erbium-doped fiber amplifiers. Theoretically, we find that this dependence can be evaluated from the fiber's absorption spectrum. This is experimentally verified for gain variations induced by a pump-power reduction. For AM CATV, AC gain tilt variations limit how much the gain can vary before composite second order distortions become too large. From this point of view, for an erbium-doped alumino-germanosilicate fiber, an operating wavelength between 1542-1555 nm is more suitable than other ones in the long wavelength range of the EDFA, normally considered for AM CATV. 相似文献
11.
M. Yamada T. Kanamori Y. Terunuma K. Oikawa M. Shimizu S. Sudo K. Sagawa 《Photonics Technology Letters, IEEE》1996,8(7):882-884
We successfully developed a fluoride-based Er/sup 3+/-doped fiber amplifier (F-EDFA). An average signal gain of 26 dB was achieved for 8 channel wavelength division multiplexed (WDM) signals in the 1532-1560 nm wavelength region with a gain excursion of less than 1.5 dB at an input signal power of -20 dBm per channel. Furthermore, we studied the amplification characteristics of the F-EDFA for WDM signals. The following experimental results were obtained. (1) For an 8-channel WDM signal in the 1532 to 1560 nm wavelength region, the gain excursion between channels can be suppressed to within 1.5 dB. However, the wavelength region allowing a gain excursion of 1.5 dB, is between 1536-1560 nm for the silica-based Er/sup 3+/-doped fiber amplifier. (2) F-EDFAs have a flat gain region between 1534-1542 nm. The gain excursion of this region is less than 0.2 dB for WDM signals. 相似文献
12.
为了解决光信号在传输过程中因信号放大引起的各信道间功率不均衡的问题,该文通过优化掺铒光纤放大器(EDFA)的结构和增加增益平坦滤波器(GFF)对信号增益谱进行平坦优化。首先通过理论分析各信道间产生不均衡增益的原因;优化掺铒光纤放大器结构由单级放大改变为两级放大,并通过光纤长度二维仿真得到最佳长度配比;并在两级放大光路间添加增益平坦滤波器滤除一级放大产生的不平坦度,再经过二次放大输出增益光信号。最后通过实验给出加入GFF前后增益谱对比图,得到增益更加平坦的输出光谱,保证在1 530~1 560 nm波段的增益平坦度保持在±0.32范围内。 相似文献
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15.
Chun Jiang Weisheng Hu Qingji Zeng 《Photonics Technology Letters, IEEE》2004,16(3):774-776
Both cooperative up-conversion and pair-induced concentration quenching of erbium-doped phosphate fiber with high doping concentration are considered for the first time in this letter. The dependence of the calculated gain on pump power is compared with measured data, and the results show that ion pair may exist in erbium-doped phosphate fiber with doping concentration of 3.8/spl times/10/sup 26/ ion/m/sup 3/. For several erbium-doped phosphate fibers with different lengths, improved gain may be obtained with higher doping concentration. 相似文献
16.
Erbium-doped fiber amplifiers (EDFAs) with enhanced optical gain obtained by incorporating narrow-bandpass optical filters into the amplifier length are studied. It is shown in theory that it is possible to increase optical gain by more than 10 dB for optical signals around the wavelength of 1.55 μm, compared with conventional EDFAs without filters. It is also shown that the gain improvement at longer wavelengths away from the amplifier gain peak is much higher than that of the EDFA with an optical isolator within the amplifier length. The optimum filter position is found to be around 42% of the total amplifier length from the input end. The effects of filter insertion loss and pump loss are discussed. This amplifier can be used as an optical preamplifier in a receiver for a wide range of wavelengths 相似文献
17.
Optical gain control (OGC) can be used to lock the inversion of an erbium-doped fiber amplifier (EDFA), assuming that the gain medium is homogeneous. However, EDF's exhibit certain degrees of spectral hole burning. As a result, when the OGC laser power and the spectral-hole depth at the laser wavelength change, the inversion of the EDFA changes accordingly with a fixed OGC cavity loss. In this work, a saturable absorber is placed in the OGC laser cavity to adjust the cavity loss dynamically and compensate the gain tilt caused by the OGC laser spectral hole burning. It is demonstrated that the steady state gain variation of a surviving channel in an optically gain controlled EDFA is improved from 1.3 dB (with a fixed loss) to 0.4 dB (with a saturable absorber in the cavity). The transient response of this gain control scheme is also discussed 相似文献
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19.
Analytical expressions of the guided mode field distribution:analysis and comparison 总被引:3,自引:0,他引:3
Ning Hua Zhu Yi Kun Lin Zheng De Wu Weigan Lin 《Quantum Electronics, IEEE Journal of》1992,28(6):1424-1428
Methods for determining the parameters of the three different approximate solutions for the fundamental mode field distribution of Ti:LiNbO3 optical waveguides by using the variational technique are presented. This analysis gives closer approximation not only to the field distribution, but also to the propagation constant. Comparison with the exact results for the exponential index distribution in depth shows that these trial functions are closer to the real solution. It is also shown that these solutions are as accurate as the effective index method for Ti:LiNbO3 strip waveguides. The analysis provides an approach for comparing and assessing these solutions 相似文献
20.
Motoshima K. Suzuki N. Shimizu K. Kasahara K. Kitayama T. Yasui T. 《Lightwave Technology, Journal of》2001,19(11):1759-1767
The design scheme for an erbium-doped fiber amplifier (EDFA) with automatic channel-by-channel gain and power regulation function is discussed with much emphasis on the pump power control scheme and the requirement for feedback circuitry. Based on both wavelength and time-resolved simulation technique, an amplifier repeater employing novel high-speed automatic gain control (AGC) and automatic level control (ALC) functions is designed and implemented. The AGC and ALC scheme can suppress the transient power fluctuation of a surviving channel caused by adding or dropping all other channels less than 0.45 dB and keep output power constant over 9-dB input power range 相似文献