共查询到20条相似文献,搜索用时 31 毫秒
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An optical Y-branch is described which, owing to its low losses, is suitable for use in both optical multiplexing systems and measuring equipment, Different methods of attenuation, temperature, near- and far-field measurements are given for the characterisation of the branch. 相似文献
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We have measured the nonlinear optical susceptibility coefficient governing self-induced changes in the state of elliptical polarization of a monochromatic beam in 10 common solvents. These are the first such measurements at 1060 nm. We show how our results may be used to estimate self-focusing in these solvents and to clarify other non-linear optical properties. 相似文献
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光频标和光频测量研究的历史、现状和未来 总被引:4,自引:0,他引:4
本文综合评述了光频标和光频测量研究的历史、现状和未来。在上世纪最后的30年间,光频标已达到10^-11-10^-13量级的准确度,使长度单位“米”进行了重新定义,实际上成为时间单位秒的“导出单位”。最近三年来,该领域的研究出现了重大突破。这是由于飞秒锁模激光技术与光频测量技术两者出人意外的结合,使微波频标与光频标之间建立了简易可行的联系,使光频标的准确度和实用性达到了前所未有的高度,成为计量学和物理学中一个新的亮点。它的进一步发展必将给计量学和物理学带来深远的影响。 相似文献
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Self-adjusting optical filters, which passively track the wavelength of the optical signal, have been demonstrated using two-beam interference in single-mode erbium-doped fiber. Pump-probe measurements of the filter response are reported for a range of doped fiber lengths and optical input powers 相似文献
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Chen-Chia Wang Trivedi S.B. Feng Jin Khurgin J. Temple D. Hommerich U. Gad E. Fow-Sen Choa Yu-Sung Wu Corder A. 《Lightwave Technology, Journal of》2001,19(5):666-672
A new coherent optical detection technique employing coherent frequency-domain reflectometry and a novel optical frequency sensor is demonstrated for high-precision optical path-length measurements. Using pulsed laser sources, an improvement of more than two orders of magnitude in spatial resolution over conventional optical coherent frequency domain reflectometry techniques is demonstrated. Varying degrees of spatial resolution ranging from several centimeters to a few hundred nanometers are achieved. High-precision distance measurement with long baseline is also presented 相似文献
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本报道将一种新的光学效应,即磁流体热透镜耦合光磁效应,应用于高电压电流测量的初步结果。该方法最大的特点是不用偏振光,避免了易受干扰人保偏装置,提高了信噪比,同时又具有光纤传输的优点,并使得该系统简单,经济,和国际 惯用的法拉第效应相比有可能推动电流光学测量实用化的进程。结果表明实验系统可以优于1%的精度测量0-500A范围的电流。 相似文献
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We show that thermal profiling can be used to monitor optical feedback into semiconductor lasers in photonic integrated circuits, where direct optical access is impractical. The optical output power of a laser, both free-running and when exposed to optical feedback, can be quantitatively determined from thermal measurements alone, without recourse to direct optical measurements. Furthermore, the shift in threshold current resulting from optical feedback can be determined from the thermal measurements, enabling quantitative determination of the feedback coupling efficiency into the laser. 相似文献
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D. Luerssen R.J. Ram A. Hohl-AbiChedid E. Clausen Jr. J.A. Hudgings 《Photonics Technology Letters, IEEE》2004,16(7):1625-1627
Spatially resolved thermal profiling of a semiconductor optical amplifier enables measurement of the gain and saturation characteristics without recourse to direct optical measurements. We observe the spatial onset of gain saturation, quantify both the saturated and unsaturated gain, and accurately predict the optical output power. Effects such as suboptimal operating conditions are identified. Since this method is independent of optical measurements, it is ideal for use with integrated devices. 相似文献
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A low-noise, 1.1 Gb/s optical receiver has been built using a silicon a.p.d. and a GaAs f.e.t. The receiver sensitivity was evaluated using error-rate measurements, and for a bit error rate of 10?9, with no fibre, the measured optical sensitivity was ?37.0 dBm. These results are used as a basis for the calculation of maximum repeater spacings for 1.1 Gb/s systems operating at 0.85 ?m and 1.25 ?m wavelengths. 相似文献
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An advanced envelope detection method has been developed with a novel optical PLL without electrical 10 MHz timebase synchronisation. The principle of this method and the results of 160 Gbit/s far-end measurements using this technique are presented. 相似文献
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Kuijk M. Knupfer B. Heremans P. Vounckx R. Borghs G. 《Photonics Technology Letters, IEEE》1995,7(6):646-648
We present the results of a scaling study of monolithic differential pairs of optical thyristors. The devices are depleted thyristors, intended for high-frequency and high-sensitivity operation. According to the measurements, the optical switching energy scales with area and equals to 15 aJ/μm2. The smallest pair with mesas of 10×15 μm2 operates with 2.6 fJ of light input. Sub-femtojoule optical switching energy is expected in the near future 相似文献
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The results of measurements on a GaAs-double-heterostructure (DHS) laser used as an optical amplifier are reported. The laser's amplifying guide is coupled to an optical fiber with a rectangular core. The laser amplifier can be operated either in the traveling-wave or the resonator mode. The gain, noise, and performance of the amplifier when driven hard into saturation were measured as a function of various parameters. 相似文献
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Jiang L.A. Wong S.T. Grein M.E. Ippen E.P. Haus H.A. 《Quantum Electronics, IEEE Journal of》2002,38(8):1047-1052
The use of optical cross correlations for characterizing timing jitter is investigated. Applications, limitations, and correspondence to radio frequency measurements are presented and clarified. The probability density function of the timing jitter of semiconductor mode-locked lasers is deconvolved from the cross-correlation measurements with the aid of pulse characterization techniques. 相似文献
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Yarn evenness is usually obtained with capacitive systems evaluating mass per unit length variations. More recently, optical sensors have been proposed. In this paper, we present experimental results of yarn evenness evaluation with an optical measuring system, sensitive to the light absorbed and diffused by a moving yarn. Results obtained with the optical sensor are compared with measurements performed by means of a capacitive commercial tester. Good agreement in measured count variation CV is obtained.
Moreover, optical and capacitive measurements, simultaneously done on the same thread, allow to obtain a reliable comparison between the two measurement methods, in particular for what concerns yarn signal spectrograms. 相似文献
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An online measurement method using an optical rotary connector is proposed for continuously monitoring optical fibre loss characteristics during manufacture. This method provides a complete transmission loss spectrum and OTDR measurements of optical fibres during the drawing process. The results coincide with corresponding offline cutback measurements to better than ±0.2 dB/km. 相似文献
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Schwerdt M. Berger J. Schuppert B. Petermann K. 《Electromagnetic Compatibility, IEEE Transactions on》1997,39(4):386-390
Compact and nonperturbing integrated optical E-field sensors are used for electric field measurements. The theoretical sensitivity of an integrated optical sensor system is limited by the shot noise. In conventional sensors, however the minimum detectable electric field strength is limited by the relative intensity noise (RIN) of the laser diode. Achieving the theoretical sensitivity a new sensor system is presented. Using a balanced optical receiver both a signal gain and a reduction of the RIN at the optical receiver is obtained. The principle function and the potential of the balanced detection scheme in comparison with existing concepts as well as first measurements are presented, yielding a sensitivity of less than 300 μV/(m√Hz) with standard laser diodes and a receiving dipole length of 40 mm 相似文献