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1.
A generator of chaos in wavelength is reported. It is formed by a wavelength-tunable laser diode with a time delayed feedback loop in which a wavelength nonlinear-linear device is introduced. The dynamical regime of wavelength emission thus obtained is ruled by a differential difference equation. Experimental results are compared with numerical simulations and with previous theoretical and experimental results 相似文献
2.
A method of multichannel processing to compute correlation products simultaneously is introduced. The signals that process are encoded on a single light beam through the use of an electro-optic modulators that induce optical delays greater than the coherence length of light. The coherence-modulated light beam thus obtained is then spatially and temporally modulated through an acousto-optic Bragg cell. The potential number of channels is estimated to be approximately 5-10. The method can be combined with other existing systems, such as time-, space-, or frequency-multiplexed correlators, to increase the channel number. The method also applies to high-resolution spectral analysis. 相似文献
3.
Duraffourg L. Merolla J.-M. Goedgebuer J.-P. Butterlin N. Rhodes W.T. 《Quantum Electronics, IEEE Journal of》2001,37(1):75-79
Unexpected results have been obtained in measurements of dark-count rate and quantum efficiency (QE) for a germanium avalanche photodiode operating in the photon counting regime at 1540-nm wavelength. A liquid-nitrogen cooled Ge single-photon avalanche diode (SPAD) exhibited both a low dark-count rate and a QE of the order of 1%, which is at least one order of magnitude higher than the values reported for such a device. The data offer hope for future diodes that might match such performance. Reasons for the device's extraordinarily good performance, a performance level not matched by the other 17 APDs in the collection investigated, are not understood. Such high quantum efficiency germanium devices could be used in one-bit-per-photon communication systems operating in the 1540-nm telecommunications window 相似文献
4.
An electrooptic modulation method based on signal coding through optical delays larger than the source coherence length is described. The method is illustrated with the simultaneous transmission of several signals by path-difference multiplexing. In this method, the signals are coded as a sequence of optical delays introduced by a series of electrooptic modulators working as delay lines. Decoding is carried out by temporal correlation performed by another sequence of optical delays introduced by birefringent plates, and matched to those used at the emission process. The permissible delays are shown to be ruled by the source coherence length and by the number of laser modes. 相似文献
5.
Grossard N. Forte H. Vilcot J.-P. Beche B. Goedgebuer J.-P. 《Photonics Technology Letters, IEEE》2001,13(8):830-832
We designed and fabricated an electrooptic transverse magnetic-transverse electric mode converter with phase mismatch control integrated in AlGaAs-GaAs. The electrode scheme, which is reported for the first time in such a device, insures a high polarization conversion efficiency with low-driving voltages 相似文献
6.
Hanna M. Porte H. Goedgebuer J.-P. Rhodes W.T. 《Quantum Electronics, IEEE Journal of》2000,36(11):1333-1338
The soliton optical phase stability versus amplified spontaneous noise is investigated in a recirculation loop experiment in the presence of in-line filters. The behavior of phase fluctuations is shown to be in good agreement with numerical simulations. The phase standard deviation is kept below 0.15×π for distances up to 8000 km. We, therefore, demonstrate the feasibility of phase-shift keying on solitons for long-haul transmission systems 相似文献
7.
Wacogne B. Goedgebuer J.P. Onokhov A.P. Tomilin M. 《Quantum Electronics, IEEE Journal of》1993,29(4):1015-1017
The authors report a single frequency, extended cavity laser diode operating at 1500 nm wavelength and using an intracavity liquid cell wavelength filter to tune the wavelength over 6 nm by mode hopping. Continuous tuning over the free spectra range of the cavity is also demonstrated 相似文献
8.
We report a chaos-based transmission system that uses optical path differences between wavegroups produced by a short coherence source. Chaos synchronization is demonstrated in delay-differential equations involving optical delays larger than the coherence length of the source. The particular feature is all-optical chaos subtraction for message extraction and a very high masking efficiency. 相似文献
9.
Porte H. Goedgebuer J.-F. Elflein W. Terras A. Ledeventec F. Butterlin N. 《IEEE journal of selected topics in quantum electronics》1996,2(2):319-325
We report an interferometric sensor system, based on coherence modulation of light and LiNbO3 integrated optics technology. We describe a phase detection scheme designed to retrieve the absolute phase variations produced by a sensor system where the sensor signal is electronically applied to an electro-optic modulator. The system consists of an imbalanced LiNbO3 Mach-Zehnder transducer fed by a self-powered charge generating sensor, and an optoelectronic central processing unit including a second electrooptic Mach-Zehnder working as an optical demodulator and featuring a matched path-imbalance. Electrical feedback is applied to this second interferometer in an active demodulation scheme, allowing a linear tracking of the signal phase up to 7-π radians 相似文献
10.
The impact of digitisation on chaos synchronisation and message decoding in a chaotic cryptosystem is described. The sampling rates and resolutions that lead to a good decoding of the message are determined numerically and experimentally. The results are interpreted in light of Shannon's sampling theory 相似文献