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Optics, Lasers and Applications conference, RIO/ OPTILAS, Porto, Portugal; 07/2013
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IEEE Photonics Technology Letters 07/2013; -(-):-. · 2.19 Impact Factor
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ABSTRACT: Polarization bistability in VCSEL subject to orthogonally polarized optical injection is studied experimentally. It is shown that the VCSEL may exhibits a low power (2.8 µW) polarization switching and ultra-wide hysteresis cycle beyond 150 GHz.
The 10th Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR & OECC/PS), Japan 2013, Kyoto international conference center, Kyoto- Japan; 06/2013
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ABSTRACT: Polarization switching characteristics of birefringent
vertical cavity surface emitting lasers (VCSELs) subject to
polarized optical injection are investigated experimentally. The
role of the suppressed mode of VCSELs in reducing the injected
optical power required for polarization switching (PS) has been
identified. For orthogonal optical injection, the minimum optical
injection power (Pinj) to induce PS is found to occur at a
frequency detuning (FD) of −11 GHz corresponding to the
VCSEL birefringence. The value of the minimum Pinj reduced
significantly with increasing bias current. The FD for PS is
independent of the VCSEL bias current, injected power level,
and a defined range of polarization angles of the injected light.
However, for parallel optical injection, the minimum FD for PS
is normally found to be positive and dependent on the VCSEL
bias current and injected optical power.
IEEE Journal of Quantum Electronics 02/2013; 49(2):205. · 1.88 Impact Factor
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ABSTRACT: This letter investigates experimentally the effects
of circularly polarized optical feedback (CPOF) on the polarization
characteristics of vertical-cavity surface-emitting lasers
(VCSELs). It is shown that CPOF imparts up to 30% circular
polarization to the VCSEL emission. The degree of circular
polarization acquired by the VCSEL emission is determined by
the feedback power ratio and the VCSEL bias current. The
effects of COPF have been compared to the influence of other
species of linearly polarized optical feedback.
IEEE Photonics Technology Letters 07/2012; 24(14):1200. · 2.19 Impact Factor
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K. Alan Shore
01/2012: pages 355 - 380; , ISBN: 9783527639823
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ABSTRACT: Thermal effects and dynamical hysteresis in VCSELs under dc modulation have been experimentally studied. The results show that the VCSEL turn-on and turn-off currents can display both positive hysteresis and negative hysteresis, depending on the current modulation frequency and on the substrate temperature. Numerical simulations of semiconductor laser rate equations, extended to take into account thermal effects, show a good agreement with the observations.
Optics Letters 11/2010; 35(21):3688-90. · 3.40 Impact Factor
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05/2008: pages 369 - 378; , ISBN: 9783527622313
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ABSTRACT: We experimentally study chaos synchronization in unidirectionally coupled vertical-cavity surface-emitting semiconductor lasers (VCSELs) with polarization-preserved and polarization-selected optical injection. The measurements show, in agreement with theoretical predictions, that the maximum cross coefficient of 0.884 obtained with polarization-preserved optical injection is significantly higher than the maximum cross coefficient of 0.724 obtained with polarization-selected optical injection.
Optics Letters 04/2008; 33(6):587-9. · 3.40 Impact Factor
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ABSTRACT: We study experimentally the role of the bias current sweep rate in measurements of polarization switching (PS) of vertical-cavity surface-emitting lasers. We find that the size of the hysteresis cycle of the PS for increasing and decreasing current follows a power-law relationship with the speed of the current ramp. A similar relation is found for the laser turn-on. Numerical calculations based on the spin-flip model are in good agreement with the observations. We also show that the PS points and the power-law exponents depend critically on the noise level included in the simulations.
Phys. Rev. A. 03/2008; 77(4).
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ABSTRACT: The bias-current dependence of anticorrelation polarization dynamics in vertical-cavity surface-emitting lasers with long external cavity has been studied experimentally. With fixed optical feedback strength, the minimum cross-correlation coefficient exhibits exponential decay with the bias current. Strong anticorrelation is obtained at frequencies lower than 1 GHz for all bias currents. Near the relaxation oscillation frequency good correlation is found at higher bias current but poor correlation is found at lower bias currents.
Applied Physics Letters 08/2006; 89(8):081123-081123-3. · 3.84 Impact Factor
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ABSTRACT: We study the role of the bias current sweep rate in measurements of polarization switching (PS) of vertical-cavity surface-emitting lasers (VCSELs). We show that the polarization-resolved L-I (light-intensity) curve depends on the current sweep rate. As the current sweep rate increases, the PS occurs at higher bias currents for upward scans and at lower bias currents for downward scans. We also show that the delay of the dynamical bifurcation follows a power law relationship with the frequency of the ramp, in good agreement with recent theoretical predictions.
Optics Letters 04/2006; 31(6):748-50. · 3.40 Impact Factor
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ABSTRACT: The influence of the optical feedback ratio and bias current on the mean and the standard deviation of the power dropout ratio of low-frequency fluctuations in external-cavity semiconductor lasers has been studied experimentally. The power dropout ratio was found to increase with increasing optical feedback ratio and to decrease with increasing bias current.
Optics Letters 01/2006; 30(24):3332-4. · 3.40 Impact Factor
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ABSTRACT: Chaotic signals have been proposed as broadband information carriers with the potential of providing a high level of robustness and privacy in data transmission. Laboratory demonstrations of chaos-based optical communications have already shown the potential of this technology, but a field experiment using commercial optical networks has not been undertaken so far. Here we demonstrate high-speed long-distance communication based on chaos synchronization over a commercial fibre-optic channel. An optical carrier wave generated by a chaotic laser is used to encode a message for transmission over 120 km of optical fibre in the metropolitan area network of Athens, Greece. The message is decoded using an appropriate second laser which, by synchronizing with the chaotic carrier, allows for the separation of the carrier and the message. Transmission rates in the gigabit per second range are achieved, with corresponding bit-error rates below 10(-7). The system uses matched pairs of semiconductor lasers as chaotic emitters and receivers, and off-the-shelf fibre-optic telecommunication components. Our results show that information can be transmitted at high bit rates using deterministic chaos in a manner that is robust to perturbations and channel disturbances unavoidable under real-world conditions.
Nature 12/2005; 438(7066):343-6. · 36.28 Impact Factor
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ABSTRACT: An experimental demonstration of the effect of chaos pass filtering on high-frequency message transmission in the complete synchronization regime is reported. The opportunity for chaotic message decoding at frequencies up to 6 GHz is shown.
Optics Letters 12/2004; 29(21):2497-9. · 3.40 Impact Factor
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ABSTRACT: The polarization properties of vertical-cavity surface-emitting lasers (VCSELs) subject to optical feedback are studied experimentally. It is thereby demonstrated that polarization-selective optical feedback can be utilized to entirely eliminate VCSEL polarization switching over the entire device operating range.
Optics Letters 10/2004; 29(18):2151-3. · 3.40 Impact Factor
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ABSTRACT: The synchronization of unidirectionally coupled multi-transverse-mode vertical-cavity surface-emitting lasers (VCSELs) is numerically studied. It is demonstrated that synchronization can be achieved between each transverse mode of a master laser and its counterpart, a slave laser. This result opens the opportunity for multichannel chaotic communications by use of multi-transverse-mode VCSELs. It is further shown that two distinct synchronization regimes exist, complete synchronization and injection locking, which can be distinguished by the lag time between the master and the slave laser intensities.
Journal of the Optical Society of America B 09/2004; 21(10):1772-1780. · 2.18 Impact Factor
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ABSTRACT: We have experimentally demonstrated message broadcasting and decoding
using a chaotic external-cavity DFB laser transmitter and two
stand-alone DFB laser receivers. A GHz message has been successfully
broadcast to the two receivers. Message recovery was achieved with
greater than 14 dB signal-to-noise ratio.
Proc SPIE 09/2004; 5614:151-156.
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ABSTRACT: The relative intensity noise (RIN) of a semiconductor laser diode subject to optical feedback has been numerically calculated for both weak and strong optical feedback levels. Good agreement with recent experiment results was only obtained after a modified Lang–Kobayashi model was used. Multiple reflections in the external cavity are required to explain the experimentally observed variation of the upper boundary of the coherence collapse regime with injection current. RIN measurements are shown to offer a convenient method of identifying the various feedback regimes both experimentally and theoretically. The importance of incoherent optical feedback in regime IV is also stressed.
Journal of Optics B Quantum and Semiclassical Optics 07/2004; 6(8):S775. · 1.81 Impact Factor
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ABSTRACT: Synchronization of chaos is achieved experimentally in unidirectionally coupled external-cavity vertical-cavity surface-emitting semiconductor lasers operating in an open-loop regime. Synchronization is observed when the polarization of the transmitter is perpendicular to the polarization (x polarization) of the free-running receiver. The ratio of transmitter output to y-polarized receiver output power shows normal (positive-slope) synchronization. However, inverse (negative-slope) synchronization is found to arise between the transmitter output and the x-polarized receiver output power.
Optics Letters 07/2004; 29(11):1215-7. · 3.40 Impact Factor
