[Show abstract][Hide abstract] ABSTRACT: We report the experimental observation of circular polarization switching (PS) and polarization bistability (PB) in a 1300 nm dilute nitride spin-vertical cavity surface emitting laser (VCSEL). We demonstrate that the circularly polarized optical signal at 1300 nm can gradually or abruptly switch the polarization ellipticity of the spin-VCSEL from right-to-left circular polarization and vice versa. Moreover, different forms of PS and PB between right- and left-circular polarizations are observed by controlling the injection strength and the initial wavelength detuning. These results obtained at the telecom wavelength of 1300 nm open the door for novel uses of spin-VCSELs in polarization sensitive applications in future optical systems.
[Show abstract][Hide abstract] ABSTRACT: We experimentally demonstrate the control of the light polarization emitted by a 1310 nm dilute nitride spin-Vertical Cavity Surface Emitting Laser (VCSEL) at room temperature. This is achieved by means of a combination of polarized optical pumping and polarized optical injection. Without external injection, the polarization of the optical pump controls that of the spin-VCSEL. However, the addition of the externally injected signal polarized with either left- (LCP) or right-circular polarization (RCP) is able to control the polarization of the spin-VCSEL switching it at will to left- or right-circular polarization. A numerical model has been developed showing a very high degree of agreement with the experimental findings.
[Show abstract][Hide abstract] ABSTRACT: We report the first experimental observation of different forms of polarization switching and bistability in an optically injected 1300nm dilute nitride spin-VCSEL and for both (right- and left-) circularly polarized modes of the device.
[Show abstract][Hide abstract] ABSTRACT: We report the first quantum dot semiconductor disk laser operating at 1300 nm under
continuous optical pumping at room temperature. A threshold power of 21 mW and output power
above 0.5 mW have been achieved.
2014 IEEE International Semiconductor Laser Conference; 10/2014
[Show abstract][Hide abstract] ABSTRACT: We report the first optical injection experiment on a dilute nitride 1300 mm spin-VCSEL at room temperature. Effective control of the polarization of the light emitted by the spin-VCSEL is theoretically predicted and experimentally demonstrated.
[Show abstract][Hide abstract] ABSTRACT: The authors report a theoretical analysis of optically pumped 1300 nm dilute nitride spin-polarised vertical-cavity surface-emitting lasers (VCSELs) using the spin-flip model to determine the regions of stability and instability. The dependence of the output polarisation ellipticity on that of the pump is investigated, and the results are presented in twodimensional contour maps of the pump polarisation against the magnitude of the optical pump. Rich dynamics and various forms of oscillatory behaviour causing self-sustained oscillations in the polarisation of the spin-VCSEL subject to continuouswave pumping have been found because of the competition of the spin-flip processes and birefringence. The authors also reveal the importance of considering both the birefringence rate and the linewidth enhancement factor when engineering a device for high-frequency applications. A very good agreement is found with the experimental results reported by the authors?? group.
IET Optoelectronics 04/2014; 8(2):117-121. · 0.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Generation of tunable millimeter-wave (MMW) and terahertz (THz) signals is experimentally demonstrated with an optically injected 1310-nm quantum dot distributed feedback (QD DFB) laser. A novel technique for MMW and THz signal generation is proposed, which is based on the dual-mode laser operation and the four-wave mixing induced in the QD DFB under single-beam optical injection into one of its residual Fabry-Perot modes. Coarse and fine tunability of the MMW and THz signals from 117 to 954 GHz is also demonstrated by injecting the external light into different residual modes of the QD laser and by controlling the injection strength and the initial frequency detuning.
[Show abstract][Hide abstract] ABSTRACT: New theoretical results are presented on polarized optical injection of vertical-cavity surface-emitting lasers (VCSELs) based on the spin-flip model extended to consider both the azimuth and ellipticity of the injected light. Experiments to investigate these effects are performed on two 1550-nm VCSELs with different frequency spacing between the resonances of the orthogonal polarizations of the fundamental transverse mode. Excellent agreement is found between experiment and theory for the stability and polarizations of the two VCSELs subject to polarized optical injection. The input polarization angle has a strong effect on both the dynamics and polarization of each VCSEL, whereas the ellipticity of the injected light affects only the polarization.
IEEE Journal of Selected Topics in Quantum Electronics 07/2013; 19(4):1700512-1700512. · 3.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Tunable microwave signal generation with frequencies ranging from below 1 GHz to over 40 GHz is demonstrated experimentally using the period-1 dynamics induced in a 1310-nm Quantum Dot Distributed-Feedback laser under external optical injection.
[Show abstract][Hide abstract] ABSTRACT: Tunable dual-mode lasing is experimentally demonstrated in a 1310-nm quantum dot (QD) distributed-feedback (DFB) laser under single-beam optical injection. The wavelength spacing between the two lasing modes is controlled by injecting the external optical signal into different residual Fabry-Perot modes of the QD DFB laser. The influence of important parameters, i.e., injection strength and bias current, is also analyzed. The simple experimental configuration used to achieve tunable dual-mode lasing and the theoretically superior properties of the QD laser offer exciting prospects for the use of these devices in microwave signal generation and radio-over-fiber applications for future mobile communication networks.
[Show abstract][Hide abstract] ABSTRACT: Tunable microwave signal generation with frequencies ranging from below 1 GHz to values over 40 GHz is demonstrated experimentally with a 1310nm Quantum Dot (QD) Distributed-Feedback (DFB) laser. Microwave signal generation is achieved using the period 1 dynamics induced in the QD DFB under optical injection. Continuous tuning in the positive detuning frequency range of the quantum dot's unique stability map is demonstrated. The simplicity of the experimental configuration offers promise for novel uses of these nanostructure lasers in Radio-over-Fiber (RoF) applications and future mobile networks.
[Show abstract][Hide abstract] ABSTRACT: Recently the first demonstration of room temperature optical spin-injection in a dilute nitride 1300 nm VCSEL under continuous-wave optical pumping was reported by our group . The experimental results showed that the VCSEL polarisation could be controlled by the polarisation of the 980 nm pump. The six rate equations of the spin-flip model (SFM) [2-4] were used to simulate this behaviour and very good agreement was demonstrated with experiment . In the present contribution the SFM is used to predict the more general dependence of spin-VCSEL output power and polarisation on the pump power and polarisation for 1300 nm dilute nitride structures.
13' SIOE, Semiconductor and Integrated Optoelectronics Conference; 04/2013
[Show abstract][Hide abstract] ABSTRACT: We present the first elastic, space division multiplexing, and multi-granular network based on two 7-core MCF links and four programmable optical nodes able to switch traffic utilising the space, frequency and time dimensions with over 6000-fold bandwidth granularity. Results show good end-to-end performance on all channels with power penalties between 0.75 dB and 3.7 dB.
[Show abstract][Hide abstract] ABSTRACT: We report a first experimental observation of two-wavelength switching
(2WS) and bistability with a 1310nm-Quantum Dot (QDot) Distributed
Feedback (DFB) laser subject to external optical injection and operated
in reflection. We experimentally demonstrate the switching of the
emission wavelength of the QDot laser when an external optical signal is
injected into one of the subsidiary longitudinally modes located in the
longer wavelength side of the device's lasing mode. Clockwise nonlinear
switching and bistability are attained in all cases for both the
emitting and the injected mode of the QDot laser as the injection
strength is increased. Moreover, very high on-off contrast ratio is
measured in the switching (and bistability) transition of the emission
mode of the device. We have also analysed the switching properties of
the 1310-QDot DFB laser as a function of the applied bias current and
the initial wavelength detuning between the wavelengths of the external
signal and that of the device's injected mode. In general, wider
bistable loops, higher on-off contrast ratio between output states and
higher input power requirements for switching are observed as the
applied bias and initial detuning are increased. This diversity of
switching behaviors obtained with a 1310 QDot DFB laser under external
optical injection, added to the theoretically superior properties of
nanostructure lasers, offers exciting prospects for novel uses of these
devices in all-optical logic and all-optical switching/routing
applications in present and future optical telecommunication networks.
[Show abstract][Hide abstract] ABSTRACT: Two-wavelength switching operation and bistability is reported for the first time with a 1310-nm quantum-dot (QD) distributed feedback (DFB) laser. We demonstrate experimentally the switching of the lasing mode of the QD laser under external optical injection into one of the residual Fabry-Perot (FP) modes of the device. Clockwise switching and bistability occurs for both the lasing and the injected subsidiary modes of the QD DFB laser as the injection strength is increased. Moreover, very high ON-OFF contrast ratio is measured for the switching transition of the lasing mode of the device. We have also analyzed experimentally the influence of two important system parameters, namely the initial wavelength detuning and the applied bias current. The variety of switching behaviors obtained with a 1310-nm QD DFB laser added to the theoretically superior properties of nanostructure lasers offers exciting prospects for novel uses of these devices in all-optical logic and all-optical switching/routing applications in present and future optical telecommunication networks.
IEEE Journal of Selected Topics in Quantum Electronics 02/2013; 19(4):1900708. · 3.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Generation of tunable millimeter-wave (MMW) and Terahertz (THz) signals from 117 GHz to 954 GHz is experimentally demonstrated with a 1310 nm Quantum Dot Distributed Feedback laser subject to single beam optical injection.
[Show abstract][Hide abstract] ABSTRACT: We show on-demand multi-wavelength spectrum and space defragmentation in an SDM and elastic network with four programmable nodes and two multi-core fiber links. The combined approach is shown to reduce blocking and hardware requirements in small nodes.
Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference (OFC/NFOEC), 2013; 01/2013
[Show abstract][Hide abstract] ABSTRACT: We review our experimental work on the generation of microwave (MW), millimeter-wave (MMW) and THz signals using a 1310-nm Quantum Dot (QD) Distributed-Feedback (DFB) laser. Continuous tunable MW signals with frequencies going from below 1 GHz to over 40 GHz are generated by means of the period-1 dynamics induced in the QD DFB laser when subject to external optical injection into the device's lasing mode. A new technique is also reported for the generation of MMW and THz signals with an optically-injected 1310nm-QD DFB laser. This technique is based on the dual-mode lasing and Four-Wave-Mixing arising in the QD laser under single-beam optical injection into one of its subsidiary Fabry-Perot (FP) modes. Tunability of the generated MMW and THz signals from 117 GHz to 954 GHz is also demonstrated. Coarse tunability is achieved by injecting the external light into different residual FP modes of the device, whilst fine tuneability is obtained by controlling the initial frequency detuning.
Transparent Optical Networks (ICTON), 2013 15th International Conference on; 01/2013
[Show abstract][Hide abstract] ABSTRACT: In this paper, we present detailed measurements of the temperature-dependent relaxation oscillation frequency and polarization resolved linewidth enhancement factor (α) of a 1550-nm vertical cavity surface emitting laser (VCSEL). The thermal effects on these parameters are investigated for a temperature range of -20°C to 60°C. Comparison is made between the experimental observations and theoretical predictions for similar VCSELs and with those different in operating wavelength and/or materials.
[Show abstract][Hide abstract] ABSTRACT: We report on the experimental observation of optical bistability (OB) and nonlinear switching (NS) in a nanostructure laser; specifically a 1550 nm quantum dash Fabry-Perot laser subject to external optical injection and operated in reflection. Different shapes of optical bistability and nonlinear switching, anticlockwise and clockwise, with very high on-off contrast ratio (up to 180:1) between output states were experimentally measured. These results added to the potential of nanostructure lasers for enhanced performance offer promise for use in fast all-optical signal processing applications in optical networks.