Observation of phase noise reduction in photonically synthesized sub-THz signals using a passively mode-locked laser diode and highly selective optical filtering
by Guillermo Carpintero del Barrio
Criado, A R; Acedo, P; Carpintero, G; de Dios, C; Yvind, K ◦Optics Express, Vol. 20 Issue 2, pp.1253-1260 (2012)
A Continuous Wave (CW) sub-THz photonic synthesis setup based on a single Passively Mode-Locked Laser Diode (PMLLD)... more A Continuous Wave (CW) sub-THz photonic synthesis setup based on a single Passively Mode-Locked Laser Diode (PMLLD) acting as a monolithic Optical Frequency Comb Generator (OFCG) and highly selective optical filtering has been implemented to evaluate the phase noise performance of the generated sub-THz signals. The analysis of the synthesized sub-THz signals up to 120 GHz gives as a result an effective reduction of the electrical linewidth when compared to direct harmonic generation that begins at 50 GHz and becomes greater as the frequency increases. The phase noise reduction offered by the setup, along with its integration potential, cost and bandwidth, make it a promising candidate to the development of an integrated and high performance low phase noise local oscillator in the sub-THz range.
146-GHz millimeter-wave radio-over-fiber photonic wireless transmission system
by Guillermo Carpintero del Barrio
Fice, M J; Rouvalis, E; van Dijk, F; Accard, A; Lelarge, F; Renaud, C C; Carpintero, G; Seeds, A J. Optics Express, Vol. 20, Issue 2, pp. 1769-1774 (2012)
We report the experimental implementation of a wireless transmission system with a 146-GHz carrier frequency which is... more
We report the experimental implementation of a wireless transmission system with a 146-GHz carrier frequency which is generated by optical heterodyning the two modes from a monolithically integrated quantum dash dual-DFB source. The monolithic structure of the device and the inherent low noise characteristics of quantum dash gain material allow us to demonstrate the transmission of a 1 Gbps ON-OFF keyed data signal with the two wavelengths in a free-running state at 146-GHz carrier wave frequency. The tuning range of the device fully covers the W-band (75 – 110 GHz) and the F-band (90 – 140 GHz).
Enhanced Photocurrent Efficiency of a Carbon Nanotube p-n Junction Electromagnetically Coupled to a Photonic Structure
by Bryan Wong
Journal of Physics D: Applied Physics, 42, 055111 (2009)
8 views
Seen by:
Download (.pdf) Coupled-resonator optical waveguide based on layered media
In this work, we propose a coupled-resonator waveguide, using an array of layered microrings instead of a photonic... more In this work, we propose a coupled-resonator waveguide, using an array of layered microrings instead of a photonic crystal. The structure itself will work as a 1D photonic crystal along the axis of the system.
Photorefractive grating in multiple quantum well planar waveguide
E. Weinert-Rączka, M.Wichtowski, A. Ziółkowski and G. Staroń, Acta Physica Polonica A 103, 229 (2003).
A photo ref r act ive grati ng in a slab wa veguide based on a semi-insulating AlGaAs/GaAs multiple quantum well... more A photo ref r act ive grati ng in a slab wa veguide based on a semi-insulating AlGaAs/GaAs multiple quantum well structure with an electric field applied along the quantum well planes as an opticall y controlled , frequency selective mode coupling element with memory is analysed .
Spatial solitons in biased photorefractive media with quadratic electro-optic effect
A. Ziółkowski, E. Weinert-Rączka, Opto-Electron. Rev. 13, 135, (2005)
Propagation of optical beams and properties of one-dimensional (1D) spatial solitons in biased photorefractive media... more Propagation of optical beams and properties of one-dimensional (1D) spatial solitons in biased photorefractive media with quadratic electro-optic effect are analysed. An exact analytic solution of the corresponding propagation problem is presented as well as a numerical investigation of the evolution of optical beams.
Photorefractive multiple quantum wells planar waveguide
E. Weinert-Rączka, J. Gajda, M. Wichtowski, A. Ziółkowski, PAK 53, 34, (2007).
New type of planar optical waveguide with a guiding layer consisting of photorefractive multiple quantum well... more New type of planar optical waveguide with a guiding layer consisting of photorefractive multiple quantum well structure is investigated. Results of optical and electro-optical measurements and possible applications for all-optical switching of guided signals are presented
Temporal analysis of solitons in photorefractive semiconductors
Andrzej Ziółkowski, Journal of Optics, 14, 035202, (2012)
Temporal analysis of both the photorefractive mechanism and soliton propagation in a slab semiconductor waveguide is... more
Temporal analysis of both the photorefractive mechanism and soliton propagation in a slab semiconductor waveguide is presented. As an example, a structure based on GaAs/AlGaAs
MQWs was investigated. Both a numerical and simple analytical approach based on the bipolar band-transport model is used to derive a temporal photorefractive response on localized illumination. The corresponding propagation problem describing the evolution of screening soliton profiles in media with quadratic electro-optic effect was also discussed.
Understanding the rich physics of light propagation in slow photonic crystal waveguides
Proc. SPIE 7612, 76120L (2010)
We study propagation losses in slow light photonic crystal waveguides and show that dispersion engineering can reduce... more We study propagation losses in slow light photonic crystal waveguides and show that dispersion engineering can reduce the loss. We develop an improved understanding of why and how this occurs and develop an new approach to modeling these devices that provides new design insights.
Experimental investigations of the scanning functions of galvanometer-based scanners with applications in OCT
Duma V. F.*, Lee K.-S., Meemon P., Rolland J. P., Experimental investigations of the scanning functions of galvanometer-based scanners with applications in OCT , Applied Optics 50(29), 5735-5749 (2011)
- also selected in Virtual Journal for Biomedical Optics 6(11), ISSN 1931-1532, 2011
We analyse three most common profiles of scanning functions for galvanometer-based scanners (GS), the sawtooth,... more We analyse three most common profiles of scanning functions for galvanometer-based scanners (GS), the sawtooth, triangular and sinusoidal functions. They are determined experimentally with regard to the scan parameters of the input signal (i.e. frequency and amplitude). We study the differences of the output function of the GS measured as the positional error of the oscillatory mirror from the ideal function given by the input signal of the device. The limits in achieving the different types of scanning functions in terms of duty cycle and linearity are determined experimentally for the possible range of scan parameters. Of particular importance are the preservation of an imposed duty cycle and profile for the sawtooth function, the quantification of the linearity for the sinusoidal function, and the effective duty cycle for the triangular, as well as for the other functions. The range of scan amplitudes for which the stability of the oscillatory regime of the galvo mirror is stable for different frequencies is also highlighted. While the use of the device in certain scanning regimes is studied, certain rules of thumb are deduced to make the best out of the galvoscanner. Finally, the three types of scanning functions are tested with a Fourier Domain Optical Coherence Tomography (FD OCT) setup and the conclusions of the study are demonstrated in an imaging application by correlating the determined limits of the scanning regimes with the requirements of OCT.