Resonant Tunnelling Optoelectronic Circuits

Nowadays, most communication networks such as local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs) have replaced or are about to replace coaxial cable or twisted copper wire with fiber optical cables. Light-wave communication systems comprise a transmitter based on a visible or near-infrared light source, whose carrier is modulated by the information signal to be transmitted, a transmission media such as an optical fiber, eventually utilizing in-line optical amplification, and a receiver based on a photo-detector that recovers the information signal (Liu, 1996)(Einarsson, 1996). The transmitter consists of a driver circuit along a semiconductor laser or a light emitting diode (LED). The receiver is a signal processing circuit coupled to a photo-detector such as a photodiode, an avalanche photodiode (APD), a phototransistor or a high speed photoconductor that processes the photo-detected signal and recovers the primitive information signa

Advanced Photonics Congress

Abstract: We investigated the passivation of III-V semiconductor nanostructures using wet-chemical ammonium sulfide treatment and SiO x encapsulation. We achieved an ultra-low surface recombination velocity value of ~530 cm/s enabling the future development of high-performance room-temperature nanolasers

Purcell effect in the stimulated and spontaneous emission rates of nanoscale semiconductor lasers

\u3cp\u3eNanoscale semiconductor lasers have been developed recently using either metal, metallo-dielectric, or photonic crystal nanocavities. While the technology of nanolasers is steadily being deployed, their expected performance for on-chip optical interconnects is still largely unknown due to a limited understanding of some of their key features. Specifically, as the cavity size is reduced with respect to the emission wavelength, the stimulated and the spontaneous emission rates are modified, which is known as the Purcell effect in the context of cavity quantum electrodynamics. This effect is expected to have a major impact in the 'threshold-less' behavior of nanolasers and in their modulation speed; but its role is poorly understood in practical laser structures, characterized by significant homogeneous and inhomogeneous broadening and by a complex spatial distribution of the active material and cavity field. In this paper, we investigate the role of the Purcell effect in the stimulated and spontaneous emission rates of semiconductor lasers taking into account the carriers' spatial distribution in the volume of the active region over a wide range of cavity dimensions and emitter/cavity linewidths, enabling the detailed modeling of the static and dynamic characteristics of either micro-or nano-scale lasers using single-mode rate-equations analysis. The ultimate limits of scaling down these nanoscale light sources in terms of Purcell enhancement and modulation speed are also discussed showing that the ultrafast modulation properties predicted in nanolasers are a direct consequence of the enhancement of the stimulated emission rate via reduction of the mode volume.\u3c/p\u3

Métodos e sistemas para osciladores opto-electrónicos = Methods and systems for optoelectronic oscillators

NOVELTY - The method includes a system, which comprises oscillator resonant tunneling diodes with photoconductive region, diode laser, optical modulator structure, optical wave guide and electrical input port. The electrical input port accepts electrical control signal through electrical output port. The oscillator resonant tunneling diodes output electrical signals, where and optical signals are oscillated at a frequency related to electrical or optical control signals. USE - Methods for optoelectronic oscillators

Interfaces and method for wireless-optical and optical-wireless conversion

A wireless-optical interface device for converting a received wireless signal to a corresponding optical signal for transferring digital information from the wireless domain to the optical domain. The interface device includes an oscillator (e.g. a negative differential resistance oscillator such as a resonant tunnelling diode) capable of synchronisation with the wireless signal, and an optical output device (e.g. semiconductor laser) controllable by an output of the oscillator to provide the corresponding optical signal. The oscillator and the optical output device may be integrated on the same semiconductor chip. Also disclosed is a corresponding wireless-optical interface device for converting a received optical signal to a corresponding wireless signal for transferring digital information from the optical domain to the wireless domain

Optoelectronic oscillators for communication systems

We introduce and report recent developments on a novel five port optoelectronic voltage controlled oscillator consisting of a resonant tunneling diode (RTD) optical-waveguide integrated with a laser diode. The RTD-based optoelectronic oscillator (OEO) has both optical and electrical input and output ports, with the fifth port allowing voltage control. The RTD-OEO locks to reference radio-frequency (RF) sources by either optical or electrical injection locking techniques allowing remote synchronization, eliminating the need of impedance matching between traditional RF oscillators. RTD-OEO functions include generation, amplification and distribution of RF carriers, clock recovery, carrier recovery, modulation and demodulation and frequency synthesis. Self-injection locking operation modes, where small portions of the output electrical/optical signals are fed back into the electrical/optical input ports, are also proposed. The self-phase locked loop configuration can give rise to low-noise high-stable oscillations, not limited by the RF source performance and with no need of external optoelectronic conversion

Direct modulation and down scaling of light sources in generic foundry COBRA

We present an experimental study into the use of simple Fabry Perot lasers for integration in generic platforms. Such integrated FP lasers offer the advantage of freedom of placement anywhere on the chip and, easy integration with monitoring and control functions. They can play a role in short range data communications and they have a potential for 10 Gb/s direct modulation speed. We report first results on experimental realization of such lasers including eye diagrams and BER testing results

Broadband chaotic signals and breather oscillations in an optoelectronic oscillator incorporating a microwave photonic filter

We propose a technique to generate broadband chaotic and breather signals employing an optoelectronic oscillator (OEO) comprising a phase modulator (PM) and a linearly chirped fiber Bragg grating (LCFBG). The joint operation of the PM and the LCFBG forms a broadband microwave photonic filter (MPF), which allows the OEO to generate chaotic signals and breathers taking advantage of the interplay between the broadband MPF and the time-delayed feedback loop provided by a long optical fiber delay line. The breather excitations are characterized by nanosecond chaotic oscillations breathing periodically at a significantly lower time-scale determined by the OEO large delay time. A theoretical analysis based on a modified Ikeda time-delayed model to include the effect of the broadband filtering process is provided. The analysis is verified by an experiment. The proposed LCFBG-based OEO and the possibility to control in the optical domain its broadband bandpass characteristics considering the flexibility, accuracy, and precision in FBG fabrication can find applications in chaos-based communications and in fast optical processing systems, such as random number generation, or optical processing in reservoir computing taking advantage of the intrinsic multiple time scales of the LCFBG-based OEO

Ultra-low surface recombination for deeply etched III-V semiconductor nano-cavity lasers

We investigated the passivation of III-V nanostructures using ammonium sulfide and SiOx encapsulation. We achieved ultra-low surface recombination velocity of 530 cm/s enabling the future development of high-performance room-temperature nanolasers