Browsing by Author "Slight, Thomas James"
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- Chaotic dynamics in resonant tunneling optoelectronic voltage controlled oscillatorsPublication . Romeira, Bruno; Figueiredo, J. M. L.; Ironside, C. N.; Slight, Thomas JamesA new way of generating electrical and optical chaotic carriers is demonstrated using an optoelectronic voltage controlled oscillator consisting of a laser diode (LD) driven by a resonant tunneling diode (RTD) perturbed by radio-frequency signals. The high-dimensional broadband (gigahertz-wide) chaotic current produced by the RTD modulates a LD, providing a simple way to convert electrical chaotic signals into optical subcarriers that can be transmitted by conventional optical channels. Since the chaotic current and the chaotic optical subcarriers are controlled accurately and reproducibly by the RTD, we anticipate this concept can be used as the core of a compact, simple, and low-power consumption optical chaos generator for optical communications.
- A liénard oscillator resonant tunnelling diode-laser diode hybrid integrated circuit: model and experimentPublication . Slight, Thomas James; Romeira, Bruno; Wang, Liquan; Figueiredo, J. M. L.; Wasige, Edward; Ironside, C. N.We report on a hybrid optoelectronic integrated circuit based on a resonant tunnelling diode driving an optical communications laser diode. This circuit can act as a voltage controlled oscillator with optical and electrical outputs. We show that the oscillator operation can be described by Liénard’s equation, a second order nonlinear differential equation, which is a generalization of the Van der Pol equation. This treatment gives considerable insight into the potential of a monolithic version of the circuit for optical communication functions including clock recovery and chaotic source applications.
- Nonlinear dynamics of resonant tunneling optoelectronic circuits for wireless/optical interfacesPublication . Romeira, Bruno; Figueiredo, J. M. L.; Slight, Thomas James; Wang, Liquan; Wasige, Edward; Ironside, C. N.; Kelly, Anthony E.; Green, RichardWe report on experimental and modeling results on the nonlinear dynamics of a resonant-tunneling-diode-based(RTD) optoelectronic circuits that can be used as the basis of a wireless/optical interface for wireless access networks. The RTD-based circuits are optoelectronic integrated circuits that have negative differential resistance and act as optoelectronic voltage-controlled oscillators. These circuits display many of the features of classic nonlinear dynamics, including chaos and synchronization. These highly nonlinear oscillators behaves as injection-locked oscillators that can be synchronized by a small injection signal of either wireless or optical origin, and thus, can transfer phase encoded information from wireless to the optical domain or the optical to the wireless domain.
- Optical control of a resonant tunneling diode microwave-photonic oscillatorPublication . Romeira, Bruno; Figueiredo, J. M. L.; Ironside, C. N.; Kelly, Anthony E.; Slight, Thomas JamesWe report on optical injection-locking of a microwave-photonic oscillator based on the integration of a resonant tunneling diode optical waveguide photodetector with a communication laser diode. The oscillator locking was achieved with in-fiber optical powers as low as 0.2 mW, and locking ranges up to 23.8 MHz for in-fiber optical power of few milliwatts and with phase-noise suppression below 110 dBc/Hz at 10-kHz frequency offset from the center frequency. The circuit’s dynamics are well described as an optically controlled Liénard oscillator.
- Self-oscillation and period adding from resonant tunnelling diode–laser diode circuitPublication . Figueiredo, J. M. L.; Romeira, Bruno; Slight, Thomas James; Wang, Liquan; Wasige, Edward; Ironside, C. N.A hybrid optoelectronic integrated circuit comprising a laser diode driven by a resonant tunnelling diode can output various optical and electrical signal patterns that include self-sustained oscillations, subharmonic and harmonic locking and unlocked signals, with potential applications in optical communication systems.
- Synchronisation and chaos in a laser diode driven by a resonant tunnelling diodePublication . Romeira, Bruno; Figueiredo, J. M. L.; Slight, Thomas James; Wang, Liquan; Wasige, Edward; Ironside, C. N.; Quintana, J. M.; Avedillo, M. J.The authors report on a hybrid integration of a resonant tunnelling diode laser diode driver configuration that can operate as a self-oscillating circuit, and when externally perturbed shows regions of frequency division and frequency multiplication, quasi-periodic and chaotic oscillations, both in the optical and electrical outputs. The authors also demonstrate that this optoelectronic circuit is well described as a Lie´nard’s oscillator. The synchronisation capabilities of the circuit have potentially novel functions for optical communications systems including clock recovery, clock division and data encryption.