Robert Lennox

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We present an experimental investigation of a multicontact semiconductor optical amplifier. This first-generation device allows for direct control of the carrier density profile along the length of the waveguide. This is used to control the device noise figure, with a minimum value of 5 dB observed at a gain of 15 dB for an optimum carrier density profile.(More)
The consequences of tailoring the longitudinal carrier density along the active layer of a multi-contact bulk semiconductor optical amplifier (SOA) are investigated using a rate equation model. It is shown that both the noise figure and output power saturation can be optimized for a fixed total injected bias current. The simulation results are validated by(More)
This study was conducted to determine the physiological and growth responses of cotton (Gossypium hirsutum L.) to the interaction of ozonee (O3) and drought stress. Cotton (cv SJ-2) was grown in open-top chambers in the field at three levels of soil water and exposed to charcoal-filtered air (CF), nonfiltered air (NF), and NF x 1.25, and NF x 1.5 ambient O3(More)
An experimental characterisation of a multi-contact semiconductor optical amplifier using ultrashort optical pulses is presented. The SOA in question allows the injection of bias current through multiple independent electrical contacts, allowing the direct control of the carrier density. Picosecond-scale optical pulses are transmitted through the SOA. The(More)
The use of semiconductor optical amplifiers (SOA) in optical communications networks has so far been limited due to their inherent large noise figure (NF) compared to Erbium Doped Fibre Amplifiers. Therefore improvement of the noise performance of SOAs is critical to their widespread adoption in future networks. We propose to reduce the NF of the SOA by(More)
A bulk semiconductor optical amplifier (SOA) utilizing a multi-contact biasing method is characterized as a function of the bias current supplied to each section Firstly, amplified spontaneous emission spectra and characteristic light-current profiles are analyzed. Single-pass gain and noise figure of the SOA are then assessed by injecting a continuous wave(More)
Compact monolithic single-mode red emitting diode lasers are still not readily available for many wavelengths in the visible spectrum. Strontium lattice and Calcium clocks are some of the most widely investigated optical clocks worldwide and the pertinent transitions wavelengths required are in the red and blue wavelength spectral region. The current state(More)
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