Nonlinear modeling of waveguide photodetectors.

A new method of simulating photodiode nonlinearities is proposed. This model includes the effects of non-uniform absorption in three dimensions, self-heating, and is compatible with circuit components defined in the frequency domain, such as transmission lines. The saturated output power and third order output intercept points of two different waveguide photodiodes are simulated, with excellent agreement between measurement and theory.

Measurement of intermodulation distortion in high-linearity photodiodes.

Accurately characterizing third order intermodulation distortion (IMD3) in high-linearity photodiodes is challenging. Two measurement techniques are evaluated-a standard two-tone measurement and a more complicated three-tone measurement technique to measure IMD3. A model of the measurement system is developed and used to analyze the limitations of the two techniques in determining the distortion of highly linear photodiodes.

Dynamic range enhancement of a novel phase-locked coherent optical phase demodulator.

We report on a novel cancellation technique, for reducing the nonlinearity associated with the tracking phase-modulator in recently proposed phase-locked coherent demodulator for phase modulated analog optical links. The proposed cancellation technique is input RF signal power and frequency independent leading to a significant increase in dynamic range of the coherent demodulator. Furthermore, this technique demonstrates that large values of the signal-to-intermodulation ratio of the demodulated signal can be obtained even though the tracking phase modulator is fairly nonlinear, and thereby relaxing the linearity requirements for the tracking phase modulator.

Corneal pharmacokinetics of topically applied azithromycin and clarithromycin.

Purpose: To determine corneal levels of topically administered azithromycin and clarithromycin in a rabbit model.

Design: Experimental animal study.

Methods: Corneas of New Zealand albino rabbits were treated with topical azithromycin (2 mg/ml or 4 mg/ml) or clarithromycin (10 mg/ml).

Endophthalmitis caused by Acinetobacter calcoaceticus. A profile.

Purpose: To report the clinical and microbiological profile of endophthalmitis caused by Acinetobacter calcoaceticus.

Methods: A retrospective study of case series of Acinetobacter calcoaceticus endophthalmitis. Outcome measures included ability to sterilise the eye, anatomical result (clear media and attached retina) and visual recovery (visual acuity > 6/60).