J. H. Marsh

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Optical self seeding feedback techniques can be used to improve the noise characteristics of passively mode-locked laser diodes. External cavities such as fiber optic cables can increase the memory of the phase and subsequently improve the timing jitter. In this work, an improved optical feedback architecture is proposed using an optical fiber loop delay as(More)
Children with laryngotracheal stenosis undergo laryngotracheal reconstruction (LTR) to permit tracheostomy decannulation. We conducted voice assessments of 8 pediatric LTR patients with voice problems. Perceptual ratings and acoustic measures were taken in 5 patients and videolaryngoscopy/laryngostroboscopy was conducted in all 8. Results of perceptual(More)
Photonic networking technologies have the potential to revolutionise future military aircraft data communications, delivering substantial improvements in networking performance, reliability, cost and security. More particularly, wavelength division multiplexing (WDM) can provide a huge bandwidth-to-weight ratio as well as enhanced routing flexibility,(More)
We report the observation of second-harmonic generation by type I quasi phase matching in a GaAs-AlAs superlattice waveguide. Quasi phase matching was achieved through modulation of the nonlinear coefficient chi((2))(zxy), which we realized by periodically tuning the superlattice bandgap. Second-harmonic generation was demonstrated for fundamental(More)
Multi-wavelength semiconductor laser arrays (MLAs) have wide applications in wavelength multiplexing division (WDM) networks. In spite of their tremendous potential, adoption of the MLA has been hampered by a number of issues, particularly wavelength precision and fabrication cost. In this paper, we report high channel count MLAs in which the wavelengths of(More)
The monolithic integration of four 1.5 μm range AlGaInAs/InP distributed feedback lasers with a 4×1 multimode-interference optical combiner, a curved semiconductor optical amplifier, and an electro-absorption modulator using relatively simple technologies--sidewall grating and quantum well intermixing--has been demonstrated. The four channels span the(More)
We present a 10 GHz 1.55 μm all-active passively mode-locked laser based on a novel AlGaInAs/InP epitaxial structure with a three-quantum-well active layer and a passive far-field reduction layer. The device generated 1.06 ps pulses with a state-of-the-art timing jitter value of 194 fs (4-80 MHz), and a radio-frequency linewidth of 2 kHz, while(More)
This is a retrospective cohort study of adults with a primary diagnosis of deep venous thrombosis (DVT) unaccompanied by pulmonary embolism (PE), seen in 4 emergency departments in 2013 and part of 2014. The purpose was to assess the prevalence of home treatment of DVT in the present era of new oral anticoagulants. Among 96 patients with DVT and no PE, 85(More)
We present a laterally coupled 1.55 μm AlGaInAs/InP distributed feedback laser monolithically integrated with a curved tapered optical amplifier, providing an output power of 210 mW with single transverse and longitudinal mode operation exhibiting a record low linewidth of 64 kHz.
We report a monolithic photonic integrated circuit (PIC) for THz communication applications. The PIC generates up to 4 optical frequency lines which can be mixed in a separate device to generate THz radiation, and each of the optical lines can be modulated individually to encode data. Physically, the PIC comprises an array of wavelength tunable distributed(More)