Daniel D. Lofgreen

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Introduction: Optics is a viable solution to address the limitations of copper-based electronics in short-distance interconnects [1]. In these compact systems, devices must meet the stringent requirements imposed by the power budget and the thermal restriction. Recently, VCSELs have received considerable interest for board and chip level interconnects owing(More)
Vertical cavity surface emitting lasers ~VCSELs! emitting in the 1.55 mm wavelength region are attractive sources for optical networks. Advantages of VCSELs include low power consumption, efficient fiber coupling, and high volume, low cost manufacturing. Transmission at 1.55 mm allows for long distance transmission over optical fiber with low attenuation(More)
Short-cavity InGaAs/GaAs/AlGaAs lasers with first order DBRs and integrated EAMs were fabricated using a quantum well intermixing process. >5mW output was achieved at 45mA. DC extinction was >15dB at -1.5V with efficiencies up to 20dB/V. 2005 Optical Society of America OCIS codes: (140.5960) Semiconductor lasers; (250.5300) Photonic Integrated Circuits
We report on the optical design of thin selectively etched InAlGaAs tunnel-junction apertures for the realization of optically efficient long-wavelength vertical-cavity surface-emitting lasers (VCSELs). These apertures were designed to introduce minimal optical loss to the structure, facilitate single-mode operation, and yield optical mode diameters that(More)
We present five-stage bipolar-cascade vertical-cavity surface-emitting lasers emitting at 1.54 mm grown monolithically on an InP substrate by molecular beam epitaxy. A differential quantum efficiency of 120%, was measured with a threshold current density of 767 A/cm2 and voltage of 4.49 V, only 0.5 V larger than 530.8 V, the aggregate photon energy.(More)
We demonstrate a monolithically integrated particle sensor based on evanescent field scattering, well suited for use with affinity assays for pathogen recognition. Single micron sized particles may be detected, representative of spores and small bacteria. ©2004 Optical Society of America OCIS codes: (250.5300) Photonic integrated circuits; (140.5960)(More)
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