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Quantum Dots (QD) provide unique opportunities to extend all the basic properties of heterostructure lasers and move further their applications. Practical fabrication of QD lasers became possible when techniques for self-organized growth allowed fabrication of dense and uniform arrays of narrow-gap nanodomains, coherently inserted in a semiconductor crystal matrix. Using of InAs QD lasers enabled significant improvement of device performance and extension of the spectral range on GaAs substrates to mainstream telecom wavelengths. Continuous wave 1.3 μm room-temperature output power of ~300 mW single mode for edge-emitters and of 1.2 mW multimode for vertical-cavity surface-emitting lasers are realized. Long operation lifetimes are manifested. The breakthrough become possible both due to development of self-organized growth and defect-reduction techniques in QD technology.

Inter symbol interference (ISI) caused by dispersion in optical fibers is the major limiting factor on the achievable data rate or transmission distance in high-speed fiber-optic interconnects¹. Compared with optical-domain and other electrical-domain dispersion compensation methods, duobinary coding technology is used due to its higher spectral efficiency. In this paper, a monolithically integrated duobinary optical transmitter has be designed and fabricated in standard 0.18 μm CMOS technology. This transmitter consists of a duobinary encoder and a VCSEL driver. The master-slave D flip-flop structure is used to generate the wideband one bit delay which is important for the realization of duobinary signal. An open drain structure is used in VCSEL driver design to provide the higher current output in low supply voltage condition. This duobinary transmitter can operate up to 5 Gb/s with 20 mA current output. The current consumption is only 50 mA under 1.8 V supply voltage.

The low and medium frequency - 1 Hz ≤ f ≤ 100 kHz - amplitude noise characteristics of 840 nm proton-implanted VCSELs (Vertical Cavity Surface Emitting Lasers) have been investigated. Experiments clearly show that the DBR (Distributed Bragg Reflector) structure represents the main electrical noise source of VCSELs. Furthermore, the electrical noise is somehow linked to the optical noise when the laser shows a "disturbed" optical spectrum with competition between very close modes.

The beneficial role fluctuations can play in the process of phase synchronization is analyzed in terms of a model with binary input and output signals. Special attention is paid to the relation between noise-induced phase synchronization and the well-known phenomenon of stochastic resonance. Analytic predictions are compared with experimental data from a vertical cavity surface emitting laser. Various measures for aperiodic stochastic resonance, frequency entrainment and stochastic phase synchronization reveal a satisfactory agreement between theory and experiment.

The frequency noise of a laser has a direct influence on the lineshape and the linewidth. We present here the frequency-noise spectrum we obtained with selectively-oxidized Vertical-Cavity Surface-Emitting Lasers (VCSELs) emitting in the range of 850nm. We noticed different parts in the spectrum: a 1/fⁿ part in the low-frequency range, independent of the output power, and a white-noise part in the high-frequency range, inversely dependent of the output power. The link with the laser lineshape is theoretically performed.

A numerical approach based on dynamic importance sampling (DIMS) is applied to investigate polarization switches in vertical-cavity surface-emitting lasers. A polarization switch is described as an activation process in a two-dimensional nonequilibrium system. DIMS accelerates the simulations and allows access to noise intensities that were previously forbidden, revealing qualitative changes in the shape of the transition paths with noise intensity.

ZnSSe/ZnMgSSe MQW structures were grown by molecular beam epitaxy on GaAs substrates. The band gap of ZnMgSSe barriers was approximately 3 eV at room temperature. Cathodoluminescence, X-ray diffraction, optical, scanning electron beam, and atomic force microscopy were all used for structure characterization. Decay of the ZnMgSSe solid solution in at least two phases was observed. Improvement in the quality of the crystal lattice and surface morphology was achieved by mismatching the ZnMgSSe from the GaAs substrate by increasing the lattice period by 0.24%.

We are developing a robust, compact, and affordable photonic proximity sensor for munition fuze applications. Successful implementation of this sensor will provide a new capability for direct fire applications. The photonic component development exploits pioneering work and unique expertise at ARDEC, ARL, and Sandia National Laboratories by combining key optoelectronic technologies to design and demonstrate components for this fuzing application [Ruff, et al. 1994; Stann, et al. 1996; Simonis, et al. 2000; Liu, et al. 2000]. The technologies employed in the optical fuze design are vertical cavity surface-emitting lasers (VCSELs), the p-i-n or metal-semiconductor-metal (MSM) photodetectors, and miniature lenses optics. This work will culminate in a robust, fully integrated, g-hardened component design suitable for proximity fuzing applications. This compact sensor will replace costly assemblies that are based on discrete lasers, photodetectors, and bulk optics. It will be mass manufacturable and impart huge savings for such applications. The specific application under investigation is for gun-fired munitions. Nevertheless, numerous civilian uses exist for this proximity sensor in automotive, robotics and aerospace applications. This technology is also applicable to robotic ladar and short-range 3-D imaging.

Inter symbol interference (ISI) caused by dispersion in optical fibers is the major limiting factor on the achievable data rate or transmission distance in high-speed fiber-optic interconnects¹. Compared with optical-domain and other electrical-domain dispersion compensation methods, duobinary coding technology is used due to its higher spectral efficiency. In this paper, a monolithically integrated duobinary optical transmitter has be designed and fabricated in standard 0.18 μm CMOS technology. This transmitter consists of a duobinary encoder and a VCSEL driver. The master-slave D flip-flop structure is used to generate the wideband one bit delay which is important for the realization of duobinary signal. An open drain structure is used in VCSEL driver design to provide the higher current output in low supply voltage condition. This duobinary transmitter can operate up to 5 Gb/s with 20 mA current output. The current consumption is only 50 mA under 1.8 V supply voltage.

Quantum Dots (QD) provide unique opportunities to extend all the basic properties of heterostructure lasers and move further their applications. Practical fabrication of QD lasers became possible when techniques for self-organized growth allowed fabrication of dense and uniform arrays of narrow-gap nanodomains, coherently inserted in a semiconductor crystal matrix. Using of InAs QD lasers enabled significant improvement of device performance and extension of the spectral range on GaAs substrates to mainstream telecom wavelengths. Continuous wave 1.3 µm room-temperature output power of ∼300 mW single mode for edge-emitters and of 1.2 mW multimode for vertical-cavity surface-emitting lasers are realized. Long operation lifetimes are manifested. The breaktrough became possible both due to development of self-organized growth and defect-reduction techniques in QD Technology.