IEEE Journal of Quantum Electronics

A two modes rate equation model for vertical-cavity surface-emitting lasers (VCSELs) subject to optical feedback from an extremely short external cavity (ESEC) is presented. By making use of it we develop a map of bistability to investigate the parametric dependence of polarization properties of VCSELs in such configuration, finding out a periodic dependence of the polarization switching (PS) curr... View full abstract»

The effect of isotropic optical feedback from an extremely short external cavity on the emission properties of vertical-cavity surface-emitting lasers (VCSELs) is experimentally investigated. When changing the external cavity length a modulation of the total power and the wavelength emitted by the VCSEL is observed with a period of half the wavelength of operation of the device. When biasing the V... View full abstract»

As wavelength converters based on four-wave mixing (FWM) in semiconductor optical amplifiers (SOAs) attract more attention, dynamic effects and wavelength dependent performance become key aspects to be investigated. Such issues are particularly important, as complex configurations are likely to be used to overcome challenges like tunability and polarization dependence. In this paper a numerical mo... View full abstract»

The electroluminescence of a Type II InAs-GaSb superlattice heterodiode has been studied as a function of injection current and temperature in the spectral range between 3 and 13 μm. The heterodiode comprises a Be-doped midwavelength infrared (MWIR) superlattice with an effective bandgap around 270 meV and an undoped long wavelength infrared (LWIR) superlattice with an effective bandgap of 115 ... View full abstract»

The evanescent coupling from a photonic crystal resonator to a micron-thick optical fiber is investigated in detail by using a three-dimensional finite-difference time-domain (3D-FDTD) method. Properly designed photonic crystal cavity and taper structures are proposed, and optimal operating conditions are found to enhance the coupling strength while suppressing other cavity losses including the co... View full abstract»

A rigorous model is developed for determining single-photon quantum efficiency (SPQE) of single-photon avalanche photodiodes (SPADs) with simple or heterojunction multiplication regions. The analysis assumes nanosecond gated-mode operation of the SPADs and that band-to-band tunneling of carriers is the dominant source of dark current in the multiplication region. The model is then utilized to opti... View full abstract»

The mode frequency and the quality factor of nanowire cavities are calculated from the intensity spectrum obtained by the finite-difference time-domain (FDTD) technique and the Pade´ approximation. In a free-standing nanowire cavity with dielectric constant ε=6.0 and a length of 5 μm, quality factors of 130, 159, and 151 are obtained for the HE11 modes with a wavelength ar... View full abstract»

We present a procedure for the characterization of packaged Er-Yb-codoped phosphate glass waveguides. The procedure is based on precise measurements of the output optical powers when the waveguide is diode-laser pumped at 980 nm. The dependence of these optical powers on the input pump power is then fitted to the results from a numerical model that describes in detail the propagation of the optica... View full abstract»

We present a comprehensive theoretical study of pulsed stimulated Raman scattering in silicon wires. The pulse dynamics is described by a system of coupled equations, which describes intrinsic waveguide optical losses, phase shift and losses due to free-carriers (FCs) generated through two-photon absorption (TPA), first- and second-order frequency dispersion, self-phase and cross-phase modulation,... View full abstract»

We present the design and demonstration of unitraveling carrier (UTC) photodiodes fabricated using a novel quantum-well (QW) intermixing and metal-organic chemical vapor deposition (MOCVD) regrowth fabrication platform. The photodiodes discussed here were realized on the same chip as high gain centered QW active regions, intermixed passive centered well waveguides, and low optical confinement offs... View full abstract»

A 1534-nm fiber laser pumped Er:YAG laser action at room temperature has been demonstrated with high efficiency at two emission wavelengths: 1645 and 1617 nm. Multiwatt continuous-wave power was demonstrated at both wavelengths and active electrooptic Q-switch operation with >90% Q-switch efficiency was achieved at 1645 nm. Etalon tuned wavelength selection showed excellent agreement with theoreti... View full abstract»

The use of the high-power Tm3+-doped silica fiber laser as a pump source for Ho3+-doped silica and Ho3+-doped fluoride fiber lasers for the generation of 2.1-μm radiation is demonstrated. The Ho3+-doped silica fiber laser produced a maximum output power of 1.5 W at a slope efficiency of ∼82%; one of the highest slope efficiencies measured for a fi... View full abstract»

Mathematical modeling is used to study the influence of pump wavelength on the emission of an Er(0.5 at.%):YAG laser on the transition 4S32/→4I152/ (561 nm). Three pump wavelengths (direct pumping: 488 nm, upconversion pumping: 800 and 810 nm) are investigated and the corresponding laser emission regimes are discussed. For upconversion pumping, we f... View full abstract»

In this paper, the output characteristics of an oxide-confined AlGaAs-As quantum well vertical-cavity surface-emitting laser (VCSEL) under orthogonal optical injection are mapped as a function of the strength of the optical injection and the detuning between the injection frequency and the free-running frequency of the solitary laser, for a very large range of frequency detuning (from -82 to 89 GH... View full abstract»

The dynamics of a short-cavity, electrooptically tunable microchip laser is studied using the Maxwell-Bloch equations for a unidirectional ring cavity. Within this model, the electrooptic tuning medium is treated rigorously by a wave propagation equation and the electrooptic tuning is equivalent to introducing a time varying perturbation to the boundary condition. With the help of an approximate a... View full abstract»