IEEE Journal of Quantum Electronics

The analytical expressions for the time-averaged AM and FM noise power spectra of a directly modulated semiconductor laser are presented by small-signal analysis. The FM and the AM noise spectra for such a laser depend both on the modulation intensity and on the modulation frequency View full abstract»

A simple model is presented which takes into account interference effects in the common three-layer p-i-n diode epitaxial structure used for measurement of electroabsorption effects in multiple quantum well material. Antireflection coatings or surface roughening are not required to extinguish Fabry-Perot oscillations in the reflectance and transmittance spectra which improves the accuracy of the e... View full abstract»

Effects of lateral heat and carrier diffusion on the maximum output intensity, above which thermal runaway takes place, are determined for cw semiconductor lasers. The effects are depicted by an aspect ratio of cavity length to stripe width and a dimensionless quantity representing the efficiency of heat transfer. A concise criterion for no thermal runaway is given. The results show that the outpu... View full abstract»

We calculate the |conduction, heavy hole⟩- |split-off hole, heavy hole⟩ (CHSH) Auger rates in strained In0.53+xGa 0.47-xAs on InP, a widely used material system for quantum well lasers. The bandstructure is obtained from an eight-band tight binding model with spin-orbit coupling, strain effects being included via the deformation potential theory. Adding excess In de... View full abstract»

Simulations of optical guided waves in three-dimensional waveguide structures by a full vector beam propagation method are described. Two sets of coupled equations governing the propagation of the transverse electric and magnetic fields are derived systematically. Polarization dependence and coupling due to the vectorial nature of the electromagnetic fields are considered in the formulations. The ... View full abstract»

Emission energy shift due to high carrier density at threshold in multiple quantum well (MQW) laser diodes is investigated theoretically. This energy shift is evaluated through the Schrodinger and the Poisson equations self-consistently as well as the calculation of the gain spectra with carrier-dependent lifetime broadening. The band filling and the gain broadening effects show a blue shift on th... View full abstract»

We report extensive experimental and theoretical studies on the properties of an optical bistable device called the charge-induced self-feedback device (CSFD) which is a variation of a self electro-optic effect device (SEED). In the mechanism, a novelty: of the CSFD consists of the feedback due to field-screening, resulting in independent switchings of optical beams focused at different spots on t... View full abstract»

Injection seeding has proven to be a practical method of controlling the spectral output of a laser in an efficient and reliable manner. To achieve satisfactory injection seeding performance, a sufficiently large seed must be employed. To characterize the required seed, an injection seeding theory is developed here which establishes two interrelated concepts, threshold for injection seeding and sp... View full abstract»

An optical frequency comb (OFC) generator was realized for accurate optical frequency difference measurement of 1.5 μm wavelength semiconductor lasers by using a high frequency LiNbO3 electrooptic phase modulator which was installed in a Fabry-Perot cavity. It was confirmed that the span of the OFC was wider than 4 THz. By using semiconductor lasers whose spectrum linewidths were na... View full abstract»

A small-signal analysis of direct modulation of laser diodes is presented. The analysis is valid over a wide frequency range, up to the frequency corresponding to the round trip time of the active region. This theory is best for laser diodes with small active regions but with large and complicated optical cavities. Optical resonances may occur in this range, resulting in a large response to direct... View full abstract»

A TE-cylindrical wave threshold gain and threshold current analysis is presented for circular grating distributed feedback (CG-DFB) and circular grating distributed-Bragg-reflector (CG-DBR) lasers. Mode properties of CG-DFB/DBR lasers are discussed. It is found that the threshold gain, threshold current density and threshold current of CG-DBR lasers can be much lower than those of CG-DFB lasers View full abstract»

A new, ultrafast, low loss, all-optical switch based on the cascaded second-order nonlinearity is proposed. The device is based on an integrated Mach-Zehnder interferometer where quasi-phase matching produces a nonlinear phase shift with a different sign in each arm of the interferometer. A full treatment of the nonlinear phase shift indicates that the proposed device, if fabricated in AlGaAs, cou... View full abstract»

Periodic pulse-train amplitude modulations have been observed in a Kerr-lens self-mode-locked Ti:sapphire laser when the size of an intracavity slit is reduced below its optimal value for stable mode locking. These transient processes are dominated by 100-500 kHz periodic pulse-energy modulations and are inherent to the Kerr-lens mode-locking mechanism based on the intensity dependent transverse-b... View full abstract»

Experiments have been designed and performed to determine the effects on the seeding efficiency of injection seed energy and power, alignment, and spatial mode matching between single longitudinal mode seed lasers and a power oscillator. The absorption features of H2 O have allowed the characterization of the seeding efficiency by selectively absorbing the laser output energy correspond... View full abstract»

Coherent radiation is generated around 94, 112, and 118 nm by frequency tripping in Ar and Kr crystals. The center wavelength of the tuning ranges can be shifted by 0.1 to 0.2 nm with temperature. The spectral widths of the tuning ranges in Ar increase from 0.03 to 0.15 nm for a reduction of the sample thickness from 3 mm to 5.5 μm. The conversion efficiency saturates for film thicknesses aroun... View full abstract»