IEEE Journal of Quantum Electronics

The effects of valence band mixing on the nonlinear gains of quantum-well lasers are studied theoretically for the first time. The analysis is based on the multiband effective-mass theory and the density matrix formalism with intraband relaxation taken into account. The gain and the gain-suppression coefficient of a quantum-well laser are calculated from the complex optical susceptibility obtained... View full abstract»

It is shown that suitable modifications of the free-space-propagation operator in the standard fast-Fourier-transform beam propagation procedure yield a far more rapid code in the context of semiconductor rib waveguide calculations. The procedure curtails the diffraction experienced by the high-order Fourier components of the electric field and mirrors the structure of the recently introduced fini... View full abstract»

The OMDR (optical-microwave double resonance) spectrum of 87 Rb with the aim of using a frequency-stabilized GaAs semiconductor laser instead of an Rb lamp as a pumping source in a gas-cell-type Rb frequency standard. Natural isotope 87Rb was sealed in a glass cell with buffer gases (Ar/N2=1.2, total pressure=39 torr). The double resonance signal in the 5<... View full abstract»

A modular equivalent circuit representation for modeling and analyzing open guided-wave structures, which takes into account both the guided and the continuous spectra, is discussed. In the development of the technique approximations that are valid for integrated optics in III-V compound semiconductors are utilized. The validity of these approximately was assessed on the basis of both physical arg... View full abstract»

Two related schemes for detecting X-rays based on (1) the scattering and (2) the reflection of a pulsed optical probe beam by carriers produced by the absorption of a single energetic X-ray photon are described. The detection method is based on the strong carrier density dependence of the (complex) index of refraction of the exciton absorption lines in a GaAs/AlGaAs multiple-quantum-well structure... View full abstract»

The grating-coupled surface emitter (GSE) consists of a gain section between two grating sections, which are not necessarily identical. The gratings act as both distributed Bragg reflectors and output couplers. An analysis that applies to arbitrary grating shapes and has provisions to include the presence of a substrate reflector to reduce the radiated power into that medium is carried out. Thresh... View full abstract»

Two experiments were carried out to measure the stored energy and heat deposited in the laser medium and to determine the heat parameter χ, defined as the heat deposited per unit of stored energy. The stored energy was calculated from small-signal gain measurements. The heat deposition was calculated from interferometric measurements of the thermally induced optical path length changes of the ... View full abstract»

A simple expression for the noise in the photocurrent generated by the detection of light from an ideal superluminescent source is derived using a quantum amplifier model. The excess noise factor X is found to be related to the photocurrent Id, electronic charge e, spontaneous emission coupling factor K , and full width at half maximum power of the em... View full abstract»

A multitemperature accelerated life test conducted to determine the lifetime and reliability of semiconductor lasers for long-term space applications is discussed. The primary cause of failure during two of these life tests (heat sink temperatures of -20°C and 50°C, respectively) was identified as carbon contamination on the front facet resulting in an initially rapid but saturable decreas... View full abstract»

An experimental and theoretical study of the effect of carrier-density nonuniformity on frequency modulation (FM) characteristics of 1.3-μm λ/4-phase-shifted distributed-feedback (DFB) lasers is discussed. The static frequency chirping is measured using a recently developed method that is free from dynamical chirping as well as thermal frequency shift. The amount of chirping shows a stro... View full abstract»

Lithium-rich lithium niobate of excellent optical homogeneity can be fabricated by a vapor transport equilibration (VTE) technique. The high-optical-quality, uniformly birefringent crystals noncritically phase match for second-harmonic generation of 532-nm radiation from 1064-nm Nd:YAG radiation at 238°C. The refractive indexes and their temperature dependence have been measured and used to de... View full abstract»

Stimulated emission from a series of AlGaAs-GaAs single-quantum-well heterostructures is demonstrated for well-widths as thin as 8.5 Å at 22 K. These undoped samples, grown by molecular beam epitaxy, are the thinnest single quantum wells reported to support stimulated emission. Laser thresholds are quite low despite the fact that the single well is undoped and of dimensions that were previou... View full abstract»

The change in refractive index Δn produced by injection of free carriers in InP, GaAs, and InGaAsP is theoretically estimated. Bandfilling (Burstein-Moss effect), bandgap shrinkage, and free-carrier absorption (plasma effect) are included. Carrier concentrations of 1016/cm3 to 1019/cm 3 and photon energies of 0.8 to 2.0 eV are considered. ... View full abstract»

A simple expression for the spectral linewidth of passive-coupled-cavity (PCC) semiconductor lasers is presented. Experimentally observed linewidth narrowing and periodic variation of the linewidth as functions of the injection current and the gap between the active cavity (laser) and the passive cavity (graded index, or GRIN rod) can be satisfactorily explained by this formula View full abstract»

If a light signal is passed into the resonant cavity of an actively oscillating injection laser, an electrical signal at the difference between the laser and light signal frequencies flows through the wire supplying the DC bias to the laser. A small-signal analysis of heterodyne detection with such a laser oscillator that is based solely on rate equations and introduces the externally applied sign... View full abstract»

A theoretical description of a spatially-hole-burned distributed feedback laser is presented. A simple model, based in a semiclassical treatment of the gain-coupled distributed-feedback laser, description, reveals effective pulse shortening, the simultaneous presence of active and self-Q-switching effects, and single-pulse generation properties. Realization of a dynamic distributed-feedba... View full abstract»

The technique of using optical feedback to enhance the phase-conjugation process of stimulated Brillouin scattering is experimentally and theoretically investigated. Several feedback arrangements are experimentally studied and demonstrate the ability to reduce significantly the threshold power requirement, enhance the efficiency, and improve the phase-conjugate fidelity of the Brillouin process. S... View full abstract»

A Green's function approach to the analysis of semiconductor lasers is formulated in a form suitable for complex cavity structures. Both the spontaneous emission rate and the effective phase-amplitude coupling factor can be accurately evaluated. For distributed-feedback (DFB) lasers, the spontaneous emission rate is strongly dependent on both the facet reflectivities and the grating coupling coeff... View full abstract»

A model analysis of the second-harmonic electromagnetic wave generated by the Cherenkov effect in an optical channel waveguide made of an anisotropic dielectric is discussed. With the effective-refractive-index method the waveguide is modeled by two slab-type waveguides. Both TE and TM waves are considered, and the polarization dependence of the second-harmonic power is studied. Numerical results ... View full abstract»

A 0.5-GW-peak-power solid-state laser source that is based on injection seeding a Q-switched Nd:Glass laser is discussed. In the first experimental demonstration, a Q-switched oscillator producing 101 mJ was seeded by a train of 11-ps pulses from a CW (continuous-wave) mode-locked laser to produce injection-mode-locked pulses under a 91-ns envelope. A theoretical analysis of inje... View full abstract»

CW (continuous-wave) operation of end-pumped four-level glass lasers is modeled to obtain expressions for threshold, slope efficiency, and figures of merit. The thermal effects ultimately limiting performance in these lasers is also discussed. Basic design consideration for optimum performance of an end-pumped CW Nd:glass laser intended for mode locking are presented. On the basis of these investi... View full abstract»

The injection locking of a KrF unstable resonator module has been studied experimentally using a dye-laser-amplified, frequency-doubled seed pulse generated from the 496.5-nm output of an etalon-narrowed argon-ion laser. Partial injection locking was observed starting at input powers of 0.1 W, with greater than 90% injection locking being achieved at input powers of over 1 kW. The output linewidth... View full abstract»

The electrical characteristics of a doubling circuit (or LC -inversion circuit) used to excite a TEA (transversely excited atmospheric) N2 laser have been studied, and a theoretical model for the voltage and current oscillations in the circuit is proposed. The theoretical predictions are in excellent agreement with the experimental data, and thus the shape of the voltage and cu... View full abstract»

The effect of excited-state absorption (ESA) at the laser wavelength in transversely pumped pulsed-dye-laser amplifiers is theoretically examined. Assuming steady-state conditions, it is shown that ESA along with ground-state absorption introduces a nonlinear loss term in the amplifier equation. An improved expression for the saturated gain is obtained, and it is shown that the amplifier extractio... View full abstract»