IEEE Journal of Quantum Electronics

Bistability has been observed in the tuning characteristic and power versus current relation of a 1.3 μm grating-tuned external-cavity semiconductor laser. Tuning-direction reversal, current variations, and feedback interruption can change the output power and threshold current at a given wavelength. These effects are shown theoretically to be due to the coupling of the semiconductor gain and... View full abstract»

The amplification properties of a tunable single transverse mode laser diode can be exploited to be used as ann times 1wavelength division switch. This kind of switch is expected to play an important role in telecommunications systems, especially when signals are not synchronous or when signal bit rates are various. The light amplification ratio between a desired main-mode wavelength an... View full abstract»

A technique for chirp-compensation in a CPM laser is presented. By using the change of the incident angle to multilayer dielectric cavity mirrors, the intracavity second-order dispersionphi'(omega)is adjusted without any additional elements. It is confirmed that the optimum value ofphi'(omega) = +2.1 times 10^{-28}s2obtained when up-chirp was compensated and pulses... View full abstract»

The output of a picosecond cascade-pumped controlled transient oscillation (CTO) dye laser has been amplified to the millijoule level. Single-mode operation and frequency selection with a spectral width of 0.2 nm were achieved by using an angle-tuned narrow-band interference filter. A plasma shutter was employed as a pulse clean-up device for these high-power laser pulses. This device had a transm... View full abstract»

Time-resolved Sr I and Sr II population densities have been measured in an Sr+ recombination laser. The results indicate that the Sr vapor is fully ionized during the longitudinal discharge pulse and that 3 percent of this ionization persists until the start of the next pulse some 265 μs later. A lower limit of1.3-2.6 times 10^{20}m-3was placed on the electron density du... View full abstract»

Using a coherent radiation-semiconductor interaction model based upon the time dependent perturbation technique, the occurrence of optical nutation has been analytically investigated in direct-gap semiconductors such as GaAs, GaSb, InAs, and Hg1-xCdxTe, duly irradiated by near resonant laser beams. The present approach is much more simplified and straightforward than the conv... View full abstract»

In this paper, we propose and demonstrate a new kind of optical bistable scheme which is based on an AHPT (avalanche heterojunction phototransistor) and an LD. The operating principles of the AHPT and the completed bistable devices are discussed in details. A simple assumption is made to simplify the analysis. When the AHPT-LD-BOD works in the steady state, it presents four operating modes, which ... View full abstract»

We have obtained over 250 mW of CW laser emission at 1084 nm from a neodymium-doped single crystal of lithium niobate when the rod was end pumped by 1 W from a Kr+ laser at 752 nm. Thresholds of less than 30 mW are obtained with a weak output coupler, rising to 220 mW with a 35 percent transmitting output mirror. The laser could be tuned over 3 nm around the peak at 1084.4 nm with a thin, uncoated... View full abstract»

This paper describes a TE CW CO2laser with a special gas flow scheme and an auxiliary discharge configuration. In this laser system, mixed gas was forced to flow through a structure of square tubes with meshes on both sides. An array of auxiliary electrodes was added to produce a dc auxiliary discharge between these electrodes and a tubular cathode. By introducing these structures, unif... View full abstract»

Novel features of nonlinear guided waves in saturable thin-film waveguides are obtained. It is shown that the presence of saturation can strongly modify the behavior of TE waves in comparison to films having a Kerr-like nonlinearity. The fundamental mode index is seen to become bounded by limits determined by the saturation level. The example of symmetric waveguide is analyzed and the dispersion p... View full abstract»

A time-dependent theory has been developed to model the behavior of doped-InSb, optically bistable etalons operating at room temperature and illuminated by a pulsed CO2laser. Good agreement can be obtained between this semi-empirical theory and experiment. The reduction of switching times to ∼ 1 ns by n-type doping has been demonstrated experimentally. View full abstract»

The lateral modes of broad area lasers are investigated theoretically. The nonlinear interaction between optical field and effective refractive index leads to a saturable nonlinearity in the governing field equation, so that self-modulated solutions are found to be stable with increased current injection above saturation intensity. We derive approximate analytical solutions for traveling wave fiel... View full abstract»

Some aspects of the power-dependent attenuation of TE waves guided by structures consisting of an optical linear thin film (Corning 7059 glass) deposited onto the surface of a substrate (glass doped with CdSxSe1-xsemiconductor) exhibiting both positive and negative nonlinearities at two different wavelengths are studied numerically. It is shown that even a weak attenuation wi... View full abstract»

The generation of broadly tunable FIR laser emission by pumping Raman transitions in NH3with 300 mJ, 50 ns duration pulses from a continuously tunable CO2laser is reported. FIR laser outputs up to 4 mJ and a photon conversion efficiency as high as 16 percent have been obtained. View full abstract»

A general theory of semiconductor lasers is presented in which the static and dynamic properties are expressed in terms of the effective left and right reflectivities at a given reference plane in the laser. The theory applies to Fabry-Perot and DFB solitary lasers and to laser configurations with strong optical feedback or strong light injection. View full abstract»

Self-defocusing of 45 ps CO2laser pulses was observed in InSb at intensities as low as 1 MW/cm2. This self-defocusing was caused by the two-photon absorption generated free carriers and the resulting self-phase modulation. In addition to demonstrating spatial beam modulation in this material at 10.6 μm, the present experiment also confirms directly that such a process oc... View full abstract»

The pump power stability range of solid-state laser resonators operating in the TEM00mode has been thoroughly investigated. It has been shown that, for a very general resonator containing intracavity optical systems, rod thermal lensing engenders a pump power stability range which is a characteristic parameter of laser material and pump cavity, but is independent of resonator configurat... View full abstract»

Compositional changes in the n-clad layer within the channel region of channel substrate planar (CSP) type semiconductor lasers have been observed. As a consequence, a large optical cavity (LOC) or an enhanced substrate loss (ESL) version of the CSP geometry may result, both of which may have significantly different characteristics from those of a conventional CSP laser. The CSP-LOC generally has ... View full abstract»

Picosecond time-resolved absorption at 2.2, 3.4, and 3.9 μm produced by photogenerated carriers in intrinsic Ge and semi-insulating CdSe has been measured at room temperature. For Ge, the peak absorbance changes as the square of the probe wavelength. The absorption profile as a function of delay time relative to the excitation pulse rises with a resolution-limited risetime (< 10 ps) and de... View full abstract»

The theory of probe beam amplification via degenerate optical wave mixing in a Kerr medium is presented. This theory includes consideration of the self-phase modulation, two-wave mixing, and multiwave mixing terms in the coupled-wave equations. Both analytical solutions, under the assumptions of a nondepleted pump beam and a transparent Kerr medium, and numerical solutions with these assumptions r... View full abstract»

The effects of geometrical asymmetries on the optoelectronic properties of CSP-DH lasers using self-consistent calculations of the optical field and the electron-hole distribution in the active layer are analyzed and compared with device measurements. Laser properties modeled include gain profile, threshold, slope efficiency, near field, and far field. This analysis shows that small geometrical as... View full abstract»