共查询到20条相似文献,搜索用时 15 毫秒
1.
Mode-guiding mechanisms responsible for bistable properties of twin-stripe lasers are discussed with particular reference to optical injection effects. Calculations of the change in lasing field intensity as a function of both optical input power and injection current levels are presented. 相似文献
2.
A wave-optical model that is coupled to a microscopic gain theory is used to investigate lateral mode behavior in group-III nitride quantum-well lasers. Beam filamentation due to self-focusing in the gain medium is found to limit fundamental-mode output to narrow stripe lasers or to operation close to lasing threshold. Differences between nitride and conventional near-infrared semiconductor lasers arise because of band structure differences, in particular, the presence of a strong quantum-confined Stark effect in the former. Increasing mirror reflectivities in plane-plane resonators to reduce lasing threshold current tends to exacerbate the filamentation problem. On the other hand, a negative-branch unstable resonator is found to mitigate filament effects, enabling fundamental-mode operation far above threshold in broad-area lasers 相似文献
3.
Watanabe M. Fujiki H. Mukai S. Ogura M. Yajima H. Shimoyama K. Gotoh H. 《Quantum Electronics, IEEE Journal of》1994,30(10):2232-2234
Switching between two cross-coupled lateral modes in gain-guided twin-stripe lasers has been experimentally observed with current injection of nominally identical pulses, which strongly indicates bistability. Near- and far-field patterns at both facets are presented, which clearly shows a skewed light field which couples from under one stripe to under the other. Cross-coupled mode operation was obtained only for relatively long cavity lasers, which is consistent with the theory for twin-stripe lasers with high interstripe gain 相似文献
4.
A concept for a twin-stripe semiconductor laser is presented in which the simultaneous gain and refractive index variation induced by carriers injected into one stripe can be converted into either a pure amplitude or a pure frequency variation in the lasing supermode. Applications include high-frequency chirp-free amplitude modulation, reduced line width and pure phase modulation. 相似文献
5.
A numerical solution is presented to the problem of lateral current spreading in double heterostructure twin-stripe lasers when lateral diffusion of carriers and bimolecular recombination effects are present. The current components flowing into both the p-type confining layer and the active layer are solved simultaneously, subject to the boundary conditions imposed at the heterojunction. This yields the two-dimensional potential and the current density distributions in the p-type confining layer and the lateral carder density distribution in the active region. Diffusion and bimolecular radiative recombination effects are included in the solution of the current distribution in the active layer. The lateral current and carrier density distributions along the active layer are presented for single- and twin-stripe devices for a variety of electrode injection currents. The paper highlights the influence of device geometry and diffusion on the carrier distributions found beneath the stripes of twin-stripe lasers. 相似文献
6.
A numerical procedure for the investigation of the lateral modes of semiconductor lasers with an external cavity is described. The propagation of the optical field inside the semiconductor laser is carried out via a standard beam-propagation scheme, while the method of coordinate scaling with the generalized Huygens-Fresnel integral allows for a computationally efficient propagation of the field in the external cavity. Using an eigenfunction solver based on the Prony method, it is shown that a simple external-cavity configuration comprising a broad area laser, a collimation lens, and a uniform end reflector can exhibit a complex modal behavior. Compared to a solitary broad area laser, optimized external cavities can yield enhanced modal discriminations, resulting in a single-lateral-mode operation with output power in excess of 100 mW along with a clean, single-lobed far-field pattern. The spatial-filtering action of the broad-area laser is highlighted, and we also discuss of the role played by the wavefront curvature of the beam incident upon the broad-area laser for achieving an efficient suppression of the higher order modes along with minimum increase of the threshold current 相似文献
7.
Lateral-mode frequency locking in the high-power operation of narrow-ridge semiconductor lasers is shown to be attributable to carrier-induced third-order nonlinearities. Not only are known experimental characteristics of beam steering explained with this theory, but new insights into the nature of beam steering, such as its inherent bistable behavior, are obtained 相似文献
8.
An experimental and theoretical investigation of how the polarization mode competition and beat frequency of Er-doped fiber distributed-feedback lasers depend on perturbations such as localized transverse forces, back reflections, or changes in pump polarization is reported. Good agreement between the experiments and a comprehensive theoretical model is obtained. Use of a dual-polarization laser as a transverse force sensor with a resolution on the order of 1-100 nN/√Hz above 20 Hz is also discussed 相似文献
9.
10.
11.
Mode characteristics of hexagonal resonators are numerically simulated by the two-dimensional (2-D) finite-difference time-domain
(FDTD) technique. For the hexagonal resonator with the side length of 3 μm and the refractive index of 3.2, the mode quality
(Q) factors decrease from 104 to 102 as the resonant wavelength increases from 1.1 to 3.2 μm. The modes have a relatively high Q factor as their even and odd states have different mode wavelengths and different Q factors, i.e., they are accidentally degenerate modes. The azimuthal mode numbers obtained from mode field distribution for
the accidentally degenerate modes satisfy the mode number relation derived from the symmetry characteristics for the split
of double-degenerate modes. Furthermore, the numerical results indicate that an output waveguide parallel to one of the sides
is the better scheme for directional emission. For the hexagonal resonator with 3 m side length and 0.3 μm wide output waveguide,
the Q factor of 5.05×103 and output efficiency of 33% are obtained at the mode wavelength of 1.29 μm. 相似文献
12.
13.
The spectrum behavior below the threshold in DFB lasers has been investigated. Analysis shows that the emission spectrum has peaks predicted by the threshold theory and proper valleys between large peaks. The results of our analysis should aid in the evaluation of DFB structure parameters. 相似文献
14.
We use traveling wave coupling theory to investigate the time domain characteristics of tapered semiconductor lasers with DBR gratings.We analyze the influence of the length of second order gratings on the power and spectrum of output light,and optimizing the length of gratings,in order to reduce the mode competition effect in the device,and obtain the high power output light wave with good longitudinal mode characteristics. 相似文献
15.
Derry P.L. Fu R.J. Hong C.S. Chan E.Y. Figueroa L. 《Quantum Electronics, IEEE Journal of》1992,28(12):2698-2705
The effect of high temperature on the threshold gain and threshold current density of an In0.15Ga0.85As strained quantum-well laser is examined both theoretically and experimentally. It is found that the nonlinearity of the gain-versus-current relationship increases with temperature. The implications of this result on laser cavity design for optimal high-temperature performance are discussed. The effect of high temperature on modulation bandwidth is also considered. While the numerical results are specific to an In0.15 Ga0.85As strained quantum-well laser, qualitatively they apply to all quantum-well lasers 相似文献
16.
17.
18.
19.
20.
Impedance characteristics of quantum-well lasers 总被引:1,自引:0,他引:1
Weisser S. Esquivias I. Tasker P.J. Ralston J.D. Romero B. Rosenzweig J. 《Photonics Technology Letters, IEEE》1994,6(12):1421-1423
We derive theoretical expressions for the impedance of quantum-well lasers below and above threshold based on a simple rate equation model. These electrical laser characteristics are shown to be dominated by purely electrical parameters related to carrier capture/transport and carrier re-emission. The results of on-wafer measurements of the impedance of high-speed In0.35Ga0.65 As/GaAs multiple-quantum-well lasers are shown to be in good agreement with this simple model, allowing us to extract the effective carrier escape time and the effective carrier lifetime, and to estimate the effective carrier capture/transport time 相似文献