Two-dimensional analysis of self-sustained pulsation for narrow-stripe AlGaAs lasers

Analysis and design of vertical-cavity surface-emitting lasers for self-sustained pulsation operation

“…2], it is observed that the reduction of mode gain (i.e., reduction of carrier concentration) decreases the FWHM of the optical field (i.e., increases the lateral confinement of the optical mode) which implies that has a negative value. Therefore, the numerical analysis in [13] verifies (12) in explaining the generation mechanism of SSP.…”

“…It is shown in [10] that has a negative (11) value for index guiding but a positive value for gain or antiindex guiding devices such that the device with index-guiding structure enhances SSP. In fact, it is shown in [13] that an edge-emitting device with a strong index-guiding structure enhances SSP through the presence of self-focusing effect (i.e., In [13, Fig. 2], it is observed that the reduction of mode gain (i.e., reduction of carrier concentration) decreases the FWHM of the optical field (i.e., increases the lateral confinement of the optical mode) which implies that has a negative value.…”

“…It seems that oxide-confined VCSEL's have much stronger index-guiding structures than those in edge-emitting lasers and SSP operation can be easily achieved by the negative value of However, SSP similar to that occurred in edge-emitting lasers [13] has not been observed in VCSEL's and the reason can be explained by the presence of in (12). It can be shown that the diffraction loss increases with the reduction of the effective lateral guide-width (i.e., the effective aperture of the core region) of the devices [14].…”

“…The condition of SSP given in [15] is equal to where two extra terms, and , are observed in the expression of . In order to take into account the influence of the mixing effect, the condition of SSP should be modified as below: (13) where .…”

Dependence of the injection current at lasing threshold on structure and losses in AlGaN/GaN lasers

“…1. A narrow stripe laser is simulated here because this type of laser is able to produce enough saturable absorption for self sustained pulsations (SSP) to occur as was demonstrated for an AlGaAs laser in which SSP occurs for stripe widths less than 2.5 m [17]. SSP is a practical method for reducing excess noise in semiconductor lasers, especially in the field of optical disc systems [18].…”