Scattering losses from dielectric apertures in vertical-cavity lasers

High-performance small vertical-cavity lasers: a comparison of measured improvements in optical and current confinement in devices using tapered apertures

“…4. The index step is calculated based upon the overlap of the index perturbation with the standing wave [17], which agrees with the index-step calculated based upon the change in the resonant wavelength [3], [17] except in the thickest regions where the perturbation of the oxide moves a second cavity resonance within the mirror stopband. One can see that the taper positioned at the standing-wave Peak has a much higher index gradient, and this results in increased scattering losses.…”

“…In addition, the excellent scaling of the slope efficiency of tapered apertured devices sets an upper bound on the drop of less than 10% at 2 m. Despite this slight inaccuracy, our conclusions about the relative amounts of optical scattering from various aperture designs should be similar. We show the scattering loss in comparison to the theoretical preditcions from [3] in Fig. 6.…”

“…The excess loss generally turns on sharply [3], [4] (roughly as where is the device radius) and will have an exponentially greater effect on threshold. These losses have been dramatically reduced by confining the mode with apertures rather than etched pillars [4], [5].…”

Numerical investigation of self-heating effects of oxide-confined vertical-cavity surface-emitting lasers

“…In general, the total optical modal loss can be expressed as , where is the photon lifetime, and is the loss due to the DBR mirrors. is the loss due to aperture scattering [43], refractive index fluctuation of the alloys [44], and surface roughness [45]. is due to free carrier [46] and intervalence band [47] absorptions.…”

Polymer-coated vertical-cavity surface-emitting laser diode vapor sensor

“…The diffraction loss is strongly dependent on the aperture radius and the refractive index discontinuities for single-mode aperture sizes and thus strongly dependent on the exact structure of the VCSEL. 7,8 Both the threshold current and the the differential quantum efficiency increase with φ until φ = π/2. This is in accordance with the expected results as the gain required for lasing is expected to increase as the mirror reflectance decreases.…”