Effects of optical feedback on static and dynamic characteristics of vertical-cavity surface-emitting lasers

Abstract

We present a numerical study of the effects of optical feedback on the static and dynamic characteristics of verticalcavity surface-emitting lasers (VCSEL's) under both single-mode and two-mode operations. Our model includes transverse effects such as carrier diffusion and spatial hole burning (SHB) and is therefore capable of including gain-saturation-induced coupling among transverse modes. For short external cavities (30 m), optical feedback can completely suppress higher order transverse modes. For relatively long external cavities (1 cm), VCSEL's follow a period-doubling route to chaos. Numerical results show that multimode VCSEL's exhibit self-pulsations at higher feedback levels compared with the single-mode case.

Different regimes of low-frequency fluctuations in vertical-cavity surface-emitting lasers

“…The high reflectivity of the output mirror in VCSELs might justify inclusion of multiple external-cavity round trips even for a low feedback rate, as first suggested by Law and Agrawal. 22 Inclusion of multiple round-trip terms in the field equation would most probably yield a better quantitative agreement with experiments, since it adds correction factors to the gain and frequency of the steadystate, external-cavity modes. 23,24 However our results show that both types of LFF are complementary and co-exist in the same model [Eqs.…”

Optical feedback in vertical-cavity surface-emitting lasers

“…This particular device was chosen because it operates in a single mode up to 6 mA, corresponding to the fundamental mode (TEM or LP in fiber mode notation). This allows us to isolate feedback effects for a single mode and avoid more complex multimode interaction due to spatial hole burning [5].…”

“…Several groups have modeled feedback in VCSELs by defining effective cavity lengths and reflectivities for the VCSEL and using the FP model [5], [9], [7].…”

“…Heinrich et al [12] showed experimentally that fiber feedback could have a significant effect on the spectrum and output power of multimode VCSELs. Law et al [5] J.-F. P. Seurin was with the Department of Electrical and Computer Engineering, the University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA. He is now with Princeton Optronics, Princeton, NJ 08543-8627 USA.…”

“…Optical feedback is generally considered to be detrimental to the performance of lasers because, under certain conditions, feedback can cause significant changes in spectrum [3], [4], power instabilities [5]- [7], relative intensity noise [8], [9], and polarization switching [10], [11].…”