Thermal analysis of high-bandwidth and energy-efficient 980 nm VCSELs with optimized quantum well gain peak-to-cavity resonance wavelength offset

Abstract

The static and dynamic performance of vertical-cavity surface-emitting lasers (VCSELs) used as light-sources for optical interconnects is highly influenced by temperature. We study the effect of temperature on the performance of high-speed energy-efficient 980 nm VCSELs with a peak wavelength of the quantum well offset to the wavelength of the fundamental longitudinal device cavity mode so that they are aligned at around 60 °C. A simple method to obtain the thermal resistance of the VCSELs as a function of ambient temperature is described, allowing us to extract the active region temperature and the temperature dependence of the dynamic and static parameters. At low bias currents, we can see an increase of the −3 dB modulation bandwidth f−3dB with increasing active region temperature, which is different from the classically known situation. From the detailed analysis of f−3dB versus the active region temperature, we obtain a better understanding of the thermal limitations of VCSELs, giving a basis for next generation device designs with improved temperature stability.

Fabrication and Characterization of Low-Threshold Single Fundamental Mode VCSELs With Dielectric DBR Mirror

“…The calculated values of Rth under different ambient temperature are plotted in Fig. 6, which is comparable to the counterpart of the GaAs-based VCSELs [18], [20]. The thermal resistances increase with increasing ambient temperature.…”

“…In VCSELs, a temperature increase can be caused by an ambient temperature increase and, more importantly, by the internal heating of the active region. A high temperature in internal device will degrade the output performance and lifetime [16]- [18]. The thermal behavior of the VCSELs can be characterized by thermal resistance.…”

“…The thermal behavior of the VCSELs can be characterized by thermal resistance. According to the relationship of emission spectra and dissipated power, the thermal resistance Rth can be determined from Rth= ∆T/∆Pdiss= (∆λ/∆Pdiss)/(∆λ⁄ ∆T) [18], [19]. ∆λ⁄∆Pdiss is estimated by the fundamental mode peak emission wavelength shift rate versus the variation of the dissipated power, where the Pdiss= I×V-Poutput.…”

“…The thermal resistances increase with increasing ambient temperature. According to the ambient-temperature-dependent thermal resistance, the actual temperature in active region can be calculated from Tactive=Tambient+Rth×Pdiss [18], [20]. Fig.…”

Performance Characteristics of Conventional Vertical Cavity Surface Emitting Lasers VCSELs at 1300 nm

“…As illustrated in Figure 4, the amplified signal wavelength shifts to the longer wavelength with increasing temperature from T=16 to 28 o C, due to that both the cavity mode and material gain spectrum is changing with temperature (Piprek et al, 1998, Chaqmaqchee & Balkan 2014. The influence of temperature on the device performance with optimized quantum wells intensity peak to cavity wavelength offset were studied elsewhere (Calves et al, 2006& Li et al, 2017. The VCSEL is biased just below threshold of 0.84 mA.…”