Gain spectrum engineering for temperature-insensitive 980 nm VCSEL performance using heterogeneous quantum wells

Abstract

Lasers with stable temperature-dependent performance are increasingly demanded in high-speed optical interconnects. We present a temperature stable 980-nm wavelength vertical-cavity surface-emitting lasers featuring an asymmetric quantum wells active region engineered. This design broadened the gain spectrum and significantly reduced the temperature sensitivity of the modulation bandwidth under constant bias current. Through comprehensive simulations and experimental analysis, we demonstrated that the proposed asymmetric quantum well structures outperformed conventional symmetric quantum well structure across the range of 298 K – 358 K. Key improvements included a 41.75 % reduction in threshold current variation rate over the range of 298 K – 358 K, alongside decreases in modulation bandwidth variation of 53.98 %, 62.47 %, and 55.18 % at bias currents of 3 mA, 4 mA, and 5 mA respectively. Experimentally, by photoluminescence measurements, heterogenous quantum well structures demonstrated significant spectrum broadening and multi-wavelength photon emission at both room temperature and low temperatures (1.7 K – 150 K). This design is particularly suitable for data centers and 5G networks, where thermal stability is critical.