Electrically pumped quantum-dot III-V lasers grown directly on silicon for integrated photonics
Silicon-based photonic/electronic integration gets a boost from InAs/GaAs lasers grown directly without wafer bonding.
Researchers from University College London (London, England), the University of Sheffield (Sheffield, England), and Cardiff University (Cardiff, Wales) have fabricated III-V semiconductor lasers directly on silicon, removing a hurdle to the hybrid integration of lasers with silicon photonic circuits.1 The previous, more complicated and costly, method of combining III-V lasers with silicon consisted of wafer bonding, in which the lasers are made separately, then bonded to the silicon photonic circuit.
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The researchers grew electrically pumped continuous-wave (CW) indium arsenide/gallium arsenide (InAs/GaAs) quantum-dot (QD) lasers on silicon that emit at a wavelength of 1300 nm, have a room-temperature output power of 105 mW, can operate at temperatures up to 120 °C, and have a threshold current density of only 62.5 A/cm2. The 3100 hours of CW operation leads to an extrapolated mean time to failure of 100,158 hours.
“The techniques that we have developed permit us to realize the Holy Grail of silicon photonics — an efficient and reliable electrically driven semiconductor laser directly integrated on a silicon substrate,” says Alwyn Seeds, Head of the Photonics Group at University College London. “Our future work will be aimed at integrating these lasers with waveguides and drive electronics, leading to a comprehensive technology for the integration of photonics with silicon electronics."
The research was funded by the Engineering and Physical Sciences Research Council (EPSRC; Swindon, England) and was led by Cardiff University.
1. Siming Chen et al., Nature Photonics (2016); doi: 10.1038/nphoton.2016.21; http://www.nature.com/nphoton/journal/vaop/ncurrent/full/nphoton.2016.21.html