On-chip laser source with low relative intensity noise (RIN) is required not only for coherent systems, but also for atomic clocks and lidar-related applications. The RIN of the light source can seriously affect the efficiency of information transmission. Due to the lattice mismatch between the III-V material and the silicon substrate, the epitaxial growth produces a relative high dislocation defect density, which acts as non-radiative recombination centers through the Shockley-Read-Hall (SRH) process. This high defect density adversely affects the threshold current and noise characteristics of the epitaxial quantum dot (QD) laser on silicon.
This paper presents that the RIN characteristics of QD lasers can be further improved by the optical injection effect. The master-slave injection locking scheme is shown in Fig. 1. In the stable injection-locked area, the RIN is reduced from – 157 dB/Hz down to – 168 dB/Hz by adjusting the injection ratio and frequency detuning. Overall, this work brings new insights for designing integrated injection-locked QD lasers on a silicon chip for low noise applications.
Further details will be presented at the NUSOD 2022 conference.
Fig.1 Schematic representation of an optically injection-locked QD laser as well as the electronic structure and carrier dynamics into the QD.
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