Abstract
In this paper, we present measurements and simulations of the small-signal modulation response of monolithic continuous-wave 1.3 μm InAs/GaAs quantum dot (QD) narrow ridge-waveguide lasers on a silicon substrate. The 2.5 mm-long lasers investigated demonstrate 3 dB modulation bandwidths of 1.6 GHz, D-factors of 0.3 GHz/mA 1/2 , modulation current efficiencies of 0.4 GHz/mA 1/2 , and K-factors of 2.4 ns and 3.7 ns. Since the devices under test are not designed for high-speed operation due to their long length and hence long photon lifetime, the modulation response curves are used as a fitting template for numerical simulations with spatiotemporal resolution to gain insight into the underlying laser physics. The obtained parameter set is used to unveil the true potential of the laser material in an optimized device geometry by modeling the small-signal response at different cavity lengths, mirror reflectivities, and for different numbers of QD layers. The simulations predict a maximum 3 dB modulation bandwidth of 5 GHz to 7 GHz for a 0.75 mm-long cavity with 99% and 60% high-reflection coatings and ten QD layers. Modeling the impact of dislocations on the dynamic performance qualitatively reveals that enhanced non-radiative recombination in the wetting layer leaves the modulation bandwidth of QD lasers on silicon almost unaffected, while dislocation-induced optical loss does not pose a problem, as long as sufficient gain is provided by the QD active region.
| Original language | English |
|---|---|
| Article number | 8552390 |
| Pages (from-to) | 949-955 |
| Number of pages | 7 |
| Journal | Journal of Lightwave Technology |
| Volume | 37 |
| Issue number | 3 |
| Early online date | 29 Nov 2018 |
| DOIs | |
| Publication status | Published - 1 Feb 2019 |
Funding
Manuscript received August 28, 2018; revised November 15, 2018; accepted November 26, 2018. Date of publication November 29, 2018; date of current version February 21, 2019. This work was supported by UK Engineering and Physical Sciences Research Council at the University of Cambridge and at University College London UCL under Grants EP/J012904/1 and EP/J012815/1. The work of C. Hantschmann was supported by Qualcomm Inc. The work of S. Chen was supported by a Research Fellowship by the Royal Academy of Engineering under Reference No. RF201617/16/28. (Corresponding author: Constanze Hantschmann.) C. Hantschmann, A. Wonfor, R. V. Penty, and I. H. White are with the Centre for Photonic Systems, Department of Engineering, University of Cambridge, Cambridge CB3 0FA, U.K. (e-mail:, [email protected]; [email protected]; [email protected]; [email protected]).
Keywords
- Integrated optics
- modulation
- quantum dot lasers
- semiconductor device modeling
- silicon devices
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics