High-Efficiency Operation of Membrane Distributed-Reflector Lasers on Silicon Substrate

• Published in: IEEE journal of selected topics in quantum electronics Vol. 23; no. 6; pp. 1 - 8
• Main Authors: Hiratani, Takuo, Inoue, Daisuke, Tomiyasu, Takahiro, Fukuda, Kai, Amemiya, Tomohiro, Nishiyama, Nobuhiko, Arai, Shigehisa
• Format: Journal Article
• Language: English
• Published: IEEE 01.11.2017
• Subjects: Distributed Bragg reflectors; distributed-reflector laser; Membrane laser; Optical interconnections; optical interconnects; semiconductor laser; Threshold current; Vertical cavity surface emitting lasers; Waveguide lasers
• ISSN: 1077-260X; 1558-4542
• DOI: 10.1109/JSTQE.2017.2704289

To advance on-chip optical interconnections, membrane distributed-reflector (DR) lasers with low threshold current and high-efficiency operation at one side output were realized. First, a membrane distributed Bragg reflector (DBR) laser with 80-μm-long active section and 50-μm-long DBR section was fabricated to clarify the DBR reflectivity. An external differential quantum efficiency of 35% for the output from the front facet was obtained, and the DBR reflectivity was estimated to be 75%. Next, a membrane DR laser with 61- μm-long distributed feedback section and 50-μm-long DBR section was fabricated. A threshold current of 0.48 mA, external differential quantum efficiency from the front side waveguide of 26%, and light output ratio from the front to the rear sides of 13 were obtained. The lasing spectrum showed a single-mode operation with a side-mode suppression-ratio (SMSR) of 40 dB. Finally, small-signal direct modulation was carried out and a modulation current efficiency factor of 7.9 GHz/mA 1/2 and 7 GHz/mA 1/2 were, respectively, obtained for the 30-μm-long and 61-μm-long devices.