31 GHz Ge n-i-p waveguide photodetectors on Silicon-on-Insulator substrate

Abstract

We report on evanescently coupled Ge waveguide photodetectors that are grown on top of Si rib waveguides. A Ge waveguide detector with a width of 7.4mum and length of 50 mum demonstrated an optical bandwidth of 31.3 GHz at -2V for 1550nm. In addition, a responsivity of 0.89 A/W at 1550 nm and dark current of 169 nA were measured from this detector at -2V. A higher responsivity of 1.16 A/W was also measured from a longer Ge waveguide detector (4.4 x 100 mum2), with a corresponding bandwidth of 29.4 GHz at -2V. An open eye diagram at 40 Gb/s is also shown.

A perfect marriage: optics and silicon

“…Ever since the first 1 GHz silicon modulator was demonstrated in 2004, foundational technologies related to hybrid light sources, faster modulators, light guidance and photo detection have been developed and continuously refined [1][2][3]. These are the building blocks that have made integrated silicon photonic devices possible.…”

“…For the 50G silicon photonics link, the measured 3 dB bandwidth of the four photodetectors was in the range of 9.4-10.6 GHz with a measured responsiveness of approximately 0.9 A/W. As with the silicon modulators, these SiGe PIN photodetectors have been demonstrated to operate at 40 Gbps [3].…”

Structural and optical properties of axial silicon-germanium nanowire heterojunctions

“…These properties make Ge one of the most promising materials for CMOS compatible photonic components including near-infra-red photodetectors [1][2][3][4] and, possibly, lasers [5][6][7] in the important spectral region of 1.3-1.6 lm. However, it is well known that conventional Ge heteroepitaxy on Si is complicated by the 4.2% difference in Ge and Si lattice constants.…”

High-speed Ge photodetector monolithically integrated with large cross-section silicon-on-insulator waveguide

“…This has fueled significant research and development work in this area in the past few years. [1][2][3][4][5][6][7][8][9][10][11] Many silicon-based active photonics components, such as high-speed modulators and Ge photodetectors [4][5][6][7][8][9][10] have been demonstrated on submicron waveguides. However, submicron SOI waveguides still suffer from high fiber coupling loss, high polarization dependent loss, and large waveguide birefringence and phase noise.…”