C-band side-entry Ge quantum-well electroabsorption modulator on SOI operating at 1 V swing

Abstract

An electroabsorption modulator using a side-entry architecture achieved a contrast ratio exceeding 3 dB over a 3.5 nm range in the C-band, using a voltage swing of 1 V and operating at 1008C. Modulation was due to the quantum-confined Stark effect from ten Ge/SiGe quantum wells epitaxially grown on silicon-on-insulator (SOI) wafers. The device exploits an asymmetric Fabry-Perot resonator formed between the totally internally reflecting air-SiGe interface and a frustrated total internal reflection from the buried oxide layer of the SOI substrate.

Ge-on-Si photonic devices for photonic-electronic integration on a Si platform

“…Compared with FKE for bulk Ge, an abrupt change in the absorption coefficient takes place for QCSE around the absorption edge due to the stepwise change in the density of states for carriers, and an extinction ratio larger than FKE is observed [68]. The optical modulation based on QCSE has been reported for the operation wavelength of 1.42-1.54 µm and the operation speed as large as 20 GHz with the power consumption on the order of 0.1 pW or below [68,81,82,83,84,85]. For the integration with Si WGs, the thickness of relaxed SiGe buffer layer beneath the Ge/GeSi quantum wells should be reduced [84].…”

Indirect absorption in germanium quantum wells

“…7 In 2005, QCSE was first demonstrated in Ge/SiGe quantum wells 8,9 with initial results showing the possibility of modulation. 10,11 While it has not yet been tested under digital modulation to such high speeds, 12,13 power consumption has already met 2022 off-chip energy targets of <20 fJ/bit through tight integration with a Si waveguide. 13 Ge-based optoelectronic modulators employing FKE and QCSE a Electronic mail: dabm@stanford.edu show great promise in meeting the strict energy requirements with high speed operation needed to alleviate the future interconnect bottleneck.…”

An optical modulator based on a single strongly coupled quantum dot - cavity system in a p-i-n junction

“…One of the primary challenges of optical interconnects is to reduce the energy requirement, with a targeted energy-per-bit near ∼ 10 fJ/bit for chip-to-chip communication over the next decades [1]. While there has been steady progress in power and speed of directly modulated laser sources [4,5,6] and modulators with external lasers [7,8,9,10,11,12], the 10 fJ/bit target remains extremely challenging. One approach is to dramatically miniaturize the active region.…”