Lowering the energy consumption in silicon photonic devices and systems [Invited]

We review current silicon photonic devices and their performance in connection with energy consumption.Four critical issues are identified to lower energy consumption in devices and systems: reducing the influence of the thermo-optic effect, increasing the wall-plug efficiency of lasers on silicon, optimizing energy performance of modulators, and enhancing the sensitivity of photodetectors. Major conclusions are(1) Mach–Zehnder interferometer-based devices can achieve athermal performance without any extra energy consumption while microrings do not have an efficient passive athermal solution;(2) while direct bonded III–V-based Si lasers can meet system power requirement for now, hetero-epitaxial grown III–V quantum dot lasers are competitive and may be a better option for the future;(3) resonant modulators, especially coupling modulators, are promising for low-energy consumption operation even when the power to stabilize their operation is included;(4) benefiting from high sensitivity and low cost, Ge/Si avalanche photodiode is the most promising photodetector and can be used to effectively reduce the optical link power budget. These analyses and solutions will contribute to further lowering energy consumption to meet aggressive energy demands in future systems.

Effects of diluted methanol and water as foaming agents on the performance of latex foamed warm asphalt mixtures

Latex as an asphalt modifier has gained popularity in the asphalt industry as it improves the durability of asphalt pavement.However,the elastomeric properties of latex stiffen the asphalt binders,resulting in additional energy consumption during the production of asphalt mixtures,which may cause a higher emission of greenhouse gases.This is undesirable for sustainable development and the environment.In this study,the applicability of diluted methanol and water was comparatively evaluated as foaming agents in the production of warm mix asphalt(WMA)mixtures incorporating latex.Diluted methanol was used because it has a lower boiling point and latent heat than water,allowing the asphalt mixture to be produced at a lower temperature and thus consuming less energy.The performance of the foamed asphalt mixture was investigated through service characteristics,mechanical performance,and moisture susceptibility of mixtures.The service characteristics,on the other hand,were measured in a laboratory while preparing and compacting the asphalt mixture,which refers to the amount of energy required during the production and construction stages in the asphalt plant and on the construction site,respectively.The degree of energy required was assessed based on the workability index,coatability index,and the compaction energy index.The mechanical performance of asphalt mixtures was characterized by indirect tensile strength,resilient modulus,and dynamic creep tests.The resistance to moisture damage was evaluated based on the common parameter,indirect tensile strength ratio.The findings revealed that the use of diluted methanol foaming agent helped improve the workability of latex modified asphalt mixtures.The foamed latex-modified WMA demonstrated better performance compared to asphalt mixtures prepared using water as the foaming agent.