Over the past decade, photonic integrated circuits (PICs) have evolved rapidly. They have already found widespread use in telecommunication systems, where they serve as highly miniaturized optical transceivers, and are being developed for emerging applications in medical technology and sensing . Especially, silicon (Si) photonics has established itself as a scalable technology that is becoming widely available via commercial foundry platforms [2–5]. Si photonics foundries offer a wide range of devices, such as high-speed modulators and photodetectors, as well as high-quality passive waveguides. Moreover, the availability of Si photonics has catalyzed new research fields that leverage the excellent mechanical properties of Si in combination with its large refractive index. For example, integrated optical sensors based on suspended Si waveguides achieve high sensitivity, due to the high Si–air refractive index contrast that allows for high mode deconfinement [6–9]. Furthermore, optomechanical coupling and optical forces can be harnessed, for uses such as particle manipulation, telecommunication, or on-chip nonreciprocal transmission [10–12]. Movable and tunable Si photonic micro–electromechanical (MEMS) components also show promise as low-power and compact reconfigurable photonic building blocks for large scale programmable photonic circuits that can be reprogrammed for a variety of optical functions [13–19], i.e., generic field-programmable PICs (FP-PICs), similar to FP gate arrays (FPGAs) in electronics. In contrast to conventional -clad photonic devices, optomechanical and Si photonic MEMS devices feature suspended and movable parts, and exposed waveguide cores. These devices are much more susceptible to environmental influences such as exposure to dust, gas composition, and humidity levels, and, therefore, require a robust packaging solution to ensure reliable operation over extended time periods. Hermetic sealing in inert gas or vacuum, protecting the photonic MEMS from such environmental influence, is crucial for their reliable performance, and serves as a prerequisite for their commercialization [20–22].
Set citation alerts for the article
Please enter your email address