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Silicon-photonic devices are tuned by selective photo removal of chalcogenide glass upper claddings. Phase delays in Mach-Zehnder interferometers and coupling ratios of ring resonators are adjusted. The transfer functions of devices remain stable following trimming.

Self-assembled monolayers (SAMs) of organic molecules are widely employed in surface chemistry and biology, and serve as ultra-fine lithographic resists. Due to their small thickness of only a few nanometers, the analysis of patterned monolayer surfaces using conventional methods requires thorough point-by-point scanning using complicated equipment. In the work reported herein, patterned monolayers are simply and directly observed using a bright-field optical microscope. Features as narrow as 500 nm are properly recognized. The monolayers modify the spectral reflectivity pattern of a silica-on-silicon thin film, and introduce a contrast between bare and monolayer-coated regions of the substrate. The method can also distinguish between regions of single-layer and bi-layer coatings. The observations are supported by calculations, and by control experiments using atomic force microscopy, scanning Raman spectrometry and scanning reflection spectrometry. We show here that chemical reactions leading to the formation of a bi-layer of SAMs correspond to an optical contrast visible to the naked eye. This contrast, in turn, could provide a simple and effective differentiation between monolayers and adsorbed analytes, with possible applications in chemical and/or biological sensing. The method is also applicable to the study of graphene-on-SAM devices.

The rapid post-fabrication trimming of the group index in hybrid chalcogenide-on-silicon Mach-Zehnder interferometers is demonstrated. Index changes of 0.065 are achieved through photo-induced mass transfer in an As10Se90 layer.

A hybrid Mach-Zehnder interferometer with directly bonded LiNbO3 on silicon-on-insulator waveguides is designed and demonstrated. The transfer function of the device shows a pi phase shift subject to an external field of 0.5 V/micro-meter

The low-temperature bonding of lithium-niobate to silicon and of indium-phosphide to silicon is reported. The bonding technique is based on modifications to the surfaces of the substrates to-be-bonded, through the deposition of self-assembled, single layers of organic molecules. Chemical functionalization of the monolayers promotes the subsequent formation of bonds across the interface between the two substrates. The technique could be applicable to the fabrication of hybrid-silicon active photonic devices such as light sources, amplifiers and modulators, which are more difficult to implement solely in the silicon materials platform. Compared with direct molecular bonding methods that are currently being used in the fabrication of such devices, monolayers-assisted bonding provides numerous potential advantages: the functional groups at the monolayers termini can be chosen and adjusted to accommodate specific substrates; the process is carried out at a relatively low temperature of 120–150 °C; the outgassing of by-products may be avoided; lastly, while the bonding interface is only a few nm-thin and does not disrupt optical coupling, it may nevertheless provide a relaxation of the substrate flatness and micro-roughness requirements.

Procedures for wafer bonding between silicon and InP and between silicon and LiNbO3 at temperatures below 120 °C are reported. The bonding is based on the deposition of functionalized, organic self assembled monolayers.

A versatile procedure for the low-temperature bonding of silicon and indium-phosphide to silicon is proposed and demonstrated. The procedure relies on the deposition and functionalization of self-assembled, single molecular layers on the surface of one substrate, and the subsequent attachment of the monolayer to the surface of the other substrate with or without its own monolayer coating. The process is applicable to the fabrication of hybrid-silicon, active photonic devices.

Silicon photonic devices are tuned by selective photo removal of upper chalcogenide glass layers. Phase delays in cascaded interferometer filters and couplers of ring resonators are arbitrarily adjusted. Responses remain stable following trimming.