The next-generation integration circuits (ICs) have its origination from optoelectronic integration which offers a promising strategy to simultaneously obtain the merits of electrons and photons when they serve as the information carrier, including high-density communication and high-speed information processing.
The ever-increasing demand on bandwidth and information density in ICs calls for the micro/nano functional devices capable of being fabricated in three-dimensional (3D) ICs, which is desirable for their improved performance in data processing under lower consumption. However, in such highly integrated circuits, selective electrical modulation of specific micro/nanoscale optical devices is an essential requirement for yielding more functional and more compact integrated elements but hindered by the normally used nonlinearity found in electro-optic materials.
As one of the 3D printing techniques, femtosecond laser direct writing (FsLDW) enables the immediate and addressable construction of 3D-integration optoelectronic devices utilizing organic compounds with two-photon polymerized features.
The polymerized microstructures, with doping flexibility, can be readily incorporated with organic dye molecules to produce functional devices like coherent laser sources. Apart from that, natural polymers possess excellent responsiveness to external stimuli, including temperature.
Their large thermo-optic coefficient enables the realization of the electrical tuning of resonant wavelength with high efficiency when they are fabricated into microcavity structures. The incorporation of thermo-responsive polymeric microlaser with underneath electrical microheater in the 3D fabrication manner can be used as an effective hybrid microlaser module with selective electric modulation towards optical-electronic integration.
Not quite long ago, Professor Yong Sheng Zhao's team in the Institute of Chemistry, Chinese Academy of Sciences demonstrated an in situ electrically modulated microlaser module based on 3D-printed dye-doped polymer microdisks, which is published in Science China Chemistry. The Ministry of Science and Technology of China and the National Natural Science Foundation of China financially supported this new study
The polymer matrix's thermo-optic effect enabled the tuning of lasing modes from the microdisk upon heating. The shape designability of FsLDW allows the fabrication of higher-level microstructures to manipulate light signals, including the waveguide coupled microdisks for light remote control and the coupled double-microdisk resonators for laser mode selection. The latter microstructure was further integrated with an underneath electrical microheater.
The cavity resonant wavelength, as a result, can be shifted based on resistance heating controlled optical length change through the thermo-optic effect of polymeric matrix material which enabled an electrical modulation of the output wavelength of the 3D-printed microlaser module.
