Nucleic acid aptamer-based research has focused on achieving the highest performance for bioassays. However, there are limitations in evaluating the affinity for the target analytes in these nucleic acid aptamer-based bioassays. In this study, we mainly propose graphene oxide (GO)-based electrical and optical analyses to efficiently evaluate the affinity between an aptamer and its target. We found that an aptamer-coupled GO-based chip with an electrical resistance induced by a field-effect transistor, with aptamers as low as 100 pM, can detect the target, thrombin, at yields as low as 250 pM within five minutes. In the optical approach, the fluorescent dye-linked aptamer, as low as 100 nM, was efficiently used with GO, enabling the sensitive detection of thrombin at yields as low as 5 nM. The cantilever type of mechanical analysis also demonstrated the intuitive aptamer–thrombin reaction in the signal using dBm units. Finally, a comparison of electrical and optical sensors’ characteristics was introduced in the attachment and detachment of aptamer to propose an efficient analysis that can be utilized for various aptamer-based research fields.

In this study, we propose an eight-channel monolithic optical transmitter using silicon electro-absorption modulators (EAMs) based on free-carrier injection by Schottky junctions. The transmitter consists of a 1 × 8 silicon arrayed-waveguide grating (AWG) and eight 500-μm-long EAMs on a 5.41 × 2.84 mm² footprint. It generates eight-channel dense wavelength-division multiplexing (DWDM) outputs with 1.33 nm channel spacing (Δλ) in the C-band from a single broadband light source and modulates each channel with over 3 dB modulation depth at 6 V peak-to-peak. The experimental results showed that the feasibility of a homogeneous silicon DWDM transmitter with a single light source for switch fabrics in intra-data-center interconnects over heterogeneous integration with regards to more complementary metal–oxide–semiconductor (CMOS) compatibility.

This paper demonstrates a 1 V _pp low-driving-voltage silicon electro-absorption modulator (EAM) utilizing a Schottky diode. Optical modulation using a Schottky diode was achieved through the intensity change of the guiding light due to free-carrier absorption in the semiconductor to change its absorption coefficient, not through conventional interference effects. The proposed EAM consists of a lateral metal–semiconductor junction that helps maximize free-carrier injection and extraction through a Schottky contact on rib waveguide. In order to achieve high-speed operation, traveling-wave type electrodes were designed. The fabricated EAM demonstrates a broad operational wavelength range of 50 nm for C-band with a uniform extinction ratio (ER) of 3.9 dB, even for a compact modulation length of 25 μ m with a driving voltage of 1 V _pp . Also, the traveling-wave type electrodes enabled the modulator to operate at up to 26 GHz with 13.2 GHz of 3 dB electro-optic bandwidth experimentally.