22 research outputs found
DAC-Less amplifier-less generation and transmission of QAM signals using sub-volt silicon-organic hybrid modulators
We demonstrate generation and transmission of optical signals by directly interfacing highly efficient silicon-organic hybrid (SOH) modulators to binary output ports of a field-programmable gate array. Using an SOH Mach-Zehnder modulator (MZM) and an SOH IQ modulator we generate ON-OFF- keying and binary phase-shift keying signals as well as quadrature phase-shift keying and 16-state quadrature amplitude modulation (16QAM) formats. Peak-to-peak voltages amount to only 0.27 V-pp for driving the MZM and 0.41 V-pp for the IQ modulator. Neither digital-to-analog converters nor drive amplifiers are required, and the RF energy consumption in the modulator amounts to record-low 18 fJ/bit for 16QAM signaling
10 GBd modulator directly driven by an FPGA without electrical amplification
Using standard single-ended FPGA outputs with 270 mV(pp) we demonstrate 10GBd OOK and BPSK transmission by directly driving a low-voltage silicon-organic hybrid ( SOH) modulator. The scheme does not require electronic driver amplifiers, which paves the way to energy-efficient photonic-electronic integration
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DAC-less and amplifier-less generation and transmission of 16QAM signals using a sub-volt silicon photonic modulator
We demonstrate generation and transmission of QPSK and 16QAM signals by directly interfacing highly efficient silicon-organic hybrid (SOH) modulators to GTH ports of an FPGA. Peak-to-peak voltages amount to only 0.41 V-pp. Neither digital-to-analog converters (DAC) nor drive amplifiers are required
Primary human osteoblasts with reduced alkaline phosphatase and matrix mineralization baseline capacity are responsive to extremely low frequency pulsed electromagnetic field exposure — Clinical implication possible
For many years electromagnetic fields (EMFs) have been used clinically with various settings as an exogenous stimulation method to promote fracture healing. However, underlying mechanisms of action and EMF parameters responsible for certain effects remain unclear. Our aim was to investigate the influence of defined EMFs on human osteoblasts' and osteoclasts' viability and function. Primary human osteoblasts and osteoclasts were treated 3 times weekly for 21 days during their maturation process using the Somagen® device (Sachtleben GmbH, Hamburg, Germany), generating defined extremely low-frequency pulsed electromagnetic fields (ELF-PEMFs). Certain ELF-PEMF treatment significantly increased the total protein content (up to 66%), mitochondrial activity (up to 91.1%) and alkaline phosphatase (AP) activity (up to 129.9%) of human osteoblasts during the entire differentiation process. Furthermore, ELF-PEMF treatment enhanced formation of mineralized matrix (up to 276%). Interestingly, ELF-PEMF dependent induction of AP activity and matrix mineralization was strongly donor dependent — only osteoblasts with a poor initial osteoblast function responded to the ELF-PEMF treatment. As a possible regulatory mechanism, activation of the ERK1/2 signaling pathway was identified. Maturation of osteoclasts from human monocytes was not affected by the ELF-PEMF treatment. In summary the results indicate that a specific ELF-PEMF treatment with the Somagen® device improves viability and maturation of osteoblasts, while osteoclast viability and maturation was not affected. Hence, ELF-PEMF might represent an interesting adjunct to conventional therapy supporting bone formation during fracture healing or even for the treatment of osteoporosis
Silicon-organic hybrid (SOH) integration for low-power and high-speed signal generation
Silicon-organic hybrid (SOH) integration combines silicon photonic devices with electro-optic organic cladding materials. We demonstrate that SOH modulators can be used to generate advanced modulation formats with high symbol rates at low operating voltages and low energy consumption. Moreover, we show that the SOH approach can be extended to plasmonic waveguide structures, leading to the plasmonic-organic hybrid (POH) concept