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Silicon RF power amplifiers (PAs) are in various RF front end modules (FEMs) today for handset and WLAN applications. Even though III-V semiconductor-based RF PAs can still offer superior frequency and breakdown performance with higher Pout and power-added-efficiency (PAE) and faster time-to-market, silicon-based RF PAs do have the advantages in offering higher monolithic integration with added functionalities...
This paper reports on recent advances on hybrid III-V on silicon integration using a wafer bonding technique. In particular, directly modulated hybrid laser with or without an external filter and integrated laser — electro-absorption modulators are discussed.
A III-V on Si hybrid integration is demonstrated by using Si slab waveguides with two parabolic reflective facets to increase the alignment tolerance between flip-chip bonded lasers and modulators. DC and high speed test results of the integrated transmitter are included.
This paper introduces oblique and lateral components into interleaved junction. Analytical model to characterize the complex interleaved interfaces is proposed, achieving nearly 23% reduction on energy consumption and 50% on VπLπ compared with traditional lateral junctions.
We report a 4×4 microring modulator matrix integrated with mode multiplexer and demultiplexer based on asymmetrical directional couplers (ADCs) for on-chip optical interconnect. Data transmission with the capacity of 512 Gbps is demonstrated by adopting 4 wavelengths and 4 modes multiplexing.
Ab-initio simulations of dilute germanium carbides (Ge:C) using hybrid functionals predict a direct bandgap with <1%C. Growth of dilute Ge:C shows reduced direct gap consistent with the model, with no structural defects detected. Ge:C may enable lasers and compact modulators on Si.
This work develops a third-order multi-bit switched-current (SI) delta-sigma modulator (DSM) with a four-bit switched-capacitor (SC) flash analog-to-digital converter (ADC) and incremental data weighted averaging circuit (IDWA). The 4-bit SC Flash ADC is used to improve its resolution, and the IDWA is used to reduce the nonlinearity of digital-to-analog converter (DAC) by moving the thermal noise...
Heterogeneously integrated DFB lasers, consisting of thin InP membranes coupled to low loss Si wire waveguides possess several advantages compared to traditional all-InP DFB lasers. The thin membranes give a large optical confinement factor and their small surface area results in relatively small parasitic capacitances. Both properties make these lasers very well suited for high speed direct modulation...
We explore the use of a class of metasurface (MTS), which consists of metalized cylinders arranged in a square lattice and placed on a ground plane, for the realization of antennas at terahertz (THz) frequencies. This MTS is particularly appropriate for being micromachined out of a silicon wafer by means of deep reactive ion etching (DRIE).
We have investigated CMOS photonics based on heterogeneous integration of SiGe/Ge and III–V semiconductors on Si, which gives us opportunities to enhance functionalities of Si photonics through their superior material properties for electronic-photonics integrated circuits.
We successfully demonstrated high-speed direct modulation of GaInAsP/InP membrane DFB laser on Si substrate for on-chip optical interconnection. The device showed threshold current of 0.21mA and single-mode operation with SMSR = 47dB. From small signal modulation, a record high modulation efficiency of 11GHz/mA1/2 was obtained. A 10 Gbps direct modulation with a bit-error-rate (BER) < 10−9 was...
We demonstrated the direct modulation in InAs/GaAs quantum dot (QD) lasers on Si. The Fabry-Pérot QD laser was integrated on Si by direct bonding method, and a cavity was formed by the as-cleaved facets without HR/AR coatings. The bonded laser was operated at room temperature with a threshold current of 40 mA and a maximum output power of 30 mW (single facet). A 6 Gbps non-return-to-zero (NRZ) signal...
Ultra-high data rate is required for future cloud computing and interconnects systems, for which integrated optical transceivers provide promising solutions. We report 66 Gb/s, on-off keying (OOK) operation of a silicon microring modulator (MRM) consuming a low power of 15 fJ/bit. To the best of our knowledge, this result features the fastest binary shift keying operation using a MRM.
All CMOS modulator based on directional coupler configuration is presented, simulated, and analyzed. The device structure utilizes the silicon-organic hybrid platform. The waveguides are made of arrays of silicon nanowires on a bulk silicon dioxide substrate. While the cladding and the voids between the silicon nanowires are filled with an electro-optic polymer. When the voltage applied across the...
Recently differential-mode inverter has been introduced, which has shown significant promise for low-power applications due to its modularity, symmetry, and reduced component count. Initially a continuous modulation scheme was adopted which has now been superseded using hybrid modulation that introduces discontinuity in modulation or yields topological switching that results in enhanced efficiency,...
We demonstrate a frequency-domain modulation spectroscopy system in the terahertz (THz) range based on the self-heterodyne technique to enhance the sensitivity of the small spectral change measurement. To evaluate the effectiveness of our system, we measured absorption of the THz wave caused by photo-induced free carriers generated in a high-resistive (4000 Ωcm) Si substrate. The 400-μm-thick Si substrate...
Direct modulation of membrane DFB laser was carried out. Small signal response showed −3dB bandwidth of 9.5 GHz at a bias current of 1 mA. This corresponds to modulation current efficiency factor of 9.8 GHz/mA½.
We demonstrate BPSK modulation using a silicon traveling-wave modulator at data rate up to 48 Gb/s, with 7.4 Vpp differential RF driving voltage. The performance of the silicon BPSK modulator is compared with a commercial Lithium Niobate phase modulator, showing better dispersion tolerance.
Photonic BiCMOS is a novel technology for fabricating electronic-photonic integrated circuits. Broadband silicon photonics devices such as germanium photodiodes and depletion type Mach-Zehnder modulators were monolithically integrated in a high performance SiGe BiCMOS baseline process. Integration aspects and first examples of demonstrator circuits shall be reviewed.
A novel technique for Peak-to-Average Power Ratio (PAPR) reduction based on dithering is presented. The dithering method consists of adding a pre-defined random noise pattern to the transmitter time-domain Orthogonal Frequency Division Multiplexing (OFDM) symbol. The noise addition is performed to reduce the high peaks of the time-domain OFDM symbol. For each OFDM symbol, there is a process of selecting...
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