Despoina Petousi

Analysis of Optical and Electrical Tradeoffs of Traveling-Wave Depletion-Type Si Mach–Zehnder Modulators for High-Speed Operation

Fundamental limiting factors regarding high-speed performance of broadband depletion-type silicon (Si) Mach-Zehnder modulators (MZMs) are studied. Optical and electrical measurements of MZMs with traveling wave electrodes (TWE) reveal significant dependences between optoelectrical bandwidth and design parameters. An equivalent circuit model is implemented to fit measured modulator characteristics. Using the model, the limits of TWE depletion-type Si MZM systems are studied under the requirement of specific driving voltage. By comparing phase shifters with different doping concentration or junction position, we explore the fundamental optical and electrical tradeoffs which are limiting high-speed operation.

Monolithic photonic-electronic QPSK receiver for 28Gbaud

The paper presents the first fully monolithic photonic-electronic single-polarization QPSK receiver for 56Gbps (28Gbaud). The receiver sub-system was realized in photonic BiCMOS technology and demonstrates integration capabilities for state-of-the-art coherent systems.

Performance Limits of Depletion-Type Silicon Mach–Zehnder Modulators for Telecom Applications

In this study we discuss the performance limits of depletion-type Silicon Mach-Zehnder Modulators in terms of the critical factors of linearity, loss and required driving voltage. We introduce the parameters for already existing phase shifters and discuss optimized designs that can meet system specifications in order to make this type of modulators competitive toward the leading technologies.

A Monolithically Integrated Segmented Linear Driver and Modulator in EPIC 0.25-

In this paper, a monolithically integrated segmented linear driver and Mach-Zehnder modulator (MZM) are presented. The transmitter is fabricated in electronic-photonic integrated circuit 0.25-μm SiGe:C BiCMOS technology, with fT/fmax = 190 GHz. The driver and the modulator are divided into 16 segments and the MZM phase shifter has a total length of 6.08 mm. The segmented driver delivers a maximum of 4 Vpp differentially, featuring a gain of 13 dB and total harmonic distortion below 5%. Electro-optical time-domain measurements using PAM-4 modulation format are performed, demonstrating optical eye-diagrams up to 25 Gbaud. The electro-optical bandwidth of the transmitter is 18 GHz. The power dissipation of the driver is 1.5 W, resulting in an energy per bit of 30 pJ/bit at 50 Gb/s. The reported optical transmitter demonstrates for the first time an implementation of a linear driver integrated with an MZM in a Si monolithic process.

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In this work, a monolithically integrated segmented driver and Mach-Zehnder modulator (MZM) in 0.25 μm SiGe:C BiCMOS technology is presented. The driver and the modulator are divided in 16 segments and the MZM has a total length of 6.08 mm. The driver has a maximum gain of 14.5 dB. Electro-optical time-domain measurements were performed and an optical eye-diagram with more than 13 dB of extinction ratio at 28 Gb/s is demonstrated. The driver dissipates a total of 2 W of DC power. To the best knowledge of the authors, the presented work shows the highest extinction ratio achieved at 28 Gb/s in silicon modulators.

m SiGe:C BiCMOS Platform

In this letter, a dual-drive Si depletion-type Mach-Zehnder modulator (MZM) monolithically integrated with a segmented driver using 0.25-μm SiGe:C photonic bipolar complementary metal-oxide-semiconductor technology is demonstrated. The phase shifter on each MZM arm has a total length of 6.048 mm and is divided into 16 sections, driven by the driver segments. Extinction ratio (ER) higher than 11 dB is shown at 28 and 32 Gb/s at ON-OFF keying with a differential input voltage swing of 800 mVpp (3.5 Vpp on the phase shifters). The power consumption equals to 64 pJ/b at 28 Gb/s. This is one of the highest ER values shown by a monolithically integrated Si MZM at this data rate.

A monolithically integrated segmented driver and modulator in 0.25 µm SiGe:C BiCMOS with 13 dB extinction ratio at 28 Gb/s

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 examples of demonstrator circuits shall be reviewed.

Monolithically Integrated High-Extinction-Ratio MZM With a Segmented Driver in Photonic BiCMOS

Two types of silicon dual-ring resonator-based high-speed optical modulators are proposed. With two microring resonators cascaded either in series or in parallel, the transmission spectrum evolves from a deep notch to a sharp peak with the resonators operating in a push-pull manner. The frequency chirp of the modulated signals can be highly suppressed by choosing a proper working wavelength.

BiCMOS silicon photonics platform for fabrication of high-bandwidth electronic-photonic integrated circuits

The introduction of advanced optical modulation formats for coherent data transmission and multilevel signalling enlarges the transmission capacities but also requires more complex opto-electronic components. The need for cost efficient compact solutions is the main driver for photonic-electronic integration technologies. In the framework of the European Project GALACTICO a new mixed technology platform for advanced transceivers is being developed. The technology relies on the cost efficient Germanium-on-Silicon technology, and SiGe BiCMOS technology together with GaAs technology [1]. A selection of the best suited materials and solutions ready to deploy is made to provide the performance required for transmitter and receiver of next generation networks operated at capacities beyond Terabit/s.

Silicon dual-ring resonator-based push-pull modulators

This paper presents the design and characterization of a monolithically integrated optical transmitter fabricated in the 0.25 µm SiGe:C BiCMOS EPIC technology of IHP. The prototype comprises a 15-segment depletion-type Si Mach-Zehnder modulator (MZM) with total length of 5.67 mm and multichannel driver amplifier exhibiting integrated 4-bit digital-to-analog converter (DAC) functionality. In 2-bit operation, electro-optical (E/O) pulse-amplitude-modulation (PAM)-4 eye diagrams up to 20 GBd are demonstrated, in good agreement with E/O co-simulation results. The driver delivers a differential output swing of 4 Vpp across all 15 segments, dissipating 1.1 W of power, which translates into an energy consumption of 27.5 pJ/bit at 40 Gb/s.