Gianlorenzo Masini

A Grating-Coupler-Enabled CMOS Photonics Platform

We have developed a silicon photonics platform that allows monolithic integration with electronic circuits in a CMOS-compatible process. In this platform, vertical couplers are found to be a superior solution compared to traditional edge-coupling techniques. Grating couplers are an essential element in developing the optical wafer-scale test infrastructure, which in turn, enables the development of the photonic device library. The photonic devices were assembled into a 4 × 10 Gb/s transceiver die that also contains modulator drive, control, and receive electronics.

Metal–semiconductor–metal near-infrared light detector based on epitaxial Ge/Si

In this letter we report on a metal–semiconductor–metal photodetector based on thick relaxed Ge layers, epitaxially grown on silicon after insertion of a low-temperature-grown Ge buffer layer. The detector shows a good responsivity at normal incidence at both 1.3 and 1.55 μm, with a maximum responsivity of 0.24 A/W at 1.3 μm under a 1 V bias. A response time of about 2 ns has been measured.

Ge-on-Si approaches to the detection of near-infrared light

We review our recent results on Ge-based near-infrared photodetectors grown on silicon. We fabricated metal-semiconductor-metal photodetectors based on epitaxial pure-Ge grown on silicon by chemical vapor deposition. Material characterization and device performances are illustrated and discussed. Exploiting a novel approach based on evaporation of polycrystalline-Ge on silicon, we also realized efficient near-infrared photodiodes with good speed and sensitivity. Finally, multiple-element devices were designed, fabricated, and tested, such as a voltage-tunable wavelength-selective photodetector based on a SiGe superlattice and a linear array of 16 photodetectors in poly-Ge on Si.

Si based optoelectronics for communications

Si based optoelectronic devices have recently successfully entered the market of optical communications. This fact is stimulating renewed efforts in the design of optoelectronic components based on the well-established Si technology. In this paper, the motivations supporting these efforts and the major obstacles to be overcome are presented. Moreover, an overview of the state of the art of different classes of silicon based optoelectronic devices (waveguides, detectors, light sources etc.) is given.

Ge on Si p-i-n photodiodes operating at 10Gbit∕s

We report on fast p-i-n photodetectors operating in the near infrared and realized in pure germanium on silicon. The diodes were fabricated by chemical vapor deposition at 600°C without affecting the crystal quality and allowing the integration with standard silicon processes. We demonstrate responsivities of 0.4 and 0.2A∕W at 1.3 and 1.55μm, respectively, as well as operation at 10Gbit∕s.

Monolithically integrated high-speed CMOS photonic transceivers

We demonstrate monolithically integrated 4×10 Gb/s WDM transceivers built in a production 130 nm SOI CMOS process. Only light sources are external to the chip. 40 Gb/s error-free, bidirectional transmission is demonstrated.

High-Speed Near Infrared Optical Receivers Based on Ge Waveguide Photodetectors Integrated in a CMOS Process

We discuss our approach to monolithic intergration of Ge photodectors with CMOS electronics for high-speed optical transceivers. Receivers based on Ge waveguide photodetectors achieve a sensitivity of 14.2 dBm ( bit error rate (BER)) at 10 Gbps and 1550 nm.

2.5 Gbit/s polycrystalline germanium-on-silicon photodetector operating from 1.3 to 1.55 μm

We report on a fast polycrystalline germanium-on-silicon heterojunction photodetector for the near-infrared. The device exhibits a pulse response faster than 200 ps, allowing operation at 2.5 Gbit/s as testified by open eye diagrams. This polycrystalline device, with responsivities of 16 and 5 mA/W at 1.3 and 1.55 μm, respectively, and dark currents of 1 mA/cm2, is entirely integrable on standard silicon electronics and is an appealing low-cost candidate for fiber-to-the-home communication networks.

A 1550nm, 10Gbps monolithic optical receiver in 130nm CMOS with integrated Ge waveguide photodetector

This paper introduce the worlds first, high-speed optical receiver using Ge waveguide photodetectors monolithically integrated in the CMOS process. The integrated receiver achieves a sensitivity of -14.2 dBm (10-12 BER) at 10 Gbps and 1550 nm.

A multi-wavelength 3D-compatible silicon photonics platform on 300mm SOI wafers for 25Gb/s applications

Recently Silicon Photonics has generated an outstanding interest for integrated optical communications. In this paper we describe a 300mm Silicon Photonics platform designed for 25Gb/s and above applications at the three typical communication wavelengths and compatible with 3D integration. Main process features and device results are described.