Giannis Kanakis

High Speed Direct Modulation of a Heterogeneously Integrated InP/SOI DFB Laser

An integrated laser source to a silicon photonics circuit is an important requirement for optical interconnects. We present direct modulation of a heterogeneously integrated distributed feedback laser on and coupled to a silicon waveguide. We demonstrate a 28 Gb/s pseudo-random bit sequence non-return-to-zero data transmission over 2 km non-zero dispersion shifted fiber with a 1-dB power penalty. Additionally, we show 40-Gb/s duobinary modulation generated using the bandwidth limitation of the laser for both back-to-back and fiber transmission configurations. Furthermore, we investigate the device performance for the pulse amplitude modulation (PAM-4) at 20 GBd for high-speed short-reach applications.

A 64 Gb/s PAM-4 linear optical receiver

We present a linear optical receiver realized on 130 nm SiGe BiCMOS. Error-free operation assuming FEC is shown at bitrates up to 64 Gb/s (32 Gbaud) with 165mW power consumption, corresponding to 2.578 pJ/bit.

Photonic integration enabling new multiplexing concepts in optical board-to-board and rack-to-rack interconnects

New broadband applications are causing the datacenters to proliferate, raising the bar for higher interconnection speeds. So far, optical board-to-board and rack-to-rack interconnects relied primarily on low-cost commodity optical components assembled in a single package. Although this concept proved successful in the first generations of opticalinterconnect modules, scalability is a daunting issue as signaling rates extend beyond 25 Gb/s. In this paper we present our work towards the development of two technology platforms for migration beyond Infiniband enhanced data rate (EDR), introducing new concepts in board-to-board and rack-to-rack interconnects. The first platform is developed in the framework of MIRAGE European project and relies on proven VCSEL technology, exploiting the inherent cost, yield, reliability and power consumption advantages of VCSELs. Wavelength multiplexing, PAM-4 modulation and multi-core fiber (MCF) multiplexing are introduced by combining VCSELs with integrated Si and glass photonics as well as BiCMOS electronics. An in-plane MCF-to-SOI interface is demonstrated, allowing coupling from the MCF cores to 340x400 nm Si waveguides. Development of a low-power VCSEL driver with integrated feed-forward equalizer is reported, allowing PAM-4 modulation of a bandwidth-limited VCSEL beyond 25 Gbaud. The second platform, developed within the frames of the European project PHOXTROT, considers the use of modulation formats of increased complexity in the context of optical interconnects. Powered by the evolution of DSP technology and towards an integration path between inter and intra datacenter traffic, this platform investigates optical interconnection system concepts capable to support 16QAM 40GBd data traffic, exploiting the advancements of silicon and polymer technologies.

16×1 dual polarization SOI MUX/DEMUX for flexible-grid optical networks

We demonstrate a bandwidth selective and wavelength flexible 16×1 MUX/DEMUX device with on-chip polarization multiplexing functionality. Experimental demonstration on data traffic conditions revealed excellent performance for operation in Flex-Grid application scenarios.

16 × 1 Packaged MUX/DEMUX for Flexible-Grid Optical Networks

A comprehensive experimental study on the performance of a packaged flexible-grid compliant 16 × 1 packaged MUX/DEMUX device is presented. The device relies on a bandwidth and wavelength selective filtering element array integrated on an SOI platform, equipped with on-chip polarization multiplexing functionality. Multilateral operating credentials are demonstrated through the evaluation of the device in 2 × 1 MUX, 1 × 2 DEMUX and PolMUX configurations scenarios under realistic data traffic conditions, thus confirming its suitability for next-generation flexible-grid optical networks.

PAM-4 and Duobinary direct modulation of a hybrid InP/SOI DFB laser for 40 Gb/s transmission over 2 km single mode fiber

We demonstrate 40 Gb/s PAM-4 and Duobinary direct modulation of a heterogeneously integrated InP on SOI DFB laser. Transmission measurement was performed using a 2 km NZ-DSF with a PRBS 215 and 1.5 Vpp swing voltage.

Optical PAM-4 generation through polarization multiplexing in single-polarization single-mode VCSELs

PAM-4 modulation is considered a key enabler for scaling capacity in datacenter networks, due to its bandwidth efficiency and implementation simplicity. We propose a novel technique for optical generation of four-level signals by means of polarization multiplexing, leveraging the single-polarization operation of a double-mesa single-mode VCSEL with 20.5 GHz 3-dB bandwidth. The scheme obviates the need for linear electronic drivers and circumvents the requirement for driving the VCSEL in its linear regime. Experimental results verify the scheme, exhibiting BER within FEC standards at 28 Gb/s. Comparison with an electrical PAM-4 modulated VCSEL demonstrates superior performance of the proposed concept.