GALACTICO is an innovative and industrially-driven project exploring photonic integration for high-speed coherent systems. GALACTICO technology highlights related to the design and development of new integrated components and systems that can be disseminated are described in this page.

GALACTICO 44 Gb/s QPSK transmission with GaAs IQ modulator

A GaAs IQ modulator module with >27 GHz 3-dB bandwith and driving voltage (Vpi) as low as 3V has been fabricated by U2t. The modulator performance was demonstrated in successful transmission of 44 Gb/s QPSK over 2000 km recirculating loop experiment. A live demonstration was set-up at ECOC 2012 (U2t booth). A quad (4x) GaAs IQ modulator array photonic integrated circuit was fabricated. The IQ modulators in the array exhibit >27 GHz 3-dB bandwidth and a Vpi of 3V.

From Left to right: packaged high bandwidth GaAs modulator module, 44 Gb/s QPSK constellation diagram (after 30 loops) recorded in 2000 km recircluating loop experiment using the IQ modulator achieving BER performance within FEC limit of 3.8×10-3, live IQ GaAs modulator demo set-up by U2t @ ECOC 2012.

GALACTICO up to 150 Gb/s QAM modulation using GaAs IQ modulator array

A GaAs IQ modulator array chip has been fabricated by U2t and tested by the Karlsruhe Institute of Technology (KIT) in a collaborative effort. The IQ modulator demonstrated up to 150 Gb/s data rate using 64QAM format @ 25 Gbaud. QPSK, 16QAM and 32 QAM were also demonstrated at 25 Gbaud.

Fabricated IQ GaAs modulator array mounted on KIT probe station for testing

GALACTICO develops new-gen silicon/Ge coherent Rx for 100G and beyond OTN

GALACTICO has implemented the migration towards dense photonic receiver chips using cost-effective and dense silicon photonic integration. The following milestones were successfully achieved: Demonstration of 23 GHz Ge diodes with 50 nA dark current and >0.8 A/W responsivity Demonstration of silicon nano-waveguide coherent receiver boards including DP functionality achieving >100x form factor reduction against micrometer, low index contrast silicon technology.


Top: a) optimized SOI DP coherent receiver board, b) packaging concept for twin (2x) carrier DP receiver module. Bottom: c) Ge diode measured performance and d) Ge diodes grown on 220 nm silicon substrate.

GALACTICO 100G dual polarization (DP) - QPSK coherent receiver hybrid photonic integrated chip (PIC)

The PIC integrates an array of vertically illuminated InP photodetectors on a passive silicon-on-insulator (SOI) coherent receiver board using high precision flip-chip technology. The SOI board integrates a polarization splitter and 2x MMI-based 90°-hybrids. SOI PLC technology is developed at IHP whereas, the hybrid PIC assembly in standard 100G coherent receiver package is done by U2t. To learn more please follow our GFP 2012 publication entitled: “Hybrid Integration of Coherent Receivers for Terabit Ethernet on SOI Waveguide PLC” at GFP 2012 conference.

Left: SOI PLC snapshot showing waveguides crossings following the 4x4 MMI output ports. Middle: flip-chip integrated InP PD array on the SOI receiver board. Right: hybrid PIC assembled in standard coherent receiver photonic package.


Latest News

GALACTICO new invited papers

GALACTICO invited paper in JLT: Publication title: “Monolithic GaAs Electro-Optic IQ Modulator Demonstrated at 150 Gbit/s with 64QAM”. Link to paper

GALACTICO invited paper in ICTON 2013: Publication title: “Cost-effective Broadband GaAs IQ Modulator Array for Long-Reach OFDM-PONs”. Link to conference website

Invited paper in Frontiers in Optics reporting GaAs modulator technology: Publication title: “Non-linear nano-photonics”. Link to conference website

GALACTICO post-deadline paper @ OFC 2013: Publication title: “First Monolithic GaAs IQ Electro-optic Modulator, Demonstrated at 150 Gbit/s with 64-QAM”. Link to paper

GALACTICO contributed paper @ OFC 2013, Anaheim, CA: GALACTICO presentation @ OFC 2013. Publication title: “Fabrication of the First High-speed GaAs IQ Electro-optic Modulator Arrays and Applicability Study for Low-Cost Tb/s Direct-Detection Optical OFDM Networks”. Link to paper

High speed IQ GaAs modulators: GALACTICO demonstrates 44 Gb/s QPSK transmission with GaAs IQ modulator and fabricates high speed quad IQ modulators for new generation multi-carrier OTN systems. Read more

GALACTICO demonstrates high bandwidth Ge diodes for new generation silicon integrated coherent receiver modules: Ge diodes with >23 GHz 3-dB bandwidth and record performance in terms of dark current (<50 nA) and responsivity (>0.8 A/W) have been fabricated using Germanium epi o n 220 nm SOI substrates by GALACTICO partner IHP. Read more

20/06/2012 GALACTICO @ 17th European Conference on Network and Optical Communications

GALACTICO will be presented at NOC 2012 as part of the invited presentation “Advances in Networking” given by Stefan Spälter – Nokia Siemens Networks. NOC 2012 will be held in Vilanova i la Geltru, Spain. Link to program

25/06/2012 GALACTICO goes to the 9th International Conference on Group IV Photonics

GALACTICO accepted oral presentation at GFP 2102: "Hybrid Integration of Coherent Receivers for Terabit Ethernet on SOI Waveguide PLC". GFP 2012 conference will be held on 29-31 August in San Diego California. Link to advance program


25/06/2012 GALACTICO to present at the 38th European Conference on Optical Communications

“Octary QAM as Capacity Extension for Coherent UDWDM PON”
“Flexible Optical QAM Generation with a Low-Complexity Amplified InP SOA/EAM-Based Modulator”

ECOC 2012 will be held on 16-20 September in Amsterdam. Link to conference program

04/03/2012 GALACTICO @ OFC 2012, Los Angeles, California

GALACTICO presentation @ OFC 2012. Publication title: Phase Entropy-Based Frequency Offset Estimation for Coherent Optical QAM Systems. Link to paper

06/05/2012 GALACTICO @ CLEO 2012, San Jose, California

GALACTICO presentation @ CLEO 2012. Publication title: Frequency Offset Estimation in M-QAM Coherent Optical Systems Using Phase Entropy. Link to paper

19-21/9/2011: ECOC 2011 Geneva

GALACTICO showcases at ECOC 2011 exhibition. GALACTICO was exhibited at this year ECOC through the exhibition booths set-up by U2t, Constelex and NoE EURO-FOS. Device prototypes were displayed and project brochures were distributed to the conference visitors.


20/9/2011: ECOC 2011 Geneva

IHP and TUBerlin JointLab publication at ECOC 2011. Publication title: Fully passive Si-photonic 90° hybrid for coherent receiver applications. For more info click here


20/07/2011: GALACTICO presentation at IEEE Photonics Society Summer Topicals 2011 conference.

The GALACTICO concept and the first research results were presented at the recent 2011 Photonics Society Summer Topical Meetings held in Montreal. The presentation entitled: “The European Galactico Project: Coherent Terabit Ethernet Systems Using 4 μm Rib Waveguide Silicon-on-Insulator Technology and GaAs modulators” was part of the Terabit Optical Ethernet Topical Meeting. The talk was given by CONSTELEX Technology Enablers. For more info click here.

26/5/2011: Presentation to members of the Electrical Engineering Students European Association EESTEC

Constelex presentation on "starting a technology company" focused on disseminating the challenges and requirements for creating technology start-ups, presented photonics as enabling technology in ICT and reviewed the company's business and R&D activities. For more information, please click here.