Photonic Integration


The GALACTICO integration platform will rely on 4 μm SOI PLC technology. The advantage of the technology is the very good control on waveguide properties such as birefringence (polarization dependent frequency shift PDFS) and polarization dependent loss (PDL). The GALACTICO SOI platform will offer:

  • Low insertion loss (<0.5 dB)
  • Low waveguide loss (0.1 dB/cm)
  • Intermediate index contrast

These characteristics will render the technology very attractive for implementing advanced coherent communication schemes, which require accurate phase control and balanced signals.

Hybridization of components

The key objective in the GALACTICO hybrid integration is the definition of a high precision, generic assembly process. Conventional integration techniques increase alignment tolerances by employing waveguide/component tapering. However, staying below 2dB penalty requires sub-micron precision. In order to achieve this precision, GALACTICO will address alignment in the 3 axis of integration. GALACTICO SOI integration technology will exploit the existence of the buried oxide layer in the platform. This layer will act as an “intrinsic” alignment plane (in y-direction). The position of the buried oxide will be well defined in the SOI wafer and will be used to align to the optical axis of the waveguide and the hybrid device.


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.