03 Oct 2008
A new class of photonic systems for fixed-frequency millimetre-wave applications could be used in radar, instrumentation and communications.
IPHOBAC, a three-year European project involving industrial and academic partners, is merging photonics and radio wave technologies to construct photonic devices in the millimetre-wave frequency range above 30 GHz.
"The millimetre-wave photonic (mmWP) technology can offer absolutely unique properties, such as ultra-wide tunability, extremely low phase noise or oscillator remoting," Andreas Stohr, IPHOBAC coordinator, told optics.org. "It has inherent features that cannot easily be achieved with other competing technologies or all-electric solutions, and could be a disruptive technology in multiple applications."
The project has developed packaged InP-based quantum dash mode-locked lasers emitting in the 1.5 µm range, generating frequencies from 24 GHz to 77 GHz. These devices generate a millimetre-wave tone featuring a very narrow linewidth, lower than 100 kHz, that is sufficient for use in wireless transmission.
"Another interesting feature is the very wide optical spectrum of about 13 nm that is generated with a -3dB bandwidth," commented Stohr. "This wide bandwidth makes it suitable for very short pulse generation. Using standard single mode fibre, we obtained a 480 fs pulse. Since the emitted power is 15 mW, the peak power of this pulse generator is very high."
Other systems under investigation by IPHOBAC include:
• Tunable dual-mode InP-based DBR and DFB lasers operating at 1.55 µm for optical signal generation in the 30-300 GHz range.
• T-ray transmitters, consisting of an InP-based photomixer integrated with a planar antenna. Packaged in fibre-optic package with a THz focusing lens, the transmitters can generate mm-waves from 30-325 GHz.
• Packaged 100 GHz photodiodes, including a broadband package enabling operation from DC-110 GHz. "To our knowledge these are the first packaged 1.55 µm photodetectors offering such broadband performance," said Stohr.
The IPHOBAC consortium members are:
Five industrial partners: Alcatel-Thales III-V Lab, Centre for Integrated Photonics, u2t Photonics, Thales and France Telecom.
Six academic partners: CNRS-Lille, University Politecnica de Valencia, University College London, University of Duisberg-Essen, University of Ljubljana and the Kista Photonics Research Centre.