Tyndall packaging and imec Si-Photonics Passives – Ghent University – imec, Belgium

Tyndall packaging and imec Si-Photonics Passives – Ghent University – imec, Belgium

A 4-channel true time delay optical beamforming network for mmWave applications

Photonics Research Group / IDLab, Department of Information Technology (INTEC), Ghent University – imec, Belgium


Laurens Bogaert, Johan Bauwelinck, Gunther Roelkens


Tyndall packaging + imec Si-Photonics Passives

Die Size

6mm x 3mm (full wafer to allow for post-processing)

Design tool

IPKISS software from Luceda Photonics


Next-generation wireless networks will require increasingly faster data links. One of the key enablers is the shift towards higher frequency bands, e.g. the mmWave range. These parts of the spectrum offer large portions of contiguous bandwidth and are significantly less congested than traditional communication bands. Another key enabler is beamforming, which benefits from the scaling of antenna dimensions resulting from the migration to mmWave frequencies to allow for antenna arrays in a small form factor.

This work demonstrates the implementation of a true time delay optical beamforming network (OBFN) for a 4-element antenna array. The design is based on switchable optical delay lines and offers a 5-bit tunability of the delay for each antenna element with a resolution of 1.6 ps.


  • Four channel true time delay OBFN
  • 5-bit tunable delay cells with 1.6 ps resolution (thermal tuning)
  • Packaged device: pin header for biasing of heaters and fiber array for optical I/O
Packaged optical beamforming network
4-Channel true time delay optical beamforming network before post-processing


For the fabrication of our photonic devices we use EUROPRACTICE as it offers affordable MPW services. Furthermore, we relied on the packaging services provided by Tyndall to add a fiber array to the assembly resulting in a connectorized device that can easily be used in link experiments.

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