Broadband Analog Interleavers

Broadband Analog Interleavers in BiCMOS

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Time interleaving of DACs enhances sampling rate and bandwidth
Time interleaving of DACs enhances sampling rate and bandwidth

Future optical communication systems require electrical signal sources with bandwidths exceeding the possibilities of currently available digital-to-analog converters (DACs). To generate electrical signals at still higher bandwidths, we pursue the approach of time-interleaving of multiple DACs by means of an analog multiplexer (AMUX). Via cyclic switching between multiple DACs with frequencies up to 100 GHz, a significantly higher bandwidth is achieved, compared to a single DAC.

INT has implemented a circuit for an analog 2:1 multiplexer in the SiGe BiCMOS technology SG13G3 of IHP, which is among the fastest available semiconductor technologies, with fT = 450 GHz and fmax = 650 GHz. The transparent signal path of the AMUX chip shows a bandwidth beyond 110 GHz.

Block diagram and chip photograph of the analog 2:1 interleaver.
Block diagram and chip photograph of the analog 2:1 interleaver.

An evaluation board has been developed at INT for the characterization of the chip. It allows for the use of on-wafer probes at the output of the chip, to assure high bandwidth towards the measurement instrument.

Evaluation board with assembled chip of the 2:1 AMUX.
Evaluation board with assembled chip of the 2:1 AMUX.
Measurement setup with on-wafer probe.
Measurement setup with on-wafer probe.

In joint measurements with the project partner from Fraunhofer Heinrich-Hertz-Institute (HHI), Berlin, department Photonic Networks and Systems, electrical eye diagrams up to 150 GBd were demonstrated, using digital pre-distortion of the signals.

Measured eye diagrams: PAM-4 at 150 GBd, PAM-8 at 120 GBd.
Measured eye diagrams: PAM-4 at 150 GBd, PAM-8 at 120 GBd.

The activities in the field of analog multiplexers are part of the project “ELAMUR”, funded by the Deutsche Forschungsgemeinschaft DFG.

The authors of this project’s publication “120 GBd SiGe-Based 2:1 Analog Multiplexer Module for Ultra-Broadband Transmission Systems" received the EuMIC Prize at the European Microwave Integrated Circuits Conference 2021.

EuMIC Prize for the publication "120 GBd SiGe-Based 2:1 Analog Multiplexer Module for Ultra-Broadband Transmission Systems"
EuMIC Prize for the publication "120 GBd SiGe-Based 2:1 Analog Multiplexer Module for Ultra-Broadband Transmission Systems"

INT also works on 4:1 analog Multiplexer circuit designs, to aggregate the bandwidth of four DACs.

Publications

  1. 2022

    1. C. Schmidt, T. Tannert, J. H. Choi, C. Caspar, D. Pech, S. Wünsch, G. Ropers, J. Schostak, V. Jungnickel, R. Freund, M. Grözing, and M. Berroth, “120 GBd SiGe-Based 2:1 Analog Multiplexer Module for Ultra-Broadband Transmission Systems,” in European Microwave Integrated Circuits Conference (EuMIC), 2022, pp. 169–172.
    2. J. Schostak, T. Tannert, C. Schmidt, H. Rucker, V. Jungnickel, M. Grözing, M. Berroth, and R. Freund, “150 GBd PAM-4 Electrical Signal Generation using SiGe-Based Analog Multiplexer IC,” in European Microwave Integrated Circuits Conference (EuMIC) 2022, 2022, pp. EuMIC13–3.

  2. 2021

    1. T. Tannert, M. Grözing, M. Berroth, C. Schmidt, J. H. Choi, C. Caspar, J. Schostak, V. Jungnickel, R. Freund, and H. Rucker, “Analog 2:1 Multiplexer with over 110 GHz Bandwidth in SiGe BiCMOS Technology,” in IEEE BiCMOS and Compound Semiconductor Integrated Circuits and Technology Symposium (BCICTS), 2021, p. paper 5a.3.

  3. 2018

    1. C. Schmidt, P. Zielonka, V. Jungnickel, R. Freund, T. Tannert, M. Grözing, M. Berroth, and F. Gerfers, “Behavioral Model for a High-Speed 2:1 Analog Multiplexer,” in IEEE International Midwest Symposium on Circuits and Systems (MWSCAS), Windsor, ON, Canada, 2018, pp. 1–4.

  4. 2017

    1. T. Tannert, X.-Q. Du, D. Widmann, M. Grözing, M. Berroth, C. Schmidt, C. Caspar, J. H. Choi, V. Jungnickel, and R. Freund, “A SiGe-HBT 2:1 analog multiplexer with more than 67 GHz bandwidth,” in IEEE Bipolar / BiCMOS Circuits and Technology Meeting (BCTM), Miami, Florida, USA, 2017, p. pp. 146––149.
Additional Information
  • DFG project
    Electronic Analog Multiplexer for High-Speed Communication Systems (ELAMUR)

Contact

This image shows Sefa Özbek

Sefa Özbek

M. Sc.

Research staff member

 

Prof. Dr.-Ing. Ronald Freund, MBA

Fraunhofer HHI, Head of Photonic Networks and Systems Department

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