2017

• F. Frey, R. Elschner, C. Schmidt-Langhorst, R. Emmerich, C. Schubert, J. Fischer, and R. Fischer
  Investigation of Nonlinear Inter-Channel Interference in Heterogeneous Flexible Optical Networks
  Accepted at: International ITG Conference on Systems, Communications and Coding (SCC), Hamburg, February 2017
• A. Aimone, F. Frey, R. Elschner, I. Garcia Lopez, G. Fiol, P. Rito, M. Grunder, J. Fischer, C. Schubert, A. Ulusoy, D. Kissinger, and M. Schell
  DAC-less Generation and Transmission of 32-GBd PDM-256-QAM using Ultra-Low-Power InP IQ Segmented MZM
  Accepted at: IEEE Photonics Technol. Lett.

2015

• C. Schmidt-Langhorst, R. Elschner, F. Frey, R. Emmerich, and C. Schubert
  Experimental Analysis of Nonlinear Interference Noise in Heterogeneous Flex-Grid WDM Transmission
  41th European Conf. on Opt. Commun. (ECOC), 2015, paper Tu.1.4.3
• K. Habel, L. Fernandez, S. Weide, J. Hilt, V. Jungnickel, R. Elschner, C. Schubert, F. Frey, J. K. Fischer, and R. Freund
  5 Gbit/s Real-Time Processing Using π/4 -shift DQPSK for Bidirectional Radio-Over-Fibre System
  17th International Conference on Transparent Optical Networks (ICTON), 2015, paper Tu.D2.3.
• R. Elschner, F. Frey, C. Schmidt-Langhorst, J. K. Fischer, and C. Schubert
  FPGA Implementation of a Data-Aided Single-Carrier Frequency-Domain Equalizer for Format-Flexible Receivers
  16. ITG-Fachtagung Photonische Netze, 2015
• S. Alreesh, C. Schmidt-langhorst, F. Frey, P. W. Berenguer, C. Schubert, and J. K. Fischer
  Transmission Performance of 4D 128SP-QAM With Forward Error Correction Coding
  IEEE Photonics Technol. Lett., vol. 27, no. 7, pp. 744–747, 2015
• J. K. Fischer, C. Schmidt-Langhorst, S. Alreesh, R. Elschner, F. Frey, P. W. Berenguer, L. Molle, M. Nolle, and C. Schubert
  Generation, transmission, and detection of 4-d set-partitioning QAM signals
  J. Lightwave Technol., vol. 33, no. 7, pp. 1445–1451, 2015
• M. Nölle, F. Frey, R. Elschner, C. Schmidt-Langhorst, J. K. Fischer, and C. Schubert
  Investigation of CAZAC Sequences for Data-Aided Channel Estimation Considering Nonlinear Optical Transmission
  Opt. Fiber Commun. Conf. (OFC), 2015, paper Th3G.2
• T. A. Eriksson, S. Alreesh, C. Schmidt-Langhorst, F. Frey, P. W. Berenguer, C. Schubert, J. K. Fischer, P. A. Andrekson, M. Karlsson, and E. Agrell
  Experimental Investigation of a Four-Dimensional 256-ary Lattice-based Modulation Format
  Opt. Fiber Commun. Conf. (OFC), 2015, paper W4K.3.

2014

• J. K. Fischer, R. Elschner, F. Frey, J. Hilt, C. Kottke, and C. Schubert
  Digital signal processing for coherent UDWDM passive optical networks
  15. ITG-Fachtagung Photonische Netze, 2014, pp. 1–7
• J. K. Fischer, S. Alreesh, R. Elschner, F. Frey, M. Nölle, C. Schmidt-Langhorst, and C. Schubert
  Bandwidth-variable transceivers based on four-dimensional modulation formats
  J. Lightwave Technol., vol. 32, no. 16, pp. 2886–2895, 2014.
• R. Elschner, F. Frey, C. Schmidt-Langhorst, J. K. Fischer, and C. Schubert
  Data-Aided DSP for Flexible Transceivers
  Sig. Proc. Photonic Commun. (SPPCom), 2014, paper SW1C.1.
• C. Kottke, J. K. Fischer, R. Elschner, F. Frey, J. Hilt, C. Schubert, D. Schmidt, Z. Wu, and B. Lankl
  Coherent UDWDM PON with joint subcarrier reception at OLT.
  Opt. Express, vol. 22, no. 14, pp. 16876–88, Jul. 2014
• F. Frey, R. Elschner, C. Kottke, C. Schubert, and J. K. Fischer
  Efficient Real-time Implementation of a Channelizer Filter with a Weighted Overlap-Add Approach
  40th European Conf. on Opt. Commun. (ECOC), 2014, paper Tu.3.1.3.
• M. Nölle, F. Frey, R. Elschner, C. Schmidt-Langhorst, A. Napoli, and C. Schubert
  Performance Comparison of Different 8QAM Constellations for the Use in Flexible Optical Networks
  Opt. Fiber Commun. Conf. (OFC), 2014, paper W3B.2.
• T. Richter, M. Nölle, F. Frey, and C. Schubert
  Generation and Coherent Reception of 107-GBd Optical Nyquist BPSK, QPSK, and 16QAM
  IEEE Photonics Technol. Lett., vol. 26, no. 9, pp. 877–880, 2014.

2013

• C. Schmidt-Langhorst, F. Frey, M. Nölle, R. Elschner, C. Meuer, P. Wilke Berenguer, and C. Schubert
  Optimization of subcarrier spacing of 400-Gb/s dual-carrier Nyquist PDM-16QAM in a Flexgrid scenario
  39th European Conf. on Opt. Commun. (ECOC), 2013, p. P.5.1.
• R. Elschner, F. Frey, C. Schmidt-Langhorst, J. K. Fischer, M. Nölle, and C. Schubert,
  Software-defined Transponders for Future Flexible Grid Networks
  Photonic Networks and Devices (NETWORKS), 2013, paper NT2C.4.
• J. K. Fischer, S. Alreesh, R. Elschner, F. Frey, M. Nölle, and C. Schubert
  Bandwidth-Variable Transceivers Based on 4D Modulation Formats for Future Flexible Networks
  39th European Conf. on Opt. Commun. (ECOC), 2013, paper Tu.3.C.1.
• T. Tanimura, S. Alreesh, J. K. Fischer, C. Schmidt-Langhorst, F. Frey, C. Meuer, R. Elschner, L. Molle, and C. Schubert
  Nonlinear Transmission of 6PolSK-QPSK Signals using Coded Modulation and Digital Back Propagation
  Opt. Fiber Commun. Conf. (OFC), 2013, paper OTu3B.3.

2012

• J. K. Fischer, S. Alreesh, R. Elschner, F. Frey, C. Meuer, L. Molle, C. Schmidt-Langhorst, T. Tanimura, and C. Schubert
  Experimental Investigation of 126-Gb/s 6PolSK-QPSK signals
  Opt. Express, vol. 20, no. 26, pp. B232–7, Dec. 2012.
• R. Elschner, F. Frey, C. Meuer, J. K. Fischer, S. Alreesh, C. Schmidt-Langhorst, L. Molle, T. Tanimura, and C. Schubert
  Experimental Demonstration of a Format-Flexible Single Carrier Coherent Receiver using Data-Aided Digital Signal Processing
  38th European Conf. on Opt. Commun. (ECOC), 2012, vol. 20, no. 27, paper We.1.A.4.
• R. Elschner, F. Frey, C. Meuer, J. K. Fischer, S. Alreesh, L. Molle, T. Tanimura, and C. Schubert
  Experimental demonstration of a format-flexible single-carrier coherent receiver using data-aided digital signal processing
  Opt. Express, vol. 20, no. 27, pp. 28786–28791, 2012.

• J. K. Fischer, S. Alreesh, R. Elschner, F. Frey, C. Meuer, L. Molle, T. Tanimura, and C. Schubert
  Experimental Investigation of 126-Gb/s 6PolSK-QPSK Signals
  38th European Conf. on Opt. Commun. (ECOC), 2012, vol. 2, no. 1, paper We.1.C.4.