160 Gbit/s OTDM Long-Haul Transmission with Long-Term Stability Using RZ-DPSK Modulation Format. - Sebastian Ferber; Carsten Schmidt-Langhorst; Reinhold Ludwig; Christof Boerner; Colja Schubert; Vincent Marembert; Marcel Kroh; Hans-Georg Weber (IEICE Trans. Commun., 2005)

Beyond 100G - high-capacity transport technologies for next generation optical core networks. - Johannes Karl Fischer; Markus Nölle; Lutz Molle; Carsten Schmidt-Langhorst; Jonas Hilt; Reinhold Ludwig; Colja Schubert (Future Network & Mobile Summit, 2012)

Narrow guard-band distributed Nyquist-WDM using fiber frequency conversion. - Thomas Richter 004; Robert Elschner; Carsten Schmidt-Langhorst; Tomoyuki Kato; Shigeki Watanabe; Colja Schubert (OFC/NFOEC, 2013)

Nonlinear transmission of 6PolSK-QPSK signals using coded modulation and digital back propagation. - Takahito Tanimura; Saleem Alreesh; Johannes Karl Fischer; Carsten Schmidt-Langhorst; Felix Frey; Christian Meuer; Robert Elschner; Lutz Molle; Colja Schubert (OFC/NFOEC, 2013)

Transmission of 512SP-QAM Nyquist-WDM signals. - Johannes Karl Fischer; Carsten Schmidt-Langhorst; Saleem Alreesh; Robert Elschner; Felix Frey; Pablo Wilke Berenguer; Lutz Molle; Markus Nolle; Colja Schubert (ECOC, 2014)

Tolerances for add/drop operation of a coherent multiplexing node based on fiber frequency conversion. - Thomas Richter 004; Carsten Schmidt-Langhorst; Robert Elschner; Tomoyuki Kato; Takahito Tanimura; Shigeki Watanabe; Colja Schubert (ECOC, 2014)

Performance comparison of different 8QAM constellations for the use in flexible optical networks. - Markus Nölle; Felix Frey; Robert Elschner; Carsten Schmidt-Langhorst; Antonio Napoli; Colja Schubert (OFC, 2014)

Coherent in-line substitution of OFDM subcarriers using fiber-frequency conversion and free-running lasers. - Thomas Richter 004; Carsten Schmidt-Langhorst; Robert Elschner; Tomoyuki Kato; Takahito Tanimura; Shigeki Watanabe; Colja Schubert (OFC, 2014)

Distributed generation of a 400-Gb/s Nyquist 16QAM dense superchannel by fiber-frequency conversion. - Thomas Richter 004; Carsten Schmidt-Langhorst; Robert Elschner; Tomoyuki Kato; Shigeki Watanabe; Colja Schubert (OFC, 2014)

Coherent reception and 126 GHz bandwidth digital signal processing of CO-OFDM superchannel generated by fiber frequency conversion. - Takahito Tanimura; Tomoyuki Kato; Ryo Okabe; Shoichiro Oda; Thomas Richter 004; Robert Elschner; Carsten Schmidt-Langhorst; Colja Schubert; Jens C. Rasmussen; Shigeki Watanabe (OFC, 2014)

Spatially distributed aggregation of a polarization-division multiplexed superchannel by frequency conversion in fiber. - Thomas Richter 004; Robert Elschner; Carsten Schmidt-Langhorst; Tomoyuki Kato; Takahito Tanimura; Shigeki Watanabe; Colja Schubert (ECOC, 2015)

Distributed 1-Tb/s all-optical aggregation capacity in 125-GHz optical bandwidth by frequency conversion in fiber. - Thomas Richter 004; Carsten Schmidt-Langhorst; Robert Elschner; Lutz Molle; Saleem Alreesh; Tomoyuki Kato; Takahito Tanimura; Shigeki Watanabe; Johannes Karl Fischer; Colja Schubert (ECOC, 2015)

Experimental analysis of nonlinear interference noise in heterogeneous flex-grid WDM transmission. - Carsten Schmidt-Langhorst; Robert Elschner; Felix Frey; Robert Emmerich; Colja Schubert (ECOC, 2015)

Experimental investigation of a four-dimensional 256-ary lattice-based modulation format. - Tobias A. Eriksson; Saleem Alreesh; Carsten Schmidt-Langhorst; Felix Frey; Pablo Wilke Berenguer; Colja Schubert; Johannes K. Fischer; Peter A. Andrekson; Magnus Karlsson 001; Erik Agrell (OFC, 2015)

Broadband coherent-optical add/drop multiplexing over 400-GHz bandwidth by fiber frequency conversion. - Tomoyuki Kato; Takahito Tanimura; Thomas Richter 004; Carsten Schmidt-Langhorst; Robert Elschner; Colja Schubert; Shigeki Watanabe (OFC, 2015)

Investigation of CAZAC sequences for data-aided channel estimation considering nonlinear optical transmission. - Markus Nolle; Felix Frey; Robert Elschner; Carsten Schmidt-Langhorst; Johannes K. Fischer; Colja Schubert (OFC, 2015)

Generation of ultra-dense superchannels using frequency conversion in optical fibers. - Thomas Richter 004; Carsten Schmidt-Langhorst; Robert Elschner; Tomoyuki Kato; Takahito Tanimura; Shigeki Watanabe; Colja Schubert (OFC, 2015)

Versatile coherent in-line 4-, 16-, 32-QAM subcarrier add/drop-multiplexing by optical frequency conversion. - Carsten Schmidt-Langhorst; Thomas Richter 004; Robert Elschner; Tomoyuki Kato; Takahito Tanimura; Shigeki Watanabe; Colja Schubert (OFC, 2015)

In-line optical signal multiplexing by polarization-insensitive fiber frequency conversion. - Tomoyuki Kato; Takahito Tanimura; Takeshi Hoshida; Thomas Richter 004; Robert Elschner; Carsten Schmidt-Langhorst; Colja Schubert; Shigeki Watanabe (OFC, 2016)

112 Gb/s PDM-PAM4 Generation and 80 km Transmission Using a Novel Monolithically Integrated Dual-Polarization Electro-Absorption Modulator InP PIC. - Moritz Baier; Francisco M. Soares; Zhennan Zheng; Carsten Schmidt-Langhorst; Robert Elschner; Felix Frey; Marko Gruner; Johannes Karl Fischer; Colja Schubert; Martin Moehrle; Norbert Grote; Martin Schell (ECOC, 2017)

Fiber Nonlinearity Mitigation in 800-km Transmission of a 1.6-Tb/s Superchannel Using Waveband-Shift-Free Optical Phase Conjugation. - Carsten Schmidt-Langhorst; Isaac Sackey; Robert Elschner; Tomoyuki Kato; Takahito Tanimura; Shigeki Watanabe; Takeshi Hoshida; Colja Schubert (ECOC, 2017)

Colorless C-band WDM system enabled by coherent reception of 56-GBd PDM-16QAM using an high-bandwidth ICR with TIAs. - Robert Emmerich; Robert Elschner; Carsten Schmidt-Langhorst; Gijs van Elzakker; Jan Hoffmann 003; Andreas Umbach; Colja Schubert (OFC, 2017)

Continuously tunable optical frequency shift of 1.6-Tb/s superchannel up to THz-range by polarization switched frequency conversion. - Tomoyuki Kato; Shigeki Watanabe; Takahito Tanimura; Thomas Richter 004; Robert Elschner; Carsten Schmidt-Langhorst; Colja Schubert; Takeshi Hoshida (OFC, 2017)

Novel wavelength-shift-free optical phase conjugator used for fiber nonlinearity mitigation in 200-Gb/s PDM-16QAM transmission. - Isaac Sackey; Robert Elschner; Carsten Schmidt-Langhorst; Tomoyuki Kato; Takahito Tanimura; Shigeki Watanabe; Takeshi Hoshida; Colja Schubert (OFC, 2017)

Any-to-Any Signal Frequency Shifting Across Entire C-Band Using Continuously Tuneable Optical Frequency Shifter. - Tomoyuki Kato; Shigeki Watanabe; Takahito Tanimura; Carsten Schmidt-Langhorst; Isaac Sackey; Robert Elschner; Colja Schubert; Takeshi Hoshida (ECOC, 2018)

Improving Achievable Information Rates of 64-GBd PDM-64QAM by Nonlinear Transmitter Predistortion. - Robert Elschner; Robert Emmerich; Carsten Schmidt-Langhorst; Felix Frey; Pablo Wilke Berenguer; Johannes K. Fischer; Helmut Grießer; Danish Rafique; Jörg-Peter Elbers; Colja Schubert (OFC, 2018)

Fiber-Optic Frequency Shifting of THz-Range WDM Signal Using Orthogonal Pump-Signal Polarization Configuration. - Tomoyuki Kato; Shigeki Watanabe; Takahito Tanimura; Robert Elschner; Carsten Schmidt-Langhorst; Colja Schubert; Takeshi Hoshida (OFC, 2018)

Distributed Aggregation and Reception of a 400-Gb/s Net Rate Superchannel in a Single-Photodiode 110-GHz Kramers-Kronig Receiver. - Isaac Sackey; Carsten Schmidt-Langhorst; Robert Emmerich; Robert Elschner; Tomoyuki Kato; Takahito Tanimura; Shigeki Watanabe; Takeshi Hoshida; Colja Schubert (OFC, 2018)

64-GBd DP-Bipolar-8ASK Transmission Over 120 km SSMF Employing a Monolithically Integrated Driver and MZM in 0.25-μm SiGe BiCMOS Technology. - Gilda Raoof Mehrpoor; Carsten Schmidt-Langhorst; Benjamin Wohlfeil; Robert Elschner; Danish Rafique; Robert Emmerich; Annika Dochhan; Iria Garcia Lopez; Pedro Rito; Despoina Petousi; Dietmar Kissinger; Lars Zimmermann; et al. (OFC, 2019)

Characterization and Linearization of High Bandwidth Integrated Optical Transmitter Modules. - Markus Nölle; M. Sezer Erkilinç; Robert Emmerich; Carsten Schmidt-Langhorst; Robert Elschner; Colja Schubert (ECOC, 2020)

Experimental Comparison of Fiber Nonlinearity Mitigation: Intra-Modal FWM versus Inter-Modal FWM. - Isaac Sackey; Carsten Schmidt-Langhorst; Colja Schubert; Johannes Karl Fischer; Ronald Freund (OFC, 2020)

PON transceiver technologies for ≥50 Gbits/s per λ: Alamouti coding and heterodyne detection [Invited]. - M. Sezer Erkilinç; Robert Emmerich; Kai Habel; Volker Jungnickel; Carsten Schmidt-Langhorst; Colja Schubert; Ronald Freund (JOCN, 2020)

Performance Evaluation of an Interband All-Optical Wavelength Converter for Cost-Effective High-Capacity Optical Networks. - Isaac Sackey; Robert Elschner; Robert Emmerich; Carsten Schmidt-Langhorst; D. D. Groß; Georg Rademacher; Yoshinari Awaji; Hideaki Furukawa; Takemi Hasegawa; Colja Schubert; Ronald Freund (ECOC, 2021)

Semantic Security for Indoor THz-Wireless Communication. - Rebekka Schulz; Onur Günlü; Robert Elschner; Rafael F. Schaefer; Carsten Schmidt-Langhorst; Colja Schubert; Robert F. H. Fischer (ISWCS, 2021)

Enabling S-C-L-Band Systems with Standard C-Band Modulator and Coherent Receiver using Nonlinear Predistortion. - Robert Emmerich; Matheus Ribeiro Sena; Robert Elschner; Carsten Schmidt-Langhorst; Isaac Sackey; Colja Schubert; Ronald Freund (OFC, 2021)

Characterization of Dispersion-Tailored Silicon Strip Waveguide for Wideband Wavelength Conversion. - Hidenobu Muranaka; Tomoyuki Kato; Shun Okada; Tokuharu Kimura; Yu Tanaka; Tsuyoshi Yamamoto; Isaac Sackey; Gregor Ronniger; Carsten Schmidt-Langhorst; Colja Schubert; Takeshi Hoshida (OECC/PSC, 2022)

Design and Characterization of Dispersion-Tailored Silicon Strip Waveguides toward Wideband Wavelength Conversion. - Hidenobu Muranaka; Tomoyuki Kato; Shun Okada; Tokuharu Kimura; Yu Tanaka; Tsuyoshi Yamamoto; Isaac Sackey; Gregor Ronniger; Robert Elschner; Carsten Schmidt-Langhorst; Colja Schubert; Takeshi Hoshida (IEICE Trans. Electron., 2023)

Experimental Validation of Partitioned MIMO Equalizer with Low-Resolution Interface for Mitigation of Mode-Group Coupling in SDM Transmission over 3-Mode Fiber. - Nicolas Braig-Christophersen; Aymeric Arnould; Robert Elschner; Carsten Schmidt-Langhorst; Ruben S. Luis; Pamir Oezsuna; Kallyan Das; Juan L. Moreno Morrone; Robert Emmerich; Kazuhiko Aikawa; Hideaki Furukawa; Georg Rademacher; et al. (OFC, 2025)

Dynamic Adaptation of IP Virtual Network Topologies over Multi-Granular (Wavelength and Waveband) Optical Networks Supported by ETSI TeraFlowSDN multi-layer Control. - Lluis Gifre; Andrea Sgambelluri; Carlos Manso; M. Enrico; H. Zaid; Nicola Sambo; Waleed Akbar; Carsten Schmidt-Langhorst; F. Javier Vilchez; C. Schubert; Ricard Vilalta; Behnam Shariati; et al. (OFC, 2025)

Autonomous Service Provisioning and Self-Healing in Multi-Band Multi-Domain IPoWDM Networks. - H. Zaid; Abdelrahmane Moawad; Behnam Shariati; Robert Emmerich; Alessio Giorgetti; Ramon Casellas; Carsten Schmidt-Langhorst; E. Fernandez; Pablo Pavón-Mariño; Filippo Cugini; Vignesh Karunakaran; Emilio Riccardi; et al. (OFC, 2025)