System Impact of Cascaded All-Optical Wavelength Conversion of D(Q)PSK Signals in Transparent Optical Networks. - Robert Elschner; Christian-Alexander Bunge; Klaus Petermann (J. Networks, 2010)

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)

Characterization of polarization insensitive FOPA using a polarization-maintaining highly non-linear fiber. - Isaac Sackey; Thomas Richter 004; Christian Meuer; Robert Elschner; Mahmoud Jazayerifar; Klaus Petermann; 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)

Efficient real-time implementation of a channelizer filter with a weighted overlap-add approach. - Felix Frey; Robert Elschner; Christoph Kottke; Colja Schubert; Johannes K. Fischer (ECOC, 2014)

Impact of SBS on polarization-insensitive single-pump optical parametric amplifiers based on a diversity loop scheme. - Mahmoud Jazayerifar; Isaac Sackey; Robert Elschner; Stefan Warm; Christian Meuer; Colja Schubert; Klaus Petermann (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)

Kerr nonlinearity compensation in a 5×28-GBd PDM 16-QAM WDM system using fiber-based optical phase conjugation. - Francesco Da Ros; Isaac Sackey; Robert Elschner; Thomas Richter 004; Christian Meuer; M. Nolle; Mahmoud Jazayerifar; Klaus Petermann; Christophe Peucheret; Colja Schubert (ECOC, 2014)

Design and performance evaluation of an OPC device using a dual-pump polarization-independent FOPA. - Isaac Sackey; Francesco Da Ros; Thomas Richter 004; Robert Elschner; Mahmoud Jazayerifar; Christian Meuer; Christophe Peucheret; Klaus Petermann; 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)

Characterization of a fiber-optical parametric amplifier in a 5 × 28-GBd 16-QAM DWDM system. - Isaac Sackey; Robert Elschner; Markus Nölle; Thomas Richter 004; Lutz Molle; Christian Meuer; Mahmoud Jazayerifar; Stefan Warm; Klaus Petermann; 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)

Non-reciprocal gain due to counter-propagating pumps in a polarization-independent FOPA with diversity loop. - Isaac Sackey; Mahmoud Jazayerifar; Robert Elschner; Thomas Richter 004; Christian Meuer; Klaus Petermann; 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)

5 Gbit/s real-time processing using π/4-shift DQPSK for bidirectional radio-over-fibre system. - Kai Habel; Luz Fernandez del Rosal; Stefan Weide; Jonas Hilt; Volker Jungnickel; Robert Elschner; Colja Schubert; Felix Frey; Johannes Karl Fischer; Ronald Freund (ICTON, 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)

Terahertz Technologies to Deliver Optical Network Quality of Experience in Wireless Systems Beyond 5G. - Alexandros-Apostolos A. Boulogeorgos; Angeliki Alexiou; Thomas Merkle; Colja Schubert; Robert Elschner; Alexandros Katsiotis; Panagiotis Stavrianos; Dimitrios Kritharidis; Panteleimon-Konstantinos Chartsias; Joonas Kokkoniemi; Markku J. Juntti; Janne J. Lehtomäki; et al. (IEEE Commun. Mag., 2018)

Wireless Terahertz System Architectures for Networks Beyond 5G. - Alexandros-Apostolos A. Boulogeorgos; Angeliki Alexiou; Dimitrios Kritharidis; Alexandros Katsiotis; Georgia D. Ntouni; Joonas Kokkoniemi; Janne J. Lehtomäki; Markku J. Juntti; Dessy Yankova; Ahmed Mokhtar; Jean-Charles Point; José Machado 002; et al. (CoRR, 2018)

100 Gbit/s Terahertz-Wireless Real-Time Transmission Using a Broadband Digital-Coherent Modem. - Carlos Castro; Robert Elschner; Thomas Merkle; Colja Schubert (5G World Forum, 2019)

Ethernet Transmission over a 100 Gb/s Real-Time Terahertz Wireless Link. - Carlos Castro; Robert Elschner; José Machado 002; Thomas Merkle; Colja Schubert; Ronald Freund (GLOBECOM Workshops, 2019)

Experimental Validation of Coherent DSP for Combined Fibre-Optical / Terahertz-Wireless Links. - Carlos Castro; Robert Elschner; Thomas Merkle; Colja Schubert (ISWCS, 2019)

32 GBd 16QAM Wireless Transmission in the 300 GHz Band using a PIN Diode for THz Upconversion. - Carlos Castro; Simon Nellen; Robert Elschner; Isaac Sackey; Robert Emmerich; Thomas Merkle; Björn Globisch; David de Felipe; Colja Schubert (OFC, 2019)

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)

Analysis of Joint Impairment Mitigation in a Hybrid Optic-THz Transmission System. - Carlos Castro; Robert Elschner; Colja Schubert (SPAWC, 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)

100 Gb/s Real-Time Transmission over a THz Wireless Fiber Extender using a Digital-Coherent Optical Modem. - Carlos Castro; Robert Elschner; Thomas Merkle; Colja Schubert; Ronald Freund (OFC, 2020)

Hybrid fiber-optical/THz-wireless link transmission using low-cost IM/DD optics. - Francisco Rodrigues; Ricardo Ferreira; Carlos Castro; Robert Elschner; Thomas Merkle; Colja Schubert; António Luis Jesus Teixeira (OFC, 2020)

Experimental Demonstrations of High-Capacity THz-Wireless Transmission Systems for Beyond 5G. - Carlos Castro; Robert Elschner; Thomas Merkle; Colja Schubert; Ronald Freund (IEEE Commun. Mag., 2020)

Data Converter Interleaving: Current Trends and Future Perspectives. - Christian Schmidt 001; Hiroshi Yamazaki; Gregory Raybon; Peter Schvan; Erwan Pincemin; S. J. Ben Yoo; Daniel J. Blumenthal; Takayuki Mizuno; Robert Elschner (IEEE Commun. Mag., 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)

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)

Optoelectronic Heterodyne THz Receiver for 100-300 GHz Communication Links. - Milan Deumer; Oliver Stiewe; Simon Nellen; Sebastian Lauck; Steffen Breuer; Robert B. Kohlhaas; Colja Schubert; Robert Elschner; Ronald Freund; Martin Schell (IEEE Access, 2024)

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)

High-Capacity THz Wireless Transmission Supporting Future 6G Optical Networks. - Colja Schubert; Robert Elschner; Oliver Stiewe; In-Ho Baek; Simon Schütze; Andreas Maaßen; Kallyan Das; Robert B. Kohlhaas; Simon Nellen; Milan Deumer; Thomas Merkle; Axel Tessmann; et al. (OFC, 2025)