Article
Optics
Sutapa Ghosh, Gadi Eisenstein
Summary: Dual comb spectroscopy (DCS) is a broadband technique that offers high resolution and fast data acquisition. Current designs are based on fiber or solid-state lasers, which require complicated stabilization setups. This work describes a hybrid dual-comb spectrometer that combines a broadband fiber laser and a mode-locked semiconductor laser. The mutual coherence time of 100 seconds has been achieved by injection locking the semiconductor laser to a continuous laser.
Article
Engineering, Electrical & Electronic
Elizabeth Chen, Brandon Buscaino, Joseph M. Kahn
Summary: We present an architecture for wavelength-division-multiplexed coherent data center links using resonator-enhanced electro-optic frequency comb generators. The phase noise in each frequency comb is determined by the optical phase noise of the seed laser and the phase noise of the microwave oscillator. We propose an analog coherent receiver that performs carrier recovery on all wavelength channels using only two phase-locked loops.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Kaile Li, Yuanxiang Chen, Yongtao Huang, Yitong Li, Ying Han, Jia Fu, Jianguo Yu
Summary: A novel 0.36 THz photonic-assisted terahertz-wave signal generation scheme utilizing a single phase modulator as optical frequency comb generator has been demonstrated through simulation. The scheme successfully achieved high-frequency stability of desired optical carriers, enabling the performance evaluation of 4 Gbit/s QPSK signal or 2 Gbaud 16 QAM signal under different transmission scenarios with a bit error ratio below the HD-FEC threshold.
OPTICAL FIBER TECHNOLOGY
(2021)
Article
Optics
Yu Zheng, Hongxiang Wang, Yuefeng Ji
Summary: PPMS-CPR proposed in this paper utilizes the phase noise parameters from master and slave channels for coarse phase pre-recovery, and employs maximum likelihood estimation (MLE) to compensate residual phase noise, effectively solving the weakened phase coherence between master and slave channels while maintaining low computational complexity. Simulation results demonstrate that PPMS-CPR shows good tolerance for frequency comb linewidth and transmission distance, with performance comparable to ICPR and only about 7.1% complexity when the number of channels is 101.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Optics
Yu Zheng, Hongxiang Wang, Yu Zhang
Summary: Using optical frequency combs as WDM laser sources in coherent optical communication systems has the potential for low-cost, low-complexity, and large-capacity communications. A master-slave carrier phase recovery method using optical phase conjugation is proposed to solve the weakening of phase coherence caused by chromatic dispersion and mitigate nonlinear effects. Simulation results show that the proposed method outperforms conventional MS-CPR and ICPR, achieving a lower bit error rate (BER) in a long-haul system with high-order modulation signals.
OPTICS COMMUNICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Maria Morant, Luis Gonzalez-Guerrero, Cyril C. Renaud, Roberto Llorente
Summary: This paper introduces and demonstrates a photonic THz generation technique utilizing an optical frequency comb and multicore fiber transmission, showing the feasibility and advantages of remote generation and simplified digital signal processing. The performance of the proposed technique is evaluated experimentally, highlighting the benefits of using comb generation to reduce frequency offset fluctuation and simplify DSP.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Physics, Multidisciplinary
Naoya Kuse, Kenji Nishimoto, Yu Tokizane, Shota Okada, Gabriele Navickaite, Michael Geiselmann, Kaoru Minoshima, Takeshi Yasui
Summary: A low phase noise THz wave is provided by a frequency-stabilized Kerr microresonator soliton comb, which significantly reduces the relative phase noise between two tones. This photonics-based technique shows superior phase noise compared to other photonic THz oscillators, and a measurement technique beyond the limit of frequency-multiplied microwave is demonstrated.
COMMUNICATIONS PHYSICS
(2022)
Article
Engineering, Electrical & Electronic
Elizabeth Chen, Larry A. Coldren, Joseph M. Kahn
Summary: Multi-wavelength analog coherent links using mode-locked laser (MLL) frequency combs as transmitter and local oscillator (LO) sources are proposed. Carrier recovery (CR) is achieved using optical phase-locked loops (PLLs), while polarization demultiplexing and static phase offset removal are performed using cascaded optical phase shifters. The proposed design shows reduced power consumption and improved phase-error performance compared to other designs.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Hilmi Othman, Xing Ouyang, Cleitus Antony, Frank Smyth, Paul D. Townsend
Summary: The spectrally-sliced coherent receiver offers a cost-effective solution for optical access networks. It allows for reduced bandwidth of analog front-end components and analog-to-digital convertors compared to traditional intradyne coherent receivers. In this experimental study, we achieved a single-polarization 50 Gb/s QPSK C-band transmission over 40 km of standard fiber using receiver bandwidths as low as 6.25 GHz. The use of an array of local oscillator lines derived from an injection locked gain-switched optical frequency comb demonstrates the potential for a compact photonic integrated circuit. The results show that, with practical comb parameter values, the receiver can operate with less than a 1 dB sensitivity penalty compared to a conventional intradyne receiver, making it a promising solution for next-generation access networks.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Claudio Porzi, Fabio Falconi, Marc Sorel, Paolo Ghelfi, Antonella Bogoni
Summary: This paper reports on the characterization of a photonic integrated circuit (PIC) for generating RF carriers in the millimeter-wave to sub-THz region. Experimental results demonstrate effective selection of frequencies and noise reduction, offering new insights for optimizing future wireless communication and sensing network systems.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Optics
Yongqi Li, Xiaohong Hu, Haihao Cheng, Yishan Wang, Yanzhao Yang, Shun Wu
Summary: We demonstrated an all-fiber compact Erbium-doped optical frequency comb based on optical reference. The comb stabilization was achieved by locking the repetition rate and optical comb tooth to RF and CW references respectively. The system showed stable locking for almost five hours, with a fraction instability of 4.3 x10-12 and 2.8 x10-13 at 1 s and 10 s gate times respectively. Our acetylene-stabilized fiber comb offers a feasible solution for outdoor applications in fiber sensing, laser stabilization, and spectrum analysis.
OPTICS COMMUNICATIONS
(2023)
Article
Optics
Xiaobo Zeng, Huiling Ren, Mengfan Fu, Hexun Jiang, Lilin Yi, Weisheng Hu, Qunbi Zhuge
Summary: This paper proposes an optical frequency comb (OFC) based coherent architecture for high-capacity and wavelength division multiplexing (WDM) transmission in data centers, achieving large frequency offset (FO) tolerance. Extensive simulations and experiments verify the performance of the system.
Article
Computer Science, Information Systems
Lakshmi Narayanan Venkatasubramani, Aneesh Sobhanan, Anirudh Vijay, R. David Koilpillai, Deepa Venkitesh
Summary: The study explores the use of nonlinear semiconductor optical amplifiers (SOAs) to generate optical phase conjugates for compensating distortions in short distance optical fiber transmission caused by Kerr nonlinearity and chromatic dispersion in coherent multi-carrier lightwave signals. Experimental results demonstrate significant improvement in link budget using SOA-based phase conjugators in a 100 km standard single mode fiber link, showcasing promising bit error rate performance for QPSK and 16QAM coherent OFDM signals. Additional investigation through numerical simulations indicates potential enhancements in link budget with proposed schemes for 16QAM and 64QAM CO-OFDM signals.
Article
Chemistry, Multidisciplinary
Gleb Nazarikov, Simon Rommel, Weiming Yao, Idelfonso Tafur Monroy
Summary: This study demonstrates the synchronization of two integrated semiconductor distributed Bragg reflector lasers using injection locking, showing substantial linewidth reduction and frequency stabilization. The generated signals with high signal purity and suppression of unwanted components prove the feasibility of injection locking for high-quality signal generation at sub-THz and THz frequencies.
APPLIED SCIENCES-BASEL
(2021)
Article
Optics
Pengpeng Zhou, Wei Sun, Shiyong Liang, Shaolong Chen, Zhiqiang Zhou, Yao Huang, Hua Guan, Kelin Gao
Summary: In high-precision spectroscopic measurements, a dual-referenced laser frequency stabilization scheme combining wavemeter and optical frequency comb can effectively suppress long-term drift and improve measurement accuracy.
Article
Physics, Applied
Hiroshi Ito, Norihiko Shibata, Tadao Nagatsuma, Tadao Ishibashi
Summary: We have developed a novel terahertz-wave detector on a SiC platform using an InP/InGaAs FMB diode. The detector exhibits a low noise equivalent power and has successfully integrated a waveguide coupler and filters.
APPLIED PHYSICS EXPRESS
(2022)
Article
Optics
Ratmalgre Koala, Kei Iyoda, Weijie Gao, Yuji Matsuura, Masayuki Fujita, Tadao Nagatsuma
Summary: Existing interconnects suffer from high losses and low data throughput, while emerging data-intensive technologies require low-loss, short-range interconnects. In this study, we developed an efficient 22-Gbit/s terahertz fiber link using a tapered silicon interface as a coupler between the dielectric waveguide and hollow core fiber. By investigating the optical properties of hollow-core fibers with core diameters of 0.7 mm and 1 mm, we achieved a coupling efficiency of -60% and a 3-dB bandwidth of 150 GHz in the 0.3-THz band over a 10 cm fiber.
Article
Engineering, Electrical & Electronic
Julian Webber, Takumi Yamamoto, Naoki Nishigami, Yosuke Nishida, Masayuki Fujita, Tadao Nagatsuma
Summary: The paper presents an experiment on wireless communication in the terahertz band using a resonant tunneling diode receiver (Rx) and uni-travelling carrier photodiode transmitter. The use of intermediate-frequency-based transmission enables a low-complexity envelope-detection type Rx architecture for complex-modulated signals. Data rates of 60 and 68 Gbit/s are achieved for quadrature phase shift keying modulation and 16-level quadrature amplitude modulation respectively, with forward error correction enabling data recovery.
ELECTRONICS LETTERS
(2023)
Article
Optics
Brendan M. M. Heffernan, Yuma Kawamoto, Keisuke Maekawa, James Greenberg, Rubab Amin, Takashi Hori, Tatsuya Tanigawa, Tadao Nagatsuma, Antoine Rolland
Summary: Future wireless communication infrastructure will depend on terahertz systems to meet the increasing demand for high-bandwidth, ultra-fast wireless data transfer. To achieve this, compact, low-power, and low noise terahertz radiation sources are being developed. One promising approach is combining photonic-integrated optical frequency combs with fast photodiodes for difference frequency generation in the THz. In this experiment, wireless communication was demonstrated using a 300 GHz carrier wave generated by photomixing of two optical tones from diode lasers injection locked to a dissipative Kerr soliton frequency microcomb. Transfer rates of 80 Gbps were achieved using homodyne detection, and 60 Gbps were transmitted simultaneously for both data and clock signals in a dual-path wireless link. This experimental demonstration paves the way for low-noise and integrated photonic millimeter-wave transceivers for future wireless communication systems.
Article
Engineering, Electrical & Electronic
Ratmalgre Koala, Kei Iyoda, Masayuki Fujita, Tadao Nagatsuma
Summary: The authors investigated the transmission performance of orthogonal polarization fundamental modes in a dielectric silicon terahertz waveguide for doubling the data rate. The maximum data rate under on-off keying modulation at 0.3-THz band with practical error-free condition (bit-error rate < 10(-11)) is comparable for both polarizations, reaching 20 Gbit/s.
ELECTRONICS LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Li Yi, Yihan Li, Tadao Nagatsuma
Summary: This article provides an overview of recent progress in photonic radar systems, focusing on hardware components, imaging technology, and radar imaging applications in the millimeter wave to terahertz frequency bands. The potential for high-resolution imaging techniques enabled by photonic radar systems is also discussed.
IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS
(2023)
Editorial Material
Engineering, Electrical & Electronic
Guillermo Carpintero, Elliott Brown, Tadao Nagatsuma, Pham Tien Dat, Lute Maleki, Daniel Yap, Andreas Stohr
Summary: This Special Issue of the IEEE/OSA Journal of Selected Topics in Quantum Electronics on Terahertz Photonics provides an overview of the latest developments in the field, covering a wide range from 100 GHz to 10 THz. Terahertz Photonics has played a leading role in accessing the Terahertz range, enabling important demonstrations in areas such as broadband communications, spectroscopy, and imaging through innovative THz sources and detectors.
IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Akihiko Hirata, Tubasa Saijo, Yuma Kawamoto, Tadao Nagatsuma, Issei Watanabe, Norihiko Sekine, Akifumi Kasamatsu
Summary: This study experimentally evaluated the transmission characteristics of a 120-GHz-band close-proximity wireless link using split-ring resonator (SRR) millimeter-wave absorber integrated on planar slot antennas. The results showed that the integration of the absorber reduced signal fluctuations and enabled successful transmission of high-speed data over the wireless link.
IEICE TRANSACTIONS ON ELECTRONICS
(2023)
Article
Optics
Daniel Headland, Masayuki Fujita, Guillermo Carpintero, Tadao Nagatsuma, Withawat Withayachumnankul
Summary: The absence of a suitable standard device platform for terahertz waves is hindering the widespread adoption and exploitation of terahertz technology. However, establishing a common platform using substrateless all-silicon microstructures can consolidate design efforts and move beyond disconnected efforts. The all-silicon microstructures offer low loss, compactness, designability, physical rigidity, ease of manufacture, and versatility in integrating various functional devices and systems.
Proceedings Paper
Engineering, Electrical & Electronic
Keisuke Maekawa, Yuma Kawamoto, Tomoya Nakashita, Toki Yoshioka, Takashi Hori, Brendan M. Heffernan, James Greenberg, Rubab Amin, Tatsuya Tanigawa, Antoine Rolland, Tadao Nagatsuma
Summary: We propose a THz wireless link using photonics-based signal generators with ultralow amplitude- and phase-noise Brillouin laser sources for the transmitter and receiver. Furthermore, we demonstrate the successful transmission of over-100-Gbit/s signals at 300 GHz with on-line signal processing.
2023 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION, OFC
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
Mohamed Shehata, Ke Wang, Julian Webber, Masayuki Fujita, Tadao Nagatsuma, Withawat Withayachumnankul
Summary: We propose and experimentally demonstrate a Nyquist pulse that significantly improves the error rate of a 311 GHz photonic-terahertz communications system compared to a normalized timing-jitter of 22.5% and 1.44 Gbit/s bit rate.
2023 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION, OFC
(2023)
Article
Engineering, Electrical & Electronic
Sumer Makhlouf, Oleg Cojocari, Martin Hofmann, Tadao Nagatsuma, Sascha Preu, Nils Weimann, Heinz-Wilhelm Huebers, Andreas Stoehr
Summary: This manuscript reports on the latest achievements in terahertz sources and receivers, providing a comprehensive overview of their working principles and applications in THz systems.
IEEE JOURNAL OF MICROWAVES
(2023)
Article
Engineering, Electrical & Electronic
Hiroshi Ito, Yuma Kawamoto, Takahiro Ohara, Tadao Nagatsuma, Tadao Ishibashi
Summary: In this study, a terahertz-wave balanced mixer was developed on a SiC substrate using epi-layer-transferred InP/InGaAs Fermi-level managed barrier diodes. The mixer exhibited a wide intermediate frequency bandwidth and high inter-port isolations. It also achieved a low noise equivalent power at high local-oscillator power.
IEICE ELECTRONICS EXPRESS
(2023)
Article
Engineering, Electrical & Electronic
Daniel Jonathan Headland, Yosuke Nishida, Xiongbin Yu, Masayuki Fujita, Tadao Nagatsuma
Summary: This study presents an effective method for connecting a terahertz oscillator chip with a broadband all-intrinsic-silicon dielectric waveguide through backside coupling. By using resonant tunneling diodes as compact electronic terahertz oscillators, terahertz waves from 270 GHz to 404 GHz were successfully observed.
IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
Yuma Kawamoto, Toki Yoshioka, Norihiko Shibata, Daniel Headland, Masayuki Fujita, Ryo Koma, Ryo Igarashi, Kazutaka Hara, Jun-ichi Kani, Tadao Nagatsuma
Summary: This paper proposes a novel silicon diplexer for frequency-division multiplexing in the 300 GHz band. The integrated filters in the diplexer can suppress crosstalk and provide high isolation, making it highly beneficial for terahertz-range wireless communications applications. The diplexer has been successfully used in a simultaneous error-free wireless transmission of 300 GHz and 335 GHz channels at a data rate of 36 Gbit/s.
2022 ASIA-PACIFIC MICROWAVE CONFERENCE (APMC)
(2022)