Article
Engineering, Electrical & Electronic
Taiji Sakamoto, Masaki Wada, Shinichi Aozasa, Ryota Imada, Takashi Yamamoto, Kazuhide Nakajima
Summary: By adjusting the length of the erbium-doped fiber, a 12-core EDFA can operate in both C and L bands, demonstrating good amplification characteristics and applicability for inline amplified transmission systems. The study found that for long-distance SDM transmission, MDL impacts the power efficiency of randomly coupled multi-core EDFAs.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Chemistry, Multidisciplinary
Yaping Liu, Zhiqun Yang, Xutao Wang, Yongmin Jung, Lin Zhang
Summary: This paper proposes a new design for few-mode erbium-doped fiber amplifiers (FM-EDFAs) that achieves significantly reduced differential modal gain (DMG) through strong mode coupling. A new numerical model based on a fiber transfer matrix is used to systematically investigate the DMGs of FM-EDFAs and analyze two different types of six-mode fiber amplifiers as exemplar demonstrations.
APPLIED SCIENCES-BASEL
(2022)
Article
Engineering, Electrical & Electronic
Charles Matte-Breton, Rene-Jean Essiambre, Colin Kelly, Younes Messaddeq, Sophie LaRochelle
Summary: We report the characterization of a cladding-pumped multicore fiber with annular erbium doping for low gain compression over the C-band. The experimental results show that significant reduction in gain compression of multicore cladding-pump amplifiers can be achieved with the proposed annular doping design in the cladding.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Tetsuya Hayashi, Taiji Sakamoto, Yusuke Yamada, Roland Ryf, Rene-Jean Essiambre, Nicolas Fontaine, Mikael Mazur, Haoshuo Chen, Takemi Hasegawa
Summary: Randomly-coupled multi-core fiber (MCF) technology has gained attention for its applicability in long-haul transmission systems. Compared to weakly-coupled MCFs, randomly-coupled MCFs can achieve higher spatial channel density and lower transmission loss using existing single-mode fiber core designs. This article provides an overview of the advancements in randomly-coupled MCF technology, including its classification, design, optical property characterization methods, and performance improvements in transmissions.
PROCEEDINGS OF THE IEEE
(2022)
Article
Engineering, Electrical & Electronic
Taiji Sakamoto, Ryota Imada, Kazuhide Nakajima
Summary: This paper proposes cross-sectional design guidelines suitable for a power efficient cladding-pumped coupled multi-core erbium-doped fiber amplifier (MC-EDFA). Numerical calculations and experimental verification were conducted to investigate the optimal core-to-cladding ratio (R-cc) for achieving high power conversion efficiency (PCE) in different operational bandwidths (C- or L-band) of the amplifier. The results showed that the PCE in the C-band amplifier improves as R-cc increases, whereas the PCE in the L-band amplifier maximizes at a specific R-cc value.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Hitoshi Takeshita, Yusuke Shimomura, Kohei Hosokawa
Summary: This work investigates the feasibility of improving the energy efficiency of a cladding-pumped multicore (MC) EDFA by utilizing bidirectional (BD) pumping. It demonstrates that the optical power loss due to equalization can be reduced by controlling the optical power ratio of the forward and backward pumps. Under optimized conditions, a 1.7% pump conversion efficiency improvement and a 24% reduction in total optical pump power compared to conventional MC-EDFA were achieved.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Hirotaka Ono, Makoto Yamada
Summary: The analysis focuses on the power consumption of optical repeater subsystems in a multicore fiber link, comparing the power consumption of subsystems using multicore EDFAs with those using multiple single-core EDFAs. The results indicate that multicore EDFAs have certain advantages over single-core EDFAs in terms of power consumption efficiency.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Chemistry, Multidisciplinary
Andis Supe, Sergejs Olonkins, Aleksejs Udalcovs, Ugis Senkans, Rihards Murnieks, Lilita Gegere, Dmitrijs Prigunovs, Jurgis Grube, Edgars Elsts, Sandis Spolitis, Oskars Ozolins, Vjaceslavs Bobrovs
Summary: This study investigated the characteristics and performance of a cladding-pumped erbium/ytterbium co-doped fiber amplifier (EYDFA) through numerical simulations to identify the optimal configuration. The results showed that a 7-meter long EYDF and co-propagating pump direction with specific pump source parameters yielded the best performance, providing high gain and low noise figure for amplifying 40 DWDM channels. Additionally, the study examined EYDFA gain bandwidth, output power, and sensitivity to absorption and emission cross-sections, demonstrating the impact on amplification efficiency through energy transfer between Yb3+ and Er3+.
APPLIED SCIENCES-BASEL
(2021)
Article
Engineering, Electrical & Electronic
Hrishikesh Srinivas, Oleksiy Krutko, Joseph M. Kahn
Summary: Scaling up cable capacity in long-haul optical communication is a goal of spatial-division multiplexing (SDM). Multicore or multimode fiber systems promise higher integration, but efficient coupling of pump light and mode-dependent gain control pose challenges. We propose an integrated multimode amplifier design that excites only four pump spatial modes and predicts flat gain, low noise figure, and minimal mode-dependent gain over a wide bandwidth.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Hao Guo, Ting Li, Fengping Yan, Guobin Ren, Wei Wang, Xiangdong Wang, Qi Qin, Guifang Wu, Jiao Gao, Baoyuan Wang, Haoyu Tan, Wenhua Ren, Ting Feng
Summary: This article reports the design and characterization of a six-mode erbium-doped fiber amplifier (6M-EDFA) for mode division multiplexing systems. The design utilizes a center-depressed optical fiber and adjustment of parameters to reduce splice loss. Through analysis and optimization, high gain and low differential modal gain are achieved. The performance of the designed amplifier is verified using a MDM transmission system.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Qiang Qiu, Zhimu Gu, Le He, Yang Chen, Yang Lou, Xinyue Zhao, Xiaoke Yin, Wenzhen Li, Shaokun Liu, Jinggang Peng, Haiqing Li, Yingbin Xing, Yingbo Chu, Nengli Dai, Jinyan Li
Summary: This paper introduces a high power-efficiency, low differential mode gain few-mode amplifier based on an M-type double-cladding fiber, and verifies its feasibility in large-capacity long-haul mode division multiplexing transmission.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Optics
Xin Liu, Ruohui Wang, Fengyi Chen, Xueguang Qiao
Summary: We propose and demonstrate a novel method for improving the sensitivity of fiber-optic interferometric accelerometers based on multi-core fiber space division multiplexing technology. In this method, MCF is used to replace the single-mode fiber as the sample arm of the conventional interferometers. The proposed accelerometer has a working frequency bandwidth from 0.5 Hz to 90 Hz, and achieves a 5-fold sensitivity enhancement from 191.15 rad/g for single-core to 965.25 rad/g at 80 Hz. The multicore fiber solution can be an universal method to enhance acceleration sensitivity of all interferometric accelerometers. Moreover, the same sensitivity of the sensors can be achieved by using shorter length of MCF, which can further reduce the size of three-components accelerometers.
OPTICS AND LASER TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Yang Lou, Yang Chen, Zhimu Gu, Qiang Qiu, Chanjuan Shi, Le He, Yingbin Xing, Jinggang Peng, Haiqing Li, Yingbo Chu, Nengli Dai, Jinyan Li
Summary: The report introduces the use of Er3+ and Ce3+ in phosphosilicate fiber to regulate SESA and extend the L-band gain bandwidth. The addition of Ce3+ weakens the SESA effect, leading to an extension of the longest wavelength to 1623 nm.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Zhiqi Li, Li Pei, Jingjing Zheng, Jianshuai Wang, Wenxuan Xu, Lei Shen, Li Zhong
Summary: In this paper, a well-matched triple-layered-core few-mode erbium-doped fiber (FM-EDF) was proposed and fabricated for low differential modal gain (DMG). Based on the fabricated FM-EDF, an amplifier was constructed experimentally. Results show that after long-haul FMF transmission and single-stage amplification, the difference in the output signal power is lower than 1.8 dB at the receiver. The fabricated FM-EDF is beneficial for practical MDM systems with high stability and signal channel equalization.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Wiktor Walasik, Robert E. Tench, Gustavo Rivas, Jean-Marc Delavaux, Ian Farley
Summary: We present the performance of CW and pulsed single-clad PM Tm-doped fiber amplifiers optimized for the wavelength band from 1760 to 1960 nm. In the CW regime, we achieved high output power levels up to 3 W with a two-stage TDFA designed for operation at 1760 nm. The optimized two-stage TDFA demonstrated OSNR values >55 dB in 0.1 nm. In the pulsed regime, the amplifier performed with input pulses of 50-100 ns and repetition rates from 100 kHz to 1 MHz. The output pulse shape was studied in detail with square and shaped input pulses, resulting in an optimized square output pulse shape with average output powers of 2 W and peak output powers of 20 W (10% duty cycle) with pulse energies of 1.6 mu J.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Optics
Yang Hong, Natsupa Taengnoi, Kyle R. H. Bottrill, Naresh K. Thipparapu, Yu Wang, Jayanta K. Sahu, David J. Richardson, Periklis Petropoulos
Summary: This study reports the longest 50-Gb/s/lambda O-band wavelength-division multiplexed transmission system to date. By using in-house built bismuth-doped fiber amplifiers and Kramers-Kronig detection-assisted single-sideband transmission, the challenges of fiber loss and chromatic dispersion are overcome. The experimental results demonstrate that a transmission distance of up to 100 km can be achieved on all 50-Gb/s channels without the need for in-line optical amplification.
Article
Optics
Dmytro Suslov, Eric numkam Fokoua, Daniel Dousek, Ailing Zhong, Stanislav Zvanovec, Thomas Bradley, Francesco Poletti, David J. Richardson, Matej Komanec, Radan Slavik
Summary: We achieved simultaneous low coupling loss and low back-reflection between a hollow core fiber and standard single mode optical fiber through the combination of an angled interface and an anti-reflective coating. Experimental optimization of the interface angle was performed to achieve the best performance, and parasitic cross-coupling to higher-order modes was examined and controlled.
Article
Optics
Radan Slavik, Eric R. Numkam Fokoua, Thomas D. Bradley, Austin A. Taranta, Matej Komanec, Stanislav Zvanovec, Vincent Michaud-Belleau, Francesco Poletti, David J. Richardson
Summary: The low-loss hollow core fibers have been challenging to measure using conventional techniques due to their low levels of backscattering. However, recent studies have shown that their backscattering coefficient increases when filled with air, making them measurable with commercially available instruments. This approach enables distributed characterization and fault-finding in commercial optical communication networks.
Article
Optics
Eric Numkam Fokoua, Seyed Abokhamis Mousavi, Gregory T. Jasion, David J. Richardson, Francesco Poletti
Summary: In recent years, advances in hollow-core optical fiber technology have resulted in reduced attenuation levels comparable to solid-core fibers. This has renewed interest in the technology and the expectation of achieving highly transparent light propagation across all wavelengths. This review examines the physical mechanisms driving attenuation in both legacy photonic bandgap and antiresonant hollow-core fibers. It discusses intrinsic and extrinsic loss mechanisms, as well as provides scaling rules and design guidelines for low-loss hollow-core fibers.
ADVANCES IN OPTICS AND PHOTONICS
(2023)
Article
Engineering, Electrical & Electronic
Xuhao Wei, Austin Taranta, Bo Shi, Meng Ding, Zitong Feng, David J. Richardson, Francesco Poletti, Radan Slavik
Summary: Thermal phase sensitivity in optical fibers is undesirable for fiber interferometers and applications requiring a fixed phase. Using hollow core fiber reduces thermal phase sensitivity, and coiling the fiber further reduces this sensitivity significantly.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Optics
Zitong Feng, Hesham Sakr, John R. Hayes, Eric Numkam Fokoua, Meng Ding, Francesco Poletti, David J. Richardson, Radan Slavik
Summary: Optical fibers with a low thermal coefficient have been developed for frequency and timing transmission. A new hollow core fiber with a thin acrylate coating has been shown to have a stable thermal coefficient over a wide temperature range and can be insensitive to temperature around -134 degrees C.
Article
Optics
Xinyang Liu, Jayanta K. Sahu, Regina Gumenyuk
Summary: In this study, a tunable Tm-doped fiber laser (TDFL) generating dissipative solitons in the net-normal dispersion regime from 1700 nm to 1900 nm is demonstrated. The laser delivers pulses with spectral widths ranging from 10 nm to 23 nm and pulse durations from 8.7 ps to 18.3 ps. Stretched-free pulse amplification at the gain edge and gain peak is implemented to further scale the power of the laser signal. This laser, with a maximum achieved power of 140 mW and compressed pulse duration of 478 fs, is highly desirable for applications such as optical sensing, biological imaging, and industrial machining considering the diverse utility of this wavelength band.
Article
Optics
Kunhao Ji, Di Lin, Ian A. Davidson, Siyi Wang, Joel Carpenter, Yoshimichi Amma, Yongmin Jung, Massimiliano Guasoni, David J. Richardson
Summary: Higher-order Poincare sphere (HOPS) beams with spatially variable polarization and phase distributions have unique applications in optical communication and microscopy. Generating these beams with high peak power from compact laser systems remains a challenge. In this study, we demonstrate the controlled generation of HOPS beams using coherent beam combination from an Yb-doped multicore fiber (MCF) amplifier, achieving peak powers up to 14 kW for similar to 92 ps pulses.
PHOTONICS RESEARCH
(2023)
Article
Engineering, Electrical & Electronic
John D. Downie, Yongmin Jung, Sergejs Makovejs, Merrion P. Edwards, David J. Richardson
Summary: We compare different options for amplification in trans-oceanic repeatered submarine systems using multicore fiber transmission. Our analysis focuses on relative cable capacity and relative system cost/bit. We evaluate the optical performance of parallel single-core erbium-doped fiber amplifiers (SC-EDFAs) and multicore erbium-doped fiber amplifiers (MC-EDFAs) with various configurations. Key parameters like noise figure, amplifier bandwidth, electrical-to-optical conversion efficiency, and amplifier cost impact the expected capacity and cost/bit performance. Our findings show that MC-EDFAs with either core- or cladding-pumping may offer lower cost/bit compared to parallel SC-EDFAs, but cladding-pumping could reduce cable capacities due to higher noise figure and potentially lower amplifier bandwidth.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Ziwei Zhai, Jayanta K. K. Sahu
Summary: This article presents the fabrication of erbium/ytterbium (Er/Yb) co-doped phospho-alumino-silicate fibers (EYDFs) using modified chemical vapor deposition (MCVD) and solution doping technique to achieve extended gain in the L-band. The spectroscopic properties and optical amplification in the L-band were studied for fibers with different doping concentrations and Yb-to-Er ratios when pumped at 1480 nm. Higher Yb-to-Er ratio improved the amplifier gain and suppressed the signal-induced excited-state absorption (ESA) effect, resulting in a maximum gain of 15.5 dB at 1625 nm for the fiber with an Yb-to-Er ratio of 3.5. The gain coefficient was 0.039 dB/mW and the saturation output power was 21.5 dBm at 1600 nm.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Optics
Yang Hong, Natsupa Taengnoi, Kyle R. H. Bottrill, Yu Wang, Jayanta K. Sahu, Periklis Petropoulos, David J. Richardson
Summary: We built an optical recirculating loop based on bismuth-doped fiber amplifier (BDFA) to investigate the performance of amplified O-band transmission over long distances. Both single-wavelength and wavelength-division multiplexed (WDM) transmission were studied with various direct-detection modulation formats. We reported on (a) transmission over lengths of up to 550 km in a single-channel 50-Gb/s system operating at wavelengths ranging from 1325 nm to 1350 nm, and (b) rate-reach products up to 57.6 Tb/s-km (after accounting for the forward error correction redundancy) in a 3-channel system.
Article
Optics
Ziwei Zhai, Arindam Halder, Daniel Negut, Jayanta k. Sahu
Summary: We experimentally compare the performance of radiation-resistant cerium co-doped erbium-doped fiber amplifiers (EDFAs) exposed to high-dose gamma-radiation in the C and L bands. The results show that cerium is an effective co-dopant for suppressing radiation-induced attenuation and the Ce co-doped EDF exhibits good radiation tolerance and amplification performance. This study is of great importance for achieving radiation stability in space-based optical communications.
Article
Engineering, Electrical & Electronic
Cong Zhang, Eric Numkam Fokoua, Songnian Fu, Meng Din, Francesco Poletti, David J. Richardson, Radan Slavik
Summary: We have studied and demonstrated the fusion splicing between single mode fiber (SMF) and nested anti-resonant node-less fiber (NANF) using angle-cleaved technique. With accurate angle-cleaving and improved offset splicing technique, we achieved a connection loss of 1.25 dB and back-reflection below -40 dB. Our research highlights the improved performance of the communication system through reduced round-trip induced multipath interference.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Optics
Vincent Michaud-Belleau, Eric R. Numkam Fokoua, Peter Horak, Natalie Wheeler, Shuichiro Rikimi, Thomas D. Bradley, David J. Richardson, Francesco Poletti, Jerome Genest, Radan Slavik
Summary: The impact of thermal noise on the performance of hollow-core optical fibers is assessed by comparing several interferometers optimized for phase sensitivity. Measurements show that the thermal noise level in the 20 to 200 kHz range is mainly determined by the thermo-optic contribution from the gas that fills the core, regardless of the exact hollow-core fiber design. The lowest thermal noise power per unit optical length ever measured in a fiber (approximate to 1.3 x 10(-17) (rad(2)/Hz)/m at 30 kHz) is achieved using a large-mode-area hollow-core fiber evacuated and sealed at 0.15 atm. Filling the core with a low-polarizability noble gas can further reduce the noise density in this spectral range.
Proceedings Paper
Engineering, Electrical & Electronic
Shuichiro Rikimi, Thomas W. Kelly, Peter Horak, Ian A. Davidson, Yong Chen, Simon Bawn, Thomas D. Bradley, Austin A. Taranta, Francesco Poletti, David J. Richardson, Natalie Wheeler
Summary: We demonstrate transient changes in the optical properties of antiresonant hollow core fibres due to sub-atmospheric gas pressure and gas-induced differential refractive index. Experimental results show that these changes are higher at shorter wavelengths and must be considered for accurate fibre characterization.
MICRO-STRUCTURED AND SPECIALTY OPTICAL FIBRES VII
(2022)
