Transition metal dichalcogenides (TMDs), particularly molybdenum ditelluride (MoTe2), exhibit unique phase-dependent properties that make this a promising candidate in optoelectronic and optical applications, including photodetectors, light-emitting diodes, optical modulators, and saturable absorbers (SAs). Although previous studies have attempted to utilize MoTe2 SA in pulsed fiber lasers, a comprehensive study investigating the impact of these distinct phases on the performance of fiber lasers remains largely unexplored. This study investigates the nonlinear optical properties and fiber laser performance of multilayered 1T’-MoTe2 (semi-metallic phase) and 2H-MoTe2 (semiconducting phase) SAs utilizing evanescent field interactions. Our findings reveal that 1T’-MoTe2, characterized by a stronger saturable absorption with high modulation depth, enables the generation of Q-switched laser pulses, while 2H-MoTe2, with its comparatively lower saturable absorption coefficient and a moderate modulation depth, facilitates stable mode-locked femtosecond pulse generation. This work provides insights into the phase-dependent saturable absorption characteristics of MoTe2, offering guidance for selecting and engineering TMD-based SAs for tailored pulsed fiber laser applications.
{"title":"Phase-Engineered MoTe2 Saturable Absorbers for Diverse Fiber Pulse Laser Operations","authors":"Pulak Chandra Debnath;Hyeonkyeong Kim;Jong Hyuk Yim;Seongju Ha;Siheon Ryu;Taeyol Min;Youngdong Yoo;Dong-Il Yeom","doi":"10.1109/JLT.2025.3623401","DOIUrl":"https://doi.org/10.1109/JLT.2025.3623401","url":null,"abstract":"Transition metal dichalcogenides (TMDs), particularly molybdenum ditelluride (MoTe<sub>2</sub>), exhibit unique phase-dependent properties that make this a promising candidate in optoelectronic and optical applications, including photodetectors, light-emitting diodes, optical modulators, and saturable absorbers (SAs). Although previous studies have attempted to utilize MoTe<sub>2</sub> SA in pulsed fiber lasers, a comprehensive study investigating the impact of these distinct phases on the performance of fiber lasers remains largely unexplored. This study investigates the nonlinear optical properties and fiber laser performance of multilayered 1T’-MoTe<sub>2</sub> (semi-metallic phase) and 2H-MoTe<sub>2</sub> (semiconducting phase) SAs utilizing evanescent field interactions. Our findings reveal that 1T’-MoTe<sub>2</sub>, characterized by a stronger saturable absorption with high modulation depth, enables the generation of Q-switched laser pulses, while 2H-MoTe<sub>2</sub>, with its comparatively lower saturable absorption coefficient and a moderate modulation depth, facilitates stable mode-locked femtosecond pulse generation. This work provides insights into the phase-dependent saturable absorption characteristics of MoTe<sub>2</sub>, offering guidance for selecting and engineering TMD-based SAs for tailored pulsed fiber laser applications.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 1","pages":"273-279"},"PeriodicalIF":4.8,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145814464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We demonstrate a two-dimensional (2D) vector accelerometer based on hole-assisted three-core fiber (HATCF) cantilever with annular inertial mass block. The accelerometer is built by fixing the annular inertial mass block at half the length of the HATCF cantilever. Due to the inherent mode couplings between three cores, the reflection spectrum of the accelerometer contains two resonant peaks sensitive to the amplitude and direction of vibration. The annular inertial mass block is used to adjust the resonant frequency of HATCF cantilever and increase the acceleration sensitivity. The reflected light intensities of the two resonant peaks of HATCF are monitored by the edge filtering method to determine the magnitude of the vibration acceleration. The accelerometer has the maximum acceleration sensitivity of 20.86 mV/mg at the resonant frequency of 150 Hz. The minimum acceleration sensitivity within the operated frequency band of 2-140 Hz is 23.44 mV/g. The proposed 2D vector accelerometer has the advantages of high sensitivity and compact structure, which is conducive to the miniaturization and integration of optical fiber multi-dimensional accelerometers.
{"title":"Two-Dimensional Vector Accelerometer Based on Hole-Assisted Three-Core Fiber Cantilever With Annular Inertial Mass Block","authors":"Peng Ye;Jing Yang;Yuhan Zhang;Wensi Tang;Shan Gao;Zheng Zhu;Jinhui Shi;Libo Yuan;Chunying Guan","doi":"10.1109/JLT.2025.3624069","DOIUrl":"https://doi.org/10.1109/JLT.2025.3624069","url":null,"abstract":"We demonstrate a two-dimensional (2D) vector accelerometer based on hole-assisted three-core fiber (HATCF) cantilever with annular inertial mass block. The accelerometer is built by fixing the annular inertial mass block at half the length of the HATCF cantilever. Due to the inherent mode couplings between three cores, the reflection spectrum of the accelerometer contains two resonant peaks sensitive to the amplitude and direction of vibration. The annular inertial mass block is used to adjust the resonant frequency of HATCF cantilever and increase the acceleration sensitivity. The reflected light intensities of the two resonant peaks of HATCF are monitored by the edge filtering method to determine the magnitude of the vibration acceleration. The accelerometer has the maximum acceleration sensitivity of 20.86 mV/mg at the resonant frequency of 150 Hz. The minimum acceleration sensitivity within the operated frequency band of 2-140 Hz is 23.44 mV/g. The proposed 2D vector accelerometer has the advantages of high sensitivity and compact structure, which is conducive to the miniaturization and integration of optical fiber multi-dimensional accelerometers.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 1","pages":"379-385"},"PeriodicalIF":4.8,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145814466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-17DOI: 10.1109/JLT.2025.3622744
Qiquan Wang;Baojian Wu;Ke Qiu;Feng Wen;Kun Qiu
We present a theoretical model of few-mode polarization controller-based erbium-doped fiber amplifier (PC-EDFA) to investigate the polarization dependencies of modal gain and differential modal gain (DMG). Taking the amplification of the single LP11e or LP11o mode as an example, the polarization-dependent gain (PDG) of a single-paddle PC-EDFA is theoretically calculated and experimentally verified, with a minimal PDG of less than 0.2 dB by optimizing the PC rotation angle. The PC-EDFA is further integrated into a 100 Gb/s DP-QPSK transmission system under polarization disturbance and the measured Q-factor satisfies Q = −0.3523× PDG+14.08 (in dB). The simultaneous amplification of the LP01, LP11e and LP11o modes in the PC-EDFA is also considered, and the polarization-dependent net and total gains ($text{PDNG}$ and $text{PDTG}$) are introduced, which are respectively associated with MIMO-free and MIMO-aided mode division multiplexing systems. In addition, the polarization dependencies of differential modal net and total gains ($text{DMNG}$ and $text{DMTG}$) are discussed.
{"title":"Investigation on Polarization-Dependent Characteristics of FM-EDFAs Using Erbium-Doped Fiber Polarization Controllers: Theory and Experiments","authors":"Qiquan Wang;Baojian Wu;Ke Qiu;Feng Wen;Kun Qiu","doi":"10.1109/JLT.2025.3622744","DOIUrl":"https://doi.org/10.1109/JLT.2025.3622744","url":null,"abstract":"We present a theoretical model of few-mode polarization controller-based erbium-doped fiber amplifier (PC-EDFA) to investigate the polarization dependencies of modal gain and differential modal gain (DMG). Taking the amplification of the single LP<sub>11e</sub> or LP<sub>11o</sub> mode as an example, the polarization-dependent gain (PDG) of a single-paddle PC-EDFA is theoretically calculated and experimentally verified, with a minimal PDG of less than 0.2 dB by optimizing the PC rotation angle. The PC-EDFA is further integrated into a 100 Gb/s DP-QPSK transmission system under polarization disturbance and the measured Q-factor satisfies Q = −0.3523× PDG+14.08 (in dB). The simultaneous amplification of the LP<sub>01</sub>, LP<sub>11e</sub> and LP<sub>11o</sub> modes in the PC-EDFA is also considered, and the polarization-dependent net and total gains (<inline-formula><tex-math>$text{PDNG}$</tex-math></inline-formula> and <inline-formula><tex-math>$text{PDTG}$</tex-math></inline-formula>) are introduced, which are respectively associated with MIMO-free and MIMO-aided mode division multiplexing systems. In addition, the polarization dependencies of differential modal net and total gains (<inline-formula><tex-math>$text{DMNG}$</tex-math></inline-formula> and <inline-formula><tex-math>$text{DMTG}$</tex-math></inline-formula>) are discussed.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"43 24","pages":"11094-11103"},"PeriodicalIF":4.8,"publicationDate":"2025-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145665738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
High beam quality fiber combiners (FCs) operating in the mid-infrared (MIR) spectral range are highly desirable for power enhancement of MIR lasers, particularly for compact quantum cascade lasers. However, fabricating an MIR FC with both high output beam quality and robust power endurance remains challenging. In this work, the first high-beam-quality MIR FC for laser power scaling is designed and fabricated. The FC is constructed using Ge-As-S chalcogenide fibers with high laser resistance. It consists of three few-mode input fibers with core/cladding diameters of 40 μm/240 μm, and a multi-mode output fiber with core/cladding diameters of 100 μm /250 μm. The 3x1 Ge-As-S FC has a total length of 60 cm. It shows port transmission efficiencies as high as 86.0% at 4.6 μm and 87.6% at 2 μm. An output power of 9.1 W at 2 μm and an output beam quality of M2 = 3.81 at 4.6 μm are achieved with this FC, representing the highest combined output power and the highest output beam quality reported for an MIR FC.
{"title":"High Beam Quality 3×1 Chalcogenide Fiber Combiner for Mid-Infrared Power Scaling","authors":"Tianying Qiu;Sisheng Qi;He Ren;Xian Feng;Weiwei Lv;Kangzhen Tian;Zhiyong Yang;Long Zhang","doi":"10.1109/JLT.2025.3622652","DOIUrl":"https://doi.org/10.1109/JLT.2025.3622652","url":null,"abstract":"High beam quality fiber combiners (FCs) operating in the mid-infrared (MIR) spectral range are highly desirable for power enhancement of MIR lasers, particularly for compact quantum cascade lasers. However, fabricating an MIR FC with both high output beam quality and robust power endurance remains challenging. In this work, the first high-beam-quality MIR FC for laser power scaling is designed and fabricated. The FC is constructed using Ge-As-S chalcogenide fibers with high laser resistance. It consists of three few-mode input fibers with core/cladding diameters of 40 μm/240 μm, and a multi-mode output fiber with core/cladding diameters of 100 μm /250 μm. The 3x1 Ge-As-S FC has a total length of 60 cm. It shows port transmission efficiencies as high as 86.0% at 4.6 μm and 87.6% at 2 μm. An output power of 9.1 W at 2 μm and an output beam quality of M<sup>2</sup> = 3.81 at 4.6 μm are achieved with this FC, representing the highest combined output power and the highest output beam quality reported for an MIR FC.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 1","pages":"267-272"},"PeriodicalIF":4.8,"publicationDate":"2025-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145814467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chaos correlation optical time domain reflectometry (OTDR), which has the advantage of no trade-off between resolution and dynamic range compared with conventional OTDR, can be used for fiber fault detection. This paper proposes a bit-quantization method for OTDR by quantizing the time-domain signal collected by the oscilloscope into a bit-signal amplitude. The experimental results show that the spatial resolution of quantized data of different bits is not degraded, and the dynamic range is only slightly reduced by comparing the cross-correlation functions (CCF) calculated based on experimental data and bit data. The OTDR spatial resolution of 1-bit data is 3 cm, and the dynamic range is reduced by less than 1 dB compared to conventional OTDR. It theoretically validates the feasibility of using simple sampling devices such as 1-bit data samplers for OTDR in the future without significantly degrading OTDR performance.
{"title":"Self-Chaotic Microlasers for Optical Time Domain Reflectometry Using Bit Quantization Method","authors":"Yong-Shi Luo;Jian-Cheng Li;Gang Chen;Ya-Li Li;Yang Shi;You-Ling Chen;Yue-De Yang;Jin-Long Xiao;Yong-Zhen Huang","doi":"10.1109/JLT.2025.3621685","DOIUrl":"https://doi.org/10.1109/JLT.2025.3621685","url":null,"abstract":"Chaos correlation optical time domain reflectometry (OTDR), which has the advantage of no trade-off between resolution and dynamic range compared with conventional OTDR, can be used for fiber fault detection. This paper proposes a bit-quantization method for OTDR by quantizing the time-domain signal collected by the oscilloscope into a bit-signal amplitude. The experimental results show that the spatial resolution of quantized data of different bits is not degraded, and the dynamic range is only slightly reduced by comparing the cross-correlation functions (CCF) calculated based on experimental data and bit data. The OTDR spatial resolution of 1-bit data is 3 cm, and the dynamic range is reduced by less than 1 dB compared to conventional OTDR. It theoretically validates the feasibility of using simple sampling devices such as 1-bit data samplers for OTDR in the future without significantly degrading OTDR performance.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 1","pages":"243-250"},"PeriodicalIF":4.8,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145814507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-15DOI: 10.1109/JLT.2025.3622116
Ishani De;Ankita Gaur;Vipul Rastogi
For scaling the transmission capacity of fiber communication systems, the development of fiber and fiber amplifiers based on orbital angular momentum (OAM) modes is attractive. We propose a novel fiber design of dual concentric core photonic crystal fiber (DCC-PCF) that supports 30 OAM modes (up to $ell = 8$) in each core with adequate inter-core power isolation. All the transmitted modes have effective mode areas greater than 110 μm2 and non-linear coefficients less than $1.2, {{mathrm{W}}^{ - 1}}{mathrm{k}}{{mathrm{m}}^{ - 1}}$. For WDM-OAM amplification, we have considered 13 wavelength channels from 1530 nm to 1590 nm and 30+30 OAM modes, making the total number of signal channels required to be amplified 780. The gain performance of the proposed design has been extensively analyzed through numerical simulations, considering various pump configurations and design parameter variations. With the cladding pump configuration that multiplexes both the 980 nm and 1480 nm pump wavelengths, we achieve intra-core DMG of less than 0.5 dB and overall DMG of less than 2 dB. The proposed WDM-OAM-EDFA will play a crucial role in relay amplification in long-haul communication systems.
{"title":"WDM Amplification of 30+30 OAM Modes in Dual Concentric Core Erbium-Doped Photonic Crystal Fiber Amplifier","authors":"Ishani De;Ankita Gaur;Vipul Rastogi","doi":"10.1109/JLT.2025.3622116","DOIUrl":"https://doi.org/10.1109/JLT.2025.3622116","url":null,"abstract":"For scaling the transmission capacity of fiber communication systems, the development of fiber and fiber amplifiers based on orbital angular momentum (OAM) modes is attractive. We propose a novel fiber design of dual concentric core photonic crystal fiber (DCC-PCF) that supports 30 OAM modes (up to <inline-formula><tex-math>$ell = 8$</tex-math></inline-formula>) in each core with adequate inter-core power isolation. All the transmitted modes have effective mode areas greater than 110 μm<sup>2</sup> and non-linear coefficients less than <inline-formula><tex-math>$1.2, {{mathrm{W}}^{ - 1}}{mathrm{k}}{{mathrm{m}}^{ - 1}}$</tex-math></inline-formula>. For WDM-OAM amplification, we have considered 13 wavelength channels from 1530 nm to 1590 nm and 30+30 OAM modes, making the total number of signal channels required to be amplified 780. The gain performance of the proposed design has been extensively analyzed through numerical simulations, considering various pump configurations and design parameter variations. With the cladding pump configuration that multiplexes both the 980 nm and 1480 nm pump wavelengths, we achieve intra-core DMG of less than 0.5 dB and overall DMG of less than 2 dB. The proposed WDM-OAM-EDFA will play a crucial role in relay amplification in long-haul communication systems.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 1","pages":"251-259"},"PeriodicalIF":4.8,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145814471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Compared to black phosphorus (BP), violet phosphorus (VP) exhibits higher carrier mobility and better oxidation resistance, showing great promise in the field of passive Q-switching. In this work, two-dimensional (2D) VP nanosheets were successfully prepared using the liquid phase exfoliation (LPE) method. Their nonlinear optical properties and saturable absorption characteristics were investigated through non-degenerate pump-probe techniques, Z-scan and I-scan measurements, demonstrating that they meet the essential requirements for high-performance passive Q-switches. Furthermore, the prepared 2D VP nanosheets were employed as saturable absorbers (SAs) in all-solid-state lasers to achieve passive Q-switching operation. With slight adjustment, passive Q-switched pulse outputs were realized at working wavelengths of 1.0 μm and 1.9 μm, with repetition rates of 1.1 MHz and 124.1 kHz, respectively. This represents the highest pulse repetition frequency achieved to date for 2D VP nanosheets employed as passive Q-switches in the 1.0 μm and 1.9 μm, highlighting the excellent optical modulation performance of 2D VP nanosheets and further demonstrating their tremendous potential in the field of all-solid-state ultrafast photonics.
{"title":"Violet Phosphorus Saturable Absorbers Employed for Generating High-Repetition-Rate Pulse Lasers in 1.0 μm and 1.9 μm","authors":"Yibo Qin;Bingzheng Yan;Shixin Zhang;Chuanmeng Zhang;Xiaojie Yang;Junyu Liu;Yaoyao Qi;Jie Ding;Zhenxu Bai;Yulei Wang;Zhiwei Lu","doi":"10.1109/JLT.2025.3621852","DOIUrl":"https://doi.org/10.1109/JLT.2025.3621852","url":null,"abstract":"Compared to black phosphorus (BP), violet phosphorus (VP) exhibits higher carrier mobility and better oxidation resistance, showing great promise in the field of passive Q-switching. In this work, two-dimensional (2D) VP nanosheets were successfully prepared using the liquid phase exfoliation (LPE) method. Their nonlinear optical properties and saturable absorption characteristics were investigated through non-degenerate pump-probe techniques, Z-scan and I-scan measurements, demonstrating that they meet the essential requirements for high-performance passive Q-switches. Furthermore, the prepared 2D VP nanosheets were employed as saturable absorbers (SAs) in all-solid-state lasers to achieve passive Q-switching operation. With slight adjustment, passive Q-switched pulse outputs were realized at working wavelengths of 1.0 μm and 1.9 μm, with repetition rates of 1.1 MHz and 124.1 kHz, respectively. This represents the highest pulse repetition frequency achieved to date for 2D VP nanosheets employed as passive Q-switches in the 1.0 μm and 1.9 μm, highlighting the excellent optical modulation performance of 2D VP nanosheets and further demonstrating their tremendous potential in the field of all-solid-state ultrafast photonics.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 1","pages":"236-242"},"PeriodicalIF":4.8,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145814463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-15DOI: 10.1109/JLT.2025.3622123
Huijie Li;Xingliang Li;Mengmeng Han;Shumin Zhang
A self-starting harmonic mode-locked Mamyshev oscillator (HML-MO) based on the integration of overlapping filter passbands and a multimode interferometer is proposed. Different orders of harmonic mode-locked dissipative soliton pulses (HMLDSPs) were observed. The experimental results indicate that with a fixed spectral filtering interval and polarization controller (PC) state, the order of HMLDSPs increases with pump power, reaching up to the 26th order. Additionally, when the PC state and pump power were fixed, the order of HMLDSPs and the output power of the HML-MO decreased as the filter spacing increased. By carefully adjusting the pump power and PC states, dissipative soliton pulses with a fundamental repetition rate were also achieved. These research results are expected to expand the potential applications of the Mamyshev oscillator (MO) and deepen the understanding of multimodal dynamic phenomena.
{"title":"Self-Starting Harmonic Mode-Locking Yb-Doped Fiber Mamyshev Oscillator Based on Multimode Interference Filtering","authors":"Huijie Li;Xingliang Li;Mengmeng Han;Shumin Zhang","doi":"10.1109/JLT.2025.3622123","DOIUrl":"https://doi.org/10.1109/JLT.2025.3622123","url":null,"abstract":"A self-starting harmonic mode-locked Mamyshev oscillator (HML-MO) based on the integration of overlapping filter passbands and a multimode interferometer is proposed. Different orders of harmonic mode-locked dissipative soliton pulses (HMLDSPs) were observed. The experimental results indicate that with a fixed spectral filtering interval and polarization controller (PC) state, the order of HMLDSPs increases with pump power, reaching up to the 26th order. Additionally, when the PC state and pump power were fixed, the order of HMLDSPs and the output power of the HML-MO decreased as the filter spacing increased. By carefully adjusting the pump power and PC states, dissipative soliton pulses with a fundamental repetition rate were also achieved. These research results are expected to expand the potential applications of the Mamyshev oscillator (MO) and deepen the understanding of multimodal dynamic phenomena.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 1","pages":"280-287"},"PeriodicalIF":4.8,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145814512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-14DOI: 10.1109/JLT.2025.3621254
Ke Cui;Tong Su;Xianglei Pan;Jiayi Wan;Aoran Zheng
Phase-sensitive optical time-domain reflectometry (Ф-OTDR) has made groundbreaking development in recent years and shows significant application potentials across various fields such as oceanographic exploration, perimeter security, and geological surveying. Contemporary Ф-OTDR systems are capable of supporting detection range up to more than one hundred kilometers, with sampling interval typically on the order of meters. This implies that the number of sensing channels of the Ф-OTDR system has reached tens of thousands to hundreds of thousands. For each sensing channel, the task of high-precision phase demodulation must be accomplished. This is a very tight computation-demanding requirement, and it is quite challenging to realize the real-time demodulation of the Ф-OTDR system. This paper proposes the first multi-channel, high-throughput real-time data processing architecture based on field programmable gate array (FPGA) platform. The designed architecture mainly includes the arctan calculation through the CORDIC algorithm, and the phase unwrapping through the unscented Kalman filtering. To support the high throughput Kalman filtering module, an improved division method based on Newton-Raphson iteration is introduced and implemented in the pipelined fashion. Besides that, a multi-channel scheduling control module is designed to involve 18 Kalman filtering modules working in parallel to swallow all raw data of the Ф-OTDR system in real time. Compared to floating-point computation results, the precision error of the calculation on FPGA is verified to be less than 0.03%. The entire design was implemented on the Xilinx VCU128 FPGA platform. Experimental results demonstrate that the proposed method can process in real time over 2500 channels (2 m sampling interval) of optical intensity data with the data width of 16 bits under the pulse repetition rate of 20 KHz (corresponding to the processing rate of 50 million per second). The proposed phase interrogator can achieve the signal-to-noise ratio (SNR) of up to 45.9 dB.
{"title":"A Real-Time Phase Interrogator Design of the Ф-OTDR System","authors":"Ke Cui;Tong Su;Xianglei Pan;Jiayi Wan;Aoran Zheng","doi":"10.1109/JLT.2025.3621254","DOIUrl":"https://doi.org/10.1109/JLT.2025.3621254","url":null,"abstract":"Phase-sensitive optical time-domain reflectometry (Ф-OTDR) has made groundbreaking development in recent years and shows significant application potentials across various fields such as oceanographic exploration, perimeter security, and geological surveying. Contemporary Ф-OTDR systems are capable of supporting detection range up to more than one hundred kilometers, with sampling interval typically on the order of meters. This implies that the number of sensing channels of the Ф-OTDR system has reached tens of thousands to hundreds of thousands. For each sensing channel, the task of high-precision phase demodulation must be accomplished. This is a very tight computation-demanding requirement, and it is quite challenging to realize the real-time demodulation of the Ф-OTDR system. This paper proposes the first multi-channel, high-throughput real-time data processing architecture based on field programmable gate array (FPGA) platform. The designed architecture mainly includes the arctan calculation through the CORDIC algorithm, and the phase unwrapping through the unscented Kalman filtering. To support the high throughput Kalman filtering module, an improved division method based on Newton-Raphson iteration is introduced and implemented in the pipelined fashion. Besides that, a multi-channel scheduling control module is designed to involve 18 Kalman filtering modules working in parallel to swallow all raw data of the Ф-OTDR system in real time. Compared to floating-point computation results, the precision error of the calculation on FPGA is verified to be less than 0.03%. The entire design was implemented on the Xilinx VCU128 FPGA platform. Experimental results demonstrate that the proposed method can process in real time over 2500 channels (2 m sampling interval) of optical intensity data with the data width of 16 bits under the pulse repetition rate of 20 KHz (corresponding to the processing rate of 50 million per second). The proposed phase interrogator can achieve the signal-to-noise ratio (SNR) of up to 45.9 dB.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"43 24","pages":"11127-11138"},"PeriodicalIF":4.8,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145665732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study proposes a synergistic control method combining energy modulation and adjustable slit manipulation for refractive index modulation (RIM) area apodization during femtosecond laser point-by-point (PbP) fabrication of high-quality apodized fiber Bragg gratings (AFBGs). We established an inverse coordination model between pulse energy and slit width to dynamically control the inscription area following Gaussian distribution, where higher pulse energy combined with narrower slit width creates longer inscription regions at the grating center, while lower energy with wider slit width produces shorter inscription regions at both grating ends. For experimental validation, we developed a femtosecond laser PbP collaborative inscription system. Results demonstrated a significant expansion of the single-pulse energy tuning range for PbP-FBG fabrication from 30 nJ to 150 nJ, effectively overcoming the key challenge of limited energy adjustability in PbP inscription. The fabricated 6-mm-long AFBG using polyimide-coated single-mode fiber exhibited remarkable performance characteristics: over 78% reflectivity and a side lobe suppression ratio (SLSR) exceeding 21.3 dB in the reflection spectrum. This approach provides enhanced flexibility for PbP-based fabrication of high-quality AFBGs, thereby substantially improving FBG performance.
{"title":"Femtosecond Laser Fabrication of Apodized FBG via Synergistic Control of Pulse Energy – Adjustable Slit","authors":"Jingtao Xin;Du Wang;Mingli Dong;Guiyu Wang;Pengcheng Liu;Yanming Song;Lianqing Zhu","doi":"10.1109/JLT.2025.3621223","DOIUrl":"https://doi.org/10.1109/JLT.2025.3621223","url":null,"abstract":"This study proposes a synergistic control method combining energy modulation and adjustable slit manipulation for refractive index modulation (RIM) area apodization during femtosecond laser point-by-point (PbP) fabrication of high-quality apodized fiber Bragg gratings (AFBGs). We established an inverse coordination model between pulse energy and slit width to dynamically control the inscription area following Gaussian distribution, where higher pulse energy combined with narrower slit width creates longer inscription regions at the grating center, while lower energy with wider slit width produces shorter inscription regions at both grating ends. For experimental validation, we developed a femtosecond laser PbP collaborative inscription system. Results demonstrated a significant expansion of the single-pulse energy tuning range for PbP-FBG fabrication from 30 nJ to 150 nJ, effectively overcoming the key challenge of limited energy adjustability in PbP inscription. The fabricated 6-mm-long AFBG using polyimide-coated single-mode fiber exhibited remarkable performance characteristics: over 78% reflectivity and a side lobe suppression ratio (SLSR) exceeding 21.3 dB in the reflection spectrum. This approach provides enhanced flexibility for PbP-based fabrication of high-quality AFBGs, thereby substantially improving FBG performance.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"43 24","pages":"11049-11057"},"PeriodicalIF":4.8,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145665812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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