Enhancing the intensity of detection light is a key strategy for reducing the Angle Random Walk (ARW) coefficient in optical gyroscopes. Recent studies on broadband light-source-driven resonant fiber-optic gyroscopes (RFOGs) have demonstrated their potential for high sensitivity and simplified design. However, a major limitation of this approach is its low power efficiency. To reduce the ARW, the light source must operate at high power levels, which presents significant challenges for integration and engineering applications. In this study, we propose a novel optical configuration with high reciprocity, utilizing polarization-maintaining fiber and 90° polarization-axis-rotated fusion splicing (90°-PRS) technology to optimize the gyroscope's transmission characteristics. As a result, both light source utilization efficiency and detection resolution are substantially improved. The experimental results demonstrate that, under identical input conditions, the light source efficiency has increased by a factor of 1.86, and the ARW has decreased by 1.3 dB. Our approach provides a crucial solution for realizing low-power, broadband light-source-driven RFOGs, with significant potential for engineering applications.
{"title":"Enhancement of Power Utilization Efficiency and Resolution in Broadband Light-Source-Driven Resonant Fiber-Optic Gyroscopes","authors":"Lingyu Li;Yuqiang Wei;Xiaofu Liu;Guochen Wang;Wei Gao;Boya Zhang","doi":"10.1109/JLT.2025.3629692","DOIUrl":"https://doi.org/10.1109/JLT.2025.3629692","url":null,"abstract":"Enhancing the intensity of detection light is a key strategy for reducing the Angle Random Walk (ARW) coefficient in optical gyroscopes. Recent studies on broadband light-source-driven resonant fiber-optic gyroscopes (RFOGs) have demonstrated their potential for high sensitivity and simplified design. However, a major limitation of this approach is its low power efficiency. To reduce the ARW, the light source must operate at high power levels, which presents significant challenges for integration and engineering applications. In this study, we propose a novel optical configuration with high reciprocity, utilizing polarization-maintaining fiber and 90° polarization-axis-rotated fusion splicing (90°-PRS) technology to optimize the gyroscope's transmission characteristics. As a result, both light source utilization efficiency and detection resolution are substantially improved. The experimental results demonstrate that, under identical input conditions, the light source efficiency has increased by a factor of 1.86, and the ARW has decreased by 1.3 dB. Our approach provides a crucial solution for realizing low-power, broadband light-source-driven RFOGs, with significant potential for engineering applications.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 2","pages":"704-709"},"PeriodicalIF":4.8,"publicationDate":"2025-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915576","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}
The previous common understanding of chirped-pulse phase-sensitive optical time-domain reflectometry (CP-ϕOTDR) was that the strain measurement range hinges on precisely matching the detection bandwidth to the chirp bandwidth. Increasing the shot-to-shot measurement range (SSMR) necessarily raises the sampling rate proportionally, posing significant challenges to signal processing and increasing sampling costs. This paper reveals that using only a detection bandwidth equivalent to a portion of the chirp bandwidth can achieve almost the same SSMR, with only a minor difference attributable to the statistical randomness inherent in Rayleigh scattering. Meanwhile, it shows noticeable degradation of sensitivity. The simulations reveal a balance point between detection bandwidth and sensitivity loss. At this balance point, sensitivity loss is threefold while saving one-third of the bandwidth. Beyond this point, further increasing the detection bandwidth yields diminishing sensitivity improvements, whereas reducing the detection bandwidth below this point leads to rapid sensitivity degradation. Experimental validation shifts this balance point to one-fourth, primarily due to measurement deviations. This study provides design guidelines for employing CP-ϕOTDR cost-effectively in large SSMR applications with acceptable sensitivity loss, such as seismic or ocean wave monitoring.
{"title":"On the Detecting Bandwidth of Chirped Pulse ϕ-OTDR","authors":"Zhigeng Ye;Pengbai Xu;Kunhua Wen;Jun Yang;Yuwen Qin","doi":"10.1109/JLT.2025.3628906","DOIUrl":"https://doi.org/10.1109/JLT.2025.3628906","url":null,"abstract":"The previous common understanding of chirped-pulse phase-sensitive optical time-domain reflectometry (CP-ϕOTDR) was that the strain measurement range hinges on precisely matching the detection bandwidth to the chirp bandwidth. Increasing the shot-to-shot measurement range (SSMR) necessarily raises the sampling rate proportionally, posing significant challenges to signal processing and increasing sampling costs. This paper reveals that using only a detection bandwidth equivalent to a portion of the chirp bandwidth can achieve almost the same SSMR, with only a minor difference attributable to the statistical randomness inherent in Rayleigh scattering. Meanwhile, it shows noticeable degradation of sensitivity. The simulations reveal a balance point between detection bandwidth and sensitivity loss. At this balance point, sensitivity loss is threefold while saving one-third of the bandwidth. Beyond this point, further increasing the detection bandwidth yields diminishing sensitivity improvements, whereas reducing the detection bandwidth below this point leads to rapid sensitivity degradation. Experimental validation shifts this balance point to one-fourth, primarily due to measurement deviations. This study provides design guidelines for employing CP-ϕOTDR cost-effectively in large SSMR applications with acceptable sensitivity loss, such as seismic or ocean wave monitoring.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 2","pages":"718-726"},"PeriodicalIF":4.8,"publicationDate":"2025-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915563","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 : 2025-11-05DOI: 10.1109/JLT.2025.3629324
Yang Cheung;Zhenguo Jing;Pengdong Cao;Boda Yu;Yuefeng Qi;Wei Peng
Owing to its diaphragm-free structure, the fiber-optic Fabry-Perot etalon (FPE) sensor exhibits an exceptionally large dynamic range and rapid response characteristics for dynamic pressure sensing. However, its practical application is significantly impeded by its inherently low sensitivity. The optical Vernier effect has been demonstrated as an effective tool for enhancing the sensitivity of fiber-optic interferometric sensors. Previous studies have primarily focused on the design of Vernier-effect-based sensors via various cascaded interferometer configurations for sensitivity enhancement. In practical implementations, an interrogation system comprising a broadband light source and an optical spectrum analyzer (OSA) is typically employed to capture the Vernier spectrum. However, the fixed cavity length of the reference interferometer inherently restricts the flexible adjustment of sensitivity for such sensors. Furthermore, the low sampling rate of conventional OSAs fundamentally limits the dynamic sensing performance of Vernier-effect-based sensors. In this study, we propose a programmable Vernier envelope acquisition (PVEA) technique based on a modulated grating Y-branch (MG-Y) laser for enhancing the sensitivity of FPE sensors. The MG-Y laser performs wavelength scanning over the range of 1527–1567 nm with a sampling interval (SI) of 8 pm, thus enabling the acquisition of the transmission spectrum of the FPE sensor and its corresponding free spectral range (FSR). Benefiting from the flexible wavelength tuning capability of the MG-Y laser, the Vernier envelope was acquired by programmatically adjusting the laser's wavelength sampling interval, ultimately enabling different levels of sensitivity amplification for the FPE sensor without relying on an OSA. The technique was validated using an FPE sensor with a cavity length of 1500 µm, achieving sensitivity enhancement factors of 11.10 and 17.69. Dynamic pressure sensing was successfully demonstrated, exhibiting a measured response time of 320 ms. Furthermore, this technique is adaptable to other types of interferometric sensors.
{"title":"Enhanced Sensitivity for Dynamic Pressure Measurements Using a Fiber-Optic FPE Sensor via Programmable Vernier Envelope Acquisition","authors":"Yang Cheung;Zhenguo Jing;Pengdong Cao;Boda Yu;Yuefeng Qi;Wei Peng","doi":"10.1109/JLT.2025.3629324","DOIUrl":"https://doi.org/10.1109/JLT.2025.3629324","url":null,"abstract":"Owing to its diaphragm-free structure, the fiber-optic Fabry-Perot etalon (FPE) sensor exhibits an exceptionally large dynamic range and rapid response characteristics for dynamic pressure sensing. However, its practical application is significantly impeded by its inherently low sensitivity. The optical Vernier effect has been demonstrated as an effective tool for enhancing the sensitivity of fiber-optic interferometric sensors. Previous studies have primarily focused on the design of Vernier-effect-based sensors via various cascaded interferometer configurations for sensitivity enhancement. In practical implementations, an interrogation system comprising a broadband light source and an optical spectrum analyzer (OSA) is typically employed to capture the Vernier spectrum. However, the fixed cavity length of the reference interferometer inherently restricts the flexible adjustment of sensitivity for such sensors. Furthermore, the low sampling rate of conventional OSAs fundamentally limits the dynamic sensing performance of Vernier-effect-based sensors. In this study, we propose a programmable Vernier envelope acquisition (PVEA) technique based on a modulated grating Y-branch (MG-Y) laser for enhancing the sensitivity of FPE sensors. The MG-Y laser performs wavelength scanning over the range of 1527–1567 nm with a sampling interval (SI) of 8 pm, thus enabling the acquisition of the transmission spectrum of the FPE sensor and its corresponding free spectral range (FSR). Benefiting from the flexible wavelength tuning capability of the MG-Y laser, the Vernier envelope was acquired by programmatically adjusting the laser's wavelength sampling interval, ultimately enabling different levels of sensitivity amplification for the FPE sensor without relying on an OSA. The technique was validated using an FPE sensor with a cavity length of 1500 µm, achieving sensitivity enhancement factors of 11.10 and 17.69. Dynamic pressure sensing was successfully demonstrated, exhibiting a measured response time of 320 ms. Furthermore, this technique is adaptable to other types of interferometric sensors.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 2","pages":"787-793"},"PeriodicalIF":4.8,"publicationDate":"2025-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915618","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 : 2025-11-05DOI: 10.1109/JLT.2025.3629373
Haokun Yang;Gerard Tatel;Liang Chen;Xiaoyi Bao
Viscosity is a key physical parameter that governs fluid motion in a wide spectrum of scientific, biomedical, and industrial applications. This study introduces a compact all-fiber viscometer based on an off-core optical fiber cantilever integrated with a microsphere for viscosity measurement via vibrational damping analysis. The cantilever's free end is immersed in the test liquid and driven by a mechanical actuator, while the viscosity-dependent damping is extracted from the optical response of an interferometric cavity formed between the off-core fiber and the microsphere. The phase delay between the excitation and vibration signals serves as the primary sensing parameter, offering amplitude-insensitive and real-time readout. The all-fiber architecture ensures a miniaturized footprint and requires only a small sample volume (∼50 μL). Experimental validation demonstrates a strong correlation between the measured phase delay and viscosities ranging from 1.144 mPa·s to 8.029 mPa·s. The proposed viscometer offers a robust and practical solution for real-time viscosity monitoring, with potential applications in biomedical diagnostics, industrial process control, and microfluidic systems.
{"title":"Fiber-Optic Viscometer Based on Damping Rate of Off-Core Microsphere Cantilever","authors":"Haokun Yang;Gerard Tatel;Liang Chen;Xiaoyi Bao","doi":"10.1109/JLT.2025.3629373","DOIUrl":"https://doi.org/10.1109/JLT.2025.3629373","url":null,"abstract":"Viscosity is a key physical parameter that governs fluid motion in a wide spectrum of scientific, biomedical, and industrial applications. This study introduces a compact all-fiber viscometer based on an off-core optical fiber cantilever integrated with a microsphere for viscosity measurement via vibrational damping analysis. The cantilever's free end is immersed in the test liquid and driven by a mechanical actuator, while the viscosity-dependent damping is extracted from the optical response of an interferometric cavity formed between the off-core fiber and the microsphere. The phase delay between the excitation and vibration signals serves as the primary sensing parameter, offering amplitude-insensitive and real-time readout. The all-fiber architecture ensures a miniaturized footprint and requires only a small sample volume (∼50 μL). Experimental validation demonstrates a strong correlation between the measured phase delay and viscosities ranging from 1.144 mPa·s to 8.029 mPa·s. The proposed viscometer offers a robust and practical solution for real-time viscosity monitoring, with potential applications in biomedical diagnostics, industrial process control, and microfluidic systems.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 2","pages":"760-766"},"PeriodicalIF":4.8,"publicationDate":"2025-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915605","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 : 2025-11-04DOI: 10.1109/JLT.2025.3628641
Yaqi Yong;Binjie Li;Junyi Hu;Shuang Liu;Huilian Ma
Resonant fiber-optic gyroscopes (RFOGs) driven by broadband light sources represent a critical pathway toward high-precision fiber optic gyroscopes. However, in conventional broadband source-driven RFOGs, the self-interference components of clockwise and counterclockwise propagating light do not carry rotation information, yet contribute to undesired DC intensity. This introduces additional optical noise, thereby degrading the system's angular random walk (ARW). In this paper, a broadband source-driven RFOG with optical cancellation is implemented, where a 2 × 2 coupler replaces traditional circulators and Y-branch splitters. The π/2-phase between transmitted and coupled waves in the 2 × 2 coupler enables optical cancellation. Theoretical and experimental results demonstrate that this method effectively suppresses spurious DC components, significantly reducing both shot noise and relative intensity noise. Finally, a prototype RFOG was developed with a 130 m-long and 18.3 cm-diameter fiber ring resonator. Static tests were performed under both optical cancellation and non-cancellation configurations. The one-hour static test results demonstrated a 2.85 dB reduction in ARW with optical cancellation enabled, this confirms the scheme's significant contribution to gyroscope precision enhancement. Furthermore, the optical cancellation approach simplifies the optical path configuration and reduces signal processing circuit complexity, thereby enhancing the prospects for future compact RFOG integration.
{"title":"Improving Sensitivity of Broadband Source-Driven Resonant Fiber Optic Gyroscopes by Optical Cancellation","authors":"Yaqi Yong;Binjie Li;Junyi Hu;Shuang Liu;Huilian Ma","doi":"10.1109/JLT.2025.3628641","DOIUrl":"https://doi.org/10.1109/JLT.2025.3628641","url":null,"abstract":"Resonant fiber-optic gyroscopes (RFOGs) driven by broadband light sources represent a critical pathway toward high-precision fiber optic gyroscopes. However, in conventional broadband source-driven RFOGs, the self-interference components of clockwise and counterclockwise propagating light do not carry rotation information, yet contribute to undesired DC intensity. This introduces additional optical noise, thereby degrading the system's angular random walk (ARW). In this paper, a broadband source-driven RFOG with optical cancellation is implemented, where a 2 × 2 coupler replaces traditional circulators and Y-branch splitters. The π/2-phase between transmitted and coupled waves in the 2 × 2 coupler enables optical cancellation. Theoretical and experimental results demonstrate that this method effectively suppresses spurious DC components, significantly reducing both shot noise and relative intensity noise. Finally, a prototype RFOG was developed with a 130 m-long and 18.3 cm-diameter fiber ring resonator. Static tests were performed under both optical cancellation and non-cancellation configurations. The one-hour static test results demonstrated a 2.85 dB reduction in ARW with optical cancellation enabled, this confirms the scheme's significant contribution to gyroscope precision enhancement. Furthermore, the optical cancellation approach simplifies the optical path configuration and reduces signal processing circuit complexity, thereby enhancing the prospects for future compact RFOG integration.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 1","pages":"331-337"},"PeriodicalIF":4.8,"publicationDate":"2025-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145814465","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}
In this paper, an optical fiber vector magnetic field and temperature dual-parameter sensor based on multimode intermodal interference (MMI) is proposed and experimentally demonstrated. The sensor head is prepared by using magnetic fluid (MF) encapsulated single-mode fiber (SMF) -six-hole single-core fiber (SHSCF) -noncore fiber (NCF) -SMF structure. Wherein offset splicing between the lead-in SMF and the SHSCF is adopted to obtain a noncircular symmetry structure and effectively excite higher-order modes. In addition, employing a segment of NCF to be sandwiched between the SHSCF and the lead-out SMF is further to generate richer higher-order modes. Experimental results indicate that the transmission spectrum intensity of the sensor is highly sensitive to the magnetic field, while the wavelength shift of the transmission spectrum is extremely sensitive to temperature. Therefore, wavelength shift can be used to monitor temperature, and intensity can be used to measure the magnetic field. In our experiments, magnetic field intensity sensitivity, direction sensitivity and temperature sensitivity of the proposed fiber sensor were 1.34 dB/mT, 0.23 dB/°, and 2.31 nm/°C, respectively. The proposed optical fiber sensor has a compact structure, is easy to fabricate, and exhibits high sensitivity. It provides a novel sensing solution for the simultaneous measurement of magnetic field and temperature by combining the MF’s optical absorption and refractive index tunability through intensity and wavelength demodulation methods.
{"title":"Temperature-Compensated Optical Fiber Sensor for Dual-Parameter Measurement of Vector Magnetic Field and Temperature Based on Magnetic Fluid","authors":"Chenglong Jiang;Ronghui Xu;Jingyu Lai;Zhiyuan Chen;Danlin Feng;Ming Chen;Shiliang Qu;Libo Yuan","doi":"10.1109/JLT.2025.3628725","DOIUrl":"https://doi.org/10.1109/JLT.2025.3628725","url":null,"abstract":"In this paper, an optical fiber vector magnetic field and temperature dual-parameter sensor based on multimode intermodal interference (MMI) is proposed and experimentally demonstrated. The sensor head is prepared by using magnetic fluid (MF) encapsulated single-mode fiber (SMF) -six-hole single-core fiber (SHSCF) -noncore fiber (NCF) -SMF structure. Wherein offset splicing between the lead-in SMF and the SHSCF is adopted to obtain a noncircular symmetry structure and effectively excite higher-order modes. In addition, employing a segment of NCF to be sandwiched between the SHSCF and the lead-out SMF is further to generate richer higher-order modes. Experimental results indicate that the transmission spectrum intensity of the sensor is highly sensitive to the magnetic field, while the wavelength shift of the transmission spectrum is extremely sensitive to temperature. Therefore, wavelength shift can be used to monitor temperature, and intensity can be used to measure the magnetic field. In our experiments, magnetic field intensity sensitivity, direction sensitivity and temperature sensitivity of the proposed fiber sensor were 1.34 dB/mT, 0.23 dB/°, and 2.31 nm/°C, respectively. The proposed optical fiber sensor has a compact structure, is easy to fabricate, and exhibits high sensitivity. It provides a novel sensing solution for the simultaneous measurement of magnetic field and temperature by combining the MF’s optical absorption and refractive index tunability through intensity and wavelength demodulation methods.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 1","pages":"310-322"},"PeriodicalIF":4.8,"publicationDate":"2025-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145814511","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}
Distributed acoustic sensors (DAS) based on coding technology can extend the sensing distance while ensuring high spatial resolution. However, due to the high sidelobe level of the aperiodic autocorrelation function of coding sequences, the crosstalk level between adjacent sensing positions in coded DAS systems is relatively high, which limits the final performance of the system. In this paper, based on constant modulus polyphase coding sequences, a novel receiver scheme is proposed to significantly improve the crosstalk suppression of coded DAS systems. The receiver adopts an asymmetric correlator receiver (ACR), which correlates the received signal with a new coding sequence derived from but different from the original transmitted coding sequence. The paper presents the generation method of the new sequence and theoretical calculations show that the ACR can significantly reduce the sidelobe level of the aperiodic autocorrelation function by more than 20 dB, which suggests a prominent crosstalk suppression capability of the ACR in coded DAS. On a sensing fiber of 5 km embedded by a vibration region of 1.525 m near the fiber end, a DAS system based on polyphase coding and ACR simultaneously achieves higher spatial resolution and better signal-to-noise (SNR) than conventional schemes based on repeated single probe pulse. Moreover, the crosstalk due to coding sequence is suppressed by more than 10 dB through the adoption of ACR, lowering the noise floor level from about -50 dB/Hz to about -65 dB/Hz and making the system more robust at power fading positions.
{"title":"Polyphase Coding and Asymmetric Correlator Receiver Based Distributed Acoustic Sensor With Enhanced Crosstalk Suppression","authors":"Guodong Deng;Silan Gao;Tianfang Zhang;Jie Lv;Linghao Cheng;Hao Liang;Bai-Ou Guan","doi":"10.1109/JLT.2025.3628871","DOIUrl":"https://doi.org/10.1109/JLT.2025.3628871","url":null,"abstract":"Distributed acoustic sensors (DAS) based on coding technology can extend the sensing distance while ensuring high spatial resolution. However, due to the high sidelobe level of the aperiodic autocorrelation function of coding sequences, the crosstalk level between adjacent sensing positions in coded DAS systems is relatively high, which limits the final performance of the system. In this paper, based on constant modulus polyphase coding sequences, a novel receiver scheme is proposed to significantly improve the crosstalk suppression of coded DAS systems. The receiver adopts an asymmetric correlator receiver (ACR), which correlates the received signal with a new coding sequence derived from but different from the original transmitted coding sequence. The paper presents the generation method of the new sequence and theoretical calculations show that the ACR can significantly reduce the sidelobe level of the aperiodic autocorrelation function by more than 20 dB, which suggests a prominent crosstalk suppression capability of the ACR in coded DAS. On a sensing fiber of 5 km embedded by a vibration region of 1.525 m near the fiber end, a DAS system based on polyphase coding and ACR simultaneously achieves higher spatial resolution and better signal-to-noise (SNR) than conventional schemes based on repeated single probe pulse. Moreover, the crosstalk due to coding sequence is suppressed by more than 10 dB through the adoption of ACR, lowering the noise floor level from about -50 dB/Hz to about -65 dB/Hz and making the system more robust at power fading positions.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 2","pages":"710-717"},"PeriodicalIF":4.8,"publicationDate":"2025-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915579","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}
In 3×3 coupler-based interferometric systems, the phase demodulation accuracy is affected by light source fluctuations and unequal coupler splitting ratios. Existing algorithms face challenges in simultaneously suppressing fluctuations in the light source and compensating for splitting ratio deviations in the coupler. To address this issue, an improved 3×3 coupler demodulation algorithm is proposed to achieve high-precision phase extraction. The algorithm employs ellipse fitting algorithm (EFA) to calibrate the direct current (DC) components and fringe visibility of the three interference signals. One interference signal is selected as the reference, and the remaining two signals are differentially processed against the reference to eliminate the influence of DC components. A system of equations is constructed to obtain a set of orthogonal components containing the desired phase signal, thus achieving effective compensation for asymmetries in the coupler's splitting ratio. The alternating current (AC) component coefficients in the orthogonal signals are effectively removed during the arctangent processing. Simulation results demonstrate that the orthogonal components obtains a Lissajous diagram characterized by a smooth, low-fluctuation, and highly uniform circular trajectory. The average relative error between the demodulated phase and the original signal is as low as 0.004%. Temperature sensing experiments confirm that the algorithm achieves an ultra-high sensitivity of 11,941 rad/°C with the coefficient of determination (R2) as high as 0.9992. Moreover, the average absolute error in temperature measurement is as low as 0.0055°C, demonstrating the outstanding precision and reliability of the proposed scheme. Owing to the high-precision and high-stability demodulation performance, the algorithm demonstrates significant application potential in interferometric systems based on 3×3 coupler.
{"title":"An Improved 3×3 Coupler Demodulation Scheme for High Precision Phase Extraction in Fiber Optic Interferometric Sensor","authors":"Zhen Pan;Mengfan Peng;SiSi Li;Yini Shi;Yuan Li;Nengwen Pan;Dian Fan;Ciming Zhou","doi":"10.1109/JLT.2025.3629048","DOIUrl":"https://doi.org/10.1109/JLT.2025.3629048","url":null,"abstract":"In 3×3 coupler-based interferometric systems, the phase demodulation accuracy is affected by light source fluctuations and unequal coupler splitting ratios. Existing algorithms face challenges in simultaneously suppressing fluctuations in the light source and compensating for splitting ratio deviations in the coupler. To address this issue, an improved 3×3 coupler demodulation algorithm is proposed to achieve high-precision phase extraction. The algorithm employs ellipse fitting algorithm (EFA) to calibrate the direct current (DC) components and fringe visibility of the three interference signals. One interference signal is selected as the reference, and the remaining two signals are differentially processed against the reference to eliminate the influence of DC components. A system of equations is constructed to obtain a set of orthogonal components containing the desired phase signal, thus achieving effective compensation for asymmetries in the coupler's splitting ratio. The alternating current (AC) component coefficients in the orthogonal signals are effectively removed during the arctangent processing. Simulation results demonstrate that the orthogonal components obtains a Lissajous diagram characterized by a smooth, low-fluctuation, and highly uniform circular trajectory. The average relative error between the demodulated phase and the original signal is as low as 0.004%. Temperature sensing experiments confirm that the algorithm achieves an ultra-high sensitivity of 11,941 rad/°C with the coefficient of determination (R<sup>2</sup>) as high as 0.9992. Moreover, the average absolute error in temperature measurement is as low as 0.0055°C, demonstrating the outstanding precision and reliability of the proposed scheme. Owing to the high-precision and high-stability demodulation performance, the algorithm demonstrates significant application potential in interferometric systems based on 3×3 coupler.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 2","pages":"752-759"},"PeriodicalIF":4.8,"publicationDate":"2025-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915582","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}
Conventional approaches enhance random distributed feedback (R-DFB) strength by upgrading scattering elements. Nevertheless, these methods have reached a performance plateau and neglect the physical mechanism underlying photonic localization. To overcome this limitation, a hetero-frequency symmetric cladding fiber Bragg gratings (CLFBGs) structure was proposed and fabricated via a femtosecond point-by-point inscription technique to generate multipath interference feedback. This configuration facilitates the coupling of cladding modes at distinct frequencies with the core mode individually, effectively enhancing the modal degrees of freedom within the cavity. Moreover, the symmetric structure significantly suppresses the radial energy dissipation in cladding modes, resulting in stronger core-cladding mode coupling. Therefore, it produces R-DFB enhancement and enables the transition from extended modes to localized modes (LM) in weakly disordered media. Experimental results demonstrated that, compared to single-path interference feedback, the new structure increased the spectral oscillation amplitude by 486% and reduced output power fluctuations from 0.54 mW to 0.33 mW. Moreover, the cavity quality factor (Qmean) increased from 2821 to 5239, indicating operation of the random laser (RL) in the LM regime. Further integration with a strongly scattering reflector minimized power fluctuations to 0.02 mW, and improved Qmean to 8422. These findings confirm that the designed random fiber laser (RFL) achieves exceptional temporal stability and strong photonic localization. As a result, the proposed laser could be applied in secure communications, optical sensing, and imaging.
{"title":"A Hetero-Frequency Symmetric Cladding Fiber Bragg Gratings Structure for Exciting Strong Photonic Localization in Random Fiber Laser","authors":"Shaode Li;Wei He;Xingpeng Fei;Lihang Xu;Zhehai Zhou","doi":"10.1109/JLT.2025.3629025","DOIUrl":"https://doi.org/10.1109/JLT.2025.3629025","url":null,"abstract":"Conventional approaches enhance random distributed feedback (R-DFB) strength by upgrading scattering elements. Nevertheless, these methods have reached a performance plateau and neglect the physical mechanism underlying photonic localization. To overcome this limitation, a hetero-frequency symmetric cladding fiber Bragg gratings (CLFBGs) structure was proposed and fabricated via a femtosecond point-by-point inscription technique to generate multipath interference feedback. This configuration facilitates the coupling of cladding modes at distinct frequencies with the core mode individually, effectively enhancing the modal degrees of freedom within the cavity. Moreover, the symmetric structure significantly suppresses the radial energy dissipation in cladding modes, resulting in stronger core-cladding mode coupling. Therefore, it produces R-DFB enhancement and enables the transition from extended modes to localized modes (LM) in weakly disordered media. Experimental results demonstrated that, compared to single-path interference feedback, the new structure increased the spectral oscillation amplitude by 486% and reduced output power fluctuations from 0.54 mW to 0.33 mW. Moreover, the cavity quality factor (<italic>Q<sub>mean</sub></i>) increased from 2821 to 5239, indicating operation of the random laser (RL) in the LM regime. Further integration with a strongly scattering reflector minimized power fluctuations to 0.02 mW, and improved <italic>Q<sub>mean</sub></i> to 8422. These findings confirm that the designed random fiber laser (RFL) achieves exceptional temporal stability and strong photonic localization. As a result, the proposed laser could be applied in secure communications, optical sensing, and imaging.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 1","pages":"288-295"},"PeriodicalIF":4.8,"publicationDate":"2025-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145814474","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 : 2025-10-31DOI: 10.1109/JLT.2025.3627258
Hanyu Bai;Xue Zhou;Yanan Zhang;Yong Zhao;Xuegang Li
This study presents a novel optical fiber biosensor configured for the concurrent measurement of β-actin (ACTB) and temperature. This device is built upon a single-mode optical fiber platform and uses Fast Fourier Transform (FFT) for data processing. The device’s functionality is achieved by the synergistic integration of two distinct sensing principles: surface plasmon resonance (SPR) and Mach-Zehnder interferometry (MZI). By leveraging the specific binding between ACTB antigens and immobilized antibodies on the fiber surface, the refractive index (RI) changes upon complex formation, resulting in distinct spectral shifts in both SPR and MZI channels, thus enabling precise ACTB detection. Notably, this is the first reported design to realize the dual SPR–MZI sensing effects directly on a single, continuous optical fiber—without requiring fiber fusion or splicing—greatly simplifying the fabrication process. The dual-channel configuration also allows for effective temperature compensation. Experimental results demonstrate high RI sensitivities of 2230 nm/RIU for the SPR channel and 309 nm/RIU for the MZI channel, as well as temperature sensitivities of 0.43 nm/°C (SPR) and 0.208 nm/°C (MZI). The sensor exhibits a rapid response time of 200 seconds for ACTB detection, with a sensitivity of 6.5 nm/(ng/mL), a linear detection range of 0–5 ng/mL, and a limit of detection (LOD) as low as 0.0442 ng/mL. Additionally, a straightforward SPR dip modulation technique is introduced, whereby the SPR resonance position can be effectively tuned by adjusting the fiber’s bending angle. The use of a large-diameter taper not only enhances mechanical robustness but also maintains strong optical performance. Overall, this sensor offers high sensitivity, excellent stability, rapid response, and a low-cost, easy-to-manufacture structure.
{"title":"A Splice-Free Dual-Mode Optical Fiber Biosensor for Sensitive and Temperature-Compensated β-Actin Detection via SPR and MZI Integration","authors":"Hanyu Bai;Xue Zhou;Yanan Zhang;Yong Zhao;Xuegang Li","doi":"10.1109/JLT.2025.3627258","DOIUrl":"https://doi.org/10.1109/JLT.2025.3627258","url":null,"abstract":"This study presents a novel optical fiber biosensor configured for the concurrent measurement of β-actin (ACTB) and temperature. This device is built upon a single-mode optical fiber platform and uses Fast Fourier Transform (FFT) for data processing. The device’s functionality is achieved by the synergistic integration of two distinct sensing principles: surface plasmon resonance (SPR) and Mach-Zehnder interferometry (MZI). By leveraging the specific binding between ACTB antigens and immobilized antibodies on the fiber surface, the refractive index (RI) changes upon complex formation, resulting in distinct spectral shifts in both SPR and MZI channels, thus enabling precise ACTB detection. Notably, this is the first reported design to realize the dual SPR–MZI sensing effects directly on a single, continuous optical fiber—without requiring fiber fusion or splicing—greatly simplifying the fabrication process. The dual-channel configuration also allows for effective temperature compensation. Experimental results demonstrate high RI sensitivities of 2230 nm/RIU for the SPR channel and 309 nm/RIU for the MZI channel, as well as temperature sensitivities of 0.43 nm/°C (SPR) and 0.208 nm/°C (MZI). The sensor exhibits a rapid response time of 200 seconds for ACTB detection, with a sensitivity of 6.5 nm/(ng/mL), a linear detection range of 0–5 ng/mL, and a limit of detection (LOD) as low as 0.0442 ng/mL. Additionally, a straightforward SPR dip modulation technique is introduced, whereby the SPR resonance position can be effectively tuned by adjusting the fiber’s bending angle. The use of a large-diameter taper not only enhances mechanical robustness but also maintains strong optical performance. Overall, this sensor offers high sensitivity, excellent stability, rapid response, and a low-cost, easy-to-manufacture structure.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 1","pages":"386-392"},"PeriodicalIF":4.8,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145814510","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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