Pub Date : 2024-09-10DOI: 10.1109/LPT.2024.3457492
Ruoqi Wang;Wenrui Wang;Jun Hu;Biying Zhou;Xueqian Bai;Lingyun Ye;Kaichen Song
A highly sensitive method utilizing coarse frequency sampling and Vernier effect for optoelectronic oscillator (OEO) based fiber Bragg grating (FBG) sensing system is proposed and experimentally demonstrated. To generate the Vernier effect, the frequency sampling interval is set close to the free spectral range of the OEO. Cubic spline fitting and power normalization were applied to obtain smooth sampling curve. The peak frequency of the fitted curve was chosen to measure the spectral shift. In the temperature test experiment, a controllable sensitivity was achieved by changing the sampling interval. The sensitivity of 222.84kHz $/^{circ }$ C was obtained, which was 127.26 times higher than that of traditional single-loop OEO. Our method requires no modifications to the sensing circuit. Furthermore, it can be used in other OEO-based sensors, indicating promising application prospects.
{"title":"Highly Sensitive Optoelectronic Oscillator-Based FBG Sensor via Coarse Sampling and Vernier Effect","authors":"Ruoqi Wang;Wenrui Wang;Jun Hu;Biying Zhou;Xueqian Bai;Lingyun Ye;Kaichen Song","doi":"10.1109/LPT.2024.3457492","DOIUrl":"10.1109/LPT.2024.3457492","url":null,"abstract":"A highly sensitive method utilizing coarse frequency sampling and Vernier effect for optoelectronic oscillator (OEO) based fiber Bragg grating (FBG) sensing system is proposed and experimentally demonstrated. To generate the Vernier effect, the frequency sampling interval is set close to the free spectral range of the OEO. Cubic spline fitting and power normalization were applied to obtain smooth sampling curve. The peak frequency of the fitted curve was chosen to measure the spectral shift. In the temperature test experiment, a controllable sensitivity was achieved by changing the sampling interval. The sensitivity of 222.84kHz\u0000<inline-formula> <tex-math>$/^{circ }$ </tex-math></inline-formula>\u0000C was obtained, which was 127.26 times higher than that of traditional single-loop OEO. Our method requires no modifications to the sensing circuit. Furthermore, it can be used in other OEO-based sensors, indicating promising application prospects.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-09-05DOI: 10.1109/LPT.2024.3454648
Danping Lin;Shaohua Tao
An approach for edge-enhanced imaging based on the optical element that generates a curvilinear vortex beam with intensity and phase distributions along arbitrary curves was proposed, which is different from the classic edge-enhanced imaging method with a 4f imaging system. It is demonstrated that the image edge can be enhanced by modulating the optical element that generates the curvilinear vortex beam with a ring or ellipse trajectory. By setting the factor that determines the ring or elliptical trajectory of the curvilinear vortex beam, the intensity distribution of the optical element can be controlled, resulting in directional enhancement of the image. Furthermore, by clipping the optical element, the image edge can be enhanced in the selective region. It is helpful for the further applications of the optical element that generates the curvilinear vortex beams in optical imaging, especially higher contrast and resolution images.
{"title":"Arbitrary Tunable Edge-Enhanced Imaging Based on Curvilinear Vortex Filter","authors":"Danping Lin;Shaohua Tao","doi":"10.1109/LPT.2024.3454648","DOIUrl":"10.1109/LPT.2024.3454648","url":null,"abstract":"An approach for edge-enhanced imaging based on the optical element that generates a curvilinear vortex beam with intensity and phase distributions along arbitrary curves was proposed, which is different from the classic edge-enhanced imaging method with a 4f imaging system. It is demonstrated that the image edge can be enhanced by modulating the optical element that generates the curvilinear vortex beam with a ring or ellipse trajectory. By setting the factor that determines the ring or elliptical trajectory of the curvilinear vortex beam, the intensity distribution of the optical element can be controlled, resulting in directional enhancement of the image. Furthermore, by clipping the optical element, the image edge can be enhanced in the selective region. It is helpful for the further applications of the optical element that generates the curvilinear vortex beams in optical imaging, especially higher contrast and resolution images.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-09-04DOI: 10.1109/LPT.2024.3454358
Xiaojun Zhu;Jiayi Qian;Wen Liu;Shuai Li;Yongjuan Ji;Juan Cao;Guoan Zhang;Yan Cai;Yongjie Yang
A knee-flexion angle sensor based on spherical fused triple-clad fiber (TCF) is proposed and demonstrated. The optical path difference between the core and cladding modes in the angle sensor changes as the knee joint flexion angle changes, resulting in deviations in the interference spectrum. We conducted comparison experiments on various TCF lengths. When the TCF length is 3 cm, the maximum sensor’s angle detection range is from $0~^{circ }$ to $110~^{circ }$ . The angle sensitivity of the sensor is −0.35 nm/°, and the linear regression coefficient (R2) is 99.6 %, respectively. Furthermore, in the temperature range of 30- $90~^{circ }$ C, the maximum temperature sensitivity is 0.08 nm/°C, and the R2 is 99.8 %. The sensor has the advantage of being compact, easy to manufacture, and highly repeatable, making it suitable for real-time human health monitoring and rehabilitation.
{"title":"A Knee-Flexion Angle Optical Fiber Sensor Based on Spherical Fused Triple-Clad Fiber","authors":"Xiaojun Zhu;Jiayi Qian;Wen Liu;Shuai Li;Yongjuan Ji;Juan Cao;Guoan Zhang;Yan Cai;Yongjie Yang","doi":"10.1109/LPT.2024.3454358","DOIUrl":"10.1109/LPT.2024.3454358","url":null,"abstract":"A knee-flexion angle sensor based on spherical fused triple-clad fiber (TCF) is proposed and demonstrated. The optical path difference between the core and cladding modes in the angle sensor changes as the knee joint flexion angle changes, resulting in deviations in the interference spectrum. We conducted comparison experiments on various TCF lengths. When the TCF length is 3 cm, the maximum sensor’s angle detection range is from \u0000<inline-formula> <tex-math>$0~^{circ }$ </tex-math></inline-formula>\u0000 to \u0000<inline-formula> <tex-math>$110~^{circ }$ </tex-math></inline-formula>\u0000. The angle sensitivity of the sensor is −0.35 nm/°, and the linear regression coefficient (R2) is 99.6 %, respectively. Furthermore, in the temperature range of 30-\u0000<inline-formula> <tex-math>$90~^{circ }$ </tex-math></inline-formula>\u0000C, the maximum temperature sensitivity is 0.08 nm/°C, and the R2 is 99.8 %. The sensor has the advantage of being compact, easy to manufacture, and highly repeatable, making it suitable for real-time human health monitoring and rehabilitation.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-09-04DOI: 10.1109/LPT.2024.3454265
Min Wang;Gao Wei;Tiancheng Qiu;Siyuan Lei;Kangkang Han
In this letter, a novel spoof surface plasmon polaritons (SSPPs) bandpass filtering unit (BP-FU) is proposed. The equivalent circuit model of BP-FU is given and by establishing its ABCD-matrix, the pass band and forbidden band are analysed theoretically, which behaves the feature of bandpass. Meanwhile, the simulated dispersion curve of BP-FU shows bandpass feature. Subsequently, the proposed BP-FU is applied to design a bandpass filtering transmission line (TL). The TL obtains the bandpass filtering feature spontaneously due to the periodically arranged BP-FUs. The TL consisting of BP-FUs can be excited by the methods like exciting traditional unit and a transverse magnetic wave propagates along the TL. The field characteristic is as same as classical SSPPs TL. The measured results of the prototype of the TL shows a passband from 6.66 GHz to 10.06 GHz and ultrawide stopbands ( $vert S_{21}vert lt $ -22 dB) from nearly 0 GHz to 5.36 GHz and 10.89 GHz to 40 GHz. The measured results indicate good application prospect in single conductor multifunction circuit.
{"title":"A Compact SSPPs Unit With Bandpass Feature and its Application in Bandpass Transmission Line","authors":"Min Wang;Gao Wei;Tiancheng Qiu;Siyuan Lei;Kangkang Han","doi":"10.1109/LPT.2024.3454265","DOIUrl":"https://doi.org/10.1109/LPT.2024.3454265","url":null,"abstract":"In this letter, a novel spoof surface plasmon polaritons (SSPPs) bandpass filtering unit (BP-FU) is proposed. The equivalent circuit model of BP-FU is given and by establishing its ABCD-matrix, the pass band and forbidden band are analysed theoretically, which behaves the feature of bandpass. Meanwhile, the simulated dispersion curve of BP-FU shows bandpass feature. Subsequently, the proposed BP-FU is applied to design a bandpass filtering transmission line (TL). The TL obtains the bandpass filtering feature spontaneously due to the periodically arranged BP-FUs. The TL consisting of BP-FUs can be excited by the methods like exciting traditional unit and a transverse magnetic wave propagates along the TL. The field characteristic is as same as classical SSPPs TL. The measured results of the prototype of the TL shows a passband from 6.66 GHz to 10.06 GHz and ultrawide stopbands (\u0000<inline-formula> <tex-math>$vert S_{21}vert lt $ </tex-math></inline-formula>\u0000-22 dB) from nearly 0 GHz to 5.36 GHz and 10.89 GHz to 40 GHz. The measured results indicate good application prospect in single conductor multifunction circuit.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142173983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-09-03DOI: 10.1109/LPT.2024.3454151
Liushu Pan;Shengquan Li;Jian Chen;Mingcheng Luo;Long Zhang;Linbojie Huang;Kwai Hei Li;Xinke Tang
In this letter, the fabrication and characterization of a miniaturized optical hydrophone for detecting underwater acoustic signals is demonstrated. A light emitter and detector are fabricated on a GaN-based device at chip scale through the monolithic integration approach. By incorporating a deformable PDMS film embedded with TiO2 nanoparticles, the sound vibration can be effectively converted into photocurrent changes. The millimeter-sized hydrophone can detect hydro-acoustic signals ranging from 0.1 Hz to 250 Hz, with an optimum sensitivity of about $2.3times 10 ^{-14}$ A/ $mu $ Pa at around 48 Hz and a minimum detectable pressure of about 4 Pa. It is capable of distinguishing waves originating from two distinct acoustic sources with a frequency difference as low as 0.2 Hz. This cost-effective, chip-scale design with high stability holds great potential for a variety of applications that necessitate identifying low-frequency acoustic signals in underwater environments.
{"title":"Miniaturized GaN-Based Optical Hydrophones for Underwater Low-Frequency Acoustic Detection","authors":"Liushu Pan;Shengquan Li;Jian Chen;Mingcheng Luo;Long Zhang;Linbojie Huang;Kwai Hei Li;Xinke Tang","doi":"10.1109/LPT.2024.3454151","DOIUrl":"10.1109/LPT.2024.3454151","url":null,"abstract":"In this letter, the fabrication and characterization of a miniaturized optical hydrophone for detecting underwater acoustic signals is demonstrated. A light emitter and detector are fabricated on a GaN-based device at chip scale through the monolithic integration approach. By incorporating a deformable PDMS film embedded with TiO2 nanoparticles, the sound vibration can be effectively converted into photocurrent changes. The millimeter-sized hydrophone can detect hydro-acoustic signals ranging from 0.1 Hz to 250 Hz, with an optimum sensitivity of about \u0000<inline-formula> <tex-math>$2.3times 10 ^{-14}$ </tex-math></inline-formula>\u0000 A/\u0000<inline-formula> <tex-math>$mu $ </tex-math></inline-formula>\u0000Pa at around 48 Hz and a minimum detectable pressure of about 4 Pa. It is capable of distinguishing waves originating from two distinct acoustic sources with a frequency difference as low as 0.2 Hz. This cost-effective, chip-scale design with high stability holds great potential for a variety of applications that necessitate identifying low-frequency acoustic signals in underwater environments.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 letter, a dual-band polarization-independent terahertz (THz) metamaterial absorber (MA) based on metal-insulator-metal (MIM) configuration is proposed and measured. The flexible material polyimide is chosen as the substrate. The periodic metal array cell on the top surface is fabricated utilizing four F-shaped metal strips, and due to the high symmetry of the structure, the designed absorber is insensitive to polarization. Furthermore, the impact of structural parameters on the absorption characteristics is numerically investigated, and the results indicate that the absorption peak can be flexibly adjusted by changing the length of the top metal strip. The proposed MA achieves near-perfect absorption at 0.555 THz and 0.797 THz under normal TE and TM polarized incidence, with Q-factors of 23.56 and 45.28, respectively. This work provides a new design strategy for the realization of multi-band THz MA.
在这封信中，我们提出并测量了一种基于金属-绝缘体-金属（MIM）配置的、与偏振无关的双波段太赫兹（THz）超材料吸收器（MA）。基底选用柔性材料聚酰亚胺。由于结构的高度对称性，所设计的吸收器对极化不敏感。此外，还对结构参数对吸收特性的影响进行了数值研究，结果表明可以通过改变顶部金属带的长度来灵活调整吸收峰值。在正常 TE 和 TM 极化入射条件下，所提出的 MA 在 0.555 THz 和 0.797 THz 实现了近乎完美的吸收，Q 系数分别为 23.56 和 45.28。这项工作为实现多波段 THz MA 提供了一种新的设计策略。
{"title":"Dual-Band Polarization-Independent Terahertz Absorber Based on F-Shaped Multimode Structure","authors":"Daotong Li;Dongyi Sui;Kai-Da Xu;Dongxu Wang;Ying Liu;Siyuan Luo;Naoki Shinohara","doi":"10.1109/LPT.2024.3454175","DOIUrl":"10.1109/LPT.2024.3454175","url":null,"abstract":"In this letter, a dual-band polarization-independent terahertz (THz) metamaterial absorber (MA) based on metal-insulator-metal (MIM) configuration is proposed and measured. The flexible material polyimide is chosen as the substrate. The periodic metal array cell on the top surface is fabricated utilizing four F-shaped metal strips, and due to the high symmetry of the structure, the designed absorber is insensitive to polarization. Furthermore, the impact of structural parameters on the absorption characteristics is numerically investigated, and the results indicate that the absorption peak can be flexibly adjusted by changing the length of the top metal strip. The proposed MA achieves near-perfect absorption at 0.555 THz and 0.797 THz under normal TE and TM polarized incidence, with Q-factors of 23.56 and 45.28, respectively. This work provides a new design strategy for the realization of multi-band THz MA.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-08-30DOI: 10.1109/LPT.2024.3449922
Jing He;Jing He
In the letter, a grouped artificial neural network (G-ANN) based equalizer is proposed and experimentally demonstrated for the rotated and probabilistically shaped 64 quadrature amplitude modulation (RPS 64QAM) orthogonal frequency division multiplexing (OFDM) in W-band radio-over-fiber (ROF) system. PS OFDM can achieve capacity improvement and flexible rate adaptability. Then, the rotated QAM scheme is applied after PS to increase the noise tolerance and resist selective frequency fading in ROF system. In addition, a deep learning equalizer using G-ANN is proposed for RPS 64QAM OFDM. The numerical analysis indicates that the proposed G-ANN equalizer has a better performance and lower training overhead compared with the ANN equalizer. The experimental results show that, after 20 km standard single mode fiber (SSMF) and 1 m wireless transmission, compared to RPS without and with ANN equalizer, the sensitivity improvement of RPS OFDM with the proposed G-ANN equalizer can achieve 1.5dB and 0.6dB at BER of $10^{-5}$ . Meanwhile, the receiver sensitivity of RPS can be improved 1.6 dB compared with PS at normalized generalized mutual information (NGMI) of 0.83.
{"title":"A Grouped-ANN Equalizer for the Rotated PS 64QAM OFDM in W-Band ROF System","authors":"Jing He;Jing He","doi":"10.1109/LPT.2024.3449922","DOIUrl":"https://doi.org/10.1109/LPT.2024.3449922","url":null,"abstract":"In the letter, a grouped artificial neural network (G-ANN) based equalizer is proposed and experimentally demonstrated for the rotated and probabilistically shaped 64 quadrature amplitude modulation (RPS 64QAM) orthogonal frequency division multiplexing (OFDM) in W-band radio-over-fiber (ROF) system. PS OFDM can achieve capacity improvement and flexible rate adaptability. Then, the rotated QAM scheme is applied after PS to increase the noise tolerance and resist selective frequency fading in ROF system. In addition, a deep learning equalizer using G-ANN is proposed for RPS 64QAM OFDM. The numerical analysis indicates that the proposed G-ANN equalizer has a better performance and lower training overhead compared with the ANN equalizer. The experimental results show that, after 20 km standard single mode fiber (SSMF) and 1 m wireless transmission, compared to RPS without and with ANN equalizer, the sensitivity improvement of RPS OFDM with the proposed G-ANN equalizer can achieve 1.5dB and 0.6dB at BER of \u0000<inline-formula> <tex-math>$10^{-5}$ </tex-math></inline-formula>\u0000. Meanwhile, the receiver sensitivity of RPS can be improved 1.6 dB compared with PS at normalized generalized mutual information (NGMI) of 0.83.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142143597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-08-29DOI: 10.1109/LPT.2024.3451456
Li Liu;Lijun Zhang;Chen Chen;Xiang Li;Ying Qiu;Ping Zhao;Cong Hu;Jiazhu Duan
To meet the evolving demands of optical communication and optical signal processing, we propose a programmable optical filter based on a finite impulse response (FIR) structure, consisting of twelve amplitude tuning modules and phase tuning modules. The genetic algorithm is introduced to simultaneously manipulate the twelve electrodes, hence the proposed optical filter could obtain efficiently reconfigurable ability. The experimental results demonstrate that under the guidance of the genetic algorithm, the bandpass shape of the FIR filter could be tuned to a variety of waveforms. The fitting errors between the experimental and simulated curves are less than 4.5%. Especially, the passband ripples could be as low as 0.24 dB.
{"title":"Programmable Optical Filter Combining a FIR Structure and Intelligent Algorithms","authors":"Li Liu;Lijun Zhang;Chen Chen;Xiang Li;Ying Qiu;Ping Zhao;Cong Hu;Jiazhu Duan","doi":"10.1109/LPT.2024.3451456","DOIUrl":"https://doi.org/10.1109/LPT.2024.3451456","url":null,"abstract":"To meet the evolving demands of optical communication and optical signal processing, we propose a programmable optical filter based on a finite impulse response (FIR) structure, consisting of twelve amplitude tuning modules and phase tuning modules. The genetic algorithm is introduced to simultaneously manipulate the twelve electrodes, hence the proposed optical filter could obtain efficiently reconfigurable ability. The experimental results demonstrate that under the guidance of the genetic algorithm, the bandpass shape of the FIR filter could be tuned to a variety of waveforms. The fitting errors between the experimental and simulated curves are less than 4.5%. Especially, the passband ripples could be as low as 0.24 dB.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142143546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We have developed a passive semiconductor mode-locked laser on a semi-insulating (S.I.) substrate, which significantly reduces parasitic capacitance. This allows for efficient direct modulation and improved performance, making it ideal for RF fundamental and subharmonic injection locking using a Ground-Signal-Ground probe with relatively lower RF power to reduce timing jitter. Hybrid mode-locking was observed at RF powers as low as –20 dBm for the fundamental frequency, with higher power required for subharmonic frequencies. Experimental results demonstrate significant performance improvements, including linewidth reduction from 40 kHz (free-running laser) to sub-hertz levels after RF fundamental injection locking, phase noise reduction by over 40 dBc/Hz at a 10 kHz offset, and a decrease in timing jitter from 7.2 ps to approximately 80 fs with an injected fundamental RF power of –5 dBm. Subharmonic injection locking offers simplified modulation requirements and circuitry, although it requires a higher injection RF power. These significant improvements highlight the potential of our approach for advanced optical communication and optical clock systems.
{"title":"Ultrastable 10 GHz Mode-Locked Laser on Semi-Insulating Substrate Through RF Injection Locking","authors":"Mohanad Al-Rubaiee;Bocheng Yuan;Yizhe Fan;Simeng Zhu;John Marsh;Lianping Hou","doi":"10.1109/LPT.2024.3451690","DOIUrl":"https://doi.org/10.1109/LPT.2024.3451690","url":null,"abstract":"We have developed a passive semiconductor mode-locked laser on a semi-insulating (S.I.) substrate, which significantly reduces parasitic capacitance. This allows for efficient direct modulation and improved performance, making it ideal for RF fundamental and subharmonic injection locking using a Ground-Signal-Ground probe with relatively lower RF power to reduce timing jitter. Hybrid mode-locking was observed at RF powers as low as –20 dBm for the fundamental frequency, with higher power required for subharmonic frequencies. Experimental results demonstrate significant performance improvements, including linewidth reduction from 40 kHz (free-running laser) to sub-hertz levels after RF fundamental injection locking, phase noise reduction by over 40 dBc/Hz at a 10 kHz offset, and a decrease in timing jitter from 7.2 ps to approximately 80 fs with an injected fundamental RF power of –5 dBm. Subharmonic injection locking offers simplified modulation requirements and circuitry, although it requires a higher injection RF power. These significant improvements highlight the potential of our approach for advanced optical communication and optical clock systems.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142169686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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