We propose a theoretical model to describe external-cavity distributed feedback semiconductor lasers and investigate the impact of the number of external feedback points on linewidth and side-mode suppression ratio th...We propose a theoretical model to describe external-cavity distributed feedback semiconductor lasers and investigate the impact of the number of external feedback points on linewidth and side-mode suppression ratio through numerical simulation. The simulation results demonstrate that the linewidth of external-cavity semiconductor lasers can be reduced by increasing the external cavity length and feedback ratio, and adding more external feedback points can further narrow the linewidth and enhance the side mode suppression ratio. This research provides insight into the external cavity distributed feedback mechanism and can guide the design of high-performance external cavity semiconductor lasers. .展开更多
Optical chaos has attracted widespread attention owing to its complex dynamic behaviors.However,the time delay signature(TDS)caused by the external cavity mode reduces the complexity of optical chaos.We propose and nu...Optical chaos has attracted widespread attention owing to its complex dynamic behaviors.However,the time delay signature(TDS)caused by the external cavity mode reduces the complexity of optical chaos.We propose and numerically demonstrate the critical dispersion of chirped fiber Bragg grating(CFBG)for eliminating the TDS of laser chaos in this work.The critical dispersion,as a function of relaxation frequency and bandwidth of the optical spectrum,is found through extensive dynamics simulations.It is shown that the TDS can be eliminated when the dispersion of CFBG is above this critical dispersion.In addition,the influence of dispersive feedback light and output light from a laser is investigated.These results provide important quantitative guidance for designing chaotic semiconductor lasers without TDS.展开更多
Narrow linewidth light source is a prerequisite for high-performance coherent optical communication and sensing.Waveguide-based external cavity narrow linewidth semiconductor lasers(WEC-NLSLs)have become a competitive...Narrow linewidth light source is a prerequisite for high-performance coherent optical communication and sensing.Waveguide-based external cavity narrow linewidth semiconductor lasers(WEC-NLSLs)have become a competitive and attractive candidate for many coherent applications due to their small size,volume,low energy consumption,low cost and the ability to integrate with other optical components.In this paper,we present an overview of WEC-NLSLs from their required technologies to the state-of-the-art progress.Moreover,we highlight the common problems occurring to current WEC-NLSLs and show the possible approaches to resolving the issues.Finally,we present the possible development directions for the next phase and hope this review will be beneficial to the advancements of WEC-NLSLs.展开更多
This paper investigates the steady-state behavior of a semiconductor laser subject to arbitrary levels of external optical feedback by means of an iterative travelling-wave (ITW) model. Analytical expressions are deve...This paper investigates the steady-state behavior of a semiconductor laser subject to arbitrary levels of external optical feedback by means of an iterative travelling-wave (ITW) model. Analytical expressions are developed based on an iterative equation. We show that, as in good agreement with previous work, in the weak-feedback regime of operation except for a phase shift the ITW model will be simplified to the Lang-Kobayashi (LK) model, and that in the case where this phase shift is equal to zero the ITW model is identical to the LK model. The present work is of use in particular for distinguishing the coherence-collapse regime from the strong-feedback regime where low-intensity-noise and narrow-linewidth laser operation would be possible at high feedback levels with re-stabilization of the compound laser system.展开更多
A self-seeded fiber laser incorporated with a fiber Bragg grating external cavity semiconductor laser (FBG-ECL) and a Mach-Zehnder interferometer (MZI) were reported in this paper. The MZI provided a Q-switching with ...A self-seeded fiber laser incorporated with a fiber Bragg grating external cavity semiconductor laser (FBG-ECL) and a Mach-Zehnder interferometer (MZI) were reported in this paper. The MZI provided a Q-switching with response time in the order of micro-seconds. The FBG-ECL provided narrow pulses as seeds to shorten the Q-switched pulses. Experimentally, pulse width of 0.8 μs was measured, which was one fifth of the pulse width without self-seeding.展开更多
The design concept of semiconductor optical amplifier(SOA)and gain chip used in wavelength tunable lasers(TL)is discussed in this paper.The design concept is similar to that of a conventional SOA or a laser;however,th...The design concept of semiconductor optical amplifier(SOA)and gain chip used in wavelength tunable lasers(TL)is discussed in this paper.The design concept is similar to that of a conventional SOA or a laser;however,there are a few different points.An SOA in front of the tunable laser should be polarization dependent and has low optical confinement factor.To obtain wide gain bandwidth at the threshold current,the gain chip used in the tunable laser cavity should be something between SOA and fixed-wavelength laser design,while the fixed-wavelength laser has high optical confinement factor.Detailed discussion is given with basic equations and some simulation results on saturation power of the SOA and gain bandwidth of gain chip are shown.展开更多
For different external cavity lengths, lasing wavelength variation of fiber grating external cavity semiconductor laser (FGECSL) with ambient temperature has been investigated theoretically, and the theoretical result...For different external cavity lengths, lasing wavelength variation of fiber grating external cavity semiconductor laser (FGECSL) with ambient temperature has been investigated theoretically, and the theoretical results are in agreement with reported experimental observations.展开更多
The self-mixing fringes which shift due to every one-twentieth wavelength displacement of the target are observed. Taking advantage of the dual reflectors in the external cavity of lasers, the resolution of the sensor...The self-mixing fringes which shift due to every one-twentieth wavelength displacement of the target are observed. Taking advantage of the dual reflectors in the external cavity of lasers, the resolution of the sensors has been improved by 10 times. The role of the each reflector has been discussed in detail.展开更多
A simple and cost-effective multi-wavelength fiber ring laser based on a chirped Moire fiber grating (CMFG) and a semiconductor optical amplifier (SOA) is proposed. Stable triple-wavelength lasing oscillations at ...A simple and cost-effective multi-wavelength fiber ring laser based on a chirped Moire fiber grating (CMFG) and a semiconductor optical amplifier (SOA) is proposed. Stable triple-wavelength lasing oscillations at room temperature are experimentally demonstrated. The measured optical signal-to-noise ratio (SNR) reaches the highest value of 50 dB and the power fluctuation of each wavelength is less than 0.2 dB within a 1-h period. To serve as a wavelength selective element, the CMFG possesses excellent comb-like filtering characteristics including stable wavelength interval and ultra-narrow passband, and its fabrication method is easy and flexible. The lasing oscillation shows a narrower bandwidth than SOA-based multi-wavelength fiber lasers utilizing some other kinds of wavelength selective components. Methods to optimize the laser performance are also discussed.展开更多
Effects of facet reflectivity of a laser diode on the performance of fiber Bragg grating semiconductor lasers are studied experimentally. Facet reflectivity of less than 10-4 is necessary to obtain stable oscillation ...Effects of facet reflectivity of a laser diode on the performance of fiber Bragg grating semiconductor lasers are studied experimentally. Facet reflectivity of less than 10-4 is necessary to obtain stable oscillation wavelength.展开更多
A full-open-cavity wavelength-tunable random fiber laser(WT-RFL) with compact structure and hundreds of picometers tuning range is proposed and demonstrated. A π fiber Bragg grating(FBG) is used in the WT-RFL as a fi...A full-open-cavity wavelength-tunable random fiber laser(WT-RFL) with compact structure and hundreds of picometers tuning range is proposed and demonstrated. A π fiber Bragg grating(FBG) is used in the WT-RFL as a filter to select lasing wavelengths. The two random Bragg grating arrays(RBGAs) and a section of high gain erbium-doped fiber result in a low lasing threshold and high stability. A numerical model to analyze the tunable characteristics is developed. The results show that the laser threshold is 22 m W, and the maximum peak-power fluctuation is 0.55 d B. To the best of our knowledge, it is the first time that a compact and full-open-cavity WT-RFL with two RBGAs and a π-FBG is proposed.展开更多
Numerical simulations based on a multimode rate-equation model is used to study the effect of fiber Bragg grating (FBG) external cavity reflectors on the performance of multimode semiconductor lasers. The factors affe...Numerical simulations based on a multimode rate-equation model is used to study the effect of fiber Bragg grating (FBG) external cavity reflectors on the performance of multimode semiconductor lasers. The factors affecting the relative intensity noise and the wavelength stable range are discussed. Design principles for the parameter selection of semiconductor lasers with FBG external cavity reflectors are given based on the numerical results.展开更多
Multi-wavelength fiber ring laser based on the semiconductor optical amplifier(SOA)with sampled fiber Bragg grating(SFBG)in a Sagnac loop interferometer as the wavelength-selective filter is proposed.Four lasing wavel...Multi-wavelength fiber ring laser based on the semiconductor optical amplifier(SOA)with sampled fiber Bragg grating(SFBG)in a Sagnac loop interferometer as the wavelength-selective filter is proposed.Four lasing wavelengths with 1.8 nm spacing have been generated stably at room temperature.The proposed laser has the advan-tages such as removal of the high-cost circulator,flexibility in channel-spacing tuning,and simple all-optical fiber configuration,which has potential applications in high-capacity wavelength-division-multiplexed(WDM)systems and mechanical sensors.展开更多
The output intensity variations of the laser used in a prism coupling system are observed and found to be induced by the external optical feedback, which comes from the reflection on the prism. The intensity variation...The output intensity variations of the laser used in a prism coupling system are observed and found to be induced by the external optical feedback, which comes from the reflection on the prism. The intensity variations are explained with laser theory. The trough in the intensity variation corresponds to the position of the prism when the output light beam propagates perpendicularly to the prism. Based on the trough a new method for rotating the prism and reading out the step numbers is proposed, by which the angle 0° in the system need not to be calibrated. It is proven by experiment that the new method would improve the accuracy of the refractive index up to ±0.00001 and thickness to ±1 nm.展开更多
<div style="text-align:justify;"> The basic principle of sensing is the combination of F-P cavity interference and fiber grating reflection. A hybrid structure sensor probe has been designed based on t...<div style="text-align:justify;"> The basic principle of sensing is the combination of F-P cavity interference and fiber grating reflection. A hybrid structure sensor probe has been designed based on the combination of an F-P cavity of liquid-filled thermometer structure, and a fiber grating with an elastic diaphragm, herein F-P cavity is used for temperature sensing, and the fiber grating is used for pressure sensing. By adopting the dual optical path structure, the dual-parameter detection of temperature and depth is realized, which solves the problem of low accuracy caused by the cross response of temperature and pressure of a single sensor device and the calculation of the depth information of the ocean with empirical formulas. Compared with traditional sensors, the sensitivity is effectively improved. Theoretical analysis shows that the sensitivity of the F-P cavity with a thermometer structure filled with kerosene reaches 1.334 nm/?C, and the depth sensitivity of the fiber grating is 284.6 pm/Mpa within the ocean depth range of 0 - 400 m. </div>展开更多
文摘We propose a theoretical model to describe external-cavity distributed feedback semiconductor lasers and investigate the impact of the number of external feedback points on linewidth and side-mode suppression ratio through numerical simulation. The simulation results demonstrate that the linewidth of external-cavity semiconductor lasers can be reduced by increasing the external cavity length and feedback ratio, and adding more external feedback points can further narrow the linewidth and enhance the side mode suppression ratio. This research provides insight into the external cavity distributed feedback mechanism and can guide the design of high-performance external cavity semiconductor lasers. .
基金the National Natural Science Foundation of China(Grant No.62105190)the Natural Science Foundation of Shanxi Province of China(Grant No.20210302124268)+1 种基金the Scientific and Technological Innovation Programs of Higher Education Institutions of Shanxi Province of China(Grant No.2021L285)the Youth Researchof Shanxi University of Finance and Economics(Grant No.QN-202015)。
文摘Optical chaos has attracted widespread attention owing to its complex dynamic behaviors.However,the time delay signature(TDS)caused by the external cavity mode reduces the complexity of optical chaos.We propose and numerically demonstrate the critical dispersion of chirped fiber Bragg grating(CFBG)for eliminating the TDS of laser chaos in this work.The critical dispersion,as a function of relaxation frequency and bandwidth of the optical spectrum,is found through extensive dynamics simulations.It is shown that the TDS can be eliminated when the dispersion of CFBG is above this critical dispersion.In addition,the influence of dispersive feedback light and output light from a laser is investigated.These results provide important quantitative guidance for designing chaotic semiconductor lasers without TDS.
基金Jiangsu Province Key R&D Program(Industry Prospect and Common Key Technologies)(No.BE2014083)Jiangxi Natural Science Foundation Project(No.2019ACBL20054)。
文摘Narrow linewidth light source is a prerequisite for high-performance coherent optical communication and sensing.Waveguide-based external cavity narrow linewidth semiconductor lasers(WEC-NLSLs)have become a competitive and attractive candidate for many coherent applications due to their small size,volume,low energy consumption,low cost and the ability to integrate with other optical components.In this paper,we present an overview of WEC-NLSLs from their required technologies to the state-of-the-art progress.Moreover,we highlight the common problems occurring to current WEC-NLSLs and show the possible approaches to resolving the issues.Finally,we present the possible development directions for the next phase and hope this review will be beneficial to the advancements of WEC-NLSLs.
文摘This paper investigates the steady-state behavior of a semiconductor laser subject to arbitrary levels of external optical feedback by means of an iterative travelling-wave (ITW) model. Analytical expressions are developed based on an iterative equation. We show that, as in good agreement with previous work, in the weak-feedback regime of operation except for a phase shift the ITW model will be simplified to the Lang-Kobayashi (LK) model, and that in the case where this phase shift is equal to zero the ITW model is identical to the LK model. The present work is of use in particular for distinguishing the coherence-collapse regime from the strong-feedback regime where low-intensity-noise and narrow-linewidth laser operation would be possible at high feedback levels with re-stabilization of the compound laser system.
文摘A self-seeded fiber laser incorporated with a fiber Bragg grating external cavity semiconductor laser (FBG-ECL) and a Mach-Zehnder interferometer (MZI) were reported in this paper. The MZI provided a Q-switching with response time in the order of micro-seconds. The FBG-ECL provided narrow pulses as seeds to shorten the Q-switched pulses. Experimentally, pulse width of 0.8 μs was measured, which was one fifth of the pulse width without self-seeding.
文摘The design concept of semiconductor optical amplifier(SOA)and gain chip used in wavelength tunable lasers(TL)is discussed in this paper.The design concept is similar to that of a conventional SOA or a laser;however,there are a few different points.An SOA in front of the tunable laser should be polarization dependent and has low optical confinement factor.To obtain wide gain bandwidth at the threshold current,the gain chip used in the tunable laser cavity should be something between SOA and fixed-wavelength laser design,while the fixed-wavelength laser has high optical confinement factor.Detailed discussion is given with basic equations and some simulation results on saturation power of the SOA and gain bandwidth of gain chip are shown.
文摘For different external cavity lengths, lasing wavelength variation of fiber grating external cavity semiconductor laser (FGECSL) with ambient temperature has been investigated theoretically, and the theoretical results are in agreement with reported experimental observations.
基金Supported by the National Natural Science Foundation of China under Grant No 60438010.
文摘The self-mixing fringes which shift due to every one-twentieth wavelength displacement of the target are observed. Taking advantage of the dual reflectors in the external cavity of lasers, the resolution of the sensors has been improved by 10 times. The role of the each reflector has been discussed in detail.
基金supported by the National Natural Science Foundation of China (No.60771008)the National "863" Program of China (No.2007AA01Z258)+1 种基金the Support Plan for New Century Excellent Talents (No.NCET-05-0091)the Science Fund of Beijing Jiaotong University (No.2007XM003)
文摘A simple and cost-effective multi-wavelength fiber ring laser based on a chirped Moire fiber grating (CMFG) and a semiconductor optical amplifier (SOA) is proposed. Stable triple-wavelength lasing oscillations at room temperature are experimentally demonstrated. The measured optical signal-to-noise ratio (SNR) reaches the highest value of 50 dB and the power fluctuation of each wavelength is less than 0.2 dB within a 1-h period. To serve as a wavelength selective element, the CMFG possesses excellent comb-like filtering characteristics including stable wavelength interval and ultra-narrow passband, and its fabrication method is easy and flexible. The lasing oscillation shows a narrower bandwidth than SOA-based multi-wavelength fiber lasers utilizing some other kinds of wavelength selective components. Methods to optimize the laser performance are also discussed.
文摘Effects of facet reflectivity of a laser diode on the performance of fiber Bragg grating semiconductor lasers are studied experimentally. Facet reflectivity of less than 10-4 is necessary to obtain stable oscillation wavelength.
基金supported by the National Natural Science Foundation of China (NSFC) (Nos. 61875185 and U1939207)the Scientific Instrument Developing Project of the Chinese Academy of Sciences+1 种基金the Strategic Priority Research Program A of the CAS (No. XDA22010201)the Shenzhen Science and Technology Research Funding (No. JCYJ20190814110601663)
文摘A full-open-cavity wavelength-tunable random fiber laser(WT-RFL) with compact structure and hundreds of picometers tuning range is proposed and demonstrated. A π fiber Bragg grating(FBG) is used in the WT-RFL as a filter to select lasing wavelengths. The two random Bragg grating arrays(RBGAs) and a section of high gain erbium-doped fiber result in a low lasing threshold and high stability. A numerical model to analyze the tunable characteristics is developed. The results show that the laser threshold is 22 m W, and the maximum peak-power fluctuation is 0.55 d B. To the best of our knowledge, it is the first time that a compact and full-open-cavity WT-RFL with two RBGAs and a π-FBG is proposed.
文摘Numerical simulations based on a multimode rate-equation model is used to study the effect of fiber Bragg grating (FBG) external cavity reflectors on the performance of multimode semiconductor lasers. The factors affecting the relative intensity noise and the wavelength stable range are discussed. Design principles for the parameter selection of semiconductor lasers with FBG external cavity reflectors are given based on the numerical results.
基金supported by the National“863” Project of China(2007AA01Z258)the National Natural Science Foundation of China(60771008)+2 种基金Program for New Century Excellent Talents in University(NCET-06-0076)Beijing Natural Science Foundation(4082024)the Beijing Jiaotong University Foundation(2006XM003)
文摘Multi-wavelength fiber ring laser based on the semiconductor optical amplifier(SOA)with sampled fiber Bragg grating(SFBG)in a Sagnac loop interferometer as the wavelength-selective filter is proposed.Four lasing wavelengths with 1.8 nm spacing have been generated stably at room temperature.The proposed laser has the advan-tages such as removal of the high-cost circulator,flexibility in channel-spacing tuning,and simple all-optical fiber configuration,which has potential applications in high-capacity wavelength-division-multiplexed(WDM)systems and mechanical sensors.
文摘The output intensity variations of the laser used in a prism coupling system are observed and found to be induced by the external optical feedback, which comes from the reflection on the prism. The intensity variations are explained with laser theory. The trough in the intensity variation corresponds to the position of the prism when the output light beam propagates perpendicularly to the prism. Based on the trough a new method for rotating the prism and reading out the step numbers is proposed, by which the angle 0° in the system need not to be calibrated. It is proven by experiment that the new method would improve the accuracy of the refractive index up to ±0.00001 and thickness to ±1 nm.
文摘<div style="text-align:justify;"> The basic principle of sensing is the combination of F-P cavity interference and fiber grating reflection. A hybrid structure sensor probe has been designed based on the combination of an F-P cavity of liquid-filled thermometer structure, and a fiber grating with an elastic diaphragm, herein F-P cavity is used for temperature sensing, and the fiber grating is used for pressure sensing. By adopting the dual optical path structure, the dual-parameter detection of temperature and depth is realized, which solves the problem of low accuracy caused by the cross response of temperature and pressure of a single sensor device and the calculation of the depth information of the ocean with empirical formulas. Compared with traditional sensors, the sensitivity is effectively improved. Theoretical analysis shows that the sensitivity of the F-P cavity with a thermometer structure filled with kerosene reaches 1.334 nm/?C, and the depth sensitivity of the fiber grating is 284.6 pm/Mpa within the ocean depth range of 0 - 400 m. </div>