A multiwavelength tunable ring-cavity erbium-doped fiber laser(EDFL)based on a Lyot filter was presented.For the proposed Lyot filter,a comb filter consisting of an EDF-polarization-maintaining fiber(EDF-PMF),a polari...A multiwavelength tunable ring-cavity erbium-doped fiber laser(EDFL)based on a Lyot filter was presented.For the proposed Lyot filter,a comb filter consisting of an EDF-polarization-maintaining fiber(EDF-PMF),a polarization controller(PC),and a circulator with four ports was used to suppress the mode competition.The light transmission direction was guaranteed by the circulator.For the proposed fiber laser,tunable single,dual,triple,quadruple,quintuple,sextuple,and septuple wavelengths were realized.A single-wavelength laser output with an optical signal-to-noise ratio(SNR)of up to30.56 dB was realized,and a tuning range of 1590.54 nm to 1599.54 nm was achieved by tuning the PC.The stability of the single,dual,triple,and quadruple-wavelength center power fluctuations was less than 0.05 dB,0.98 dB,5.07 dB,and7.71 dB respectively.When the laser was operated in the multiwavelength condition,the SNR was more than 20.97 dB.The proposed erbium-doped fiber laser is suitable for fiber-sensing system applications.展开更多
We demonstrate an ultrafast fiber laser based on transition metal dichalcogenide materials which are tungsten disulfide(WS2) and molybdenum disulfide(MoS_2) as saturable absorber(SA). These materials are fabricated vi...We demonstrate an ultrafast fiber laser based on transition metal dichalcogenide materials which are tungsten disulfide(WS2) and molybdenum disulfide(MoS_2) as saturable absorber(SA). These materials are fabricated via a simple drop-casting method. By employing WS_2, we obtain a stable harmonic mode-locking at the threshold pump power of 184 mW, and the generated soliton pulse has 3.48 MHz of repetition rate. At the maximum pump power of 250 mW, we also obtain a small value of pulse duration, 2.43 ps with signal-to-noise ratio(SNR) of 57 dB.For MoS_2 SA, the pulse is generated at 105 mW pump power with repetition rate of 1.16 MHz. However, the pulse duration cannot be detected by the autocorrelator device as the pulse duration recorded is 468 ns, with the SNR value of 35 dB.展开更多
We demonstrate a Q-switched erbium-doped fiber laser(EDFL) using a newly developed zinc oxide-(ZnO) based saturable absorber(SA). The SA is fabricated by embedding a prepared ZnO powder into a poly(vinyl alcohol)film....We demonstrate a Q-switched erbium-doped fiber laser(EDFL) using a newly developed zinc oxide-(ZnO) based saturable absorber(SA). The SA is fabricated by embedding a prepared ZnO powder into a poly(vinyl alcohol)film. A small piece of the film is then sandwiched between two fiber ferrules and is incorporated in an EDFL cavity for generating a stable Q-switching pulse train. The EDFL operates at 1560.4 nm with a pump power threshold of 11.8 mW, a pulse repetition rate tunable from 22.79 to 61.43 kHz, and the smallest pulse width of 7.00 μs. The Q-switching pulse shows no spectral modulation with a peak-to-pedestal ratio of 62 dB indicating the high stability of the laser. These results show that the ZnO powder has a great potential to be used for pulsed laser applications.展开更多
BACKGROUND The goal of periodontal disease treatment is to completely remove bacteria and promote wound healing.The erbium-doped yttrium aluminum garnet(Er:YAG)laser is commonly used to treat periodontal disease.Advan...BACKGROUND The goal of periodontal disease treatment is to completely remove bacteria and promote wound healing.The erbium-doped yttrium aluminum garnet(Er:YAG)laser is commonly used to treat periodontal disease.Advanced platelet-rich fibrin+(A-PRF+)secrets growth factors that accelerates soft-and hard-tissue regeneration and wound healing.Herein I present 2 cases of patients with oral diseases treated with a combination of Er:YAG laser and A-PRF+.CASE SUMMARY Case 1 was a female with pocket depth bone loss over 8 mm and infection of tooth 31 and 41,and severe advanced periodontitis with grade III mobility.Case 2 was a male with tooth 22 root end apical swelling and infection and alveolar bony defects.Clinical outcomes were recorded at 6 and 36 mo.In case 1,the Er:YAG laser was used to perform open flap debridement(100 mJ/pulse,15 Hz)and remove calculus and granulation tissue(50 mJ/pulse,30 Hz).In case 2 the laser was used to create a semilunar full thickness flap incision(80 mJ/pulse,20 Hz)and eliminate the pathogen(100 mJ/pulse,15 Hz).In both patients,A-PRF+mixed with bone was used to fill bone defects,and A-PRF+autologous membranes were used to cover tension-free primary flaps.There was no recurrent infection at 36 mo,and tissue regeneration and would healing occurred.CONCLUSION Debridement with an Er:YAG laser followed by treatment with A-PRF+is effective for the treatment periodontal diseases with bone defects.展开更多
GeSe nanosheets were prepared by ultrasonic-assisted liquid<span><span><span style="font-family:;" "=""> </span></span></span><span><span><sp...GeSe nanosheets were prepared by ultrasonic-assisted liquid<span><span><span style="font-family:;" "=""> </span></span></span><span><span><span><span style="font-family:Verdana;">phase exfoliation (LPE), and the nonlinear saturated absorption performance was experimentally studied. The modulation depth and saturation intensity of the prepared GeSe saturable absorber (SA) were 15% and 1.44 MW/cm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">, respectively. Us</span><span style="font-family:Verdana;">ing the saturated absorption characteristics of GeSe SA, a passively Q-switched </span><span style="font-family:Verdana;">erbium-doped fiber laser was systematically demonstrated. As the pump</span><span style="font-family:Verdana;"> power increases, the pulse repetition frequency increases from 22.8 kHz to 77.59 </span><span style="font-family:Verdana;">kHz. The shortest pulse duration is 1.51 μs, and the corresponding pulse</span><span style="font-family:Verdana;"> energy is 46.14 nJ. Experimental results show that GeSe nanosheets can be used as high-efficiency SA in fiber lasers. Our results will provide a useful reference for demonstrating pulsed fiber lasers based on GeSe equipment.</span></span></span></span>展开更多
<span style="font-family:Verdana;">T</span><span style="font-family:Verdana;font-size:12px;">he T</span><span style="font-family:Verdana;font-size:12px;">i&l...<span style="font-family:Verdana;">T</span><span style="font-family:Verdana;font-size:12px;">he T</span><span style="font-family:Verdana;font-size:12px;">i</span><span style="font-family:Verdana;font-size:12px;">Se</span><sub><span style="font-family:Verdana;font-size:12px;">2</span></sub><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">nanosheets</span><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">were</span><span style="font-family:Verdana;font-size:12px;"> prepared by means of ultrasound-assisted liquid </span><span style="font-family:Verdana;font-size:12px;">phase exfoliation (LPE)</span><span style="font-family:Verdana;font-size:12px;"> and the </span><span style="font-family:Verdana;font-size:12px;">nonlinear </span><span style="font-family:Verdana;font-size:12px;">saturable absorption</span><span style="font-family:Verdana;font-size:12px;"> properties</span><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">were experimentally</span><span style="font-family:Verdana;font-size:12px;"> investigated. The modulation depth, saturation intensity and nonsaturable absorbance</span><span style="font-family:Verdana;font-size:12px;"> of the prepared </span><span style="font-family:Verdana;font-size:12px;">1T-TiSe</span><sub><span style="font-family:Verdana;font-size:12px;">2</span></sub><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">SA </span><span style="font-family:Verdana;font-size:12px;">were</span><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">1</span><span style="font-family:Verdana;font-size:12px;">5.7</span><span style="font-family:Verdana;font-size:12px;">%,</span><span style="font-family:Verdana;font-size:12px;"> 1.28 M</span><span style="font-family:Verdana;font-size:12px;">W/cm</span><sup><span style="font-family:Verdana;font-size:12px;vertical-align:super;">2</span></sup><span style="font-family:Verdana;font-size:12px;"> and 8.</span><span style="font-family:Verdana;font-size:12px;">2</span><span style="font-family:Verdana;font-size:12px;">%, </span><span style="font-family:Verdana;font-size:12px;">respectively</span><span style="font-family:Verdana;font-size:12px;">. Taking advantage of the saturable absorption properties of </span><span style="font-family:Verdana;font-size:12px;">T</span><span style="font-family:Verdana;font-size:12px;">i</span><span style="font-family:Verdana;font-size:12px;">Se</span><sub><span style="font-family:Verdana;font-size:12px;">2</span></sub><span style="font-family:Verdana;font-size:12px;">-based SA, a passively Q-switched erbium-doped fiber (EDF) laser was</span><span style="font-family:Verdana;font-size:12px;"> systematically demonstrated</span><span style="font-family:Verdana;font-size:12px;">. The pulse repetition rates varied from 24.50 kHz up to 73.79 kHz with the increasing pump power. The obtained shortest pulse width was 1.31 </span><span style="font-family:Verdana;font-size:12px;">μ</span><span style="font-family:Verdana;font-size:12px;">s with pulse energy of 79.28 nJ. The </span><span style="font-family:Verdana;font-size:12px;">system presented merits of low-cost SA preparation, system compactness,</span><span style="font-family:Verdana;font-size:12px;"> superb stability and high competition.</span>展开更多
A nonlinear amplifying loop mirror constructed from erbium-doped fiber is proposed for simultaneous amplification and compression of ultrashort fundamental solitons. Numerical simulations show that, the proposed devic...A nonlinear amplifying loop mirror constructed from erbium-doped fiber is proposed for simultaneous amplification and compression of ultrashort fundamental solitons. Numerical simulations show that, the proposed device performs efficient high-quality amplification and compression of solitons.展开更多
The commercialization of lithium niobate on insulator(LNOI) wafer has resulted in significant on-chip photonic integration application owing to its remarkable photonic,acousto-optic,electro-optic,and piezoelectric nat...The commercialization of lithium niobate on insulator(LNOI) wafer has resulted in significant on-chip photonic integration application owing to its remarkable photonic,acousto-optic,electro-optic,and piezoelectric nature.In recent years,a variety of high-performance on-chip LNOI-based photonic devices have been realized.In this study,we developed a 1-mol% erbium-doped lithium niobate crystal and its LNOI on a silicon substrate and fabricated an erbium-doped LNOI microdisk with high quality factor(~1.05×105).C-band laser emission at ~1530 and ~1560 nm(linewidth 0.12 nm) from the high-Q erbium-doped LNOI microdisk was demonstrated with 974-and 1460-nm pumping,with the latter having better thermal stability.This microlaser would play an important role in the photonic integrated circuits of the lithium niobate platform.展开更多
We reported on the generation of the dual-wavelength rectangular pulse in an erbium-doped fiber laser(EDFL)with a topological insulator saturable absorber.The rectangular pulse could be stably initiated with pulse wid...We reported on the generation of the dual-wavelength rectangular pulse in an erbium-doped fiber laser(EDFL)with a topological insulator saturable absorber.The rectangular pulse could be stably initiated with pulse width from 13.62 to 25.16 ns and fundamental repetition rate of 3.54 MHz by properly adjusting the pump power and the polarization state.In addition,we verified that the pulse shape of the dual-wavelength rectangular pulse can be affected by the total net cavity dispersion in the fiber laser.Furthermore,by properly rotating the polarization controllers,the harmonic mode-locking operation of the dual-wavelength rectangular pulse was also obtained.The dual-wavelength rectangular pulse EDFL would benefit some potential applications,such as spectroscopy,biomedicine,and sensing research.展开更多
Tungsten disulfide(WS_2) is a type of anisotropic-layered compound and has broadband saturable absorption features as saturable absorbers(SAs). With WS_2-based SAs, dark solitons in erbium-doped fiber(EDF) lasers are ...Tungsten disulfide(WS_2) is a type of anisotropic-layered compound and has broadband saturable absorption features as saturable absorbers(SAs). With WS_2-based SAs, dark solitons in erbium-doped fiber(EDF) lasers are first obtained. For the generated dark solitons, the center wavelength is measured to be 1530 nm, and the repetition rate is about 116.5 MHz. A series of optical spectra is exhibited. The electrical signal-to-noise ratio is better than 94 d B.Results in this paper demonstrate that WS_2-based SAs are the promising SAs for generating dark solitons in EDF lasers.展开更多
Stable Q-switched and mode-locked erbium-doped fiber lasers(EDFLs)are first demonstrated by using the novel layered palladium disulfide(PdS2),a new member of group 10 transition metal dichalcogenides(TMDs)-based satur...Stable Q-switched and mode-locked erbium-doped fiber lasers(EDFLs)are first demonstrated by using the novel layered palladium disulfide(PdS2),a new member of group 10 transition metal dichalcogenides(TMDs)-based saturable absorbers(SAs).Self-started Q-switched operation at 1567 nm was achieved with a threshold pump power of 50.6 mW.The modulation ranges of pulse duration and repetition rate were characterized as 12.6-4.5μs and 17.2-26.0 kHz,respectively.Meanwhile,a mode-locked EDFL was also obtained with a pump power threshold of 106.4 mW.The achieved pulse duration is 803 fs,corresponding to a center wavelength of 1565.8 nm and4.48 nm 3 dB bandwidth.To the best of our knowledge,the achieved pulse duration of the mode-locked EDFL in this work is the narrowest compared with all other group 10 TMD SA-based lasers.展开更多
A theoretical model of the erbium-doped waveguide ring laser is established according to the theory of erbium-doped waveguide amplifier and the transmission matrix of waveguide directional coupler. The influence of be...A theoretical model of the erbium-doped waveguide ring laser is established according to the theory of erbium-doped waveguide amplifier and the transmission matrix of waveguide directional coupler. The influence of bend radius, coupling coefficient and doped erbium ion concentration on the characteristics of waveguide ring laser is investigated. It is shown that due to the co-action of waveguide bend loss and other relevant loss there is an optimal bend radius which can provide simultaneously low threshold pumping power and high laser light output power. As one part of the resonator's loss, the laser light coupling coefficient of directional coupler has an impact on the laser property. The analysis indicates that the laser achieves the high output power when the coupling coefficient is about 0.2. The threshold pumping power is the minimum when the doped erbium ion concentration is 0.85×1026 m-3. Increasing the concentration of doped erbium ions will enhance the output power of laser light as long as the concentration doesn't introduce remarkable up-conversion effect. The results give a good theoretical basis for the design and fabrication of erbium-doped waveguide ring laser devices.展开更多
Simultaneous multiwavelength lasing is demonstrated exploiting intracavity polarization in-homogeneity in an erbium-doped fiber laser. Experiments indicate that polarization hole burning can be enhanced by the changes...Simultaneous multiwavelength lasing is demonstrated exploiting intracavity polarization in-homogeneity in an erbium-doped fiber laser. Experiments indicate that polarization hole burning can be enhanced by the changes of optical MQW waveguide bias current and the polarization states in the laser cavity. Ten wavelengths with 0.9 nm spacing are generated at room temperature.展开更多
We report an erbium-doped fiber laser passively Q-switched by a few-layer molybdenum disulfide（MoS2） saturable absorber（SA）.The few-layer MoS2 is grown by the chemical vapor deposition method and transferred onto ...We report an erbium-doped fiber laser passively Q-switched by a few-layer molybdenum disulfide（MoS2） saturable absorber（SA）.The few-layer MoS2 is grown by the chemical vapor deposition method and transferred onto the end-face of a fiber connector to form a fiber-compatible MoS2 SA.The laser cavity is constructed by using a three-port optical circulator and a fiber Bragg grating（FBG） as the two end-mirrors.Stable Q-switched pulses are obtained with a pulse duration of 1.92 μs at 1560.5 nm.By increasing the pump power from 42 to 204 mW,the pulse repetition rate can be widely changed from 28.6 to 114.8 kHz.Passive Q-switching operations with discrete lasing wavelengths ranging from 1529.8 to 1570.1 nm are also investigated by using FBGs with different central wavelengths.This work demonstrates that few-layer MoS2 can serve as a promising SA for wideband-tunable Q-switching laser operation.展开更多
We report Q-switched and mode-locked erbium-doped all-fiber lasers using ternary ReS_(2(1-x))Se_(2x) as saturable absorbers(SAs). The modulation depth and saturable intensity of the film SA are 1.8% and 0.046 MW∕cm2....We report Q-switched and mode-locked erbium-doped all-fiber lasers using ternary ReS_(2(1-x))Se_(2x) as saturable absorbers(SAs). The modulation depth and saturable intensity of the film SA are 1.8% and 0.046 MW∕cm2.In Q-switched mechanism output, the pulse was centered at 1531.1 nm with maximum pulse energy and minimum pulse width of 28.29 nJ and 1.07 μs, respectively. In mode-locked operation, the pulse was centered at1561.15 nm with pulse width of 888 fs, repetition rate of 2.95 MHz, and maximum pulse energy of 0.275 nJ. To the best of our knowledge, this is the first report on the mode-locked Er^(3+)-doped fiber laser using ternary transition metal dichalcogenides. This work suggests prospective 2 D-material SAs can be widely used in versatile fields due to their attractive optoelectronic and tunable energy bandgap properties.展开更多
We report a high power and widely tunable erbium-doped fiber (EDF) ring laser using 1480nm pump and high concentration EDF. Large tuning range up to 105nm (1513-1618 nm) has been obtained by optimizing of the EDF length.
Through the introduction of the overlapping factors between the light (pump and signal) intensities and the erbium doping distributions inside the fiber core, analytical solutions of homogeneously broadened two-level ...Through the introduction of the overlapping factors between the light (pump and signal) intensities and the erbium doping distributions inside the fiber core, analytical solutions of homogeneously broadened two-level systems for erbium-doped fiber amplifiers pumped in the 980 nm absorption band have been derived from EDFA rate equations and light propagation equations in steady-state case. By using these deduced expressions and numerical simulated methods, important features characterizing the amplifiers such as gain, pump threshold power, optimum fiber length have been analyzed and discussed.展开更多
A simple and cost-effective wavelength-switchable fiber ring laser based on a chirped moire fiber grating (CMFG)and an erbium-doped fiber amplifier (EDFA) is proposed,and stable wavelength Iasing oscillations at room ...A simple and cost-effective wavelength-switchable fiber ring laser based on a chirped moire fiber grating (CMFG)and an erbium-doped fiber amplifier (EDFA) is proposed,and stable wavelength Iasing oscillations at room temperature iS experimentally demonstrated.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 measured optical signal-to-noise ratio reaches the highest value of 50 dB and the power fluctuation of each channel output iS less than 0.5 dB within an hour.The output laser power of different channels is almost identical(difference of less than 1 dB) within the tunable range.Methods to optimize the laser performance are also discussed and the superiority of the CMFG iS experimentally demonstrated.展开更多
In an erbium-doped fiber amplifier(EDFA), erbium ions act as a three-level system. Therefore, much higher pump energy is required to achieve the population inversion in an erbium-doped fiber(EDF). This higher pump ene...In an erbium-doped fiber amplifier(EDFA), erbium ions act as a three-level system. Therefore, much higher pump energy is required to achieve the population inversion in an erbium-doped fiber(EDF). This higher pump energy requirement complicates the efficient design of an EDFA. However, efficient use of the pump power can improve the EDFA performance. The improved performance of an EDFA can be obtained by reducing the doping radius of the EDF. A smaller doping radius increases pump–dopant interactions and subsequently increases the pump–photon conversion efficiency. Decreasing the doping radius allows a larger proportion of dopant ions,which are concentrated near the core, to interact with the highest pump intensity. However, decreasing the doping radius beyond a certain limit will bring the dopant ions much closer and introduce detrimental ion–ion interaction effects. In this Letter, we show that an optimal doping radius in an EDF can provide the best gain performance. Moreover, we have simulated the well-known numerical aperture effects on EDFA gain performance to support our claim.展开更多
Transient response of an erbium-doped fiber amplifier(EDFA) is studied in an externally-modulated analog link.Double tones represented as transmitted radio frequency and dither signals are introduced.Extra modulation ...Transient response of an erbium-doped fiber amplifier(EDFA) is studied in an externally-modulated analog link.Double tones represented as transmitted radio frequency and dither signals are introduced.Extra modulation is generated owing to the EDFA’s transient response caused by a low-frequency dither signal.Therefore,the parasitic modulation is superposed to the output signals and may significantly affect in-band electrical spectra.Analytical and numerical solutions are both given,which agree well with experimental results.This work indicates that a suitable dither signal should be selected to maximize the carrier to intermodulation ratio.In-band spurious free dynamic range is optimized in the meantime.展开更多
基金Beijing Great Wall Scholars Program(Grant No.CIT&TCD20190323)Beijing Youth Talent Support Program(Grant No.Z2019042)the National Natural Science Foundation of China(Grant No.61875237).
文摘A multiwavelength tunable ring-cavity erbium-doped fiber laser(EDFL)based on a Lyot filter was presented.For the proposed Lyot filter,a comb filter consisting of an EDF-polarization-maintaining fiber(EDF-PMF),a polarization controller(PC),and a circulator with four ports was used to suppress the mode competition.The light transmission direction was guaranteed by the circulator.For the proposed fiber laser,tunable single,dual,triple,quadruple,quintuple,sextuple,and septuple wavelengths were realized.A single-wavelength laser output with an optical signal-to-noise ratio(SNR)of up to30.56 dB was realized,and a tuning range of 1590.54 nm to 1599.54 nm was achieved by tuning the PC.The stability of the single,dual,triple,and quadruple-wavelength center power fluctuations was less than 0.05 dB,0.98 dB,5.07 dB,and7.71 dB respectively.When the laser was operated in the multiwavelength condition,the SNR was more than 20.97 dB.The proposed erbium-doped fiber laser is suitable for fiber-sensing system applications.
基金Supported by the University of Malaya under Grant No PG173-2015B
文摘We demonstrate an ultrafast fiber laser based on transition metal dichalcogenide materials which are tungsten disulfide(WS2) and molybdenum disulfide(MoS_2) as saturable absorber(SA). These materials are fabricated via a simple drop-casting method. By employing WS_2, we obtain a stable harmonic mode-locking at the threshold pump power of 184 mW, and the generated soliton pulse has 3.48 MHz of repetition rate. At the maximum pump power of 250 mW, we also obtain a small value of pulse duration, 2.43 ps with signal-to-noise ratio(SNR) of 57 dB.For MoS_2 SA, the pulse is generated at 105 mW pump power with repetition rate of 1.16 MHz. However, the pulse duration cannot be detected by the autocorrelator device as the pulse duration recorded is 468 ns, with the SNR value of 35 dB.
基金Supported by the University of Malaya under Grant No PG173-2015B
文摘We demonstrate a Q-switched erbium-doped fiber laser(EDFL) using a newly developed zinc oxide-(ZnO) based saturable absorber(SA). The SA is fabricated by embedding a prepared ZnO powder into a poly(vinyl alcohol)film. A small piece of the film is then sandwiched between two fiber ferrules and is incorporated in an EDFL cavity for generating a stable Q-switching pulse train. The EDFL operates at 1560.4 nm with a pump power threshold of 11.8 mW, a pulse repetition rate tunable from 22.79 to 61.43 kHz, and the smallest pulse width of 7.00 μs. The Q-switching pulse shows no spectral modulation with a peak-to-pedestal ratio of 62 dB indicating the high stability of the laser. These results show that the ZnO powder has a great potential to be used for pulsed laser applications.
文摘BACKGROUND The goal of periodontal disease treatment is to completely remove bacteria and promote wound healing.The erbium-doped yttrium aluminum garnet(Er:YAG)laser is commonly used to treat periodontal disease.Advanced platelet-rich fibrin+(A-PRF+)secrets growth factors that accelerates soft-and hard-tissue regeneration and wound healing.Herein I present 2 cases of patients with oral diseases treated with a combination of Er:YAG laser and A-PRF+.CASE SUMMARY Case 1 was a female with pocket depth bone loss over 8 mm and infection of tooth 31 and 41,and severe advanced periodontitis with grade III mobility.Case 2 was a male with tooth 22 root end apical swelling and infection and alveolar bony defects.Clinical outcomes were recorded at 6 and 36 mo.In case 1,the Er:YAG laser was used to perform open flap debridement(100 mJ/pulse,15 Hz)and remove calculus and granulation tissue(50 mJ/pulse,30 Hz).In case 2 the laser was used to create a semilunar full thickness flap incision(80 mJ/pulse,20 Hz)and eliminate the pathogen(100 mJ/pulse,15 Hz).In both patients,A-PRF+mixed with bone was used to fill bone defects,and A-PRF+autologous membranes were used to cover tension-free primary flaps.There was no recurrent infection at 36 mo,and tissue regeneration and would healing occurred.CONCLUSION Debridement with an Er:YAG laser followed by treatment with A-PRF+is effective for the treatment periodontal diseases with bone defects.
文摘GeSe nanosheets were prepared by ultrasonic-assisted liquid<span><span><span style="font-family:;" "=""> </span></span></span><span><span><span><span style="font-family:Verdana;">phase exfoliation (LPE), and the nonlinear saturated absorption performance was experimentally studied. The modulation depth and saturation intensity of the prepared GeSe saturable absorber (SA) were 15% and 1.44 MW/cm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">, respectively. Us</span><span style="font-family:Verdana;">ing the saturated absorption characteristics of GeSe SA, a passively Q-switched </span><span style="font-family:Verdana;">erbium-doped fiber laser was systematically demonstrated. As the pump</span><span style="font-family:Verdana;"> power increases, the pulse repetition frequency increases from 22.8 kHz to 77.59 </span><span style="font-family:Verdana;">kHz. The shortest pulse duration is 1.51 μs, and the corresponding pulse</span><span style="font-family:Verdana;"> energy is 46.14 nJ. Experimental results show that GeSe nanosheets can be used as high-efficiency SA in fiber lasers. Our results will provide a useful reference for demonstrating pulsed fiber lasers based on GeSe equipment.</span></span></span></span>
文摘<span style="font-family:Verdana;">T</span><span style="font-family:Verdana;font-size:12px;">he T</span><span style="font-family:Verdana;font-size:12px;">i</span><span style="font-family:Verdana;font-size:12px;">Se</span><sub><span style="font-family:Verdana;font-size:12px;">2</span></sub><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">nanosheets</span><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">were</span><span style="font-family:Verdana;font-size:12px;"> prepared by means of ultrasound-assisted liquid </span><span style="font-family:Verdana;font-size:12px;">phase exfoliation (LPE)</span><span style="font-family:Verdana;font-size:12px;"> and the </span><span style="font-family:Verdana;font-size:12px;">nonlinear </span><span style="font-family:Verdana;font-size:12px;">saturable absorption</span><span style="font-family:Verdana;font-size:12px;"> properties</span><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">were experimentally</span><span style="font-family:Verdana;font-size:12px;"> investigated. The modulation depth, saturation intensity and nonsaturable absorbance</span><span style="font-family:Verdana;font-size:12px;"> of the prepared </span><span style="font-family:Verdana;font-size:12px;">1T-TiSe</span><sub><span style="font-family:Verdana;font-size:12px;">2</span></sub><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">SA </span><span style="font-family:Verdana;font-size:12px;">were</span><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">1</span><span style="font-family:Verdana;font-size:12px;">5.7</span><span style="font-family:Verdana;font-size:12px;">%,</span><span style="font-family:Verdana;font-size:12px;"> 1.28 M</span><span style="font-family:Verdana;font-size:12px;">W/cm</span><sup><span style="font-family:Verdana;font-size:12px;vertical-align:super;">2</span></sup><span style="font-family:Verdana;font-size:12px;"> and 8.</span><span style="font-family:Verdana;font-size:12px;">2</span><span style="font-family:Verdana;font-size:12px;">%, </span><span style="font-family:Verdana;font-size:12px;">respectively</span><span style="font-family:Verdana;font-size:12px;">. Taking advantage of the saturable absorption properties of </span><span style="font-family:Verdana;font-size:12px;">T</span><span style="font-family:Verdana;font-size:12px;">i</span><span style="font-family:Verdana;font-size:12px;">Se</span><sub><span style="font-family:Verdana;font-size:12px;">2</span></sub><span style="font-family:Verdana;font-size:12px;">-based SA, a passively Q-switched erbium-doped fiber (EDF) laser was</span><span style="font-family:Verdana;font-size:12px;"> systematically demonstrated</span><span style="font-family:Verdana;font-size:12px;">. The pulse repetition rates varied from 24.50 kHz up to 73.79 kHz with the increasing pump power. The obtained shortest pulse width was 1.31 </span><span style="font-family:Verdana;font-size:12px;">μ</span><span style="font-family:Verdana;font-size:12px;">s with pulse energy of 79.28 nJ. The </span><span style="font-family:Verdana;font-size:12px;">system presented merits of low-cost SA preparation, system compactness,</span><span style="font-family:Verdana;font-size:12px;"> superb stability and high competition.</span>
基金The authors acknowledge the support of the Research Grants Council of the Hong Kong Special Administrative Region, China (Project No. PolyU5096/98E).
文摘A nonlinear amplifying loop mirror constructed from erbium-doped fiber is proposed for simultaneous amplification and compression of ultrashort fundamental solitons. Numerical simulations show that, the proposed device performs efficient high-quality amplification and compression of solitons.
基金supported by the National Key R&D Program of China (Grant Nos. 2019YFB2203500, and 2017YFA0303700)the National Natural Science Foundation of China (Grant No. 91950107)the Foundation for Development of Science and Technology of Shanghai (Grant No. 17JC1400400)。
文摘The commercialization of lithium niobate on insulator(LNOI) wafer has resulted in significant on-chip photonic integration application owing to its remarkable photonic,acousto-optic,electro-optic,and piezoelectric nature.In recent years,a variety of high-performance on-chip LNOI-based photonic devices have been realized.In this study,we developed a 1-mol% erbium-doped lithium niobate crystal and its LNOI on a silicon substrate and fabricated an erbium-doped LNOI microdisk with high quality factor(~1.05×105).C-band laser emission at ~1530 and ~1560 nm(linewidth 0.12 nm) from the high-Q erbium-doped LNOI microdisk was demonstrated with 974-and 1460-nm pumping,with the latter having better thermal stability.This microlaser would play an important role in the photonic integrated circuits of the lithium niobate platform.
基金supported by National Natural Science Foundation of China (No.612050346)the Shenzhen Municipal Science and Technology Plan (Nos.2010B090400306,JC201105160592A,and JCYJ 20120613150130014)
文摘We reported on the generation of the dual-wavelength rectangular pulse in an erbium-doped fiber laser(EDFL)with a topological insulator saturable absorber.The rectangular pulse could be stably initiated with pulse width from 13.62 to 25.16 ns and fundamental repetition rate of 3.54 MHz by properly adjusting the pump power and the polarization state.In addition,we verified that the pulse shape of the dual-wavelength rectangular pulse can be affected by the total net cavity dispersion in the fiber laser.Furthermore,by properly rotating the polarization controllers,the harmonic mode-locking operation of the dual-wavelength rectangular pulse was also obtained.The dual-wavelength rectangular pulse EDFL would benefit some potential applications,such as spectroscopy,biomedicine,and sensing research.
基金supported by the National Key Basic Research Program of China (grant nos.2012CB821304,2013CB922401,and 2013CB922402)by the National Natural Science Foundation of China (NSFC) (grant nos.61205064,61378040,and 11078022)+1 种基金by the National Key Technology R&D Program of the Ministry of Science and Technology under grant no.2012BAC23B03by the Fund of State Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications,grant no.600100161)
文摘Tungsten disulfide(WS_2) is a type of anisotropic-layered compound and has broadband saturable absorption features as saturable absorbers(SAs). With WS_2-based SAs, dark solitons in erbium-doped fiber(EDF) lasers are first obtained. For the generated dark solitons, the center wavelength is measured to be 1530 nm, and the repetition rate is about 116.5 MHz. A series of optical spectra is exhibited. The electrical signal-to-noise ratio is better than 94 d B.Results in this paper demonstrate that WS_2-based SAs are the promising SAs for generating dark solitons in EDF lasers.
基金Research Grants Council,University Grants Committee of Hong Kong,China(GRF 152109/16E Poly U B-Q52T)。
文摘Stable Q-switched and mode-locked erbium-doped fiber lasers(EDFLs)are first demonstrated by using the novel layered palladium disulfide(PdS2),a new member of group 10 transition metal dichalcogenides(TMDs)-based saturable absorbers(SAs).Self-started Q-switched operation at 1567 nm was achieved with a threshold pump power of 50.6 mW.The modulation ranges of pulse duration and repetition rate were characterized as 12.6-4.5μs and 17.2-26.0 kHz,respectively.Meanwhile,a mode-locked EDFL was also obtained with a pump power threshold of 106.4 mW.The achieved pulse duration is 803 fs,corresponding to a center wavelength of 1565.8 nm and4.48 nm 3 dB bandwidth.To the best of our knowledge,the achieved pulse duration of the mode-locked EDFL in this work is the narrowest compared with all other group 10 TMD SA-based lasers.
基金Supported by the National Natural Science Foundation of China(Grant No.60807015)the Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.200801411037)+1 种基金the Young Teacher Cultivation Foundation of Dalian University of Technology(Grant No.893210)Doctor Start-up Founda-tion of Dalian University of Technology(Grant No.893322)
文摘A theoretical model of the erbium-doped waveguide ring laser is established according to the theory of erbium-doped waveguide amplifier and the transmission matrix of waveguide directional coupler. The influence of bend radius, coupling coefficient and doped erbium ion concentration on the characteristics of waveguide ring laser is investigated. It is shown that due to the co-action of waveguide bend loss and other relevant loss there is an optimal bend radius which can provide simultaneously low threshold pumping power and high laser light output power. As one part of the resonator's loss, the laser light coupling coefficient of directional coupler has an impact on the laser property. The analysis indicates that the laser achieves the high output power when the coupling coefficient is about 0.2. The threshold pumping power is the minimum when the doped erbium ion concentration is 0.85×1026 m-3. Increasing the concentration of doped erbium ions will enhance the output power of laser light as long as the concentration doesn't introduce remarkable up-conversion effect. The results give a good theoretical basis for the design and fabrication of erbium-doped waveguide ring laser devices.
文摘Simultaneous multiwavelength lasing is demonstrated exploiting intracavity polarization in-homogeneity in an erbium-doped fiber laser. Experiments indicate that polarization hole burning can be enhanced by the changes of optical MQW waveguide bias current and the polarization states in the laser cavity. Ten wavelengths with 0.9 nm spacing are generated at room temperature.
基金supported by the National Natural Science Foundation of China (Grant Nos.61378028,61475030,61421002,and 61377037)the National Basic Research Program of China (2012CB315701)the NCET Program (Grant No.NCET-13-0092)
文摘We report an erbium-doped fiber laser passively Q-switched by a few-layer molybdenum disulfide（MoS2） saturable absorber（SA）.The few-layer MoS2 is grown by the chemical vapor deposition method and transferred onto the end-face of a fiber connector to form a fiber-compatible MoS2 SA.The laser cavity is constructed by using a three-port optical circulator and a fiber Bragg grating（FBG） as the two end-mirrors.Stable Q-switched pulses are obtained with a pulse duration of 1.92 μs at 1560.5 nm.By increasing the pump power from 42 to 204 mW,the pulse repetition rate can be widely changed from 28.6 to 114.8 kHz.Passive Q-switching operations with discrete lasing wavelengths ranging from 1529.8 to 1570.1 nm are also investigated by using FBGs with different central wavelengths.This work demonstrates that few-layer MoS2 can serve as a promising SA for wideband-tunable Q-switching laser operation.
基金National Key R&D Program of China(2018YFB1107200)National Natural Science Foundation of China(NSFC)(61675158,21673058)+1 种基金Chinese Academy of Sciences Key Project(CAS Key Project)(QYZDBSSW-SYS031)Chinese Academy of Sciences(CAS)(XDB30000000)
文摘We report Q-switched and mode-locked erbium-doped all-fiber lasers using ternary ReS_(2(1-x))Se_(2x) as saturable absorbers(SAs). The modulation depth and saturable intensity of the film SA are 1.8% and 0.046 MW∕cm2.In Q-switched mechanism output, the pulse was centered at 1531.1 nm with maximum pulse energy and minimum pulse width of 28.29 nJ and 1.07 μs, respectively. In mode-locked operation, the pulse was centered at1561.15 nm with pulse width of 888 fs, repetition rate of 2.95 MHz, and maximum pulse energy of 0.275 nJ. To the best of our knowledge, this is the first report on the mode-locked Er^(3+)-doped fiber laser using ternary transition metal dichalcogenides. This work suggests prospective 2 D-material SAs can be widely used in versatile fields due to their attractive optoelectronic and tunable energy bandgap properties.
文摘We report a high power and widely tunable erbium-doped fiber (EDF) ring laser using 1480nm pump and high concentration EDF. Large tuning range up to 105nm (1513-1618 nm) has been obtained by optimizing of the EDF length.
基金Project supported by the Chinese Academy of Sciences
文摘Through the introduction of the overlapping factors between the light (pump and signal) intensities and the erbium doping distributions inside the fiber core, analytical solutions of homogeneously broadened two-level systems for erbium-doped fiber amplifiers pumped in the 980 nm absorption band have been derived from EDFA rate equations and light propagation equations in steady-state case. By using these deduced expressions and numerical simulated methods, important features characterizing the amplifiers such as gain, pump threshold power, optimum fiber length have been analyzed and discussed.
基金supported by the National Natural Science Foundation of China(60707007)the National High Technology Research and Development Program(2007AA01Z258,2008AA01Z15)+1 种基金the Support Plan for New Century Excellent Talents(NCET-05-0091)the Science Fund of Beijing Jiaotong University(2007XM003)
文摘A simple and cost-effective wavelength-switchable fiber ring laser based on a chirped moire fiber grating (CMFG)and an erbium-doped fiber amplifier (EDFA) is proposed,and stable wavelength Iasing oscillations at room temperature iS experimentally demonstrated.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 measured optical signal-to-noise ratio reaches the highest value of 50 dB and the power fluctuation of each channel output iS less than 0.5 dB within an hour.The output laser power of different channels is almost identical(difference of less than 1 dB) within the tunable range.Methods to optimize the laser performance are also discussed and the superiority of the CMFG iS experimentally demonstrated.
基金support from King Fahd University of Petroleum and Minerals(KFUPM)King Abdulaziz City for Science and Technology(KACST)via KACST-TIC in Solid State Lighting(Nos.EE2381 and KACST TIC R2-FP-008)
文摘In an erbium-doped fiber amplifier(EDFA), erbium ions act as a three-level system. Therefore, much higher pump energy is required to achieve the population inversion in an erbium-doped fiber(EDF). This higher pump energy requirement complicates the efficient design of an EDFA. However, efficient use of the pump power can improve the EDFA performance. The improved performance of an EDFA can be obtained by reducing the doping radius of the EDF. A smaller doping radius increases pump–dopant interactions and subsequently increases the pump–photon conversion efficiency. Decreasing the doping radius allows a larger proportion of dopant ions,which are concentrated near the core, to interact with the highest pump intensity. However, decreasing the doping radius beyond a certain limit will bring the dopant ions much closer and introduce detrimental ion–ion interaction effects. In this Letter, we show that an optimal doping radius in an EDF can provide the best gain performance. Moreover, we have simulated the well-known numerical aperture effects on EDFA gain performance to support our claim.
文摘Transient response of an erbium-doped fiber amplifier(EDFA) is studied in an externally-modulated analog link.Double tones represented as transmitted radio frequency and dither signals are introduced.Extra modulation is generated owing to the EDFA’s transient response caused by a low-frequency dither signal.Therefore,the parasitic modulation is superposed to the output signals and may significantly affect in-band electrical spectra.Analytical and numerical solutions are both given,which agree well with experimental results.This work indicates that a suitable dither signal should be selected to maximize the carrier to intermodulation ratio.In-band spurious free dynamic range is optimized in the meantime.
