A 1.55μm Fabry-Perot (F-P) thermo-optical t unable filter is fabricated.The cavity is made of amorphous silicon (a-Si) layer grown by electron-beam evaporation technique.Due to the excellent thermo-optical property o...A 1.55μm Fabry-Perot (F-P) thermo-optical t unable filter is fabricated.The cavity is made of amorphous silicon (a-Si) layer grown by electron-beam evaporation technique.Due to the excellent thermo-optical property of a-Si,the refractive index of the F-P cavity will be changed by heating;the transmittance resonant peak will therefore shift substantially.The measured tuning rang is 12nm, FWHM (full-width-at-half-maximum) of the transmissi on peak is 9nm,and heating efficiency is 0.1K/mW.The large FWHM is mainly due to th e non-ideal coating deposition and mirror undulation.Possible improvements to increase the efficiency of heating are suggested.展开更多
A tunable microwave photonic bandpass filter with high mainlobe-to-sidelobe ratio (MSR) based on a phase modulator and a dispersive device is proposed. The multi-tap characteristics of the filter are realized by slici...A tunable microwave photonic bandpass filter with high mainlobe-to-sidelobe ratio (MSR) based on a phase modulator and a dispersive device is proposed. The multi-tap characteristics of the filter are realized by slicing a broadband source using a Mach-Zehnder interferometer (MZI) which results in a high MSR of 25 dB. The tunability of the filter is realized by an optical variable delay line (OVDL) in one arm of the MZI, which changes the wavelength spacing of the sliced broadband source and results in a tunable free spectrum range (FSR) of the filter. The central frequency of the bandpass filter is tunable from 10.7 GHz to 27 GHz by changing the wavelength spacing from 0.145 nm to 0.054 nm.展开更多
A dual-band bandpass microwave photonic filter(MPF) based on stimulated Brillouin scattering(SBS) is theoretically analyzed and experimentally demonstrated. Two separated tunable laser sources(TLSs) are employed to ge...A dual-band bandpass microwave photonic filter(MPF) based on stimulated Brillouin scattering(SBS) is theoretically analyzed and experimentally demonstrated. Two separated tunable laser sources(TLSs) are employed to generate two passbands by implementing phase modulation to amplitude modulation conversion by using SBS induced sideband amplification. The center frequencies of both passbands can be independently tuned ranging from 1 GHz to 19 GHz. High resolution with 3 d B bandwidth less than 30 MHz and large out-of-band rejection about 40 d B under 25 m W optical pump power are achieved.展开更多
We recently proposed a new class of wavelength-swept lasers for swept-source optical coherence tomography (SS-OCT). It uses the same gain medium with the conventional swept lasers, but does not require any tunable f...We recently proposed a new class of wavelength-swept lasers for swept-source optical coherence tomography (SS-OCT). It uses the same gain medium with the conventional swept lasers, but does not require any tunable filters. It is based on a principle called "dispersion tuning", in which a highly dispersive medium is inserted in the laser cavity, and loss/gain modulation is applied to mode-lock the laser. Since the cavity contains no mechanical components, such as tunable filters, we could achieve the very high sweep rate. In this review paper, we describe the principle of the dispersion-tuned swept lasers in detail and present our recent work on the application to the SS-OCT system.展开更多
In this paper,we propose a method to realize microwave photonic filter(MPF) with complex coefficient,whose central frequency f 0 and 3 dB bandwidth are tunable.The complex coefficient is realized by multi-wavelength o...In this paper,we propose a method to realize microwave photonic filter(MPF) with complex coefficient,whose central frequency f 0 and 3 dB bandwidth are tunable.The complex coefficient is realized by multi-wavelength optical source and stimulated Brillouin scattering(SBS).The central frequency of the filter is tuned by adjusting the phase shift caused by SBS without changing its frequency response.The frequency selectivity of filter can be improved through increasing the bandwidth of broadband optical source(BOS) or decreasing wavelength separation to increase the taps of MPF.The mainlobeto-sidelobe suppression ratio(MSSR) of the filter is affected by the weight of each tap.When the length of fiber is 0.5544 m in birefringence fiber loop mirror(FLM),the MSSR is improved by 18.55 dB compared with that without the weight controlling.展开更多
Photonic structures with optical resonances beyond a single controllable mode are strongly desired for enhancing light±matter interactions and bringing about advanced photonic devices. However, the realization of...Photonic structures with optical resonances beyond a single controllable mode are strongly desired for enhancing light±matter interactions and bringing about advanced photonic devices. However, the realization of effective multimodal photonic structures has been restricted by the limited tunable range of mode manipulation, the spatial dispersions of electric fields or the polarization-dependent excitations. To overcome these limitations, we create a dualmode metasurface by integrating the plasmonic surface lattice resonance and the gap plasmonic modes;this metasurface offers a widely tunable spectral range, good overlap in the spatial distribution of electric fields, and polarization independence of excitation light. To show that such dual-mode metasurfaces are versatile platforms for enhancing light±matter interactions, we experimentally demonstrate a significant enhancement of second-harmonic generation using our design, with a conversion efficiency of 1±3 orders of magnitude larger than those previously obtained in plasmonic systems. These results may inspire new designs for functional multimodal photonic structures.展开更多
A switchable dual-wavelength erbium-doped fiber laser(EDFL) with tunable wavelength is demonstrated. The ring cavity consists of two branches with a fiber Bragg grating(FBG) and a spherical-shape structure as fiber fi...A switchable dual-wavelength erbium-doped fiber laser(EDFL) with tunable wavelength is demonstrated. The ring cavity consists of two branches with a fiber Bragg grating(FBG) and a spherical-shape structure as fiber filters, respectively. By adjusting the variable optical attenuator(VOA), the laser can be switched between the single-wavelength mode and the dual-wavelength mode. The spherical-shape structure has good sensitivity to the temperature. When the temperature changes from 30 °C to 190 °C, the central wavelength of the EDFL generated by the branch of spherical-shape structure varies from 1 551.6 nm to 1 561.8 nm, which means that the wavelength interval is tunable.展开更多
In this paper, we have designed and proofed a widely tunable microwave photonic filter (MPF) on the basis of self-adaptive optical carrier regeneration method through stimulated Brillouin scattering (SBS) amplificati...In this paper, we have designed and proofed a widely tunable microwave photonic filter (MPF) on the basis of self-adaptive optical carrier regeneration method through stimulated Brillouin scattering (SBS) amplification. The MPF system features with a single microwave passband as the result of the processed signal sideband beating with the regenerated optical carrier. Since the Brillouin-laser optical carrier and the SBS amplification are generated from one laser source, the optical carrier regeneration process of the proposed MPF is self- adaptive and carrier-frequency independent. Moreover, by simply varying the wavelength spacing between the optical carrier and the optical filter, the central passband of the MPF can be continuously tuned from 6 to 32 GHz, which is limited by the bandwidth of the modulator and the photodetector. The 3 dB bandwidth and the out-of-band suppression ratio of the MPF can reach 640 MHz and 21 dB, respectively.展开更多
Circular polarization selection of light is an important property of helical micro-nanostructure.The helical thin films fabricated by glancing angle deposition can provide both circular polarization selection and wave...Circular polarization selection of light is an important property of helical micro-nanostructure.The helical thin films fabricated by glancing angle deposition can provide both circular polarization selection and wavelength tuning in this work.Their selective transmissions were depicted in calculations and experiments.The wavelength tuning mechanism was revealed as the relationship between peak wavelength and deposition parameters.Therefore,tunable circular polarization components can be designed according to the mechanism mentioned above and fabricated by glancing angle deposition techniques.Potential applications include tunable optical filters,optical pulse-shapers,biosensors etc.展开更多
An all-optical format conversion from non-return-to-zero (NRZ) to return-to-zero (RZ) is presented based on cross-phase modulation (XPM) in a silicon waveguide with a detuned optical bandpass filter (OBPF). Th...An all-optical format conversion from non-return-to-zero (NRZ) to return-to-zero (RZ) is presented based on cross-phase modulation (XPM) in a silicon waveguide with a detuned optical bandpass filter (OBPF). The simulation results show that the tunable bandwidth of the OBPF leads.to RZ signals with tunable pulse width. The conversion efficiency (CE) and the pattern effect of the RZ signal are attributed to the parameters of the pump pulse and the OBPE The converted RZ signal exhibits lower timing jitter than the NRZ signal.展开更多
A tunable dual-wavelength fiber Bragg grating(FBG)laser based on a distributed feedback(DFB)laser injection is proposed and experimentally demonstrated.The wavelength spacing can be tuned by adjusting the operation te...A tunable dual-wavelength fiber Bragg grating(FBG)laser based on a distributed feedback(DFB)laser injection is proposed and experimentally demonstrated.The wavelength spacing can be tuned by adjusting the operation temperature of the DFB laser.When the DFB works at 25℃,a dual-wavelength simultaneous oscillation at 1 549.67 nm and1 553.44 nm with wavelength spacing of 3.77 nm is achieved.Our experimental results demonstrate the new concept of dual-wavelength lasing with a DFB laser injection and the technical feasibility.展开更多
A switchable and tunable ytterbium-doped fiber ring laser(YDFL) is reported and demonstrated. Employing a Sagnac loop mirror fabricated by an 85-cm-long polarization-maintaining fiber(PMF), the proposed YDFL can opera...A switchable and tunable ytterbium-doped fiber ring laser(YDFL) is reported and demonstrated. Employing a Sagnac loop mirror fabricated by an 85-cm-long polarization-maintaining fiber(PMF), the proposed YDFL can operate with stable dual-wavelength lasing or tunable single-wavelength lasing around 1 064 nm. Both stable dual-wavelength lasing and tunable single-wavelength lasing are achieved by adjusting a polarization controller in the Sagnac loop mirror. The experimental results show that the output of the proposed fiber laser with two different operation modes is rather stable at room temperature.展开更多
A widely tunable microwave photonic notch filter with adjustable bandwidth based on multi-wavelength fiber laser is proposed and demonstrated. The multi-wavelength fiber laser generates the multi-taps of the microwave...A widely tunable microwave photonic notch filter with adjustable bandwidth based on multi-wavelength fiber laser is proposed and demonstrated. The multi-wavelength fiber laser generates the multi-taps of the microwave photonic filter (MPF). In order to obtain notch frequency response, a Fourier-domain optical processor (FD-OP) is introduced to con- trol the amplitude and phase of the optical carrier and phase modulation sidebands. By adjusting the polarization con- troller (PC), different numbers of taps are got, such as 6, 8, 10 and 121 And the wavelength-spacing of the multi-wavelength laser is 0.4 nm. The bandwidth of the notch filter is changed by adjusting the number of taps and the corresponding bandwidths are 4.41 GHz, 3.30 GHz, 2.64 GHz and 2.19 GHz, respectively. With the additional phase shift introduced by FD-OP, the notch position is continuously ttmed in the whole free spectral range (FSR) of 27.94 GHz. The center frequency of the notch filter can be continuously tuned from 13.97 GHz to 41.91 GHz.展开更多
文摘A 1.55μm Fabry-Perot (F-P) thermo-optical t unable filter is fabricated.The cavity is made of amorphous silicon (a-Si) layer grown by electron-beam evaporation technique.Due to the excellent thermo-optical property of a-Si,the refractive index of the F-P cavity will be changed by heating;the transmittance resonant peak will therefore shift substantially.The measured tuning rang is 12nm, FWHM (full-width-at-half-maximum) of the transmissi on peak is 9nm,and heating efficiency is 0.1K/mW.The large FWHM is mainly due to th e non-ideal coating deposition and mirror undulation.Possible improvements to increase the efficiency of heating are suggested.
基金supported by the National Natural Science Foundation of China (No.60808004)the New Century Excellent Talents in University (No.NCET-07-0611)the Tianjin Natural Science Foundation (No.08JCYBJC14500)
文摘A tunable microwave photonic bandpass filter with high mainlobe-to-sidelobe ratio (MSR) based on a phase modulator and a dispersive device is proposed. The multi-tap characteristics of the filter are realized by slicing a broadband source using a Mach-Zehnder interferometer (MZI) which results in a high MSR of 25 dB. The tunability of the filter is realized by an optical variable delay line (OVDL) in one arm of the MZI, which changes the wavelength spacing of the sliced broadband source and results in a tunable free spectrum range (FSR) of the filter. The central frequency of the bandpass filter is tunable from 10.7 GHz to 27 GHz by changing the wavelength spacing from 0.145 nm to 0.054 nm.
基金supported by the Science and Technology Development Plan of Jilin Province(Nos.20150204003GX and 20160519010JH)the Science and Technology Plan of Changchun(No.14KG019)
文摘A dual-band bandpass microwave photonic filter(MPF) based on stimulated Brillouin scattering(SBS) is theoretically analyzed and experimentally demonstrated. Two separated tunable laser sources(TLSs) are employed to generate two passbands by implementing phase modulation to amplitude modulation conversion by using SBS induced sideband amplification. The center frequencies of both passbands can be independently tuned ranging from 1 GHz to 19 GHz. High resolution with 3 d B bandwidth less than 30 MHz and large out-of-band rejection about 40 d B under 25 m W optical pump power are achieved.
文摘We recently proposed a new class of wavelength-swept lasers for swept-source optical coherence tomography (SS-OCT). It uses the same gain medium with the conventional swept lasers, but does not require any tunable filters. It is based on a principle called "dispersion tuning", in which a highly dispersive medium is inserted in the laser cavity, and loss/gain modulation is applied to mode-lock the laser. Since the cavity contains no mechanical components, such as tunable filters, we could achieve the very high sweep rate. In this review paper, we describe the principle of the dispersion-tuned swept lasers in detail and present our recent work on the application to the SS-OCT system.
基金supported by the National Natural Science Foundation of China (No.60808004)
文摘In this paper,we propose a method to realize microwave photonic filter(MPF) with complex coefficient,whose central frequency f 0 and 3 dB bandwidth are tunable.The complex coefficient is realized by multi-wavelength optical source and stimulated Brillouin scattering(SBS).The central frequency of the filter is tuned by adjusting the phase shift caused by SBS without changing its frequency response.The frequency selectivity of filter can be improved through increasing the bandwidth of broadband optical source(BOS) or decreasing wavelength separation to increase the taps of MPF.The mainlobeto-sidelobe suppression ratio(MSSR) of the filter is affected by the weight of each tap.When the length of fiber is 0.5544 m in birefringence fiber loop mirror(FLM),the MSSR is improved by 18.55 dB compared with that without the weight controlling.
基金supported by the National Key R&D Program of China (2016YFA0301300)the National Natural Science Foundation of China (11974437 and 91750207)+6 种基金the Key-Area Research and Development Program of Guangdong Province (2018B030329001)Guangdong Special Support Program (2017TQ04C487)Guangdong Natural Science Funds for Distinguished Young Scholars (2017B030306007)Guangdong Natural Science Funds (2020A0505140004)Pearl River S&T Nova Program of Guangzhou (201806010033)the Open Fund of IPOC (BUPT) (IPOC2019A003)the Fundamental Research Funds for the Central Universities (20lgzd30)。
文摘Photonic structures with optical resonances beyond a single controllable mode are strongly desired for enhancing light±matter interactions and bringing about advanced photonic devices. However, the realization of effective multimodal photonic structures has been restricted by the limited tunable range of mode manipulation, the spatial dispersions of electric fields or the polarization-dependent excitations. To overcome these limitations, we create a dualmode metasurface by integrating the plasmonic surface lattice resonance and the gap plasmonic modes;this metasurface offers a widely tunable spectral range, good overlap in the spatial distribution of electric fields, and polarization independence of excitation light. To show that such dual-mode metasurfaces are versatile platforms for enhancing light±matter interactions, we experimentally demonstrate a significant enhancement of second-harmonic generation using our design, with a conversion efficiency of 1±3 orders of magnitude larger than those previously obtained in plasmonic systems. These results may inspire new designs for functional multimodal photonic structures.
基金supported by the National High Technology Research and Development Program of China(No.2013AA014201)the Tianjin Youth Science Foundation(No.13JCQNJC01800)
文摘A switchable dual-wavelength erbium-doped fiber laser(EDFL) with tunable wavelength is demonstrated. The ring cavity consists of two branches with a fiber Bragg grating(FBG) and a spherical-shape structure as fiber filters, respectively. By adjusting the variable optical attenuator(VOA), the laser can be switched between the single-wavelength mode and the dual-wavelength mode. The spherical-shape structure has good sensitivity to the temperature. When the temperature changes from 30 °C to 190 °C, the central wavelength of the EDFL generated by the branch of spherical-shape structure varies from 1 551.6 nm to 1 561.8 nm, which means that the wavelength interval is tunable.
基金supported by the National Natural Science Foundation of China (Grant Nos. 61501422 & 61377071)the Equipment Development Project of Chinese Academy of Sciences (Grant No. YZ201201)
文摘In this paper, we have designed and proofed a widely tunable microwave photonic filter (MPF) on the basis of self-adaptive optical carrier regeneration method through stimulated Brillouin scattering (SBS) amplification. The MPF system features with a single microwave passband as the result of the processed signal sideband beating with the regenerated optical carrier. Since the Brillouin-laser optical carrier and the SBS amplification are generated from one laser source, the optical carrier regeneration process of the proposed MPF is self- adaptive and carrier-frequency independent. Moreover, by simply varying the wavelength spacing between the optical carrier and the optical filter, the central passband of the MPF can be continuously tuned from 6 to 32 GHz, which is limited by the bandwidth of the modulator and the photodetector. The 3 dB bandwidth and the out-of-band suppression ratio of the MPF can reach 640 MHz and 21 dB, respectively.
基金the financial support of the project from the National Natural Science Foundation of China(Grant No.60977042)the Natural Science Foundation of Guangdong Provincial(Grant No.9151027501000070)
文摘Circular polarization selection of light is an important property of helical micro-nanostructure.The helical thin films fabricated by glancing angle deposition can provide both circular polarization selection and wavelength tuning in this work.Their selective transmissions were depicted in calculations and experiments.The wavelength tuning mechanism was revealed as the relationship between peak wavelength and deposition parameters.Therefore,tunable circular polarization components can be designed according to the mechanism mentioned above and fabricated by glancing angle deposition techniques.Potential applications include tunable optical filters,optical pulse-shapers,biosensors etc.
文摘An all-optical format conversion from non-return-to-zero (NRZ) to return-to-zero (RZ) is presented based on cross-phase modulation (XPM) in a silicon waveguide with a detuned optical bandpass filter (OBPF). The simulation results show that the tunable bandwidth of the OBPF leads.to RZ signals with tunable pulse width. The conversion efficiency (CE) and the pattern effect of the RZ signal are attributed to the parameters of the pump pulse and the OBPE The converted RZ signal exhibits lower timing jitter than the NRZ signal.
基金supported by the National Natural Science Foundation of China(No.60777020)the Hubei Provincial Natural Science Fund of China(No.2008CDB317)the Innovation Project of Hubei Provincial Department of Education of China(No.104892013038)
文摘A tunable dual-wavelength fiber Bragg grating(FBG)laser based on a distributed feedback(DFB)laser injection is proposed and experimentally demonstrated.The wavelength spacing can be tuned by adjusting the operation temperature of the DFB laser.When the DFB works at 25℃,a dual-wavelength simultaneous oscillation at 1 549.67 nm and1 553.44 nm with wavelength spacing of 3.77 nm is achieved.Our experimental results demonstrate the new concept of dual-wavelength lasing with a DFB laser injection and the technical feasibility.
基金supported by the National Natural Science Foundation of China(No.61007029)the National High Technology Research and Development Program of China(No.2013AA031501)+1 种基金the Projects of Zhejiang Province in China(No.2010R50007)the Program for Science and Technology Innovative Research Team in Zhejiang Normal University
文摘A switchable and tunable ytterbium-doped fiber ring laser(YDFL) is reported and demonstrated. Employing a Sagnac loop mirror fabricated by an 85-cm-long polarization-maintaining fiber(PMF), the proposed YDFL can operate with stable dual-wavelength lasing or tunable single-wavelength lasing around 1 064 nm. Both stable dual-wavelength lasing and tunable single-wavelength lasing are achieved by adjusting a polarization controller in the Sagnac loop mirror. The experimental results show that the output of the proposed fiber laser with two different operation modes is rather stable at room temperature.
基金supported by the National Natural Science Foundation of China(No.11444001)the Municipal Natural Science Foundation of Tianjin in China(No.14JCYBJC16500)
文摘A widely tunable microwave photonic notch filter with adjustable bandwidth based on multi-wavelength fiber laser is proposed and demonstrated. The multi-wavelength fiber laser generates the multi-taps of the microwave photonic filter (MPF). In order to obtain notch frequency response, a Fourier-domain optical processor (FD-OP) is introduced to con- trol the amplitude and phase of the optical carrier and phase modulation sidebands. By adjusting the polarization con- troller (PC), different numbers of taps are got, such as 6, 8, 10 and 121 And the wavelength-spacing of the multi-wavelength laser is 0.4 nm. The bandwidth of the notch filter is changed by adjusting the number of taps and the corresponding bandwidths are 4.41 GHz, 3.30 GHz, 2.64 GHz and 2.19 GHz, respectively. With the additional phase shift introduced by FD-OP, the notch position is continuously ttmed in the whole free spectral range (FSR) of 27.94 GHz. The center frequency of the notch filter can be continuously tuned from 13.97 GHz to 41.91 GHz.