Pub Date : 2009-06-14DOI: 10.1109/CLEOE-EQEC.2009.5192042
M. Belotti, M. Galli, D. Gerace, L. Andreani, A. M. Md Zain, N. Johnson, M. Sorel, Richard M. De La Rue
One of the major topics of interest in recent research on photonics is the study and development of photonic structures for fast signal processing signal for telecom applications. These kinds of structures are required to be compact and compatible with monolithic integration into one CMOS chip. The combination of one-dimensional photonic crystal structures with narrow waveguides in high refractive index contrast materials such as silicon-on insulator (SOI) can satisfy all the requirements.
{"title":"All-optical logical operation in photonic wire nano-cavities","authors":"M. Belotti, M. Galli, D. Gerace, L. Andreani, A. M. Md Zain, N. Johnson, M. Sorel, Richard M. De La Rue","doi":"10.1109/CLEOE-EQEC.2009.5192042","DOIUrl":"https://doi.org/10.1109/CLEOE-EQEC.2009.5192042","url":null,"abstract":"One of the major topics of interest in recent research on photonics is the study and development of photonic structures for fast signal processing signal for telecom applications. These kinds of structures are required to be compact and compatible with monolithic integration into one CMOS chip. The combination of one-dimensional photonic crystal structures with narrow waveguides in high refractive index contrast materials such as silicon-on insulator (SOI) can satisfy all the requirements.","PeriodicalId":346720,"journal":{"name":"CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124052227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-14DOI: 10.1109/CLEOE-EQEC.2009.5196491
D. Choi, S. Madden, D. Bulla, Rongping Wang, A. Rode, B. Luther-Davies
A chalcogenide glass (ChG) is one containing the chalcogen elements (Sulphur, Selenium or Tellerium) as a substantial constituent covalently bonded to network forming elements such as Germanium, Arsenic, or Antimony. ChG films are emerging as good candidates for integrated nonlinear optic (NLO) devices due to their high optical nonlinearities and low linear and nonlinear losses. We had already developed 2−3 micron thick As2S3 waveguides employing semiconductor processing [1] and demonstrated several NLO devices [2]. For more compact photonic integrated circuits, however, the device length reduction has to be compensated by boosting the waveguide nonlinearity coefficient, γ = (2π/λ)(n2/Aeff). The nonlinear refractive index, n2, is inherent to a material; hence the effective area of the light in the guide (Aeff) should be shrunk. This means the propagating light is to be confined tightly in the structure. The aim of this study, therefore, was to fabricate sub-micron thick, compact waveguides having low propagation loss.
{"title":"Fabrication of sub-micron Thick, low loss As2S3 planar waveguides","authors":"D. Choi, S. Madden, D. Bulla, Rongping Wang, A. Rode, B. Luther-Davies","doi":"10.1109/CLEOE-EQEC.2009.5196491","DOIUrl":"https://doi.org/10.1109/CLEOE-EQEC.2009.5196491","url":null,"abstract":"A chalcogenide glass (ChG) is one containing the chalcogen elements (Sulphur, Selenium or Tellerium) as a substantial constituent covalently bonded to network forming elements such as Germanium, Arsenic, or Antimony. ChG films are emerging as good candidates for integrated nonlinear optic (NLO) devices due to their high optical nonlinearities and low linear and nonlinear losses. We had already developed 2−3 micron thick As2S3 waveguides employing semiconductor processing [1] and demonstrated several NLO devices [2]. For more compact photonic integrated circuits, however, the device length reduction has to be compensated by boosting the waveguide nonlinearity coefficient, γ = (2π/λ)(n2/Aeff). The nonlinear refractive index, n2, is inherent to a material; hence the effective area of the light in the guide (Aeff) should be shrunk. This means the propagating light is to be confined tightly in the structure. The aim of this study, therefore, was to fabricate sub-micron thick, compact waveguides having low propagation loss.","PeriodicalId":346720,"journal":{"name":"CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124089191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-14DOI: 10.1109/CLEOE-EQEC.2009.5194747
J. Kwiatkowski, L. Gorajek, J. Jabczynski, W. Zendzian, H. Jelínková, J. Šulc, M. Němec, P. Koranda
The efficient, high energy Ho:YAG lasers can be resonantly pumped by Tm:crystalline lasers (see e.g. [1]) or applying hybrid concept with Tm:fiber lasers [2,3]. The aim of this work was to examine feasibility of tuneable work of compact hybrid laser based on Ho:YAG crystal pumped by Tm:fiber laser. The simple linear cavity with gain medium and dispersive element inside was set up. The 1% Ho:YAG rod of 4-mm diameter and 20-mm length with AR broadband coating was mounted inside water cooled copper heatsink. The pumping was realized by the Tm:fiber laser emitting up to 20 W at 1920-nm wavelength. After relay optical system the pump beam was focused to 0.33-mm diameter spot in the waist. The Ho:YAG crystal was placed in the vicinity of flat dichroic mirror (HR@2000–2200 nm, HT@1900 nm) inside a near semi-concentric cavity. The cavity length was set to obtain the best mode matching between pump and laser mode in gain medium. The output coupler was curved mirror (r=−150 mm) with 95% reflectance in 2000–;2150 nm range. In non-lasing condition the absorption efficiency of 20-mm long Ho:YAG rod has changed with pump power (50% for 4-W pump power up to 76% for 1-W pump corresponding to threshold). For laser tuning a Lyot filter consisted of Brewster angle tilted one quartz plate with 2.1-mm thickness was applied.
{"title":"Tuneable, hybrid Ho:YAG laser","authors":"J. Kwiatkowski, L. Gorajek, J. Jabczynski, W. Zendzian, H. Jelínková, J. Šulc, M. Němec, P. Koranda","doi":"10.1109/CLEOE-EQEC.2009.5194747","DOIUrl":"https://doi.org/10.1109/CLEOE-EQEC.2009.5194747","url":null,"abstract":"The efficient, high energy Ho:YAG lasers can be resonantly pumped by Tm:crystalline lasers (see e.g. [1]) or applying hybrid concept with Tm:fiber lasers [2,3]. The aim of this work was to examine feasibility of tuneable work of compact hybrid laser based on Ho:YAG crystal pumped by Tm:fiber laser. The simple linear cavity with gain medium and dispersive element inside was set up. The 1% Ho:YAG rod of 4-mm diameter and 20-mm length with AR broadband coating was mounted inside water cooled copper heatsink. The pumping was realized by the Tm:fiber laser emitting up to 20 W at 1920-nm wavelength. After relay optical system the pump beam was focused to 0.33-mm diameter spot in the waist. The Ho:YAG crystal was placed in the vicinity of flat dichroic mirror (HR@2000–2200 nm, HT@1900 nm) inside a near semi-concentric cavity. The cavity length was set to obtain the best mode matching between pump and laser mode in gain medium. The output coupler was curved mirror (r=−150 mm) with 95% reflectance in 2000–;2150 nm range. In non-lasing condition the absorption efficiency of 20-mm long Ho:YAG rod has changed with pump power (50% for 4-W pump power up to 76% for 1-W pump corresponding to threshold). For laser tuning a Lyot filter consisted of Brewster angle tilted one quartz plate with 2.1-mm thickness was applied.","PeriodicalId":346720,"journal":{"name":"CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126339411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-14DOI: 10.1109/CLEOE-EQEC.2009.5196243
Lin Xu, H. Tsang, W. Hofmann, M. Amann
High speed vertical-cavity-surface-emitting lasers (VCSELs) [1] are attractive candidates for use in future wavelength division multiplexed passive optical network (WDM-PON) systems because they may meet the stringent size, power dissipation and cost constraints of access network components. Colorless transceivers at the optical networking unit (ONU) in a WDM PON can further help reduce the costs: one approach for implementing colorless transceivers is to use a low extinction ratio non return to zero (NRZ) modulation from a VCSEL for downstream transmission and differential phase shift keying (DPSK) remodulation of the received signal in a low cost silicon photonic transceiver for upstream transmission [2]. In this paper we describe a proof-of principle implementation of such a remodulation scheme with a directly modulated VCSEL array, as shown schematically in Fig. 1. Although a discrete receiver, VCSEL array and wavelength filters were used here for implementing the transceiver at the Optical Line Terminal (OLT) (Fig 1), flip-chip mounting of the VCSEL array onto a silicon photonic integrated circuit containing the WDM multiplexer (MUX) and DPSK receivers has potential for implementing low cost multi-wavelength optical transceivers.
{"title":"10-Gb/s colorless re-modulation of signal from 1550nm vertical cavity surface emitting laser array in WDM PON","authors":"Lin Xu, H. Tsang, W. Hofmann, M. Amann","doi":"10.1109/CLEOE-EQEC.2009.5196243","DOIUrl":"https://doi.org/10.1109/CLEOE-EQEC.2009.5196243","url":null,"abstract":"High speed vertical-cavity-surface-emitting lasers (VCSELs) [1] are attractive candidates for use in future wavelength division multiplexed passive optical network (WDM-PON) systems because they may meet the stringent size, power dissipation and cost constraints of access network components. Colorless transceivers at the optical networking unit (ONU) in a WDM PON can further help reduce the costs: one approach for implementing colorless transceivers is to use a low extinction ratio non return to zero (NRZ) modulation from a VCSEL for downstream transmission and differential phase shift keying (DPSK) remodulation of the received signal in a low cost silicon photonic transceiver for upstream transmission [2]. In this paper we describe a proof-of principle implementation of such a remodulation scheme with a directly modulated VCSEL array, as shown schematically in Fig. 1. Although a discrete receiver, VCSEL array and wavelength filters were used here for implementing the transceiver at the Optical Line Terminal (OLT) (Fig 1), flip-chip mounting of the VCSEL array onto a silicon photonic integrated circuit containing the WDM multiplexer (MUX) and DPSK receivers has potential for implementing low cost multi-wavelength optical transceivers.","PeriodicalId":346720,"journal":{"name":"CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126347002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-14DOI: 10.1109/CLEOE-EQEC.2009.5192645
A. Heidt, G. Bosman, M. Becker, M. Rothhardt, Kai Schuster, J. Kobelke, H. Bartelt
The pulse energies available directly from passively mode-locked Ytterbium-doped fiber oscillators have been significantly increased during the past few years. Cavity designs with large net group velocity dispersion (GVD) have been favoured to avoid the formation of solitons which may limit the pulse energy. Recently, pulse energies above 20 nJ have been reached with all-normal dispersion (ANDi) fiber lasers. The mode-locking in these lasers is based on the spectral filtering of a highly chirped pulse in the cavity and dechirped pulse durations in the order of 100 fs have been reported [1].
{"title":"Prospects of high energy ultrashort pulse generation with frequency shifted feedback fiber oscillators","authors":"A. Heidt, G. Bosman, M. Becker, M. Rothhardt, Kai Schuster, J. Kobelke, H. Bartelt","doi":"10.1109/CLEOE-EQEC.2009.5192645","DOIUrl":"https://doi.org/10.1109/CLEOE-EQEC.2009.5192645","url":null,"abstract":"The pulse energies available directly from passively mode-locked Ytterbium-doped fiber oscillators have been significantly increased during the past few years. Cavity designs with large net group velocity dispersion (GVD) have been favoured to avoid the formation of solitons which may limit the pulse energy. Recently, pulse energies above 20 nJ have been reached with all-normal dispersion (ANDi) fiber lasers. The mode-locking in these lasers is based on the spectral filtering of a highly chirped pulse in the cavity and dechirped pulse durations in the order of 100 fs have been reported [1].","PeriodicalId":346720,"journal":{"name":"CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126442899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-14DOI: 10.1109/CLEOE-EQEC.2009.5196403
A. Sell, R. Scheu, A. Leitenstorfer, R. Huber
Ultrabroadband terahertz (THz) optoelectronics has evolved into a powerful tool in femtosecond science and technology [1,2]. Field-sensitive detection of few-cycle THz transients with a constant carrier envelope phase, center frequencies of up to 41 THz, and spectral wings approaching the near infrared has been demonstrated [3]. Nevertheless, the complexity of the required laser systems limits their operation to specialized laboratories. In addition, novel applications in field-sensitive trace gas detection or all-optical phase control of near-infrared pulses call for still higher center frequencies [4].
{"title":"Generation of phase-stable infrared transients and electro-optic detection at frequencies up to 140 THz with a compact Er:fiber laser","authors":"A. Sell, R. Scheu, A. Leitenstorfer, R. Huber","doi":"10.1109/CLEOE-EQEC.2009.5196403","DOIUrl":"https://doi.org/10.1109/CLEOE-EQEC.2009.5196403","url":null,"abstract":"Ultrabroadband terahertz (THz) optoelectronics has evolved into a powerful tool in femtosecond science and technology [1,2]. Field-sensitive detection of few-cycle THz transients with a constant carrier envelope phase, center frequencies of up to 41 THz, and spectral wings approaching the near infrared has been demonstrated [3]. Nevertheless, the complexity of the required laser systems limits their operation to specialized laboratories. In addition, novel applications in field-sensitive trace gas detection or all-optical phase control of near-infrared pulses call for still higher center frequencies [4].","PeriodicalId":346720,"journal":{"name":"CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference","volume":"2017 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126541459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-14DOI: 10.1109/CLEOE-EQEC.2009.5191732
C. Rockstuhl, C. Menzel, T. Paul, F. Lederer
Metamaterials (MM) attracted an ever increasing research interest in the past. Their main fascination derives from the possibility to attribute conceptually effective properties to them, if their characteristic length scale (being the size of the metaatoms) is much smaller than the wavelength of light. Most notably, a negative effective negative index became possible. It implies that for a certain eigenmode that is allowed to propagate inside such a MM, the real part of the wave vector and its imaginary part have opposite signs. Such negative indices were obtained, thus far, in most cases by relying on plasmonic resonances that induce an artificial magnetization. However, by taking the definition above, it is naturally anticipated that such negative refraction is a feature that can be observed in various physical systems. Indeed, similar observations were made in, e.g. plasmonic waveguides or photonic crystals. Also recently, first experimental results were presented on a negative refractive index by relying on a chirality of the metaatoms. Interesting enough, the idea to achieve negative refraction by chirality was introduced by Pendry already in 2004 [1]. There his argumentation bases nearly entirely on the dispersion relation. Nevertheless, for the observation of negative refraction the chirality has to be strongly pronounced. To induce strong chirality one may resort to appropriately shaped three-dimensional metaatoms [2] instead of quasiplanar chiral metamaterials [3] or to rely on twisted unit cells. The latter would cause an ambi-chiral media.
{"title":"Chirality as a bulk property retrieved from the dispersion relation","authors":"C. Rockstuhl, C. Menzel, T. Paul, F. Lederer","doi":"10.1109/CLEOE-EQEC.2009.5191732","DOIUrl":"https://doi.org/10.1109/CLEOE-EQEC.2009.5191732","url":null,"abstract":"Metamaterials (MM) attracted an ever increasing research interest in the past. Their main fascination derives from the possibility to attribute conceptually effective properties to them, if their characteristic length scale (being the size of the metaatoms) is much smaller than the wavelength of light. Most notably, a negative effective negative index became possible. It implies that for a certain eigenmode that is allowed to propagate inside such a MM, the real part of the wave vector and its imaginary part have opposite signs. Such negative indices were obtained, thus far, in most cases by relying on plasmonic resonances that induce an artificial magnetization. However, by taking the definition above, it is naturally anticipated that such negative refraction is a feature that can be observed in various physical systems. Indeed, similar observations were made in, e.g. plasmonic waveguides or photonic crystals. Also recently, first experimental results were presented on a negative refractive index by relying on a chirality of the metaatoms. Interesting enough, the idea to achieve negative refraction by chirality was introduced by Pendry already in 2004 [1]. There his argumentation bases nearly entirely on the dispersion relation. Nevertheless, for the observation of negative refraction the chirality has to be strongly pronounced. To induce strong chirality one may resort to appropriately shaped three-dimensional metaatoms [2] instead of quasiplanar chiral metamaterials [3] or to rely on twisted unit cells. The latter would cause an ambi-chiral media.","PeriodicalId":346720,"journal":{"name":"CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference","volume":"63 CN_suppl_1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128158145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-14DOI: 10.1109/CLEOE-EQEC.2009.5191996
O. Kimmelma, I. Tittonen
There is a vast need for compact UV-light sources e.g. in fields like spectroscopy, bioanalysis and micromachining. Pulsed UV sources extend the spectroscopic analysis to the time resolved regime. Passively Q-switched solid state lasers can produce high peak powers even at the UV range when compared to semiconductor sources. High intensity enables studies with low sample volumes and higher signal levels when compared to the semiconductor light sources in the UV range.
{"title":"Pulsed solid state UV-lasers at 374 nm and 280 nm","authors":"O. Kimmelma, I. Tittonen","doi":"10.1109/CLEOE-EQEC.2009.5191996","DOIUrl":"https://doi.org/10.1109/CLEOE-EQEC.2009.5191996","url":null,"abstract":"There is a vast need for compact UV-light sources e.g. in fields like spectroscopy, bioanalysis and micromachining. Pulsed UV sources extend the spectroscopic analysis to the time resolved regime. Passively Q-switched solid state lasers can produce high peak powers even at the UV range when compared to semiconductor sources. High intensity enables studies with low sample volumes and higher signal levels when compared to the semiconductor light sources in the UV range.","PeriodicalId":346720,"journal":{"name":"CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127944844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-14DOI: 10.1109/CLEOE-EQEC.2009.5191504
Y. Mazhirina, L. Melnikov, A. Konukhov
Two-wavelength light sources are of interest for THz-range oscillators based on difference frequency generation [1–5], and also for the oscillators, based on the optical rectification [6]. Easy way to produce pulses with frequency difference is the use of dispersion oscillating fiber [7]. We discuss the possibility to use a highly nonlinear photonic crystal fiber for generation the overlapping pulse pairs with the difference of carrier frequencies in THz range from femtosecond pulses train from only one laser. First, each pulse from the laser should be duplicated using beamsplitter. Then the pulses should be launched sequently into photonic crystal fiber. The pulse frequency is to be in anomalous dispersion regions, and pulses are to be high-order solitons. Due to Raman effect these solitons split to fundamental soliton with red shift and other smaller pulses with nonshifted frequency. Due to group velocity dispersion (GVD) the Raman-shifted pulse propagate slower depending on pulse parameters. Thus there exist some definite length in the fiber where Raman-shifted pulse collides with unshifted pulse. This distance and the value of the shift can be controlled by pulse parameters and depend on the fiber parameters. The results of numerical modeling of the nonlinear propagation of multi-soliton pairs of pulses in photonic crystal fiber are presented below.
{"title":"Generation of two colliding pulses with tunable THz-range frequency difference in high-nonlinear photonic crystal fiber","authors":"Y. Mazhirina, L. Melnikov, A. Konukhov","doi":"10.1109/CLEOE-EQEC.2009.5191504","DOIUrl":"https://doi.org/10.1109/CLEOE-EQEC.2009.5191504","url":null,"abstract":"Two-wavelength light sources are of interest for THz-range oscillators based on difference frequency generation [1–5], and also for the oscillators, based on the optical rectification [6]. Easy way to produce pulses with frequency difference is the use of dispersion oscillating fiber [7]. We discuss the possibility to use a highly nonlinear photonic crystal fiber for generation the overlapping pulse pairs with the difference of carrier frequencies in THz range from femtosecond pulses train from only one laser. First, each pulse from the laser should be duplicated using beamsplitter. Then the pulses should be launched sequently into photonic crystal fiber. The pulse frequency is to be in anomalous dispersion regions, and pulses are to be high-order solitons. Due to Raman effect these solitons split to fundamental soliton with red shift and other smaller pulses with nonshifted frequency. Due to group velocity dispersion (GVD) the Raman-shifted pulse propagate slower depending on pulse parameters. Thus there exist some definite length in the fiber where Raman-shifted pulse collides with unshifted pulse. This distance and the value of the shift can be controlled by pulse parameters and depend on the fiber parameters. The results of numerical modeling of the nonlinear propagation of multi-soliton pairs of pulses in photonic crystal fiber are presented below.","PeriodicalId":346720,"journal":{"name":"CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127946360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-14DOI: 10.1109/CLEOE-EQEC.2009.5192098
H. Guillet de Chatellus, J. Pique
Two-beam interferometry is a widely spread tool for high precision measurement, whose ultimate resolution is directly linked to the fringe spacing of the interferogram. All usual two-beam interferometers show a fringe spacing equal to a wavelength of the laser light. Here we present an interferometer where the fringe spacing is reduced by a factor of two and where the width of a fringe can be extremely narrow, leading to potential applications in very precise displacement measurement. Our interferometer is based on elementary aspects of atomic physics. The laser wavelength is tuned to an atomic transition J=1/2→J=1/2 (i.e. two-fold degenerate two level system). The laser field is initially polarized at 45° and sent to a polarizing beam splitter. Vertical and horizontal polarizations experience a relative phase shift φ and are recombined at the output. Then the resulting beam is sent into an atomic vapour and the fluorescence is recorded. When φ = 0 or π, the resulting polarization is linear (at 45° and 135° respectively) and the atom experiences continuous cycles of absorption-fluorescence. When φ = π/2 or 3π/2, the resulting polarization is circular and the atom is optically pumped onto one of the dark states |mJ = +/− ½≫ and the fluorescence vanishes. Therefore the fluorescence has a periodicity of π with the phase shift, contrary to an usual interferometer where the period is 2π. When the laser power is increased above the saturation intensity of the transition, a simple rate equation model shows that the variation of the fluorescence with φ becomes strongly anharmonic and follows an Airy function behaviour. An extremely sharp variation of the fluorescence is obtained in the vicinity of φ = π/2 and 3π/2 (Fig. 1 left). When the propagation of the laser beam is taken into account both the emitted fluorescence and the transmission of the laser field present anharmonic variations with the phase (Fig. 1 right).
{"title":"A high resolution anharmonic λ/2 fringe spacing interferometer","authors":"H. Guillet de Chatellus, J. Pique","doi":"10.1109/CLEOE-EQEC.2009.5192098","DOIUrl":"https://doi.org/10.1109/CLEOE-EQEC.2009.5192098","url":null,"abstract":"Two-beam interferometry is a widely spread tool for high precision measurement, whose ultimate resolution is directly linked to the fringe spacing of the interferogram. All usual two-beam interferometers show a fringe spacing equal to a wavelength of the laser light. Here we present an interferometer where the fringe spacing is reduced by a factor of two and where the width of a fringe can be extremely narrow, leading to potential applications in very precise displacement measurement. Our interferometer is based on elementary aspects of atomic physics. The laser wavelength is tuned to an atomic transition J=1/2→J=1/2 (i.e. two-fold degenerate two level system). The laser field is initially polarized at 45° and sent to a polarizing beam splitter. Vertical and horizontal polarizations experience a relative phase shift φ and are recombined at the output. Then the resulting beam is sent into an atomic vapour and the fluorescence is recorded. When φ = 0 or π, the resulting polarization is linear (at 45° and 135° respectively) and the atom experiences continuous cycles of absorption-fluorescence. When φ = π/2 or 3π/2, the resulting polarization is circular and the atom is optically pumped onto one of the dark states |mJ = +/− ½≫ and the fluorescence vanishes. Therefore the fluorescence has a periodicity of π with the phase shift, contrary to an usual interferometer where the period is 2π. When the laser power is increased above the saturation intensity of the transition, a simple rate equation model shows that the variation of the fluorescence with φ becomes strongly anharmonic and follows an Airy function behaviour. An extremely sharp variation of the fluorescence is obtained in the vicinity of φ = π/2 and 3π/2 (Fig. 1 left). When the propagation of the laser beam is taken into account both the emitted fluorescence and the transmission of the laser field present anharmonic variations with the phase (Fig. 1 right).","PeriodicalId":346720,"journal":{"name":"CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127959313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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