The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform

Joachim Wagner - One of the best experts on this subject based on the ideXlab platform.

Markus Pollnau - One of the best experts on this subject based on the ideXlab platform.

  • Lasing wavelength in dielectric distributed-feedback lasers with a distributed phase shift
    Solid State Lasers XXVIII: Technology and Devices, 2019
    Co-Authors: Cristine Calil Kores, Nur Ismail, Edward H. Bernhardi, Fredrik Laurell, Markus Pollnau
    Abstract:

    Distributed-feedback waveguide lasers based on Bragg-grating resonators generate ultranarrow-Linewidth Emission. Oscillation at the center of the reflection band ensures maximum reflectivity, hence ...

  • Accumulation of Distributed Phase Shift in Distributed-Feedback Resonators
    IEEE Photonics Journal, 2019
    Co-Authors: Cristine Calil Kores, Nur Ismail, Edward H. Bernhardi, Fredrik Laurell, Markus Pollnau
    Abstract:

    Distributed-feedback waveguide lasers based on Bragg-grating resonators generate ultranarrow-Linewidth Emission. Oscillation at the center of the reflection band ensures maximum reflectivity, hence minimum Linewidth. The required $\pi / 2$ phase shift is often introduced by a distributed change in effective refractive index, e.g., by widening the waveguide. Despite careful design and fabrication, the experimentally observed resonance wavelength deviates from the designed wavelength. Even when thermally induced chirp or fabrication errors are negligible, this deviation is still present. Here, we show theoretically and experimentally that this deviation is of fundamental nature. The decay of light intensity during propagation from the phase-shift center into both sides of the Bragg grating due to reflection by the periodic grating and the refractive index change causes an incomplete accumulation of designed phase shift, thereby systematically shifting the resonance to a shorter wavelength. Considering the overlap integral between the distributed phase shift and light intensity in the design provides the desired performance.

  • Integrated Al2O3:Er3+ microring and distributed feedback lasers on silicon
    2010
    Co-Authors: Edward H. Bernhardi, Kerstin Worhoff, Jonathan D. B. Bradley, R.m. De Ridder, Markus Pollnau
    Abstract:

    Integrated rare-earth-ion-doped dielectric lasers have found numerous applications in the medical, scientific, military and industrial fields, thanks to their high stability, low noise, narrow Linewidth Emission and broad wavelength tunability. Its favorable optical properties and compatibility with existing silicon waveguide technology make rare-earth-ion-doped aluminum oxide (Al2O3) a very promising gain medium to realize such integrated lasers. Al2O3:Er3+ waveguide lasers are of interest due to their Emission near 1.55 μm in the telecommunication C-band. The fabrication of low-loss Al2O3:Er3+ waveguides and internal optical gain over an 80-nm wavelength range with a peak gain of 2.0 dB/cm enabled the realization of various integrated Al2O3:Er3+ lasers on standard thermally oxidized silicon substrates. We report on the fabrication and performance of optically pumped channel waveguide ring and distributed feedback (DFB) lasers in Al2O3:Er3+. The low threshold ring-cavity lasers provide laser wavelength selection in the range 1530–1557 nm when varying the length of the output coupler from the ring. The DFB lasers exhibit output powers of more than 3 mW with slope efficiencies as high as 6.2% in single-frequency operation at 1545.2 nm with Linewidths below 15 kHz. These performance data illustrate the significance of Al2O3:Er3+ as a laser gain medium in dense wavelength division multiplexing in telecommunication networks.

I Sagnes - One of the best experts on this subject based on the ideXlab platform.

  • tunable dual frequency laser source for coherent population trapping cesium atomic clocks
    Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, 2018
    Co-Authors: Fabiola Camargo, Patrick Georges, Gaelle Lucasleclin, G Baili, Loic Morvan, D Dolfi, D Holleville, S Guerandel, I Sagnes
    Abstract:

    Coherent population trapping (CPT) has been demonstrated as an interesting technique for miniature atomic frequency references [1,2] and quantum information. It is based on the coupling of the two hyperfine ground states of an alkali atom – namely cesium (133Cs) for atomic clocks – through excitation to a common atomic level by two phase-coherent laser fields nearly resonant with the atomic transitions. The frequency difference between the two laser fields is tuned at the atomic frequency splitting in the microwave range, equal to 9.192 GHz for 133Cs atoms. Outputs powers in the mW range and narrow-Linewidth Emission (<500 kHz) are required for the two laser beams.

  • Tunable dual-frequency laser source for coherent population trapping cesium atomic clocks
    International Conference on Space Optics — ICSO 2012, 2018
    Co-Authors: Fabiola Camargo, Patrick Georges, G Baili, Loic Morvan, D Dolfi, D Holleville, S Guerandel, Gaëlle Lucas-leclin, I Sagnes
    Abstract:

    Coherent population trapping (CPT) has been demonstrated as an interesting technique for miniature atomic frequency references [1,2] and quantum information. It is based on the coupling of the two hyperfine ground states of an alkali atom – namely cesium (133Cs) for atomic clocks – through excitation to a common atomic level by two phase-coherent laser fields nearly resonant with the atomic transitions. The frequency difference between the two laser fields is tuned at the atomic frequency splitting in the microwave range, equal to 9.192 GHz for 133Cs atoms. Outputs powers in the mW range and narrow-Linewidth Emission (

  • Single-frequency optically pumped semiconductor vertical external cavity laser at 852nm for Cs atomic clock
    2011 Conference on Lasers and Electro-Optics Europe and 12th European Quantum Electronics Conference (CLEO EUROPE EQEC), 2011
    Co-Authors: Fabiola Camargo, Patrick Georges, I Sagnes, Arnaud Garnache, Gaëlle Lucas-leclin
    Abstract:

    Stable single-frequency laser with narrow Linewidth Emission (< 500kHz), fine tunability over a few GHz and output power in the 0.1W range is required to cold atom interferometry experiments. Until now different approaches have been studied in order to fulfil all these characteristics. Single frequency high power lasers have been demonstrated with distributed feedback diode lasers and tapered extended cavity diode lasers. However, these two solutions suffer from beam quality degradation at high power. A possible alternative solution to obtain a compact and simple single frequency source with narrow Linewidth and good beam quality is an optically-pumped semiconductor vertical external-cavity surface-emitting laser (OPS-VECSEL), which has already demonstrated multi watt output power in the fundamental transverse mode [1] as well as high power single frequency operation [2]. Nevertheless the majority of these works using VECSEL are focused around 1µm Emission. In this work we evaluate short external-cavities VECSEL for single-frequency Emission at 852nm dedicated to Cs atom spectroscopy.

Mircea Guina - One of the best experts on this subject based on the ideXlab platform.

  • High-Power 1.5 μm Tapered Distributed Bragg Reflector Laser Diodes for Eye-Safe LIDAR
    IEEE Photonics Technology Letters, 2020
    Co-Authors: Antti T. Aho, Topi Uusitalo, Jukka Viheriala, Mervi Koskinen, Jarno Reuna, Mircea Guina
    Abstract:

    A high-power InAlGaAs/InP tapered distributed Bragg reflector laser diode with narrow Linewidth Emission at $1.5~\mu \text{m}$ is reported. The laser has a monolithic waveguide architecture comprising a third-order grating section for longitudinal mode selection, an index-guided gain section for lateral mode filtering, and a gain-guided tapered section for power scaling. An output power of 770 mW is reported for continuous wave operation at room temperature. In pulsed mode, the laser delivered a peak power of 4.6 W with a full width at half-maximum spectral Linewidth of only 250 pm. In addition to the narrow Linewidth and high-power features, the Emission wavelength exhibits a temperature dependent shift of only 0.1 nm/°C. The parameters achieved suggest that these laser diodes would enable the realization of compact LIDAR systems with improved signal-to-noise ratio, owing to the high output power and the possibility to use narrow passband filters at receiver side, which is enabled by the narrow and temperature-stable Emission spectrum. The wavelength range around $1.5~\mu \text{m}$ also enables LIDAR systems with high output powers while maintaining eye safety, ultimately leading to improved system performance.

  • Narrow Linewidth 1118/559 nm VECSEL based on strain compensated GaInAs/GaAs quantum-wells for laser cooling of Mg-ions
    Optical Materials Express, 2012
    Co-Authors: Sanna Ranta, M. Tavast, Tomi Leinonen, Ryan J. Epstein, Mircea Guina
    Abstract:

    We report on the development of an optically-pumped vertical external-cavity surface-emitting laser emitting near 1120 nm using strain compensated quantum wells. The development is motivated by the need to achieve narrow Linewidth Emission at ~280 nm via fourth harmonic generation, which is required to cool Mg+ ions. The gain mirror had a top-emitting geometry, was grown by molecular beam epitaxy and comprised GaInAs/GaAs quantum wells strain compensated by GaAsP layers; the strain compensation was instrumental for achieving a dislocation free epitaxial structure without dark lines. We demonstrate VECSEL operation at a fundamental wavelength close to 1118 nm with a Linewidth of less than 300 kHz. Using a lithium triborate crystal we achieved frequency doubling to ~559 nm with an output power of 1.1W.

Fabiola Camargo - One of the best experts on this subject based on the ideXlab platform.

  • tunable dual frequency laser source for coherent population trapping cesium atomic clocks
    Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, 2018
    Co-Authors: Fabiola Camargo, Patrick Georges, Gaelle Lucasleclin, G Baili, Loic Morvan, D Dolfi, D Holleville, S Guerandel, I Sagnes
    Abstract:

    Coherent population trapping (CPT) has been demonstrated as an interesting technique for miniature atomic frequency references [1,2] and quantum information. It is based on the coupling of the two hyperfine ground states of an alkali atom – namely cesium (133Cs) for atomic clocks – through excitation to a common atomic level by two phase-coherent laser fields nearly resonant with the atomic transitions. The frequency difference between the two laser fields is tuned at the atomic frequency splitting in the microwave range, equal to 9.192 GHz for 133Cs atoms. Outputs powers in the mW range and narrow-Linewidth Emission (<500 kHz) are required for the two laser beams.

  • Tunable dual-frequency laser source for coherent population trapping cesium atomic clocks
    International Conference on Space Optics — ICSO 2012, 2018
    Co-Authors: Fabiola Camargo, Patrick Georges, G Baili, Loic Morvan, D Dolfi, D Holleville, S Guerandel, Gaëlle Lucas-leclin, I Sagnes
    Abstract:

    Coherent population trapping (CPT) has been demonstrated as an interesting technique for miniature atomic frequency references [1,2] and quantum information. It is based on the coupling of the two hyperfine ground states of an alkali atom – namely cesium (133Cs) for atomic clocks – through excitation to a common atomic level by two phase-coherent laser fields nearly resonant with the atomic transitions. The frequency difference between the two laser fields is tuned at the atomic frequency splitting in the microwave range, equal to 9.192 GHz for 133Cs atoms. Outputs powers in the mW range and narrow-Linewidth Emission (

  • Single-frequency optically pumped semiconductor vertical external cavity laser at 852nm for Cs atomic clock
    2011 Conference on Lasers and Electro-Optics Europe and 12th European Quantum Electronics Conference (CLEO EUROPE EQEC), 2011
    Co-Authors: Fabiola Camargo, Patrick Georges, I Sagnes, Arnaud Garnache, Gaëlle Lucas-leclin
    Abstract:

    Stable single-frequency laser with narrow Linewidth Emission (< 500kHz), fine tunability over a few GHz and output power in the 0.1W range is required to cold atom interferometry experiments. Until now different approaches have been studied in order to fulfil all these characteristics. Single frequency high power lasers have been demonstrated with distributed feedback diode lasers and tapered extended cavity diode lasers. However, these two solutions suffer from beam quality degradation at high power. A possible alternative solution to obtain a compact and simple single frequency source with narrow Linewidth and good beam quality is an optically-pumped semiconductor vertical external-cavity surface-emitting laser (OPS-VECSEL), which has already demonstrated multi watt output power in the fundamental transverse mode [1] as well as high power single frequency operation [2]. Nevertheless the majority of these works using VECSEL are focused around 1µm Emission. In this work we evaluate short external-cavities VECSEL for single-frequency Emission at 852nm dedicated to Cs atom spectroscopy.