Temperature-dependent absorption and gain of ytterbium-doped potassium double tungstates for chip-scale amplifiers and lasers

Yean Sheng Yong, Shanmugam Aravazhi, Sergio A. Vázquez-Córdova, Jennifer L. Herek, Sonia M. García-Blanco, Markus Pollnau

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

Abstract

Ytterbium-doped potassium rare-earth double tungstate thin films are excellent candidates for highly efficient waveguide lasers, as well as high-gain waveguide amplifiers, with a record-high optical gain per unit length of 935 dB/cm recently demonstrated. However, the spectroscopic properties of these highly ytterbium-doped thin films and, in particular, their temperature dependence are not well investigated. These characteristics are required for the understanding of the behavior of the fabricated optical devices and crucial for further device optimization. We experimentally determined the absorption cross-sections for a potassium ytterbium gadolinium double tungstate, KYb0.57Gd0.43(WO4)2, thin film grown lattice matched onto an undoped KY(WO4)2 substrate. At room temperature, the peak cross-section value at 981 nm and the overall absorption spectrum are very similar to those of Yb-doped bulk potassium double tungstate crystals, although Yb is now the dominating rare-earth content. The temperature-dependent study shows a significant decrease of the absorption cross-section values at 933 nm and 981 nm with increasing temperature. We verify theoretically that this is due to the temperature dependence of fractional populations in the individual Stark levels of the absorbing crystal-field multiplet, in combination with the linewidth broadening with increasing temperature. Further investigations suggest that the broadening of absorption linewidth at 981 nm originates in the intra-manifold relaxation between the two lowest Stark levels of the ground state. Finally, the implications of the spectroscopic findings on the operating characteristics of waveguide amplifiers are investigated. Amplifiers operating at 80 °C are expected to exhibit only 67% of the maximum theoretical gain at room temperature.

Original languageEnglish
Title of host publicationIntegrated Optics: Devices, Materials, and Technologies XXI
PublisherSPIE
Volume10106
ISBN (Electronic)9781510606531
DOIs
Publication statusPublished - 16 Feb 2017
EventSPIE Optoelectronics and Photonic Materials and Devices Conference, OPTO 2017 - The Moscone Center, San Francisco, United States
Duration: 30 Jan 20171 Feb 2017

Conference

ConferenceSPIE Optoelectronics and Photonic Materials and Devices Conference, OPTO 2017
Abbreviated titleOPTO
CountryUnited States
CitySan Francisco
Period30/01/171/02/17

Fingerprint

Ytterbium
tungstates
Potassium
ytterbium
potassium
Chip
Absorption
amplifiers
chips
Laser
absorption cross sections
Lasers
Dependent
Waveguide
rare earth elements
Thin Films
thin films
Cross section
Rare Earths
waveguides

Keywords

  • Integrated optics materials
  • Lasers
  • Optical amplifiers
  • Rare-earth-doped materials
  • Ytterbium

Cite this

Yong, Y. S., Aravazhi, S., Vázquez-Córdova, S. A., Herek, J. L., García-Blanco, S. M., & Pollnau, M. (2017). Temperature-dependent absorption and gain of ytterbium-doped potassium double tungstates for chip-scale amplifiers and lasers. In Integrated Optics: Devices, Materials, and Technologies XXI (Vol. 10106). [1010606] SPIE. https://doi.org/10.1117/12.2252154
Yong, Yean Sheng ; Aravazhi, Shanmugam ; Vázquez-Córdova, Sergio A. ; Herek, Jennifer L. ; García-Blanco, Sonia M. ; Pollnau, Markus. / Temperature-dependent absorption and gain of ytterbium-doped potassium double tungstates for chip-scale amplifiers and lasers. Integrated Optics: Devices, Materials, and Technologies XXI. Vol. 10106 SPIE, 2017.
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abstract = "Ytterbium-doped potassium rare-earth double tungstate thin films are excellent candidates for highly efficient waveguide lasers, as well as high-gain waveguide amplifiers, with a record-high optical gain per unit length of 935 dB/cm recently demonstrated. However, the spectroscopic properties of these highly ytterbium-doped thin films and, in particular, their temperature dependence are not well investigated. These characteristics are required for the understanding of the behavior of the fabricated optical devices and crucial for further device optimization. We experimentally determined the absorption cross-sections for a potassium ytterbium gadolinium double tungstate, KYb0.57Gd0.43(WO4)2, thin film grown lattice matched onto an undoped KY(WO4)2 substrate. At room temperature, the peak cross-section value at 981 nm and the overall absorption spectrum are very similar to those of Yb-doped bulk potassium double tungstate crystals, although Yb is now the dominating rare-earth content. The temperature-dependent study shows a significant decrease of the absorption cross-section values at 933 nm and 981 nm with increasing temperature. We verify theoretically that this is due to the temperature dependence of fractional populations in the individual Stark levels of the absorbing crystal-field multiplet, in combination with the linewidth broadening with increasing temperature. Further investigations suggest that the broadening of absorption linewidth at 981 nm originates in the intra-manifold relaxation between the two lowest Stark levels of the ground state. Finally, the implications of the spectroscopic findings on the operating characteristics of waveguide amplifiers are investigated. Amplifiers operating at 80 °C are expected to exhibit only 67{\%} of the maximum theoretical gain at room temperature.",
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Yong, YS, Aravazhi, S, Vázquez-Córdova, SA, Herek, JL, García-Blanco, SM & Pollnau, M 2017, Temperature-dependent absorption and gain of ytterbium-doped potassium double tungstates for chip-scale amplifiers and lasers. in Integrated Optics: Devices, Materials, and Technologies XXI. vol. 10106, 1010606, SPIE, SPIE Optoelectronics and Photonic Materials and Devices Conference, OPTO 2017, San Francisco, United States, 30/01/17. https://doi.org/10.1117/12.2252154

Temperature-dependent absorption and gain of ytterbium-doped potassium double tungstates for chip-scale amplifiers and lasers. / Yong, Yean Sheng; Aravazhi, Shanmugam; Vázquez-Córdova, Sergio A.; Herek, Jennifer L.; García-Blanco, Sonia M.; Pollnau, Markus.

Integrated Optics: Devices, Materials, and Technologies XXI. Vol. 10106 SPIE, 2017. 1010606.

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

TY - GEN

T1 - Temperature-dependent absorption and gain of ytterbium-doped potassium double tungstates for chip-scale amplifiers and lasers

AU - Yong, Yean Sheng

AU - Aravazhi, Shanmugam

AU - Vázquez-Córdova, Sergio A.

AU - Herek, Jennifer L.

AU - García-Blanco, Sonia M.

AU - Pollnau, Markus

PY - 2017/2/16

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N2 - Ytterbium-doped potassium rare-earth double tungstate thin films are excellent candidates for highly efficient waveguide lasers, as well as high-gain waveguide amplifiers, with a record-high optical gain per unit length of 935 dB/cm recently demonstrated. However, the spectroscopic properties of these highly ytterbium-doped thin films and, in particular, their temperature dependence are not well investigated. These characteristics are required for the understanding of the behavior of the fabricated optical devices and crucial for further device optimization. We experimentally determined the absorption cross-sections for a potassium ytterbium gadolinium double tungstate, KYb0.57Gd0.43(WO4)2, thin film grown lattice matched onto an undoped KY(WO4)2 substrate. At room temperature, the peak cross-section value at 981 nm and the overall absorption spectrum are very similar to those of Yb-doped bulk potassium double tungstate crystals, although Yb is now the dominating rare-earth content. The temperature-dependent study shows a significant decrease of the absorption cross-section values at 933 nm and 981 nm with increasing temperature. We verify theoretically that this is due to the temperature dependence of fractional populations in the individual Stark levels of the absorbing crystal-field multiplet, in combination with the linewidth broadening with increasing temperature. Further investigations suggest that the broadening of absorption linewidth at 981 nm originates in the intra-manifold relaxation between the two lowest Stark levels of the ground state. Finally, the implications of the spectroscopic findings on the operating characteristics of waveguide amplifiers are investigated. Amplifiers operating at 80 °C are expected to exhibit only 67% of the maximum theoretical gain at room temperature.

AB - Ytterbium-doped potassium rare-earth double tungstate thin films are excellent candidates for highly efficient waveguide lasers, as well as high-gain waveguide amplifiers, with a record-high optical gain per unit length of 935 dB/cm recently demonstrated. However, the spectroscopic properties of these highly ytterbium-doped thin films and, in particular, their temperature dependence are not well investigated. These characteristics are required for the understanding of the behavior of the fabricated optical devices and crucial for further device optimization. We experimentally determined the absorption cross-sections for a potassium ytterbium gadolinium double tungstate, KYb0.57Gd0.43(WO4)2, thin film grown lattice matched onto an undoped KY(WO4)2 substrate. At room temperature, the peak cross-section value at 981 nm and the overall absorption spectrum are very similar to those of Yb-doped bulk potassium double tungstate crystals, although Yb is now the dominating rare-earth content. The temperature-dependent study shows a significant decrease of the absorption cross-section values at 933 nm and 981 nm with increasing temperature. We verify theoretically that this is due to the temperature dependence of fractional populations in the individual Stark levels of the absorbing crystal-field multiplet, in combination with the linewidth broadening with increasing temperature. Further investigations suggest that the broadening of absorption linewidth at 981 nm originates in the intra-manifold relaxation between the two lowest Stark levels of the ground state. Finally, the implications of the spectroscopic findings on the operating characteristics of waveguide amplifiers are investigated. Amplifiers operating at 80 °C are expected to exhibit only 67% of the maximum theoretical gain at room temperature.

KW - Integrated optics materials

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Yong YS, Aravazhi S, Vázquez-Córdova SA, Herek JL, García-Blanco SM, Pollnau M. Temperature-dependent absorption and gain of ytterbium-doped potassium double tungstates for chip-scale amplifiers and lasers. In Integrated Optics: Devices, Materials, and Technologies XXI. Vol. 10106. SPIE. 2017. 1010606 https://doi.org/10.1117/12.2252154