Gratings with longitudinal variations in coupling coefficients: super-efficiency and unidirectionality in distributed feedback Raman fiber lasers
We propose a technique to design highly-efficient and -unidirectional DFB Raman fiber lasers based on the engineering of the grating’s coupling coefficient including a π -phase shift position in the fiber. For this purpose, first the ideal intra-cavity signal powers for different pump power levels a...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2020-01-01
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| Series: | New Journal of Physics |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1367-2630/abbc2a |
| _version_ | 1797750353276436480 |
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| author | Amirhossein Tehranchi Raman Kashyap |
| author_facet | Amirhossein Tehranchi Raman Kashyap |
| author_sort | Amirhossein Tehranchi |
| collection | DOAJ |
| description | We propose a technique to design highly-efficient and -unidirectional DFB Raman fiber lasers based on the engineering of the grating’s coupling coefficient including a π -phase shift position in the fiber. For this purpose, first the ideal intra-cavity signal powers for different pump power levels are determined for given fiber lengths. Then, the sum and difference between the counter-propagating wave intensities at each small segment within fiber lengths are calculated resulting in determining the ideal grating’s coupling functions for co- and contra-directional-pumping. The steady-state behavior of the laser using realistic parameters is finally simulated for modified coupling functions considering the Kerr nonlinearity. For a 10 W co-directional-pumped, ∼1 m long single-mode super-efficient DFB, a ∼50% increase in the laser efficiency, more than 44 dB reduction in contra-directional lasing power, ∼15 times drop in the peak power of intra-cavity signal and ∼38% decrease in the unused-pump power are found, compared to those in a standard DFB with the same coupling-length product. Although an enhanced nonlinear refractive index due to thermal gradient reduces the output power of such lasers, it is shown that the super-efficient laser presents a better performance than the standard one, under such conditions. |
| first_indexed | 2024-03-12T16:31:33Z |
| format | Article |
| id | doaj.art-786228f853e64db7a91eaef8d795b5ea |
| institution | Directory Open Access Journal |
| issn | 1367-2630 |
| language | English |
| last_indexed | 2024-03-12T16:31:33Z |
| publishDate | 2020-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | New Journal of Physics |
| spelling | doaj.art-786228f853e64db7a91eaef8d795b5ea2023-08-08T15:27:46ZengIOP PublishingNew Journal of Physics1367-26302020-01-01221010302210.1088/1367-2630/abbc2aGratings with longitudinal variations in coupling coefficients: super-efficiency and unidirectionality in distributed feedback Raman fiber lasersAmirhossein Tehranchi0Raman Kashyap1Advanced Photonics Concepts Laboratory, Department of Electrical Engineering, Polytechnique Montreal, University of Montreal , Montreal QC, H3C 3A7, CanadaAdvanced Photonics Concepts Laboratory, Department of Electrical Engineering, Polytechnique Montreal, University of Montreal , Montreal QC, H3C 3A7, Canada; Department of Engineering Physics, Polytechnique Montreal, University of Montreal , Montreal QC, H3C 3A7, CanadaWe propose a technique to design highly-efficient and -unidirectional DFB Raman fiber lasers based on the engineering of the grating’s coupling coefficient including a π -phase shift position in the fiber. For this purpose, first the ideal intra-cavity signal powers for different pump power levels are determined for given fiber lengths. Then, the sum and difference between the counter-propagating wave intensities at each small segment within fiber lengths are calculated resulting in determining the ideal grating’s coupling functions for co- and contra-directional-pumping. The steady-state behavior of the laser using realistic parameters is finally simulated for modified coupling functions considering the Kerr nonlinearity. For a 10 W co-directional-pumped, ∼1 m long single-mode super-efficient DFB, a ∼50% increase in the laser efficiency, more than 44 dB reduction in contra-directional lasing power, ∼15 times drop in the peak power of intra-cavity signal and ∼38% decrease in the unused-pump power are found, compared to those in a standard DFB with the same coupling-length product. Although an enhanced nonlinear refractive index due to thermal gradient reduces the output power of such lasers, it is shown that the super-efficient laser presents a better performance than the standard one, under such conditions.https://doi.org/10.1088/1367-2630/abbc2aBragg gratingsRaman lasersfiber optic |
| spellingShingle | Amirhossein Tehranchi Raman Kashyap Gratings with longitudinal variations in coupling coefficients: super-efficiency and unidirectionality in distributed feedback Raman fiber lasers New Journal of Physics Bragg gratings Raman lasers fiber optic |
| title | Gratings with longitudinal variations in coupling coefficients: super-efficiency and unidirectionality in distributed feedback Raman fiber lasers |
| title_full | Gratings with longitudinal variations in coupling coefficients: super-efficiency and unidirectionality in distributed feedback Raman fiber lasers |
| title_fullStr | Gratings with longitudinal variations in coupling coefficients: super-efficiency and unidirectionality in distributed feedback Raman fiber lasers |
| title_full_unstemmed | Gratings with longitudinal variations in coupling coefficients: super-efficiency and unidirectionality in distributed feedback Raman fiber lasers |
| title_short | Gratings with longitudinal variations in coupling coefficients: super-efficiency and unidirectionality in distributed feedback Raman fiber lasers |
| title_sort | gratings with longitudinal variations in coupling coefficients super efficiency and unidirectionality in distributed feedback raman fiber lasers |
| topic | Bragg gratings Raman lasers fiber optic |
| url | https://doi.org/10.1088/1367-2630/abbc2a |
| work_keys_str_mv | AT amirhosseintehranchi gratingswithlongitudinalvariationsincouplingcoefficientssuperefficiencyandunidirectionalityindistributedfeedbackramanfiberlasers AT ramankashyap gratingswithlongitudinalvariationsincouplingcoefficientssuperefficiencyandunidirectionalityindistributedfeedbackramanfiberlasers |