Topic
Equilibrium mode distribution
About: Equilibrium mode distribution is a research topic. Over the lifetime, 928 publications have been published within this topic receiving 14939 citations.
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TL;DR: In this article, the authors present simulations on the temperature profile inside of a large mode area fiber in high power operation with mode interference and show that the pump power is not homogeneously absorbed along the fiber, which in turn gives rise to an oscillating temperature profile.
Abstract: Detailed simulations on the temperature profile inside of a large mode area fiber in high power operation with mode
interference are presented. These simulations show that the pump power is not homogeneously absorbed along the fiber,
which in turn gives rise to an oscillating temperature profile along the fiber. This longitudinal temperature profile creates
an index grating with the right period to transfer energy between the interfering modes. Two cases are analyzed: mode
beating between the fundamental mode and a radially anti-symmetric mode and mode beating between the fundamental
mode and a radially symmetric mode.
6 citations
Patent•
NEC1
TL;DR: In this article, a semiconductor laser device has at least an active layer and an optical waveguide region, which includes at least a part of the active layer, wherein Δ gain /Γ is at least 85 [cm −1 /%], where Δ gain is a difference in gain between a zero-order fundamental mode and a one-order high-order mode in a lateral transverse mode of the optical wvaveguide.
Abstract: A semiconductor laser device has at least an active layer and an optical waveguide region, which includes at least a part of the active layer, wherein Δ gain /Γ is at least 85 [cm −1 /%], where Δ gain [cm −1 ] is a difference in gain between a zero-order fundamental mode and a one-order high-order mode in a lateral transverse mode of the optical wvaveguide, and Γ [%] is a total optical confinement rate of the at least part of the active layer in the zero-order fundamental mode.
6 citations
Patent•
[...]
17 Sep 1984
TL;DR: In this paper, a waveguide with a high mode eliminating part consisting of a part whose sectional area is made smaller and a mode converting part which converts the light from a lower mode to a higher mode through an optical path intercepting part vertical approximately to the light propagation direction is provided.
Abstract: PURPOSE:To obtain a mode scrambler in a short length to stabilize a branching ratio for the incidence position of light by providing a waveguide with a high mode eliminating part consisting of a part whose sectional area is made smaller and a mode converting part which converts the light from a lower mode to a higher mode through an optical path intercepting part vertical approximately to the light propagation direction CONSTITUTION:The part 27 whose sectional area is made smaller is provided between a coupling part 23 and a branching part 24, and an optical path intercepting part 28 vertical approximately to the light propagation direction is provided in the branching part 24, and exit parts 25 and 26 are connected through this optical path intercepting part 28 Rays of light made incident on two entrance parts 21 and 22 cross in the coupling part 23 and have components of the higher mode eliminated by passing the part 27 They are intercepted by the optical path intercepting part 28 and are inputted to two exit parts 25 and 26 connected to both sides of this part 28 In this process, the light of the lower mode is converted to the high of the higher mode and is distributed equally to exit parts 25 and 26 Thus, the mode scrambler is attained in a short length
6 citations
TL;DR: In this article, a new cone-shaped coiling device for beam quality improvement in large mode area (LMA) fiber laser has been designed to improve beam quality by taking mode coupling into account.
Abstract: Mode coupling, bend distortion and bend loss are important considerations in large mode area (LMA) fiber laser. Both mode coupling and mode distortion were studied in the step-index fiber in theory. The dependence of mode power on propagation distance, effective bend radius was calculated with the bend radius changing suddenly and gradually. Taking mode coupling into account, we designed a new cone-shaped coiling device for beam quality improvement. These results and design are of benefit to the applications of coiling fiber to improve beam quality for LMA fiber laser.
6 citations
TL;DR: In this paper, a new technique based on mode selective excitation and output near-field analysis was developed, which decoupled the problem into two phenomena which are effective on different scales of propagation length: azimuthal and longitudinal mode mixing.
Abstract: To study mode coupling in optical fibres a new technique is developed, based on mode selective excitation and output near-field analysis. Experimental results support decoupling of the problem into two phenomena which are effective on different scales of propagation length: azimuthal and longitudinal mode mixing. A statistical model providing a simulation of the experimental near-field patterns is developed. Comparison with measurements shows that azimuthal mixing is complete before 1 km propagation, while effects of uncomplete axial coupling are accounted for. This approach also suggests a method for measuring the steady-state distribution length, with useful system implications.
6 citations