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1997
Journal Article
Titel
Dispersive self-Q-switching in self-pulsating DFB lasers
Abstract
Self-pulsations reproducibly achieved in newly developed lasers with two distributed feedback sections and with an additional phase tuning section are investigated. The existence of the dispersive self-Q-switching mechanism for generating the high-frequency self-pulsations is verified experimentally for the first time. This effect is clearly distinguished from other possible self-pulsation mechanisms by detecting the single-mode type of the self-pulsation and the operation of one section near the transparency current density using it as a reflector with dispersive feedback. The operating conditions for generating this self-pulsation type are analyzed. It is revealed that the required critical detuning of the Bragg wavelengths of the two DFB sections is achieved by a combination of electronic wavelength tuning and current-induced heating. The previous reproducibility problems of self-pulsations in two-section DFB lasers operated at, in principle, suited current conditions are discussed, and the essential role of an electrical phase-control section for achieving reproducible device properties is pointed out. Furthermore, it is demonstrated that phase tuning can be used for extending the self-pulsation regime and for optimizing the frequency stability of the self-pulsation. Improved performance of the devices applied as optical clocks thus can be expected.
Tags
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clocks
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distributed feedback lasers
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laser frequency stability
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laser modes
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laser theory
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laser tuning
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laser variables measurement
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q-switching
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semiconductor device models
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semiconductor device testing
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semiconductor lasers
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dispersive self-q-switching
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self-pulsating dfb lasers
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distributed feedback sections
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additional phase tuning section
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dispersive self-q-switching mechanism
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high-frequency self-pulsations
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single-mode type
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transparency current density
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operating conditions
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critical detuning
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bragg wavelengths
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electronic wavelength tuning
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current-induced heating
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electrical phase-control section
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two-section dfb lasers
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optical clocks