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Optical signal inversion phenomena due to negative nonlinear absorption effect
Author(s) -
Maeda Yoshinobu,
Ikeda Seiichi,
Sakakibara Takao,
Migitaka Masatoshi
Publication year - 1997
Publication title -
electrical engineering in japan
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.136
H-Index - 28
eISSN - 1520-6416
pISSN - 0424-7760
DOI - 10.1002/(sici)1520-6416(199709)120:4<74::aid-eej10>3.0.co;2-w
Subject(s) - inversion (geology) , nonlinear system , signal (programming language) , nonlinear optical , materials science , absorption (acoustics) , optics , physics , geology , computer science , seismology , quantum mechanics , tectonics , programming language
A negative input‐output characteristic was obtained in an erbium‐doped yttrium aluminum garnet crystal which has multiple‐level energy structure: absorption can occur between a ground level and an excited level ( 4 I− 4 I) and between two other excited levels ( 4 I− 2 H) in Er 3+ . It occurred at a wavelength between 786.6 and 788.4 nm by variation of the incident laser intensity in the intensity range of 60 nW/cm 2 to 100 W/cm 2 . It is considered that an enhanced absorption occurs due to the excited‐state absorption from 4 I to 2 H, its spectra matching the wavelength dependence of the incident laser In addition, optical signal inverter phenomenon was observed using a laser diode modulated at 10 MHz. By considering multiple excited‐state absorption in detail, active functions such as an optical signal inverter could be derived from the negative nonlinear absorption effect. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 120(4): 74–80, 1997