Fiber mode coupling in transmissive and reflective tilted fiber gratings.
Fiber mode coupling in transmissive and reflective tilted fiber gratings.
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DOI：
10.1364/ao.39.001394
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发表时间：
2000-03
期刊：
影响因子：
1.9
通讯作者：
Kyung Shik Lee;Turan Erdogan
中科院分区：
文献类型：
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作者：
Kyung Shik Lee;Turan Erdogan
虽然倾斜光纤布拉格光栅中的核心模式反射和核心模式-辐射模式耦合已经被很好地理解，但在非倾斜光纤光栅中，核心模式与高阶核心和包层模式之间的耦合也很好地理解，在这里，我们详细分析了反射和透射倾斜光纤光栅中核心模式和包层模式之间的耦合。我们表明，LP（01）核心模式和精确（1m）包层模式之间的强耦合发生在几乎任何倾斜角（除了接近90度的角度）的透射倾斜光栅中，而LP（01）到-(lm)包层模式耦合（l不等于1）仅在倾斜角略低于90度（约88度）时才明显。在反射光栅中，LP（01）核心模式与精确（1m）包层模式之间的强耦合仅在小于约5度的角度下发生，而m > 1与（1m）包层模式之间的耦合仅在大于约5度的角度下发生。绑定核心模式之间的耦合表现出类似的行为，只是通常耦合更强。实验表明，在可见光和近红外波段，透射倾斜光栅与高阶束缚型核心模式和包层模式存在耦合。
Whereas core-mode reflection and core-mode-to-radiation-mode coupling in tilted fiber Bragg gratings is well understood, as is coupling between a core mode and higher-order core and cladding modes in untilted gratings, here we analyze in detail the coupling among core modes and cladding modes in reflective and transmissive tilted fiber gratings. We show that strong coupling between an LP(01) core mode and the exact (1m) cladding modes occurs in a transmissive tilted grating for nearly any tilt angle except angles close to 90 degrees, whereas the LP(01)-to-(lm) cladding mode coupling (l not equal 1) is appreciable only for tilt angles just below 90 degrees (approximately 88 degrees). In a reflective grating, strong coupling between the LP(01) core mode and the exact (1m) cladding modes occurs only for angles less than approximately 5 degrees, whereas coupling to (1m) cladding modes for m > 1 occurs only for angles greater than approximately 5 degrees. Coupling among bound core modes exhibits a similar behavior, except that in general the coupling is stronger. Experimentally we show coupling to both higher-order bound core modes and cladding modes in a transmissive tilted grating at visible and near-infrared wavelengths.