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Frequency-domain modal delay measurement for higher-order mode fiber based on stretched pulse interference
Tae-Jung Ahn1, Yongwoo Park, David J Moss
1Institut National de la Recherche Scientifique (INRS), Varennes (Montréal) QC J3X 1S2, Canada. ahn@emt.inrs.ca
Optics Letters
|December 25, 2007
Summary
We developed a new method using optical frequency-domain reflectometry (OFDR) to measure modal delay in higher-order mode fibers (HOFs). This technique achieves high temporal resolution, enabling precise mode differentiation in short fiber lengths.
Area of Science:
- Optical Engineering
- Fiber Optics Communications
- Metrology
Background:
- Higher-order mode fibers (HOFs) offer potential for increased bandwidth but require precise characterization.
- Accurate measurement of modal delay is crucial for understanding and utilizing HOFs.
- Existing modal delay measurement techniques can be complex or lack sufficient temporal resolution.
Purpose of the Study:
- To propose and demonstrate a novel, simple, and passive modal delay measurement technique for HOFs.
- To achieve high temporal resolution for distinguishing multiple modes within HOFs.
- To validate the proposed method against established measurement techniques.
Main Methods:
- Utilized optical frequency-domain reflectometry (OFDR).
- Implemented a passive, ultrafast wavelength sweeping mechanism based on dispersion-induced optical pulse stretching.
- Measured modal delays in a 5-meter HOF sample.
Main Results:
- Achieved a high temporal resolution of approximately 1.12 ps.
- Successfully discerned four excited modes in the HOF.
- Demonstrated excellent agreement between the proposed method and traditional time-domain/conventional OFDR measurements.
Conclusions:
- The proposed OFDR-based technique provides an effective and simple solution for modal delay measurement in HOFs.
- The high temporal resolution is sufficient for differentiating multiple modes.
- The technique is adaptable for modal delay measurements in longer HOFs.
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