光纤 第1-41部分：测量方法和测试程序 带宽

[中文适用范围]： 本部分IEC 60793描述了确定和测量多模光纤模态带宽的三种方法（参见IEC 60793-2-10、IEC 60793-2-30和IEC 60793-2-40系列）。基带频率响应通过确定光纤对正弦调制光源的响应在频域中直接测量。基带响应也可以通过观察窄光脉冲的展宽来测量。计算响应使用差分模式延迟（DMD）数据确定。三种方法为： • 方法A – 时域（脉冲失真）测量 • 方法B – 频域测量 • 方法C – 从差分模式延迟计算的过填充发射模态带宽（OMBc） 方法A和方法B可以使用两种发射条件之一进行：过填充发射（OFL）条件或限制模式发射（RML）条件。方法C仅针对A1-OM3至A1-OM5多模光纤定义，并使用DMD发射响应的加权求和，权重对应于过填充发射条件。根据光纤类型选择相关的测试方法和发射条件。 [外文原描述]： IEC 60793-1-41:2024 describes three methods for determining and measuring the modal bandwidth of multimode optical fibres (see IEC 60793-2-10, IEC 60793-2-30, and the IEC 60793‑2‑40 series). The baseband frequency response is directly measured in the frequency domain by determining the fibre response to a sinusoidaly modulated light source. The baseband response can also be measured by observing the broadening of a narrow pulse of light. The calculated response is determined using differential mode delay (DMD) data. The three methods are: Method A – Time domain (pulse distortion) measurement Method B – Frequency-domain measurement Method C – Overfilled launch modal bandwidth calculated from differential mode delay (OMBc) Method A and method B can be performed using one of two launches: an overfilled launch (OFL) condition or a restricted mode launch (RML) condition. Method C is only defined for A1-OM3 to A1-OM5 multimode fibres and uses a weighted summation of DMD launch responses with the weights corresponding to an overfilled launch condition. The relevant test method and launch condition is chosen according to the type of fibre. NOTE 1 These test methods are commonly used in production and research facilities and are not easily accomplished in the field. NOTE 2 OFL has been used for the modal bandwidth value for LED-based applications for many years. However, no single launch condition is representative of the laser (e.g. VCSEL) sources that are used for gigabit and higher rate transmission. This fact drove the development of IEC 60793-1-49 for determining the effective modal bandwidth of laser optimized 50 µm fibres. See IEC 60793-2-10 and IEC 61280-4-1 for more information. This fourth edition cancels and replaces the third edition published in 2010. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) the addition of a direct reference for method A and method B.