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IEVref: | 731-03-76 | ID: | |

Language: | en | Status: Standard | |

Term: | material dispersion parameter | ||

Synonym1: | |||

Synonym2: | |||

Synonym3: | |||

Symbol: | М
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Definition: | the quantity which characterizes the material dispersion defined as: $M\left(\lambda \right)=-\frac{1}{{c}_{0}}\frac{\text{d}N}{\text{d}\lambda}=\frac{\lambda {\text{d}}^{2}n}{{c}_{0}\text{d}{\lambda}^{2}}$ where
NOTE 1 – For many optical fibre materials, NOTE 2 – Pulse broadening caused by material dispersion in a unit length of optical fibre is give by | ||

Publication date: | 1991-10 | ||

Source: | |||

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Internal notes: | 2016-02-08: Editorial correction: <i>c</i> corrected to <i>c</i><sub>0</sub> in accordance with correspondence with VT 60050 convenor 2016-12-06. JGO 2016-03-07: Editorial changes: "velocity of light in vacuum" replaced by "speed of light in vacuum". See correspondence "Questions re part 731" 2015-02 and 2015-03. JGO 2017-06-02: Cleanup - Remove Attached Image 731-03-76.gif | ||

CO remarks: | |||

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VT remarks: | |||

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Domain5: |

$M\left(\lambda \right)=-\frac{1}{{c}_{0}}\frac{\text{d}N}{\text{d}\lambda}=\frac{\lambda {\text{d}}^{2}n}{{c}_{0}\text{d}{\lambda}^{2}}$

where

*n* is the refractive index,

*N* is the group index,

*λ* is the wavelength in vacuum, and

*c*_{0} is the speed of light in vacuum
*λ*_{0}, usually around 1300 nm. The sign convention is such that *M* is positive for wavelengths shorter than *λ*_{0} and negative for wavelengths longer than *λ*_{0}.
*λ*), except at or near *λ* = *λ*_{0}, where terms proportional to (Δ*λ*)^{2} are important.