Method for characterizing mode group properties of multimodal light traveling through optical components

A method for characterizing mode group properties of multimodal light traveling through an optical component, wherein said method comprises the steps of:

• launching a reference pulse of light with a wavelength λt from a light source into said optical component,
• collecting light signal output by said optical component into a Mode Group Separating optical fiber;
• detecting light signal output by said Mode Group Separating optical fiber;
• and wherein said Mode Group Separating optical fiber is a multimode fiber with an α-profile graded index core with an α-value chosen such that said Mode Group Separating optical fiber satisfies the following criterion at the wavelength λt:
• 
• Δτ
• 
• .
• L
• Δ
• ⁢
• ⁢
• T
• REF
• >
• 4
• where:
• Δτ is a time delay difference between consecutive mode groups expressed in ps/m;
• L is a length of said Mode Group Separating optical fiber expressed in m;
• ΔTREF is a Full Width at Quarter Maximum of said reference pulse expressed in ps, where the Full Width at Quarter Maximum of a reference pulse is the difference between the two time values at which the power of the reference pulse is equal to quarter of its maximum value.