Method for Characterizing Mode Group Properties of Multimodal Light Traveling Through Optical Components

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

• a light source emitting reference pulses of light with a wavelength λt;
• a Mode Group Separating optical fiber in an optical path between said light source and said optical component;
• a launch fiber launching said reference pulses of light to an input side of said Mode Group Separating optical fiber;
• means for changing said launch fiber's position in discrete steps, between a position in which said launch fiber is aligned with a core center of said Mode Group Separating optical fiber and a position in which said launch fiber is aligned with a core radius of said Mode Group Separating optical fiber;
• a detector for detecting light signal output by said optical component;
• 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 pulses 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.

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

• a light source emitting a reference pulse of light with a wavelength λt;
• launching means for launching said reference pulse of light into said optical component;
• a Mode Group Separating optical fiber collecting light signal output by said optical component;
• a detector for 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.