Variable optical attenuator

A variable optical attenuator for attenuating optical signals input from an input fiber and output to an output fiber, comprising:

• a housing;
• a variable optical filter having a filter density gradient varying between a low density region and a high density region along a filter axis, parallel to a movement path of the filter, the movement path of the filter being perpendicular to the axis of the input fiber and the output fiber;
• and
• a reciprocating means defining a carrier to which the variable optical filter is mounted, the reciprocating means providing a movement of the variable optical filter along the movement path of the filter;
• and
• a stopper mechanism, being not integrally formed with the carrier, preventing the reciprocating means from moving the filter beyond a predetermined extreme point;
• wherein
• when the variable optical filter is actuated to move along the movement path of the filter, an intersection point of the optical signal with the variable optical filter moves between the low density region and the high density region along the filter axis.

A variable optical attenuator for attenuating optical signals input from an input fiber and output to an output fiber, comprising:

• a housing;
• a variable optical filter having a filter density gradient varying between a low density region and a high density region along a filter axis, parallel to a movement path of the filter, the variable optical filter being moveably positioned in the path defined between the input fiber and the output fiber;
• and
• a reciprocating means defining a carrier to which the variable optical filter is mounted, the reciprocating means providing a movement of the variable optical filter along the movement path of the filter, the reciprocating means having a stopper mechanism, being not integrally formed with the carrier but with portions located at two opposite ends of said carrier along a direction of the movement path of the filter, to prevent the reciprocating means from moving the filter beyond a predetermined extreme point;
• wherein
• when the reciprocating means actuates the variable optical filter to move along the movement path of the filter, an intersection point of the optical signal with the variable optical filter moves between the low density region and the high density region along the filter axis.