Loop Back Device and Method of Fabrication

A loop back device comprising:

• a ferrule defining fiber openings;
• and
• a plurality of fibers defining fiber loops, the fibers having ends mounted in the fiber openings of the ferrule;
• wherein at least some of the fiber loops have different bend radiuses, the bend radiuses being formed to tune the loop back device so that each of the fiber loops has an actual insertion loss value within a selected tolerance of a desired insertion loss value.

A method for fabricating a loop back device having a plurality of fibers defining fiber loops each fiber loop having a substantially consistent insertion loss among all the fiber loops in the loop back device, the method comprising:

• determining an actual loss value associated with each of the fiber loops;
• comparing the actual loss value of each fiber loop with a desired loss value;
• when the actual loss value of any of the fiber loops is greater than the desired loss value, increasing a radius of a bend in that any of the fiber loops having the greater actual loss value until the actual loss value associated with that any of the fiber loops is within a tolerance of the desired loss value;
• when the actual loss value of the any of the fiber loops is less than the desired loss value, decreasing the radius of the bend in that any of the fiber loops having the lesser actual loss value until the actual loss value associated with that any of the fiber loops is within a tolerance of the desired loss value;
• and
• when the actual loss value of the any of the fiber loops is within the tolerance of the desired loss value, fixing the shape of the fiber loops to prevent a change in the radius of the bend.

A method for fabricating a loop back device having a plurality of fibers defining fiber loops each fiber loop having a substantially consistent insertion loss among all the fiber loops in the loop back device, the method comprising:

• mounting the plurality of fibers to a multi-termination (MT) ferrule;
• determining an actual insertion loss value associated with each of the fiber loops;
• comparing the actual insertion loss value of each fiber loop with a desired insertion loss value;
• and
• tuning to adjust an overall insertion loss of the loop back device by changing a radius of a bend in any of the fiber loops having an actual insertion loss value greater than or less than the desired insertion loss value to tune the overall insertion loss to the desired insertion loss value.