In fiber optic systems major light losses can occur at three optical junctions.
1. From source to fiber
2. From fiber to fiber
3. From fiber to photodetector
Whether these junctions are permanent splices or demountable connectors, considerable ingenuity has been used in the design of joining devices to keep the losses at a minimum.
Junction losses are most often the result of combinations of both intrinsic and extrinsic loss mechanisms, defined as follows:
1. Intrinsic. Tolerance mismatches intrinsic to the fiber such as core size mismatch, NA mismatch, core concentricity offset, and graded-index profile differences
2. Extrinsic. Loss mechanisms external to the fiber and associated with fiber end preparation ...