A method of manufacturing a fiber optic cable includes steps of extruding a first jacketing material around strength members, over armor, and to form a cavity between the strength members and beneath the armor. A GPS section receives radio waves from GPS satellites and inputs GPS information to a read-out section. Data measured by the apparatus is stored in a computer, and the computer may be used to analyze the data and to control the reaction parameters based on the analysis of the data. The laser radiation is partially absorbed on the interface such that due to induced material removal or induced material displacement the interface and thus also the laser radiation penetrate into the material.