controls and monitors the heating source 72 through a first control link 92 the process control unit 86 controls the first stepper motor 78 through a second control link 94 the process control unit 86 controls the second stepper motor 79 through a third control link 95 the process control unit 86 controls the light source 88 through a fourth control link 96 the process control unit 86 controls and monitors the optical spectrum analyzer 90 through a fifth control link 98 a second and preferred method of manufacture uses the second apparatus 84 the initial length of optical fiber 82 is held between the first clamp 74 and the second clamp 76 the process control unit 86 signals and monitors the heating source 72 the heating source 72 heats the optical fiber to within the allowed temperature range the process control unit 86 turns on the light source 88 the light source 88 couples light to the optical fiber 82 preferably the light source 88 is a white light source the optical fiber 82 transmits the light to the end of the optical fiber 82 opposite the light source 88 the light exits the optical fiber 82 the process control unit turns on the optical spectrum analyzer 90 the optical spectrum analyzer 90 detects the light that exits from the optical fiber 82 the process control unit 86 signals the first and second stepper motors 78 and 79 the first and second stepper motors 78 and 79 further separate the first and second clamps 74 and 76 this further separation stretches the optical fiber 82 as.