Whats the fiber used with the pigtailed lasers?
We use a single mode PM (polarization maintaining) Panda fiber with a cladding diameter of 125 µm and a 3mm jacket. Both ends are terminated with FC/APC connectors with a wide key that is pre-aligned and locked to the slow axis. The coupling loss from the laser to the fiber pigtail is 3 dB. In other words, the typical coupling efficiency into the fiber pigtail is 50%. The PM fiber is aligned with the polarized axis to within two degrees of the output polarization of the laser. This results in an 18 to 20-dB polarization ratio (approximately 100:1).
