Pigtail style collimator for 850nm with an f=18mm aspheric lens in an 8mm OD housing with 40dB return loss, with a 1 meter long, 0.9mm OD hytrel jacketed, 5/125µm singlemode fiber terminated with an angle polished FC/APC connector. The collimated beam diameter will be about 3.4mm at the 1/e^2 level.
