Pigtail style collimator for 633nm with an f=6mm achromat lens in a 4mm OD housing with 40dB return loss, with a 1 meter long, 0.9mm OD hytrel jacketed, 4/125µm singlemode fiber terminated with a Super PC polished FC/PC connector. The collimated beam diameter will be about 1.2mm at the 1/e^2 level.
