Disclosed is an improved optical fiber that employs a novel coating system. When combined with a bend-insensitive glass fiber, the novel coating system according to the present invention yields an optical fiber having exceptionally low losses.The coating system features (i) a softer primary coating with excellent low-temperature characteristics to protect against microbending in any environment and in the toughest physical situations and, optionally, (ii) a colored secondary coating possessing enhanced color strength and vividness.The improved coating system provides optical fibers that are useful in relatively thin-walled, low-modulus buffer tubes (i.e., “flextubes”) that can be readily accessed without special tools.