An optical fiber cable has a highly reduced diameter. The cable has a
central strength member; a number of tubes containing loosely arranged
optical fibers, each tube having a thickness, and each optical fiber
having a coating; and a protective outer jacket, wherein the filling
coefficient of optical fibers in at least one loose tube is
.gtoreq.45.degree./0. The tubes are made of a material having an
elasticity modulus .gtoreq.700 MPa; and the optical fibers are SM-R
fibers having a microbending sensitivity .ltoreq.4.0
dBkm.sup.-1/gmm.sup.-1 at a temperature of about -30.degree. C. to
+60.degree. C. at about 1550 nm.