Fiber PBL as a function of wavelength as determined for each of 8 stress points. The graph shows a fiber PBL of above 1.76 at 1064 nm wavelength. A series of such measurements gave values 1.748, 1.726, 1.763, 1.739, 1.811, 1.824, 1.800, 1.741, 1.826, 1.769, and 1.752 cm.
