a method for detecting defects in an optical device . the method includes obtaining an optical device that is a component of an optical communications system carrying information signals at a communications wavelength . infrared light is applied to the optical device . the infrared light has a wavelength corresponding to the communications wavelength . an image of the optical device is obtained while the optical device is transmitting the infrared light . the image provides multidimensional data including positional values and intensity values . the image is then analyzed to detect defects in the optical device .