Modal noise, which can cause severe distortion in signals transmitted by fiber optics, is an interference effect that is made more severe by the narrow spectral width of single-mode lasers. The linearity of these devices may be totally obscured after the optical signal has passed through the connectors and fiber lengths of a practical signal system. Dithering the laser's operating point by means of a high-frequency current (>2 GHz) has been found greatly to reduce modal noise.