| 摘要 |
<p>An arrangement (10) for forming an extended length light redirecting embedded grating (20) in an elongated solid material optical waveguide (21) includes a source (14) that directs a coherent light beam of a frequency in the ultraviolet range in a primary path (13) transversely toward the waveguide (21). A section of a diffraction grating (34) extends through the primary path (13) at a spacing from the waveguide (21), and the diffraction grating (37) has a dimension normal to the primary path (13) that exceeds the corresponding dimension of the primary path (13). Relative movement is effectuated between the waveguide (21) and diffraction grating (37) in unison, and the primary path (18), so that the light beam is diffracted at the diffraction grating (37) into two mutually frequency shifted partial light beams propagating in diverging secondary paths (15, 16). The partial light beams are caused to travel toward a shared location of the waveguide (21) where they form an interference pattern (50) that moves longitudinally of the waveguide (21) but respective high intensity fringes (51) of which extend through the waveguide (21) at respective positions that are stationary relative to the waveguide (21) to effect refractive index changes at such positions along an extended length of the waveguide (21).</p> |
