Singher L, Shamir J
Appl Opt. 1994 Mar 1;33(7):1180-6. doi: 10.1364/AO.33.001180.
Recording holographic optical elements in planar waveguides with both interfering beams being guided modes has certain advantages. We show that such holograms can be efficiently recorded when only a small fraction of the guided modes penetrates the recording material that is deposited outside the main guiding region. An integrated optic wavelength-division demultiplexer is analyzed and implemented as a specific example. In this example the holographic grating also acts as a focusing element; thus no additional collimating or focusing lenses are required.