WAVE-GUIDE HOLOGRAPHIC ELEMENTS RECORDED BY GUIDED MODES

Recording holographic optical elements in planar waveguides with both interfering beams being guided modes has certain advantages. We show t hat such holograms can be efficiently recorded when only a small fract ion of the guided modes penetrates the recording material that is depo sited outside the main guiding region. An integrated optic wavelength- division demultiplexer is analyzed and implemented as a specific examp le. In this example the holographic grating also acts as a focusing el ement; thus no additional collimating or focusing lenses are required.