Wavelength division multiplexing/demultiplexing devices having concave diffraction gratings

The present invention relates generally to wavelength division multiplexing and demultiplexing and, more particularly, to improved wavelength division multiplexing/demultiplexing devices having concave diffraction gratings. A variety of wavelength division multiplexing/demultiplexing devices are disclosed. In one embodiment, an improved wavelength division multiplexing for receiving a plurality of diverging monochromatic optical beams, for combining the plurality of diverging monochromatic optical beams into a converging multiplexed, polychromatic optical beam, and for transmitting the converging, multiplexed, polychromatic optical beam. The concave diffraction grating can be formed in a variety of ways such as, for example, in a polymer material with a reflective surface. Alternatively, the concave diffraction grating may be etched into a rigid material with a reflective surface.