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Martina
Gerken and David A. B. Miller, "Photonic nanostructures for wavelength
division multiplexing," SPIE IT Com (Information Technology and
Communication) 25-28 October 2004, Philadelphia, Pennsylvania, USA.
Proc. SPIE Vol. 5597, p. 82-96, Nanophotonics for Communication:
Materials and Devices; Michal F. Lipson, George Barbastathis, Achyut K.
Dutta, Kiyoshi Asakawa; Eds., Oct. 2004
The high angular dispersion
achieved with the photonic crystal superprism effect as well as
dispersive non-periodic photonic nanostructures promise compact
wavelength division multiplexing (WDM) devices. An important criterion
for the usefulness of such WDM devices is the number of channels that a
structure can multiplex or demultiplex. Here two different models are
developed for calculating the possible number of channels for a given
structure. The first model is based on the assumption that different
wavelength channels should propagate in mutually exclusive propagation
cones within the volume of the dispersive structure. We call these
non-overlapping channels "volume modes." The second model assumes that
it is sufficient to spatially separate the different wavelength channels
on a single output surface, e.g., the plane of the detectors or output
waveguides. Since they are only separated along one surface and not in
the entire volume, we name these modes "surface modes." As an example it
is shown that a dispersive 200-layer non-periodic thin film stack can be
used to multiplex or demultiplex approximately eight WDM channels. The
achievable number of channels is not defined by the dispersion alone but
by the product of dispersion and wavelength range over which this
dispersion is achieved.
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