
þ15 ps/nm in Figure 9.21(d)–(f), respectively. Then the index fluctuation n that
generates the specified dispersion is calculated. It is known empirically from several
calculations including Figure 9.21 that the dependence of dispersion on index
fluctuation n and channel spacing D is approximately obtained as / n/D
3
.
Because is inversely proportional to D
3
, the dispersion of an AWG with a narrow
channel spacing is highly sensitive to phase errors.
Flat Spectral-Response AWGs
Non-technical overview: When multiplexing WDM channels toge ther or demulti-
plexing them apart, one usually wants the optical passbands of the (de)multiplexer
to have ...