An optical monitoring arrangement utilizes the properties of a blazed Bragg grating
to redirect a portion of an optical signal out of the axial path and into a detecting
device. A plurality of blazed Bragg gratings are utilized, each having unique properties,
to increase the robustness of the monitor. In particular, by utilizing a plurality
of N gratings, the bandwidth of the monitor may be increased N-fold (assuming no
overlap in wavelength between gratings). Alternatively, an improvement in resolution
can be obtained by utilizing a narrower bandwidth and measuring N times the number
of raw data points within that bandwidth. A combination of increase in bandwidth
and resolution may be obtained by a comprise between these two extremes. Chirped
blazed gratings may also be employed.
