Optical Designs with Curved Detectors for Fiber Bragg Grating Interrogation Monitors.

In this paper, we evaluate the application of curved detectors and freeform optics technologies for fiber Bragg gratings (FBGs) interrogation monitors design. It is shown that, in a high-dispersion spectrograph scheme, the camera part operates in special conditions, which result in a field curvature change. This field curvature can be compensated by the use of a curved detector. When used together with freeform optics, the curved detectors allow for reduction of the number of optical components to two or even one element by merging their functions. Three design examples for the range of 810-860 nm reaching the spectral resolution limit of 89-139 pm at NA=0.14 are presented to demonstrate the achieved performance and the technological trade-offs.