DESIGN AND PERFORMANCE OF A MULTIPLE ELEMENT SLAB WAVE-GUIDE SPECTROGRAPH FOR MULTIMODE FIBEROPTIC WDM SYSTEMS

A new type of compact (< 7 cm(2)) multiple element slab waveguide spectrograph suitable for medium resolution fiber optic wavelength division multiplexing (WDM) applications in the 700 nm to 900 nm optical band is described. The spectrograph consists of a replicated diffraction grating formed on the convex edge of a multilayer glass-ceramic slab waveguide stack The grating design, based on an aberration corrected derivative of the classic Rowland spectrometer, was first verified holographically, and then implemented by replication from a ruled master grating. A combination of thick-film solder glass glazing, lamination, optical finishing and grating replication was chosen to produce a multiple element spectrograph that enables accurate spectral referencing, and can be interfaced by a passive optical fiber array and detector array alignment procedures.