Perfect Chirped Echelle Grating Wavelength Multiplexor: Design and Optimization

A new method for designing an echelle-type diffraction grating for wavelength division multiplexing (WDM), which is tuned to a single stigmatic point, is introduced. The new grating is defined by the mode and wavelength of operation in a slab waveguide, the position of the waveguides, the order of diffraction, and an arbitrary path, which is called the grating line, upon which individual facets are positioned, blazed, and curved via the outlined algorithm. A systematic design process for echelle gratings (EGs) is presented, covering all the key aspects of this device. A series of rules to improve the performance of any EG WDM device is outlined. A simulated comparison between this device, a standard Rowland grating, and a two stigmatic point grating, was undertaken with the new design performing better and comparably in each case, respectively.