摘要:
An Echelle grating has alternate first (1a) and second (1b) sets of facets (1). The first set of facets (1a) is operative to reflect incident light (4) for diffraction and the second set of facets (1b) extends between adjacent facets of the first set (1a). Only the first set of facets (1a) is metallized to enhance reflection. The second set of facets (1b) is left unmetallized. This configuration reduces polarization dependent loss (PDL).
摘要:
Diffraction gratings are formed from grooves each having a reflective facet and a non-reflective facet. The net reflection of TE (Transverse Electric) and TM (Transverse Magnetic) polarizations from the grating structure is traded off against the polarization dependent reflection, by controlling the degree of metallization of the reflective facet and by ensuring that there is no metallization of non-reflective sidewalls. other diffraction gratings are manufactured from trenches etched perpendicular to a waveguide. The trenches are metallized and back-filled with a filling material having a refractive index matched to that of the waveguide. The gratings essentially have no non-reflecting sidewalls with insignificant polarization influence from side walls.
摘要:
Diffraction gratings are formed from grooves each having a reflective facet and a non-reflective facet. The net reflection of TE (Transverse Electric) and TM (Transverse Magnetic) polarizations from the grating structure is traded off against the polarization dependent reflection, by controlling the degree of metallization of the reflective facet and by ensuring that there is no metallization of non-reflective sidewalls. other diffraction gratings are manufactured from trenches etched perpendicular to a waveguide. The trenches are metallized and back-filled with a filling material having a refractive index matched to that of the waveguide. The gratings essentially have no non-reflecting sidewalls with insignificant polarization influence from side walls.
摘要:
An Echelle grating has alternate first (1a) and second (1b) sets of facets (1). The first set of facets (1a) is operative to reflect incident light (4) for diffraction and the second set of facets (1b) extends between adjacent facets of the first set (1a). Only the first set of facets (1a) is metallized to enhance reflection. The second set of facets (1b) is left unmetallized. This configuration reduces polarization dependent loss (PDL).