In line lens-filtering-lens devices, i.e. elements arranged along a line and mountable

Official title: {In line lens-filtering-lens devices, i.e. elements arranged along a line and mountable in a cylindrical package for compactness, e.g. 3- port device with GRIN lenses sandwiching a single filter operating at normal incidence in a tubular package}

G02B6/2937 (In line lens-filtering-lens devices, i.e. elements arranged along a line and mountable) appears on 299 US grants and 191 published applications in this corpus.