The invention provides a lighting device (10) comprising (i) a plurality of elongated filaments (100) and (ii) an optical element (200), wherein: —each elongated filament (100) comprises a support (105) and a plurality of solid state light sources (110), wherein the elongated filament (100) has a first axis of elongation (120) having a first length (L1), wherein the elongated filament (100) is configured to generate filament light (101) over at least part of the first length (L1); and—the optical element (200) comprises a plurality of facets (210), wherein the optical element (200) has a second axis of elongation (220) having a second length (L2), wherein the optical element (200) has a non-circular cross-section perpendicular to the second axis of elongation (220), wherein the optical element (200) is configured between at least two of the plurality of elongated filaments (100), and wherein the optical element (200) is configured to redirect at least part of the filament light (101).