Patent ID: 7024118

Claim:
An optical time-division multiplexer that branches input light into a plurality of optical paths having different path lengths, modulates the input light propagating on each optical path by a signal to be transmitted, and combines the modulated light from the optical paths into an output light signal, wherein: the optical time-division multiplexer comprises a substrate; at least one of the optical paths includes a section of optical fiber functioning as an optical path length adjustment section; both ends of the optical fiber comprising said optical path length adjustment section are fastened to the substrate; said optical paths include spatial sections in which the branched input light propagates through a space having a refractive index different from a refractive index of the optical fiber; the optical time-division multiplexer has means for altering the optical length of the optical fiber in the optical path length adjustment section; and said means for altering the optical length of the optical fiber comprises a member mounted on the substrate, rotatable in a plane parallel to the substrate, having a surface that presses against the optical fiber, bending the optical fiber by different amounts depending on the rotational position of the member.