Methods for producing retroreflector tooling and retroreflective sheeting using laser writing techniques, and corresponding products thereof, are presented. In one embodiment, a seamless retroreflective sheet having a plurality of retroreflectors formed in a continuous retroreflective microstructured pattern is provided. In the methods described herein, a substrate having a photosensitive coating on a surface thereof is provided. A surface-relief microstructured pattern is produced in the photosensitive coating by selectively exposing the photosensitive coating to a beam of electromagnetic radiation. The exposed portions of the photosensitive coating are developed to form a retroreflective microstructured pattern on the surface of the substrate. The retroreflective microstructured pattern is then transferred into retroreflector tooling comprising the retroreflective microstructured pattern on a surface thereof. A retroreflective sheet containing the retroreflective microstructured pattern on a surface thereof is then formed from the retroreflector tooling.

There is a method for producing an optical waveguide composing an optical path conversion component having an extremely low signal loss, allowing a high surface packaging density and high speed operation, and allowing high productivity. A method for producing an optical waveguide that propagates light from a surface of a support to an oblique direction not vertical to the surface, the method for producing an optical waveguide comprising the steps of: (1) providing an anti-reflective coating on the support; (2) placing a photosensitive resin composition on the anti-reflective coating, and exposing the photosensitive resin composition to a light ray entering from a direction non-vertical to the surface of the support through a photomask for curing the composition; and (3) removing the unexposed photosensitive resin composition by development; and an optical waveguide obtained by the method.

Provided is an optical waveguide photosensitive resin composition containing a photocurable resin and a photopolymerization initiator, in which the photopolymerization initiator is a specific photoacid generator represented by the general formula (1). Accordingly, when a core layer is formed by using the optical waveguide photosensitive resin composition as a material for forming an optical waveguide, especially a core layer-forming material, excellent high transparency (low loss effect) is obtained. In the formula (1), R₁ and R₂ each represent hydrogen or an alkyl group having 1 to 15 carbon atoms, and may be identical to or different from each other.

The disclosed embodiments provide systems and methods for mitigating lensing and scattering as an optical fiber is being inscribed with a grating. The disclosed systems and methods mitigate the lensing phenomenon by surrounding an optical fiber with an index-matching material that is held in a vessel with a sealed phase mask. The sealed phase mask allows it to be in contact with a liquid index-matching material without having the liquid index-matching material seep into the grooves of the sealed phase mask. Thus, for some embodiments, the sealed phase mask may be immersed in a liquid index-matching material without adversely affecting the function of the phase mask.

Provided is a silphenylene-containing photocurable composition including: (A) a specific silphenylene having both terminals modified with alicyclic epoxy groups, and (C) a photoacid generator that generates acid upon irradiation with light having a wavelength of 240 to 500 nm. Also provided is a pattern formation method including: (i) forming a film of the photocurable composition on a substrate, (ii) exposing the film through a photomask with light having a wavelength of 240 to 500 nm, and if necessary, performing heating following the exposure, and (iii) developing the film in a developing liquid, and if necessary, performing post-curing at a temperature within a range from 120 to 300°C following the developing. Further provided is an optical semiconductor element obtained by performing pattern formation using the method. The composition is capable of very fine pattern formation across a broad range of wavelengths, and following pattern formation, yields a film that exhibits a high degree of transparency and superior light resistance. The composition may also include: (B) a specific epoxy group-containing organosilicon compound.