An optical filter assembly comprises a plurality of optical filters and a filter frame holding the plurality of optical filters in a predefined pattern. A method for manufacturing such an optical filter assembly comprises providing diced optical filters, each optical filter having a specific spectral sensitivity. A mold is provided having an open top mold cavity and one or more filling ports which are in fluid communication with the mold cavity. The optical filters are picked and placed in the predetermined pattern in the mold cavity with a gap having a predetermined gap width between the optical filters. A channel grid is formed by the gaps between the optical filters. The channel grid is filled by feeding a liquid resin having a light blocking property to the one or more filling ports, wherein said resin and said gap width are adapted to distribute the resin in the channel grid by a capillary effect. The resin is allowed to cure so as to form the filter frame.

A wavelength division device includes a substrate having one or more grooves, a plurality of filter bars disposed in the one or more grooves of the substrate, and a prism disposed on the substrate. Each of the filter bars corresponds to an optical filtering wavelength. The prism is used for to covering the plurality of filter bars. A surface of the substrate is etched to form the one or more grooves. After the plurality of filter bars are coated, the plurality of filter bars are bonded in the one or more grooves of the substrate. A resin disposed on the substrate is imprinted by a working mold to form the prism.

The present disclosure relates to a method of printing a thermoplastic film on an optical mold comprising adjusting a temperature of the optical mold to a first temperature, printing a first layer of the thermoplastic film on the optical mold once the temperature of the optical mold has reached the first temperature, applying a vacuum to the optical mold to hold the thermoplastic film on the optical mold, adjusting the temperature of the optical mold to a second temperature, printing a second layer of the thermoplastic film on the first layer of the thermoplastic film once the temperature of the optical mold has reached the second temperature, adjusting the temperature of the optical mold to a third temperature, annealing the first layer and the second layer once the temperature of the optical mold has reached the third temperature, and removing the vacuum from the optical mold permitting removal of the thermoplastic film including the annealed first layer and the annealed second layer from the optical mold.