Direct writing of a 1-to-4 optical splitter and packaging technology using a femtosecond laser

Abstract

A 1-to-N optical splitter was fabricated using a focused 785-nm femtosecond laser to directly write a series of 1-to-2 Y-junction splitters in fused silica. The femtosecond laser direct writing technique has the potential to generate not only channel waveguide, but also three-dimensional optical devices. In this paper, a 1-to-4 optical splitter and U-grooves, which are used for fiber alignment, are simultaneously fabricated in fused silica glass by using near-IR femtosecond laser pulses. The obtained splitter was characterized in terms of its optical properties at a wavelength of 1550 nm. The fiber-aligned optical splitter has a low insertion loss, less than 9 dB, including an intrinsic splitting loss of 6 dB and an excess loss due to passive alignment of a single-mode fiber.