Integration of knee-shaped self-written waveguides between optical fibers by direct illumination and tip to tip coupling

Abstract

Optical transmission efficiency of self-written polymer waveguide has been investigated. The polymer couplers were fabricated from a photopolymerizable monomer system by direct illumination from two pre-aligned single mode fibers, and by butt coupling of two extended long polymer tips at the end of fibers. Regarding direct illumination, the writing beams exhibit quasi-solitonic behavior and both show a tendency to attract each other to be merged at the middle point where the droplet deposited between the aligned fiber. Optical transmission gives insertion loss of 4.3 dB and 5.7 dB with total knee angles of (5° and 10°) respectively. Polymer bridges with larger deviation angles were not formed, since the induced beams were not merged properly to form a decent waveguide. Therefore, long polymer tips were fabricated separately and then they were butt coupled at different knee-angles. Optical transmission efficiency was measured over broadband from Ultraviolet to Infrared (UV-IR). In the butt-coupling approach average loss of 1.7 dB, 5.4 dB, 8.6 dB, 10.4 dB and 14.6 dB at measured wavelength 1550 nm were obtained for 300 μm- 300 μm coupling tips corresponding to knee-angles of (0°,5°,10°,15°, and 20°) respectively.