Low bend loss waveguides enable compact, efficient 3D photonic chips

Optics Express (Impact Factor: 3.53). 02/2013; 21(3):2978-2986. DOI: 10.1364/OE.21.002978
Source: PubMed

ABSTRACT We present a novel method to fabricate low bend loss femtosecond-laser written waveguides that exploits the differential thermal stabilities of laser induced refractive index modifications. The technique consists of a two-step process; the first involves fabricating large multimode waveguides, while the second step consists of a thermal post-annealing process, which erases the outer ring of the refractive index profile, enabling single mode operation in the C-band. By using this procedure we report waveguides with sharp bends (down to 16.6 mm radius) and high (80%) normalized throughputs. This procedure was used to fabricate an efficient 3D, photonic device known as a "pupil-remapper" with negligible bend losses for the first time. The process will also allow for complex chips, based on 10's - 100's of waveguides to be realized in a compact foot print with short fabrication times.


Available from: Alexander Arriola, Mar 22, 2014