A low insertion loss waveguide is fabricated in z-cut lithium niobate using femtosecond laser waveguide inscription. To fabricate a waveguide exhibiting both low propagation and coupling losses, we used the multiscan fabrication technique to control the size of the waveguide cross section. A minimum insertion loss of only 3.5 dB at 1550 nm was measured for the 18-mm-long waveguide when directly coupled to Corning SMF-28 fibers. Of this 3.5 dB, we attribute 2.1 dB to coupling losses, 1.1 dB to propagation losses, and 0.3 dB to Fresnel reflections. © 2007 IEEE.
|Number of pages||3|
|Journal||IEEE Photonics Technology Letters|
|Publication status||Published - 15 Jun 2007|
- Buried optical waveguides
- Femtosecond laser writing
- Lithium niobate (LN)
- Optical device fabrication