Publication Date:
2018-03-13
Description:
We report on the design, fabrication, and characterization of a $text{1550 nm}$ / $text{1950 nm}$ directional coupler based on single-crystal diamond waveguides. The input and output ports of the waveguides are connected with $text{1550 nm}$ and $text{1950 nm}$ grating couplers to allow out-of-plane light coupling. The devices are fabricated using electron-beam lithography and reactive ion etching technologies. We obtain a good performance for both the grating couplers (efficiency of $-text{10.9 dB}$ at $text{1550 nm}$ and $-text{11.6 dB}$ at $text{1950 nm}$ ) and waveguides (attenuation of $text{2.3 dB/mm}$ at $text{1550 nm}$ and $text{4.5 dB/mm}$ at $text{1950 nm}$ ). Furthermore, the actual directional coupler component is found to be quasi-lossless. By means of directional coupler calibration devices, we measure high extinction ratios between the “cross” and “through” ports ( $text{22 dB}$ at $text{1565 nm}$ and $text{21 dB}$ at $text{1949 nm}$ ), hence showing a high-efficiency wave-combining functionality. Taking into account that integrated directional couplers are essential for allowing light routing between different on-chip devices, our results pave the way for larger-scale and more complex photonic integrated circuits in single-crystal diamond thin films.
Print ISSN:
1077-260X
Electronic ISSN:
1558-4542
Topics:
Electrical Engineering, Measurement and Control Technology
