First dual-color optrode with bare laser diode chips directly butt-coupled to hybrid-polymer waveguides

We report on the design, fabrication, assembly as well as optical, electrical and thermal characterization of the first MEMS-based dual-color optrode destined for neuroscientific research. The on-probe integration of bare laser diode (LD) chips emitting at 431 nm and 655 nm and directly butt-coupled to micromachined hybrid-polymer waveguides (WGs) enables highly compact systems for optogenetics. Co-integrated microelectrodes are aligned to the optical stimulation sites in application specific electrode arrangements. Temperature sensing elements embedded below the LD pads and at other selected locations along the probe shafts enable the temperature to be monitored during system operation. A large variety of probes has been realized.