Abstract:
One key challenge encountered by photonic integrated circuit is to couple light to and from optical fibers efficiently. The standard fiber used for telecommunication or data communication is single-mode fiber (SMF), which has a mode field diameter (MFD) of less than equal to 10µm at 1550 nm. Efficient coupling from SMF to waveguide with size of hundreds of nanometers is a challenge due to the large mode field mismatch. This problem is usually addressed using two solutions, in-plane or butt edge coupling and out plane (vertical) grating coupling. To ensure good coupling efficiency along with practical feasibility, the grating on freestanding HEMT inspired GaN optical waveguide is a suitable choice for desired wavelength profile with high sensitivity. In this paper, the vertical gratings are introduced on freestanding HEMT inspired GaN optical waveguide for high pressure sensor applications.