title: Ultracompact silicon-on-insulator-based reflective arrayed waveguide gratings for spectroscopic applications.
abstract: Ultracompact reflective arrayed waveguide gratings (RAWGs) employing a half horseshoe-shaped waveguide layout and distributed Bragg reflector mirrors in the array region are designed and fabricated. Two sets of RAWGs with 400 and 200 GHz channel spacing are experimentally demonstrated for TE and TM polarizations, respectively. Because of the high-index contrast between the silicon core and the oxide cladding, these RAWGs have very compact sizes. With the off-centered light input, we obtained the minimal on-chip losses of 7 and 9 dB and cross talks of <-8 and <-5  dB for 9×400  GHz and 20×200  GHz RAWGs, respectively, for TE polarization. The measured minimal on-chip losses are 10 and 12.5 dB, and cross talks are <-11 and <-7  dB for 8×400  GHz and 10×200  GHz RAWGs, respectively, for TM polarization. These RAWGs can find applications for on-chip spectroscopic sensing.
authors.forename: Jun
authors.initials: J
authors.lastname: Zou
authors.forename: Tingting
authors.initials: T
authors.lastname: Lang
authors.forename: Zichun
authors.initials: Z
authors.lastname: Le
authors.forename: Jian-Jun
authors.initials: JJ
authors.lastname: He