title: Proposal and analysis of digital concatenated gratings.
abstract: A digital concatenated grating composed of five subgratings is proposed. Essential formulas on Bragg periods of subgratings and an analytical expression for the reflection-spectrum envelope are presented, which show how to use reflection-spectrum envelopes to construct a digital concatenated grating with uniform reflection peaks. For a perfect design, the spectral center separation of adjacent Bragg gratings will be chosen as the integral times of the reflectivity peaks' spacing. Gaussian apodization on the whole profile grating not only eliminates the sidelobes of each reflection peak but also provides a better flat reflection-spectrum envelope than that of the digital concatenated Gaussian-apodized grating.
authors.affiliation: Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China. hxyhust@yahoo.com.cn
authors.forename: Xiaoying
authors.initials: X
authors.lastname: He
authors.forename: Dexiu
authors.initials: D
authors.lastname: Huang
authors.forename: Yonglin
authors.initials: Y
authors.lastname: Yu
authors.forename: D N
authors.initials: DN
authors.lastname: Wang