title: Broad-spectral-range synchronized flat-top arrayed-waveguide grating applied in a 225-channel cascaded spectrometer.
abstract: We present a new synchronized design for flattening the passband of an arrayed-waveguide grating (AWG) over a broad wavelength range of 90 nm. A wavelength-insensitive 3-dB balanced coupler is designed to be used in duplicate in a Mach-Zehnder interferometer (MZI); the phase deviation created by one of the balanced couplers is cancelled by flipping the other coupler around. This MZI is arranged in tandem with the AWG such that the output signal of the MZI is the input signal of the AWG. We demonstrate a 5-channel, 18-nm-spacing AWG with a 0.5-dB bandwidth of 12 nm over a 90-nm spectral range. A low-loss cascaded AWG system is demonstrated by using the MZI-synchronized flat-top AWG as a primary filter.
authors.affiliation: Integrated Optical MicroSystems Group, MESA + Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands. B.I.Akca@utwente.nl
authors.forename: B I
authors.initials: BI
authors.lastname: Akca
authors.forename: C R
authors.initials: CR
authors.lastname: Doerr
authors.forename: G
authors.initials: G
authors.lastname: Sengo
authors.forename: K
authors.initials: K
authors.lastname: Wörhoff
authors.forename: M
authors.initials: M
authors.lastname: Pollnau
authors.forename: R M
authors.initials: RM
authors.lastname: de Ridder