Silicon-on-insulator eight-channel optical multiplexer based on a cascade of asymmetric Mach-Zehnder interferometers

Abstract

A monolithically integrated eight-channel optical multiplexer (Mux) with a 400 GHz channel spacing ~1550 nm is presented based on a silicon-on-insulator rib waveguide and an asymmetric Mach-Zehnder interferometer. All channels were optimized independently with integrated heaters. The fully tuned Mux shows an adjacent channel isolation of ~13 dB, an excess loss of ~2.6 dB, and a channel uniformity of ~1.5 dB over a 25 nm wavelength span. In addition, the phase tuning efficiency for different interlevel dielectric layer thicknesses and thermal crosstalk were investigated.

1 × 4 Channel Si-Nanowire Microring-Assisted Multiple Delayline-Based Optical MUX/DeMUX

“…It is interesting that the filter response shown in Fig. 2(a) is exactly the same as the spectra for another conventional device scheme where multiple DMZIs having different optical path differences are cascade connected [4].…”

“…1)). While in the previous works [4]- [8], each delayed interferometer consisting of the two delaylines is separately located, all the delaylines of proposed scheme are spatially unified in one region. Thus, the size of the proposed device can be more compact than any other DMZI-based optical DeMUX.…”

“…4, the Conv-1 scheme based on Ref. [4] consists of three DMZIs with 3-dB optical couplers, while the Conv-2 scheme based on Refs. [6] and [7] is composed of 21 DMZIs with different optical coupling ratios and proper PSs.…”

“…The flatband spectral response of the demultiplexer (DeMUX) for WDM optical links is one of the prerequisite requirements because the wavelength-control accuracy of the optical signals and temperature tolerance of several optical components can be markedly relaxed. There have been many reports on Si-nanowire optical DeMUXs that are based on microring resonators (MRR) [3], delayed Mach-Zehnder interferometers (DMZI) [4]- [8], and arrayed waveguide grating [9], [10]. Among them, the DMZI-based DeMUX is very attractive, because its filter response can be flattened with low excess loss (EL).…”

Fourier Based Combined Techniques to Design Novel Sub-Wavelength Optical Integrated Devices

“…An MMI is a well known structure widely used in photonic circuits, such us Mach-Zehnder interferometers [28] or 90 • hybrid for coherent optical receivers [29]. As shown in [29], MMI performance can be highly improved optimizing the index contrast.…”