Matthias Stegmaier

University of Münster | WWU

Driven by the rise of silicon-photonics, optical signaling is moving inexorably from the domain of long-distance communications to chip-chip and even on-chip application. If we are to have on-chip signals that are optical, an obvious question is to ask is whether we can do more than simply communicate with light. Could we, for example, store and pr...

Fully controllable phase-change materials embedded in integrated photonic circuits are a promising platform for on-chip reconfigurable devices. Successful experimental demonstrations have thus far enabled non-volatile multilevel memories and switches, optical synapses, and on-chip photonic computing. However, the origin and mechanism behind the pha...

Machines that simultaneously process and store multistate data at one and the same location can provide a new class of fast, powerful and efficient general-purpose computers. We demonstrate the central element of an all-optical calculator, a photonic abacus, which provides multistate compute-and-store operation by integrating functional phase-chang...

Phase change materials (PCMs) are highly attractive for nonvolatile electrical and all-optical memory applications because of unique features such as ultrafast and reversible phase transitions, long-term endurance, and high scalability to nanoscale dimensions. Understanding their transient characteristics upon phase transition in both the electrica...

Integrated chip-level photonics has the potential to revolutionize future computer systems by eliminating the “von-Neumann information bottleneck” and the power losses resulting from the use of electrical interconnects. Yet, the need for optical-to-electrical conversion has so far hindered the implementation of chip-level all-optical routing scheme...

We present a new implementation of phase-change chalcogenide materials onto integrated photonic circuits for on-chip non-volatile memories. In particular, we demonstrate readily multi-level transmission modulation and present an analysis on the achievability and number of accessible levels.

Phase-change materials (PCMs) integrated with nanophotonic components enable tunable integrated optical devices and hold promise for emerging applications in long-term photonic data storage by exploiting the large contrast in optical properties when switched between amorphous and crystalline phase states. The phase transitions rely on short heat pu...

Der Bedarf an immer größerer Rechenleistung wächst unablässig, kann aber in jüngerer Vergangenheit nicht mehr durch immer höhere Prozessor-Taktfrequenzen befriedigt werden, da die Signalübertragung zwischen Speicher und Prozessor selbst zum Flaschenhals geworden ist. Daher wird intensiv daran geforscht, Daten mit Licht zu übertragen. Ein wichtiger...

We demonstrate all-optical operation of nonvolatile memory cells made from phase-change materials. The cells are embedded in nanophotonic circuits and can be used at writing speeds approaching the GHz-regime.

Implementing on-chip non-volatile photonic memories has been a long-term, yet elusive goal. Photonic data storage would dramatically improve performance in existing computing architectures by reducing the latencies associated with electrical memories and potentially eliminating optoelectronic conversions. Furthermore, multi-level photonic memories...

We demonstrate methods to identify the modal composition of light guided through integrated multimode waveguides and discuss a scheme how arbitrary higher-order modes can selectively be excited. Exemplary, we show efficient and broadband polarization conversion.

Aluminum nitride (AlN) has recently emerged as a promising material for integrated photonics due to a large bandgap and attractive optical properties. Exploiting the wideband transparency, we demonstrate waveguiding in AlN-on-Insulator circuits from near-infrared to ultraviolet wavelengths using nanophotonic components with dimensions down to 40 nm...

While single-mode waveguides are commonly used in integrated photonic circuits, emerging applications in nonlinear and quantum optics rely fundamentally on interactions between modes of different order. Here we propose several methods to evaluate the modal composition of both externally and device-internally excited guided waves and discuss a techn...

Aluminum nitride (AlN)-on-insulator has emerged as a promising platform for the realization of linear and non-linear integrated photonic circuits. In order to efficiently route optical signals on-chip, precise control over the interaction and polarization of evanescently coupled waveguide modes is required. Here we employ nanophotonic AlN waveguide...