Physics &
Engineering

Technology
The invention refers to a method for fabricating layer assemblies with locally arranged nanostructures. A buried, selectively modified underlying layer is used to control the growth of nanostructures on the surface by controlling the laterally inhomogeneous strain distribution. This is done using standard lithography, etching and oxidation techniques.

IP Rights
US Patent Application March 2011

Origin
Technische Universität Berlin, Germany

The optoelectronic device comprises at least one active section, at least one absorber, and at least one electrooptic modulator. The active section contains an active element generating optical gain when a forward bias is applied.

The absorbing section contains a saturable absorber, preferably operating under a zero or reverse bias, such that the device operates in a self-pulsating mode-locked regime generating pulsed laser light. The electrooptic modulator changes its refractive index due to electrooptical effect. It can contain a stack of quantum wells, wires, or dots, whereas the refractive index being varied due to Quantum Confined Stark Effect. The change of the refractive index results in a change of the effective group velocity of the light within the device, and thus, in a change of the repetition frequency which is detected by a frequency-density detecting system.

The device can be based on an edge-emitting laser, a vertical cavity surface emitting laser, a tilted cavity laser, a distributed feedback laser, a wavelength-stabilized leaky wave laser with reflection from the back side of the substrate.

 

IP Rights
European patent application EP07000661.4 filed on 13.01.2007; US patent 7,580,595 B1; Japanese patent application 2008-162441 filed on 20.06.2008

Origin
Technische Universität Berlin

 

Here we introduce a new multi-segment all-fiber laser device 

• that emits well-defined optical pulses and/or pulse trains of well-defined but adjustable wavelength without using any external measures such as active modulation or the introduction of a saturable absorber,
• that contains several segments arranged in direction along the fiber comprising at least one active laser segment, typically two (or even more) active laser segments as well as propagation, grating, and nonlinear refraction segments,
• where these segments assume a cooperative mode of operation created by new types of self-organization based on the gain-phase coupling of the segments,
• where pulse shape, duration, repetition rate, and/or pulse power are adjusted or tuned by either the frequency detuning of the laser segments, the propagation time delays between the segments, the nonlinear phase changes induced by the segments, or by a combination of these parameters.

Recent numerical simulations of the three-segment fiber structure in a wider parameter range demonstrate that the device is also capable of novel pulsed operation regimes.

 

IP Rights
US Patent Application US 61/211,860

Origin
Humboldt-Universität zu Berlin, Germany

 

This invention provides a method for determining the frequency response of an electrooptical component, particularly, of a light-generating or light-modulating component. Optical pulses with a pulse frequency are generated. The electrooptical component is controlled by an electrical measuring signal with a measuring frequency in such a manner that an optical output signal is formed that is modulated with the measuring frequency. The measuring frequency is equal to an integral multiple of the pulse frequency plus a predetermined frequency offset. The pulses and the output signal are mixed, and a mixed product is detected whose modulation frequency corresponds to the predetermined frequency offset. The mixed product indicates the frequency response of the electrooptical component at the measuring frequency.

 

IP Rights
German Patent Application DE 10 346 379 A1; US Patent US 7,522,285 B2

Origin
Technische Universität Berlin, Germany