Improving the modulation bandwidth in semiconductor lasers by passive feedback

We explore the concept of passive-feedback lasers for direct signal modulation at 40 Gbit/s. Based on numerical simulation and bifurcation analysis, we explain the main mechanisms in these devices which are crucial for modulation at high speed. The predicted effects are demonstrated experimentally by means of correspondingly designed devices. In particular a significant improvement of the modulation bandwidth at low injection currents can be demonstrated

3D-printed optical probes for wafer-level testing of photonic integrated circuits

Wafer-level probing of photonic integrated circuits is key to reliable process control and efficient performance assessment in advanced production workflows. In recent years, optical probing of surface-coupled devices such as vertical-cavity lasers, top-illuminated photodiodes, or silicon photonic circuits with surface-emitting grating couplers has seen great progress. In contrast to that, wafer-level probing of edge-emitting devices with hard-to-access vertical facets at the sidewalls of deep-etched dicing trenches still represents a major challenge. In this paper, we address this challenge by introducing a novel concept of optical probes based on 3D-printed freeform coupling elements that fit into deep-etched dicing trenches on the wafer surface. Exploiting the design freedom and the precision of two-photon laser lithography, the coupling elements can be adapted to a wide variety of mode-field sizes. We experimentally demonstrate the viability of the approach by coupling light to edge-emitting waveguides on different integration platforms such as silicon photonics (SiP), silicon nitride (TriPleX), and indium phosphide (InP). Achieving losses down to 1.9 dB per coupling interface, we believe that 3D-printed coupling elements represent a key step towards highly reproducible wafer-level testing of edge-coupled photonic integrated circuits. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen

Hybrid external-cavity lasers (ECL) using photonic wire bonds as coupling elements

Combining semiconductor optical amplifiers (SOA) on direct-bandgap III–V substrates with low-loss silicon or silicon-nitride photonic integrated circuits (PIC) has been key to chip-scale external-cavity lasers (ECL) that offer wideband tunability along with small optical linewidths. However, fabrication of such devices still relies on technologically demanding monolithic integration of heterogeneous material systems or requires costly high-precision package-level assembly, often based on active alignment, to achieve low-loss coupling between the SOA and the external feedback circuits. In this paper, we demonstrate a novel class of hybrid ECL that overcome these limitations by exploiting 3D-printed photonic wire bonds as intra-cavity coupling elements. Photonic wire bonds can be written in-situ in a fully automated process with shapes adapted to the mode-field sizes and the positions of the chips at both ends, thereby providing low-loss coupling even in presence of limited placement accuracy. In a proof-of-concept experiment, we use an InP-based reflective SOA (RSOA) along with a silicon photonic external feedback circuit and demonstrate a single-mode tuning range from 1515 to 1565 nm along with side mode suppression ratios above 40 dB and intrinsic linewidths down to 105 kHz. Our approach combines the scalability advantages of monolithic integration with the performance and flexibility of hybrid multi-chip assemblies and may thus open a path towards integrated ECL on a wide variety of integration platforms

3D-printed optical probes for wafer-level testing of photonic integrated circuits

Wafer-level probing of photonic integrated circuits is key to reliable process control and efficient performance assessment in advanced production workflows. In recent years, optical probing of surface-coupled devices such as vertical-cavity lasers, top-illuminated photodiodes, or silicon photonic circuits with surface-emitting grating couplers has seen great progress. In contrast to that, wafer-level probing of edge-emitting devices with hard-to-access vertical facets at the sidewalls of deep-etched dicing trenches still represents a major challenge. In this paper, we address this challenge by introducing a novel concept of optical probes based on 3D-printed freeform coupling elements that fit into deep-etched dicing trenches on the wafer surface. Exploiting the design freedom and the precision of two-photon laser lithography, the coupling elements can be adapted to a wide variety of mode-field sizes. We experimentally demonstrate the viability of the approach by coupling light to edge-emitting waveguides on different integration platforms such as silicon photonics (SiP), silicon nitride (TriPleX), and indium phosphide (InP). Achieving losses down to 1.9 dB per coupling interface, we believe that 3D-printed coupling elements represent a key step towards highly reproducible wafer-level testing of edge-coupled photonic integrated circuits. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen

Multi-Chip Integration by Photonic Wire Bonding: Connecting Surface and Edge Emitting Lasers to Silicon Chips

We demonstrate coupling of surface and edge emitting InP lasers to silicon photonic chips using photonic wire bonding. We confirm that back-reflections from the silicon chip do not deteriorate the linewidth of the lasers

IMECE2004-60399 Thermal Characterization of an All-Active Microring Resonating Laser

ABSTRACT Active microring optical devices are promising candidates for use in next generation optical signal processing and sensor products. In this design, an InP based microring laser is vertically coupled to a passive feeding waveguides using a waferbonding technology. The vertical coupling is expected to detrimentally affect the operating temperature and device performance through the low thermal conductivity of the bond material. Thus, a thermal analysis is undertaken in the design stage to better understand the implications of this fabrication process. A thermal analysis of a basic microring resonator of 50 µm radius and 100 mW power dissipation is presented and thermal design variations are discussed

Codierer, Decodierer, System und Verfahren zum Übertragen verschlüsselter Daten

The invention relates to a coder for providing encrypted data which is to be transmitted via a transmission medium (200), comprising an encryption unit (104) which is designed to encrypt, in blocks, data received by the coder, and a processing unit (106). Said processing unit (106) is designed to distribute an encrypted data block randomly to a plurality of channels which are associated with the transmission medium (200), and a subblock which is to be transmitted via one the of channels and which comprises one part of the encrypted data block, together with a channel identification associated with the channel and a code value which is based on encrypted data in the subblock which is to be transmitted and the channel identification, for transmission via the associated channel of the transmission medium (200). A transmission medium for securely transmitting data comprises a multi-core optical fibre (200), wherein at least one core of said multi-core fibre (200) defines a data channel (2021-2024) for the transmission of data, and wherein at least one core of the multi-core fibre (200) defines a monitoring channel (2041,2042)