We demonstrate high speed and high power evanescently-coupled waveguide integrated modified uni-traveling-carrier (MUTC) photodiodes. Over 105 GHz bandwidth along with 2 dBm and 1.3 dBm RF output power at 100 GHz and 105 GHz, respectively, has been achieved.

To fulfill the functionality demands from the fast developing optical networks, a hybrid integration approach allows for combining the advantages of various material platforms. We have established a polymer-based hybrid integration platform (polyboard), which provides flexible optical input/ouptut interfaces (I/Os) that allow robust coupling of indium phosphide (InP)-based active components, passive insertion of thin-film-based optical elements, and on-chip attachment of optical fibers. This work reviews the recent progress of our polyboard platform. On the fundamental level, multi-core waveguides and polymer/silicon nitride heterogeneous waveguides have been fabricated, broadening device design possibilities and enabling 3D photonic integration. Furthermore, 40-channel optical line terminals and compact, bi-directional optical network units have been developed as highly functional, low-cost devices for the wavelength division multiplexed passive optical network. On a larger scale, thermo-optic elements, thin-film elements and an InP gain chip have been integrated on the polyboard to realize a colorless, dual-polarization optical 90° hybrid as the frontend of a coherent receiver. For high-end applications, a wavelength tunable 100Gbaud transmitter module has been demonstrated, manifesting the joint contribution from the polyboard technology, high speed polymer electro-optic modulator, InP driver electronics and ceramic electronic interconnects.

This paper describes a fabrication process for realizing Indium-Phosphide-based photonic-integrated circuits (PICs) with a high level of integration to target a wide variety of optical applications. To show the diversity in PICs achievable with our open-access foundry process, we illustrate two examples: a fully-integrated 20 Gb/s dual-polarization electro-absorption-modulated laser, and a balanced detector composed of avalanche photodiodes for detection of 28 Gb/s optical signals. On another note, datacenters are increasingly relying on hybrid integration of PICs from different technology platforms to increase transmission capacity, while simultaneously lowering cost, size, and power consumption. Several technology platforms require surface coupling rather than the traditional edge coupling to couple the light from one PIC to another. To accommodate the surface-coupling approach in our integration platform, we have developed a strategy to transfer the following optical Input/Output devices into our fabrication process: grating couplers, and vertical mirrors. In addition, we introduced etched facets into the process to improve the usability of our edge-coupling elements. We believe that the additional flexibility in Input/Output interfacing combined with the integration of multiple devices onto one PIC to reduce the number of PIC-to-PIC alignments can contribute significantly to the development of compact, low-cost, and high-performance datacenter modules.

We demonstrate a monolithically integrated quadrature coherent receiver photonic integrated curcuit on an InP substrate with a 90° optical hybrid and two balanced 56 GHz pin-photodetectors on chip level and as a packaged device. The presented devices enable the use of 56/64 Gbaud dual polarisation 16-QAM signals either in the C-band or the L-band.

Polarization handling is a key requirement for the next generation of photonic integrated circuits (PICs). Integrated polarization beam splitters (PBS) are central elements for polarization management, but their use in PICs is hindered by poor fabrication tolerances. In this work we present a fully passive, highly fabrication tolerant polarization beam splitter, based on an asymmetrical Mach-Zehnder interferometer (MZI) with a Si/SiO₂ Periodic Layer Structure (PLS) on top of one of its arms. By engineering the birefringence of the PLS we are able to design the MZI arms so that sensitivities to the most critical fabrication errors are greatly reduced. Our PBS design tolerates waveguide width variations of 400nm maintaining a polarization extinction ratio better than 13dB in the complete C-Band.

We demonstrate a photodetector module with a 0.8mm-RF connector and an estimated 3dB-bandwidth of 145GHz. The bandwidth of the module exceeds all other state of the art photodetector modules. The intended application of the module is for test and measurement equipment of next generation optical networks with 200GBaud.