Recent Developments in Polymer-Based Photonic Components for Disruptive Capacity Upgrade in Data Centers

Abstract

Recently developed photonic components for next-generation datacenter systems based on HHI´s PolyBoard integration platform are reviewed. Hybrid-integrated transmitters and receivers, including optical functionalities such as tunable lasers, polarization manipulators, 1x2 switches and variable optical attenuators, are presented. The flexibility of those devices provides the possibility of generating, routing and detecting multiple optical data flows, offering the potential of aggregating traffics of 1 Tb/s and beyond. In addition, vertically-stacked polymer waveguide structures are presented, opening the way towards the third dimension in photonic integration and allowing increasing the transmission capacity beyond the physical limit of standard single mode fibers. The freedom in the arrangement of the polymer waveguides allow for the matching to different multi-core fiber types, providing the possibility of processing in parallel the different optical flows. By means of micro-machining 45° mirrors on the different stack levels, the 3D stacked waveguide structure can act as an interface between multi-core fibers and planar optoelectronic devices such as photodiodes and laser diodes. Furthermore, a novel concept for a 4x4 three-dimensional optical switch based on 3D multi-mode interferometers is presented and numerically proven, showing potential for its application as interface between multi-core fibers and planar optoelectronic devices, as well as offering the possibility of reconfigurable NxN switching matrices

Co‐packaged datacenter optics: Opportunities and challenges

“…CPO will be primarily enabled by advances in photonic integration. This can be achieved on a variety of platforms, such as silica (planar lightwave circuits) [58], indium phosphide (InP) [59,60], silicon on insulator (SOI/silicon photonics) [61], silicon nitride (SiN) [62][63][64], lithium niobate (LiNbO3) [65], glass [66], and polymer [67].…”

InP-Based Foundry PICs for Optical Interconnects

“…All these parameters are very much inter-related to each other by the way that the light is coupled from the InP PIC to the other PIC (here to be named, the interconnect PIC). Figure 7 shows four of the most common hybrid-integration approaches that are reported in the literature for datacenter-and optical-interconnect applications, which we have subdivided in two types: edge coupling, and surface coupling [20][21][22][23][24][25][26][27][28][29][30][31]. We have been developing three strategies to modify our generic-foundry-service process to enable efficient coupling of light in-and out of the InP PIC for these four hybrid-integration approaches.…”

Three-dimensional long-period waveguide gratings for mode-division-multiplexing applications

“…The large propagation losses are mainly due to the material, which is developed for application at 850 nm and has a loss of about 2 dB/cm at 1550 nm. It should be possible to substantially reduce the insertion losses of the device by using low-loss polymer material developed for the C band [27] and further optimizing the fabrication parameters. As the directional couplers are highly mode-selective and Taper 1 can effectively strip off all high-order modes, the crosstalks among the three modes are negligible (< -20 dB).…”