Performance Testing of a Novel Off-plane Reflection Grating and Silicon Pore Optic Spectrograph at PANTER

An X-ray spectrograph consisting of radially ruled off-plane reflection gratings and silicon pore optics was tested at the Max Planck Institute for extraterrestrial Physics PANTER X-ray test facility. The silicon pore optic (SPO) stack used is a test module for the Arcus small explorer mission, which will also feature aligned off-plane reflection gratings. This test is the first time two off-plane gratings were actively aligned to each other and with a SPO to produce an overlapped spectrum. The gratings were aligned using an active alignment module which allows for the independent manipulation of subsequent gratings to a reference grating in three degrees of freedom using picomotor actuators which are controllable external to the test chamber. We report the line spread functions of the spectrograph and the actively aligned gratings, and plans for future development.Comment: Draft Version March 19, 201

On-Chip transmitter and receiver front-ends for ultra-broadband wired and optical-fiber communications

Increasing line rates beyond 56Gb/s is a big challenge for transceiver front-ends. We discuss recent developments towards 100Gb/s copper, +56Gb/s multi-channel single-mode VCSEL links and segmented MZM drivers for advanced modulation

Silicon pore optics mirror modules for inner and outer radii

Athena (Advanced Telescope for High Energy Astrophysics) is an x-ray observatory using a Silicon Pore Optics telescope and was selected as ESA's second L-class science mission for a launch in 2028. The x-ray telescope consists of several hundreds of mirror modules distributed over about 15-20 radial rings. The radius of curvature and the module sizes vary among the different radial positions of the rings resulting in different technical challenges for mirror modules for inner and outer radii. We present first results of demonstrating Silicon Pore Optics for the extreme radial positions of the Athena telescope. For the inner most radii (0.25 m) a new mirror plate design is shown which overcomes the challenges of larger curvatures, higher stress values and bigger plates. Preliminary designs for the mounting system and its mechanical properties are discussed for mirror modules covering all other radial positions up to the most outer radius of the Athena telescope

Real-time and DSP-free 128 Gb/s PAM-4 link using a binary driven silicon photonic transmitter

Optical transmitters for four-level pulse amplitude modulation (PAM-4) have attracted a significant amount of research in recent years, in large part due to the standardization of the format for the 200 and 400 Gigabit Ethernet optical interconnects in data centers. However, combining low-power and linear operation of the electro-optical frontend with sufficiently large bandwidths has proven challenging, especially for the 100 Gb/s/lambda links (i.e., employing 50 Gbaud PAM-4). The most straightforward solution has been to deal with the non-idealities of the modulator in the electrical domain: predistorting the signal levels and/or equalizing the frequency response with the help of digital signal processing (DSP). However, this typically requires fast digital-to-analog converters (DACs), either capable of delivering large swings (>1 Vpp) or supplemented with an additional linear amplifier to drive the optical modulator. Both options substantially increase the power consumption and the complexity of the transceiver. Rather than allocating effort to linearize the electrical to optical conversion of a single modulator, we propose a topology that performs the DAC operation in the optical domain. Two compact electro-absorption modulators in an interferometer layout are driven with NRZ data to generate the four-level signal in the optical domain. Using this topology, we demonstrate the first real-time 128 Gb/s PAM-4 transmission with a silicon photonic transmitter in a chip-to-chip link. In a back-to-back setup, we obtained a bit-error ratio (BER) of 4 x 10(-10) without requiring any DAC, DSP, or modulators with large traveling wave structures. Over 1 km of standard single mode fiber a BER of 8 x 10(-6) is recorded, still well below the KP4 forward error-coding limit. These results correspond to the lowest BERs reported for any real-time PAM-4 link at 100 Gb/s or higher, illustrating the benefit of performing the DAC operation in the optical domain

Development and manufacturing of SPO X-ray mirrors

The Silicon Pore Optics (SPO) technology has been established as a new type of X-ray optics enabling future X-ray observatories such as ATHENA. SPO is being developed at cosine together with the European Space Agency (ESA) and academic as well as industrial partners. The SPO modules are lightweight, yet stiff, high-resolution X-ray optics, allowing missions to reach a large effective area of several square meters. These properties of the optics are mainly linked to the mirror plates consisting of mono-crystalline silicon. Silicon is rigid, has a relatively low density, a very good thermal conductivity and excellent surface finish, both in terms of figure and surface roughness. For Athena, a large number of mirror plates is required, around 100,000 for the nominal configuration. With the technology spin-in from the semiconductor industry, mass production processes can be employed to manufacture rectangular shapes SPO mirror plates in high quality, large quantity and at low cost. Within the last years, several aspects of the SPO mirror plate have been reviewed and undergone further developments in terms of effective area, intrinsic behavior of the mirror plates and mass production capability. In view of flight model production, a second source of mirror plates has been added in addition to the first plate supplier. The paper will provide an overview of most recent plate design, metrology and production developments