Radiation tolerance evaluation results of IOCore, a silicon photonics integrated circuits utilizing Fabry-Perot-type quantum dot lasers

An optical transceiver that uses a Fabry-Perot-type quantum-dot laser has been shown to operate reliably in harsh environments, making it suitable for Internet of Things (IoT) edge nodes. This paper presents radiation-tolerance evaluation results for IOCore ® optical transceivers, which integrate optical transmitter and receiver functions on a single chip and use Fabry-Perot-type quantum-dot lasers as light sources. The results demonstrate sufficient tolerance for the conditions encountered in Low Earth Orbit (LEO). IOCore is designed for short-distance interconnections over multimode fibers. It focuses on applications where low power consumption and low latency are critical and supports non-return-to-zero (NRZ) signal transmission from 1 to 25 Gbps, as well as 32 Gbps, without clock and data recovery (CDR). It operates for extended periods across the temperature ranges encountered in space without performance degradation. IOCore serves as an optical building block that is flexibly combined with other optical components, such as front-pluggable transceiver modules and co-packaged modules. Satellite onboard sensing interface electronics are hard real-time systems and are expected to be typical applications for silicon photonics integrated circuits. The silicon photonics integrated circuit in IOCore comprises Mach-Zehnder interferometer (MZI) modulators, germanium photodetectors, spot-size converters (SSCs) for laser-diode (LD) coupling, and vertical grating couplers. The substrate includes a cavity and alignment markers that allow the source LD to be passively aligned and mounted into the substrate cavity on the chip. Optical fibers are connected not directly to the silicon photonic substrate but to optical pins on a separate, higher-level interface, enabling robust and low-cost connections.