Optical transmitter and receiver ICs, each with a footprint of 25 mm ² , were fabricated using a silicon photonics platform based on 40-nm-node CMOS technology. High-speed transmissions of data at 300 Gbps were demonstrated. The wire-type waveguide (WG) in the transmitter IC had a width of 350 nm and a height of 200 nm, and in the completed optical IC, it showed low propagation loss (1.62 dB/cm) for the O-band transverse electric mode and low propagation loss variation (0.15 dB/cm) at 3σ. The coupling loss of the grating couplers was reduced to 2.7 dB by using an apodization structure with a narrow trench width of 70 nm. The wafer-scale reproducibility of the WG width was excellent, as confirmed by a spectral variation analysis using a large number of the microring resonators. The surface-illumination photodetectors (PDs) of the optical receiver were made using a germanium epitaxial film and had a leakage current of less than 10 nA at 3 V and a responsivity of 0.75 A/W. The modulation efficiency of the PN-junction-type Mach-Zehnder modulators of the optical transmitter was 1.3 V ^. cm at 0 V. The uniformity of the PDs and modulators on a 300-mm wafer was very high. By using the fabricated optical transmitter and receiver ICs, data transmissions at up to 12 × 25 Gbps in the O band (1.3 μm) were demonstrated. Furthermore, low-loss filtering operation in 1:4 channel delayed interferometer-based demultiplexing was shown to enable even faster data transmissions. These results indicate that our silicon photonics platform is very useful for fabricating wideband optical ICs.

Here, we report on the design and performance of a silicon photonic micro-transceiver required to operate in 5G and 6G environments at high ambient temperatures above 105 °C. The four-channel “IOCore” micro-transceiver incorporates a 1310 nm quantum dot laser system and operates at a data rate of 25 Gbps and higher. The 5 × 5 mm micro-transceiver chip benefits from a multimode coupling interface for low-cost assembly and robust connectivity at high temperatures as well as an optical redundancy scheme, which increases reliability by over an order of magnitude.

We experimentally demonstrated a post-integrated dual-core spot-size converter (SSC) that had a coupling end with a 10-μm diameter at the edge of an Si-photonics chip. Although there was an extra loss increase as a result of post-integration, it can be reduced and, thus, the SSC is a promising candidate for practical use. The large coupling end enabled the SSC to be butt-coupled to a single mode fiber (SMF) theoretically at an optical loss of less than 0.7 dB, and post-integration of the SSC allowed us to apply complementary metal-oxide-semiconductor technologies to optoelectronic circuits on wafers before the SSC forming process. We attached the SSC to a 1.5-μm-thick Si rib waveguide. The observed near field patterns of light from the SSC were close to that of an SMF independently of light polarizations. The working wavelength range spanned more than 100 nm. The excess loss caused by the post-integration process was estimated to be 1 dB.

With the rapid growth of electronic chip's performance, electric signal limits chip I/O in power consumption, reachability, and signal quality. In this letter, we propose a new chip-let architecture for chip-level optical interconnect. An optic I/O chip-let including an ultra-small optic transceiver and electronic components is implemented. Our analysis shows that the optical interconnect based on this architecture can achieve 1/3 power consumption and 1/2 area compared with traditional board-level optical interconnect in Ethernet NIC application. By adopting the architecture we proposed, the optic I/O chip-let can support any payload IC such as CPU, GPU, switch to have optic I/O.

In this paper we report on the design and performance of a silicon photonics micro-transceiver, which is designed to operate in harsh environments including high temperature environments above 105°C and space environments. In addition, we demonstrated that the micro-transceiver modules have been applied to immersion cooling, which must be considered another harsh environmental condition due to its novelty for optical active components. The four-channel “IOCore®” micro-transceiver incorporates a 1310 nm quantum dot laser system and operates at a symbol rate of 32 GBaud and higher. The 5 x 5 mm micro-transceiver chip benefits from a multimode coupling interface for low-cost assembly and robust connectivity at high temperatures.

This paper summarizes the features, reliability, and high-temperature operation of a 5 mm×5 mm silicon photonic transceiver (IOCore) with a multimode interface, and the 32Gbps operation of a PCIe_Gen5.0. The IOCore has 4 lanes for transmission and reception, and a 1.3μm-band Fabry-Perot quantum dot laser (F-P_QDLD) is applied as the light source. Optical transceivers are installed in custom and standard modules and applied to high-performance computers (HPC), 5G +, industrial equipment, and in-vehicle computing.