Toshiaki Takai

20-Gb/s/ch High-Speed Low-Power 1-Tb/s Multilayer Optical Printed Circuit Board With Lens-Integrated Optical Devices and CMOS IC

A high-speed large-capacity optical printed circuit board (OPCB) for next-generation high-capacity routers and servers was developed. This OPCB is composed of a multilayer polymer optical waveguide, a receiver optical input/output (I/O) module (with a lens-integrated photodiode and a SiGe transimpedance amplifier), and a low-power (7.1 mW/Gb/s) transmitter optical I/O module consisting of a lens-integrated surface-emitting laser and complementary metal-oxide-semiconductor (CMOS) driver IC. A 1-Tb/s (20 Gb/s/ch × 48 ch per transmitter or receiver) large-capacity OPCB prototype was fabricated and demonstrated 20-Gb/s/ch operation.

A 25 Gb/s 65-nm CMOS Low-Power Laser Diode Driver With Mutually Coupled Peaking Inductors for Optical Interconnects

A 25 Gb/s laser diode (LD) driver has been developed on the basis of standard 65 nm CMOS technology for optical interconnects. The LD driver consists of a main driver capable of providing an average current of 30 mA and a predriver providing a gain of 20 dB. The main driver uses mutually coupled inductors to adjust the inductive peaking to improve eye patterns under various packaging conditions. The predriver uses CMOS active feedback to achieve a wide bandwidth and high gain, despite its small size and low power consumption. The fabricated circuit achieves data rates of 25 Gb/s, consumes 156 mW (6.3 mW/Gb/s) and occupies an area of 0.011 mm2 .

25-Gb/s 100-m MMF Transmission Using a Prototype 1.3-

A prototype transceiver composed of a 1.3-μm-range lens-integrated laser diode and photodiode as well as a complementary metal-oxide-semiconductor (CMOS) laser diode driver and a CMOS transimpedance amplifier for high-speed optical interconnections was developed. It demonstrated 25-Gb/s error-free 100-m multimode fiber transmission, with power dissipation of only 9 mW/Gb/s, for the first time.

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A 25-Gb/s × 4-ch optical transceiver module was developed. To obtain a compact module, CMOS analog front-end ICs, a lens integrated connector, and small LGA package was applied. The module demonstrated 25-Gb/s error-free transmission.

-Range CMOS-Based Transceiver for Optical Interconnections

A compact optical backplane was developed, and a ribbon fiber sheet and high-density connector were used to reduce the cost and wiring area. A bandwidth of 7.2-Tb/s was achieved within a 288 × 53 mm2 area inside the network equipment.

A 25-Gb/s × 4-Ch, 8 × 8 mm 2 , 2.8-mm thick compact optical transceiver module for on-board optical interconnect

A compact 25-Gbit/s × 4-ch embedded optical module (EOM) composed of a straddle-shaped optical and electrical interface was fabricated and evaluated. The fabricated EOM provides highly efficient optical coupling and large optical-coupling tolerance, and it successfully demonstrated 25-Gbit/s error-free optical transmission. These optical performance results indicate that the fabricated compact EOM can be applied for on-board and rack-to-rack optical interconnections with high transmission density.

7.2-Tb/s compact optical backplane using ribbon fiber sheet and high-density connector

A 25 Gb/s × 4-ch, 8 × 8 mm2 optical transceiver module for optical interconnection has been developed. To obtain a compact optical module suitable for chip-to-chip interconnection, a lens integrated connector, a small low temperature co-fired ceramic (LTCC) package, and a precise lens assembling technology were used. Experimental results showed that the proposed module can achieve 25 Gb/s error free transmission.

A compact 25-Gbit/s × 4ch optical interconnect module with straddle-shaped optical and electrical interface

A high-density 300-Gbit/s (25-Gbit/s × 12-ch) parallel optical-interconnect module (OIM) was fabricated by using an efficient, newly developed optical sub-assembly (OSA) techniques. The OIM module provides high heat dissipation and high optical-coupling efficiency. Furthermore, the fabricated OIM successfully demonstrated 25-Gbit/s error-free multimode transmission.

A 25 Gb/s × 4-ch, 8 × 8 mm small size optical transceiver module for optical interconnection

A 25.78-Gbit/s × 4-ch active optical cable (AOC) with a ultra-compact form factor is proposed. The size of the proposed AOC is 5.2 cm3, which is 45-% smaller than standard form factor of a μQSFP. By utilizing a high heat-dissipation structure, the proposed AOC demonstrated 25.78-Gbit/s error-free optical transmission under all-channels (4-ch) operation at case temperature (Tc) of 70 °C.

A high-density 300-Gbit/s parallel optical interconnect module with efficient optical sub-assembly techniques

Advancements in packaging technologies are required to meet the future bandwidth, and space- and energy-efficient demands of ICT systems. One of the key technologies is 2.5D packaging using a silicon interposer with through silicon vias (TSVs). However, forming the TSV and thinning the wafer makes the Si interposers cost high. Furthermore, using an organic substrate causes high electrical losses and warpage. We propose a low-temperature co-fired ceramics (LTCC) package with fine line layers to help alleviate these problems. The surface of the LTCC substrate is made very flat, so fine patterns with line/space that is 2/2μm can be formed. The LTCC package has been expected to decrease the necessary costs by simplifying the assembly process and introducing a panel-based process. Moreover, the LTCC substrate is more reliable than a Si interposer with an organic substrate and can transmit a high data rate signal at a lower loss. We demonstrated the possibility of high Bandwidth Memory (HBM) routing using the LTCC package.