Yoshinobu Nekado

100 GHz-32 ch athermal AWG with extremely low temperature dependency of center wavelength

New athermal AWG with 100 GHz-32 ch has been developed. This novel athermal AWG exhibits excellent property in temperature dependency of center wavelength less than /spl plusmn/0.01 nm under the temperature range 0 to 70/spl deg/C.

VCSEL-based parallel-optical modules for >100 Gb/s applications

We introduce solder reflow-capable high-density parallel-optical modules for >100 Gb/s optical interconnects. Polymer-waveguide-coupled parallel-optical modules are also introduced with a unique mounting technology. 1060-nm 28-Gb/s InGaAs/GaAs VCSEL realizes a good signal quality at high temperature and error free for MMF transmission beyond 500m.

Polymer waveguide-coupled 14-Gb/s × 12-channel parallel-optical modules mounted on optical PCB through Sn-Ag-Cu-solder reflow

We demonstrate a novel architecture of mounting parallel-optical modules (POMs) onto an optical printed circuit board (PCB) through Sn-Ag-Cu-solder reflow process where precisely positioned stud-pins on optical PCB and guide holes formed on POMs were mated to maintain good optical coupling. We confirmed that fabricated 14-Gb/s × 12-channel POMs achieved a good transmission performance on a test environment using evaluation boards. Then, the POM was mounted onto the optical PCB through Sn-Ag-Cu-solder reflow process actually. We report coupling loss characteristics and signal qualities at 14-Gb/s PRBS 231-1 for the optical link using POM-mounted optical PCBs.

A fully engineered QSFP AOC using solderable 4-channel optical transceiver modules

We report a solderable 4-channel VCSEL-based optical transceiver module perfect for high-volume production of QSFP AOCs. The 4-channel module can be simply mounted on a PCB together with other electronics components through a solder reflow process. We fabricated a PCBA in compliance with the standard of QSFP edge connector. The PCBA has an MCU written with a firmware included with a look-up table to control the optical module over the operating temperate range. Integrating the PCB assembly into a die-cast housing, we fabricated fully engineered QSFP AOC. As we tested a BER characteristic for 14-Gb/s ×4-channel operation, the QSFP AOC has a total jitter margin of 0.5 U.I., and achieve a BER of <;10-15.

1060-nm 10-Gb/s × 12-channel parallel-optical modules for optical interconnects

Optical interconnects has been a key technology to realize signal transmission in rack-to-rack application where active optical cables (AOCs) such as QSFP have been employed so far. At present, it is required to mount parallel-optical modules with high-density to increase multiple numbers of signals in board-to-board applications which are highly expected in the next order of rack-to-rack applications. On the other hand, power reduction is a key issue in the next generation board-to-board optical interconnects where a low power consumption as same as 10 mW/Gb/s/link is required based on the trend of power reduction. To realize low power optical interconnects, we have been proposing 1060-nm optical interconnects which also achieve high speed modulation, high reliability, and high signal quality. We fabricated TX and RX 1060-nm 10-Gb/s × 12-channel parallel-optical modules. The mechanical size is as small as 13 mm × 13 mm × 3.4 mm. Operating all 12 channels in TX and RX parallel-optical modules simultaneously, we have achieved error-free transmission over the case temperature range ranging up 15 °C to 80 °C in back-to-back. We also achieved error-free transmission for a legacy OM-2 multimode fiber of 300m with the power penalty less than 2.0 dB. By using high-efficient 1060 nm VCSELs, power reduction is expected where we achieved optical link power of 7 mW/Gb/s/link at the case temperature of 80 °C. We performed reliability tests based on Tercordia GR-468. The results show that the optical modules are highly reliable since the variation of optical output power is less than ±10 % in all reliability tests.

1.1μm single mode VCSEL-based 4-channel × 10-Gbit/s parallel-optical module

For the first time, we fabricated a 1.1 μm InGaAs/GaAs single mode VCSEL-array-based 4-channel x 10-Gbit/s parallel-optical module integrated with a driver IC. The module achieved error free 10Gbit/s transmission for the distance of > 1km.

Polymer Waveguide-Coupled Solderable Optical Modules for High-Density Optical Interconnects

To realize simple and low-cost VCSEL-based parallel-optical modules mounted onto a polymer-waveguide-embedded PCB in high density, we propose a new mounting technology using a guide pin-assisted optical coupling stabilization during a Sn-Ag-Cu solder -- reflow process. The guide holes of the 12-channel optical module and the guide pins of optical PCB are precisely shaped by a high-precision machining and photolithography technologies, respectively. The allowable optical axis displacement is +/-12 um in both x-and y-axes between the parallel-optical module and the arrayed polymer-waveguide. We fabricated VCSEL-based 14-Gb/s x 12-channel transmitter/receiver modules and 25-Gb/s x 4-channel transceiver modules based on the 12-channel packaging. The module was soldered on a polymer waveguide-embedded PCB to achieve a sufficiently low optical coupling loss. In the link tests, we successfully achieved a BER of 10^-12 for both 14-Gb/s x 12-channel and 25-Gb/s x 4-channel optical links.

28-Gb/s ×4-channel solderable optical transceiver module for QSFP28

A solderable 28-Gb/s × 4-channel VCSEL-based optical transceiver module was designed for QSFP28 MPO-type transceiver and AOC applications. The module exhibits 28.05-Gb/s × 4-channel simultaneous operation with a jitter margin of -0.4 U.I. at the case temperature of 70 °C. The 4-channel module can be simply mounted on a PCB in compliance with the standard of QSFP28 edge connector, together with other electronics components through a solder reflow process. The module was controlled by a look-up table written in an MCU. The PCBA was built in a die-cast housing. As we performed a loop back test of QSFP28 MPO-type transceiver, a BER characteristic for 28.05-Gb/s × 4-channel operation achieves a total jitter margin of -0.4 U.I. over the operating housing temperature range.

1060-nm VCSEL-based parallel-optical modules for optical interconnects

Several different kinds of VCSEL-based parallel-optical modules have been developed in Furukawa Electric for optical interconnects. As a solution for cost-effective 100-Gb/s applications, a solderable 28-Gb/s × 4-channel transceiver module has been developed to be readily integrated to QSFP28. A very high-density 28-Gb/s × 24-channel on-board optical transceiver module has been also developed to realize higher density line cards enabling a data rate of ≥12.8 Tb/s. These developed VCSEL-based optical modules are introduced.