Yokogawa Electric develops modules for 40-Gbps optical transmission systems using HBTs

Yokogawa Electric Corp. announced what it claims to be the first series of modules to be based on hetero-junction bipolar transistors and which are set to become key elements for the commercialization of 40-Gigabit per second optical transmission systems.

Yokogawa will release a driver module for use with lithium niobate modulators, indispensable for dense wavelength division multiplexing and other optical transmission systems; a driver module for electro-absorption modulators; a flip-flop module; a 1-to-2 demultiplexer module; and a 2-to-1 multiplexer module.

HBTs rely on III-V compound semiconductors and boast marginal jitter and high output power compared with conventional HEMT (High-Electron Mobility Transistors) or SiGe bipolar transistors. Basing these HBT modules for 40-Gbps optical communications on Yokogawa's knowledge of compound semiconductors allowed the company to successfully overcome technological challenges involved with making these modules on a commercial scale.

Yokogawa Electric aims to sell these HBT modules to developers of optical transmission systems for communication infrastructure such as optical transmission equipment. Each of the modules will be housed in an IC package when they are mass-produced.

Yokogawa Electric will also work on the development of 4-to-1 multiplexer and 1-to-4 demultiplexer modules with an eye on becoming the top supplier of basic modules for 40-Gbps optical transmission systems. What's more, in close cooperation with Ando Electric Co., Ltd. Yokogawa Electric will develop measuring instruments for optical transmission systems that incorporate these modules.

Combining Wavelength Division Multiplexing (WDM) and Time Division Multiplexing (TDM) technologies allows multiplexing of more wavelengths in optical communication, facilitating optical transmission at a speed in the order of terabits. Currently, however, the most feasible scenario is considered to be multiplexing four 10-Gbps signals into one 40-Gbps output. Yokogawa Electric's modules will surely accelerate the development of next-generation optical transmission systems for commercial use.

Overview of products

Driver Modules for use with Modulators:

For LN (Lithium Niobate) modulators

Output: At least 5 Vpp; Gain: 23 dB

For EA (Electro-Absorption) modulators:

Output: At least 4 Vpp; Gain: 15 dB

Logic Circuit Modules:

Flip-flop module

Retimes 40-Gbps signals.

1-to-2 demultiplexer module: Distributes a multiplexed signal to two outputs. By combining three modules, a 40-Gbps signal can be converted into 20-Gbps, and then 10-Gbps outputs.

2-to-1 multiplexer module: Multiplexes two signals into one output. By combining three modules, a 10-Gbps signal can be multiplexed into 20-Gbps, and then a 40-Gbps output.

Two hundred units are available as engineering samples for fiscal 2001 priced from 2 million yen for an engineering sample. A total of 20,000 units will be available by fiscal 2003 on a commercial basis.

For more information, visit www.yokogawa.com.