Startups continue OC-768 material wars



As established chip manufacturers de bate the merits of silicon germanium (SiGe), gallium arsenide (GaAs), and indium phosphide (InP) for 40-Gbit/sec electronics, a pair of startups have entered the market preaching some degree of material agnosticism but leading with different technologies nonetheless.

InPhi Corp. (Westlake Village, CA) aims to accommodate speeds as high as 50 Gbits/sec in the footprint and power parameters now associated with OC-192 (10-Gbit/sec) devices, according to Dr. Gopal Raghavan, co-founder (with CEO Dr. Loi Nguyen and chief financial officer Tim Semones) and chief technical officer of the company. While InPhi is exploring GaAs and CMOS, it is leading with InP with its first devices, a 4:1 multiplexer and a 1:4 demultiplexer that the company says will operate at rates greater than 50 Gbits/sec while consuming less than 900 mW. A modulator driver is expected to follow shortly, and both product sets will sample in this quarter, Raghavan says.

Because it is a fabless company, Inphi has tapped Global Communication Semiconductors to produce the chips using the latter's carbon-doped InP heterojunction bipolar transistor (HBT) process technology.

However, Raghavan hints that as the company's product line expands, other materials will make an appearance. The upcoming device set will likely include switching, FEC, and framer units; it should begin sampling in the first quarter of next year. The company is slated to announce the architecture behind the product line this month.

In contrast, Acelo Semiconductor Inc. (which, unlike many chip startups, has its own fab in Oxnard, CA) will enter the OC-768 chip space on the strength of a 20-year exclusive license from Rockwell Scientific for GaAs pseudomorphic high-electron mobility transistor (PHEMT) technology. The company currently is sampling both OC-192 and OC-768 devices, including a laser driver, modulator driver, and transimpedance amplifier (TIA) at 10 Gbits/sec and a modulator driver and TIA at 40 Gbits/sec.

The single-chip modulator drivers provide 5-Vp-p swing at 12 Gbits/sec, decreasing to approximately John Hong, company CEO and acting chief technical officer, says that for the analog portion of the signal processing chain, GaAs PHEMT represents an attractive starting point for 40-Gbit/sec devices. He foresees a second generation of devices coming from Acelo that will take advantage of InP PHEMT. For digital and mixed-signal requirements, the company will look to a proprietary InP HBT process.

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