Product Spotlight: Hamamatsu Tackles Telecom
An optical data link and a family of 2.5 Gbit/s receiver/emitter modules constitute the initial offerings in the company's fledgling communications product line.
By: Kristin Lewotsky
Known primarily for photodetectors of all types, Hamamatsu is angling for a slice of the optical communications pie with the release of a new line of components aimed at data communications applications. "We're testing out the market," said Hamamatsu VP of marketing Robert Wisner, noting that while the company may not be at the bleeding edge of technical development in the datacom field, it has the resources to follow where the market is going and develop a competitive commercial product.
In this case, the detector giant is melding its photodetector technology base with transceiver capabilities to launch a 2.5-Gbit/s emitter/receiver module for communications, HDTV, and SDH applications, as well as an optical data link for plastic fiber networks.
Into telecom
The showpiece of the strategy is a family of emitter/receiver modules, designed for telecom and datacom applications, that operate at data rates from 1 Gbit/s and 2.5 Gbit/s. Designed for use with singlemode optical fiber, the modules incorporate the L7551 or L7552 Fabry-Perot diode lasers, which generate up to 0.3 mW of output at 1.31 µm. Threshold current is 9 mA, and forward voltage is 1.1 V.
The receivers consist of indium gallium arsenide (InGaAs) p-i-n photodiodes with peak sensitivities at 1.3 or 1.5 µm and response speeds as high as 2.5 Gbit/s. Depending on the model, photosensitivity ranges from 0.5 to 0.7 V/mW, for a supply current of 30 to 60 mA, respectively. The active area is f0.8 mm.
For datacom operations, the modules incorporate silicon photodiode receivers operating at 0.8 µm. Photosensitivity ranges from 0.3 V/mW to 0.6 V/mW, and active areas vary from f0.2 to f0.3 mm.
All receivers are integrated with trans-impedance amplifiers, and are available in either a metal package or fitted with an SC receptacle.
Plastic fiber data link
Although plastic optical fiber (POF) has so far failed to gain a strong foothold in the US, it constitutes a significant market in Japan. Hamamatsu developed its optical data link specifically for this niche.
The S7141 photonic integrated circuit (IC) detector is teamed with the L7140 light-emitting diode (LED) to form an optical data link capable of operating at speeds up to 50 Mb/s. The rise and fall time for pulse operation is less than 8 ns. The photo IC offers a maximum receiving level of 5 dBm and a minimum receiving level of –17.5 dBm. Operating on 1.9 V and a 10 µA reverse current, the LED generates –7 dBm of output centered about 650 nm, with a 20-nm spectral half-width.
All components will be on display at the Hamamatsu booth during OFC '99 in San Jose, CA. Look for the company to also release a family of indium gallium arsenide (InGaAs) arrays for dense wavelength division multiplexing applications during the conference.
According to Wisner, next week's exhibit marks the company's first outing at OFC in a long while. "This is more or less an exploratory exercise as a prelude to really getting into the fiber market," he comments. "We don't expect to compete with the big guys; we're looking for more of a niche market."