A 1.4 Gb/s 12-channel parallel laser diode driver IC for optical interconnections
The authors present a 12-channel parallel laser diode (LD) driver with 16.8 Gb/s throughput. The driver IC creates skew-free output and provides temperature compensation of the optical power of the LD. The IC also suppresses ringing oscillation and crosstalk. The die is 2.5x3.5 mm/sup 2/ using a 15 GHz f/sub /spl tau// Si bipolar process. The power supply voltage is 5 V and the power consumption is 4.2 W including the PECL level input signal consumption of 1.1 W and the output signal consumption of 2.0 W at 3l mApp + 2 mA bias.
FP 15.7: A 500Mb/s, 20-Channel CMOS Laser Diode Array Driver for a Parallel Optical Bus
.For the ever-increasing demand of communication bandwidth for clustered computer interconnections, parallel optical bus technology provides a small, lightweight, flexible and low-cost alternative to the existingtechnology [l, 21. A2O-channel,500Mb/s/cha~el CMOS laser diode (LD) driver drives a vertical cavity surface emitting laser (VCSEL) array in a parallel optical bus transmitter. It has a 5OOMb/s low voltage differential signal (LVDS) input interface withwideinput commonmode range. Totaldata throughput islOGb/s. It uses a standard 3.3V power supply with 1.6W of power dissipation, with user features such as on-chip data scrambling and built-in link self-test. The chip architecture is shown in Figure 1. It consists of 20, 5OOMb/s data channels and a full (5OOMHz) and half speed (250MHz) clock interface. All inputs conform to LVDS standard [3]. The chip supports both synchronous and asynchronous modes ofoperation. In the asynchronous mode, the data pass through the chip unlatched in all 20 channels. In the synchronous mode, the input data are retimed and deskewed. The data can also be scrambled in the synchronous mode to improve the reliability of transmissionin the optical link. 18 channels are available for data transfer in this mode. The remaining 2 channels are for transferring the clock signal and the scrambling data. The scrambling pattern is generated by an on-chip pseudo-random bit generator (PRBG). The PRBG also,provides data patterns in a self-testing mode. This enables users to perform low-cost full-speed chip and link level testing.
FORTE observations of lightning radio‐frequency signatures: Capabilities and basic results
The FORTE satellite, launched on August 29, 1997, carries both radio‐frequency‐receiver and optical (imaging and photometric) payloads for the study of lightning. The radio‐frequency (RF) data for the first 7 months of operation are described, both to illustrate the satellite's capabilities and to explain the basic statistical findings so far. FORTE's multichannel RF trigger system represents a significant advance in space‐based monitoring of lightning emissions. We are able to observe even rather weak and diffuse RF emissions from lightning and are no longer limited to the brightest known events, “transionospheric pulse pairs,” or TIPPs. We do see TIPPs, and we show that the FORTE observations of TIPPs are consistent only with the second pulse's being due to a ground reflection. We find that TIPPs are basically bimodal in character, one type having a steep roll‐off of power from 38 to 130 MHz and the other being essentially flat‐spectrum in that range. The steep‐spectrum TIPPs cluster together in the manner of most RF emissions from lightning, while the flat‐spectrum events tend to maintain a wider spacing (>0.1 s) between recurrent emissions.