This research was done to choose a suitable APD detector for the development of an advanced atmospheric water vapor differential absorption lidar detection system operating either at 720, 820, or 940 nm. The results point out the benefits of using the super low ionization ratio (SLIK) structure APD for its lower noise-equivalent power, which was found to be on the order of 2 to 4 fW/Hz 1/2, with an appropriate optical system and electronics. The water vapor detection systems signal-to-noise ratio will increase by a factor of 10.

Development of advanced differential absorption lidar (DIAL) receivers is very important to increase the accuracy of atmospheric water vapor measurements. A major component of such receivers is the optical detector. In the near-infrared wavelength range avalanche photodiodes (APD's) are the best choice for higher signal-to-noise ratio, where there are many water vapor absorption lines. In this study, characterization experiments were performed to evaluate a group of silicon-based APD's. The APD's have different structures representative of different manufacturers. The experiments include setups to calibrate these devices, as well as characterization of the effects of voltage bias and temperature on the responsivity, surface scans, noise measurements, and frequency response measurements. For each experiment, the setup, procedure, data analysis, and results are given and discussed. This research was done to choose a suitable APD detector for the development of an advanced atmospheric water vapor differential absorption lidar detection system operating either at 720, 820, or 940 nm. The results point out the benefits of using the super low ionization ratio (SLIK) structure APD for its lower noise-equivalent power, which was found to be on the order of 2 to 4 fW/Hz(sup (1/2)), with an appropriate optical system and electronics. The water vapor detection systems signal-to-noise ratio will increase by a factor of 10.Refaat, Tamer F. and Halama, Gary E. and DeYoung, Russell J.Langley Research CenterDIFFERENTIAL ABSORPTION LIDAR; ATMOSPHERIC MOISTURE; AVALANCHE DIODES; MOISTURE METERS; PHOTODIODES; RADAR RECEIVERS; WATER VAPOR; CHARACTERIZATION; RADAR MEASUREMENT; FREQUENCY RESPONSE; IONIZATION; NOISE REDUCTION; SIGNAL TO NOISE RATIOS; ELECTRIC POTENTIAL; NOISE MEASUREMENT

The 2002 Workshop on Frontiers in Electronics was the third in the series of WOFE workshops. Over 70 leading experts from academia, industry, and government agencies reported on the most recent developments in their fields and exchanged views on future trends and directions of the electronics and photonics industry. The issues they addressed ranged from system-on-chip to DNA doping, from ultrathin SOI to electrotextiles, from photonics integration on the ULSI platform to wide band gap semiconductor devices and solid state lighting. The rapid pace of electronic technology evolution compels a merger of different technical areas, and WOFE-02 provided a unique opportunity for cross-fertilization of the emerging fields of microelectronics, photonics, and nanoelectronics. The workshop was informal and stimulated provocative views, visionary outlooks, and discussions on controversial issues.