A 250 m Direct Time-of-Flight Ranging System Based on a Synthesis of Sub-Ranging Images and a Vertical Avalanche Photo-Diodes (VAPD) CMOS Image Sensor.

We have developed a direct time-of-flight (TOF) 250 m ranging Complementary Metal Oxide Semiconductor (CMOS) image sensor (CIS) based on a 688 × 384 pixels array of vertical avalanche photodiodes (VAPD). Each pixel of the CIS comprises VAPD with a standard four transistor pixel circuit equipped with an analogue capacitor to accumulate or count avalanche pulses. High power near infrared (NIR) short (<50 ns) and repetitive (6 kHz) laser pulses are illuminated through a diffusing optics. By globally gating the VAPD, each pulse is counted in the in-pixel counter enabling extraction of sub-photon level signal. Depth map imaging with a 10 cm lateral resolution is realized from 1 m to 250 m range by synthesizing subranges images of photon counts. Advantages and limitation of an in-pixel circuit are described. The developed CIS is expected to supersede insufficient resolution of the conventional light detection and ranging (LiDAR) systems and the short range of indirect CIS TOF.

Demonstration of 12.5-Gbps optical interconnects integrated with lasers, optical splitters, optical modulators and photodetectors on a single silicon substrate.

One of the most serious issues in information industries is the bandwidth bottleneck in inter-chip interconnects. We propose a photonics-electronics convergence system to solve this issue. We fabricated a high density optical interposer to demonstrate the feasibility of the system by using silicon photonics integrated with an arrayed laser diode, an optical splitter, silicon optical modulators, germanium photodetectors, and silicon optical waveguides on a single silicon substrate. Error-free data transmission at 12.5 Gbps and a transmission density of 6.6 Tbps/cm2 were achieved with the optical interposer. We believe this technology will solve the bandwidth bottleneck problem in the future.

[Significance of ultrasonography for nasal fracture].

Nasal fracture is a common facial fracture. The diagnosis and evaluation of nasal fractures are commonly performed using X-ray and/or CT scans preoperatively and postoperatively. However, the diagnosis and intraoperative evaluation of nasal fractures using ultrasonography is not common. CT scans and ultrasonography studies were used to diagnosed twelve patients with nasal fractures, and ten patients were treated by closed reduction between November 2002 and February 2004. Ultrasonography was used intraoperatively to confirm adequate bone restoration. The ultrasound examinations were performed using the conventional method, with the application of ultrasound gel. The ultrasonography results and the CT scan of the nasal bone were almost the same, and ultrasonography may be suitable and sufficient for the diagnosis of nasal fractures. Moreover, objective intraoperative evaluations can only be performed using ultrasonography. Thus, we believe that ultrasonography is a useful tool for the diagnosis of nasal fractures and the evaluation of medical treatment.