Wang X.-B.,Tsinghua University |
Wang X.-B.,China Institute of Technology
Physical Review A - Atomic, Molecular, and Optical Physics
We study the measurement-device-independent quantum key distribution (MDIQKD) in practice with limited resources when there are only three different states in implementing the decoy-state method and when there are basis-dependent coding errors. We present general formulas for the decoy-state method for two-pulse sources with three different states, which can be applied to the recently proposed MDIQKD with imperfect single-photon sources such as the coherent states or the heralded states from the parametric down-conversion. We point out that the existing result for secure MDIQKD with source coding errors does not always hold. We find that very accurate source coding is not necessary. In particular, we loosen the precision of the existing result by several orders of magnitude. © 2013 American Physical Society. Source
China Institute of Technology | Date: 2013-04-15
A high-speed sampling front-end circuit is presented that includes a MDAC sampling network, a reference voltage generator circuit, a comparator array, an operational amplifier, an output short-circuit switch, an adjustable clock duty cycle stabilizer, a status control module and a feedback control module. The circuit features low power, high sampling rate and high input bandwidth of sampling network. The time constant of the MDAC sampling network and the comparator array is precisely matched one another to improve input bandwidth of the sampling network. Sampling capacitors are designed as feedback capacitors and DAC calculation capacitors, thereby the operational amplifier doubles feedback coefficient and features 50% bandwidth and 50% power. The cycle stabilizer is adopted to shorten sampling time and extend amplification phase to greatly improve sampling rate. One input reference voltage tends to simplify the design of the reference voltage generator circuit. The circuit has wide applications in pipelined A/D converters.
China Institute of Technology | Date: 2014-08-19
A device structure is provided to reduce the leakage current of semiconductor devices with a floating buried layer (FBL), includes a substrate, a first epitaxial layer, a split floating buried layer, a second epitaxial layer, a doped trench, a protected device, a surface junction termination extension (S-JTE) and a scribe street. The device and the S-JTE are designed at the second epitaxial layer and the split floating buried layer at the joint of the first and second epitaxial layers. The doped trench is penetrated through the second epitaxial layer and connected to the split floating buried layer. The substrate, the first and second epitaxial layers feature the same typed doping which is opposite to that of split floating buried layer and doped trench.
China Institute of Technology | Date: 2012-09-27
A BiCMOS current reference circuit includes a reference core, a startup circuit, and a reference current output circuit. The reference core contains a current mirror, a positive temperature coefficient current generator, and a negative temperature coefficient current generator. The current mirror generates matching branch current. The positive and negative temperature coefficient currents were added in certain proportion to generate a reference current with zero temperature coefficient at room temperature. The startup circuit starts the reference core at power-on. The reference current output circuit proportionably outputs reference current generated by the reference core. Compared with the conventional voltage reference, the circuit uses current conveying technique, so it wont be affected by DC voltage drops of power supply network, and it features low transmission loss, good matching, excellent temperature stability, small chip size and auto-startup at power-on. Its preferably suitable for applications where A/D and D/A converters require accurate reference signals.
China Institute of Technology | Date: 2012-05-04
The present disclosure provides a particle source comprising a base having a gently-shaped top, and a tip formed as a tiny protrusion on the top of the base.