High Speed Electronics And Its Application In Quantum Information

Precise time measurement is important in fundamental research field such as physics, chemistry and biology. It is always been a hinder for high speed electronics to realize time measurement in nanosecond and picosecond scale. In this thesis high speed electonics for accurate time pick-up is studied. The whole work consists of the following contents:1. The synchronization error of free space quantum key distribution (QKD) has been studied in detail. We deduced that in long distance free space QKD, the synchronization error originates from the intensity fluctuation due to atmospheric turbulence. We have introduced the constant fraction discrinator (CFD) to decrease the synchronization error. We built a high precision CFD and applied it to the synchronization testing system. The synchronization error of a 1.5km one way transimission is 95ps. When the distance extends to 3km, the error is slightly increased to 119ps with CFD.2. We have conmpleted circuit design for high speed amplifier, discriminator and narrow pulse generating etc., which are important parts for infrared single photon detector (SPD).3. We have brought the infrared SPD into raman spectroscopy researching and built a infred raman testing system. When excited with ultraviolet and visiable light, the Raman signal is fully buried by the strong fluorescence. By using infred light source as excited light, the fluorescence emission can be avoided.4. With the advantage of infrared SPD, We can measure the fluorescence lifetime with gated mode. Not only the measurement wavelength is extended to near infrared, but also the problem of dark count accumulation of traditional SPD is solved. Compared with the classic fluorescence lifetime measurement technique, this new device can provide a brandnew method to infrad fluorescence analyzing. In practice, the fluorescence emission spectrum and lifetime of Erbium dropped laserglass are measured with this new method, which confirm its feasibility.