Ranging and Velocity Detection using Period-One Oscillations in an Optically Injected Semiconductor Laser

• Main Author: 張馨勻
• Other Authors: 林凡異
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/82370223873555848607

碩士 === 國立清華大學 === 光電工程研究所 === 96 === We numerically simulated signal generation for range and velocity detecction utilizing optically injected (OI) system. OI system consists of a master laser and a slave laser. By tuning the operating parameters, the optically injected semiconductor laser can be operated in different instable regions. There are stable-locking, chaotic oscillation (CO), period-one oscillation (P1), period-two oscillation (P2) and high order oscillation regions. We research the radar for range and velocity detection with P1 state. For range detection, two schemes will be used to generate linearly chirped signal. One is directly modulating the injection strength of slave laser, and the other is indirectly modulating the injection strength of slave laser. After mixing transmitting signal and refected signal, the mixing signal can be used to evaluate the range of the target. We investigate the effect of bandwidth, period, and noise on the linewidth that determinates the resolution of the signal. By simulation, the resloution is 0.753 m utilizing directly modulating the injection strength of slave laser, and the resolution is 1.087 m utilizing indirectly modulating the injection strength of slave laser. In comparison, the resolution of the former is better than the latter. For velocity detection, there is Doppler-shift frequency when the target is moving, and we can evaluate the velocity of the target. By double-lock technology, the linewidth can be reduced with MSF. We evaluate that the resolution is 4.5 μm/s with the hypotheses. When the target moves sinusoidally or as a triangular wave, we research the relation between Doppler-shift frequency and the ratio of the target moving amplitude and the mircowave wavelength.