探测低空大气CO2浓度分布的近红外微脉冲激光雷达

提出了用来探测大气CO2分布、基于光纤1.6um波长的微脉冲激光雷达,对其性能进行了数值模拟.微脉冲激光雷达的发射机以半导体激光器加光纤放大器为核心,饱和输出功率37dBm;接收机采用了近红外光电倍增管和光子计数器,量子效率1%;一种偏正无关性纤维光学环形器作为发射/接收转换器,分波/合波器、隔离器、滤波器、耦合器都采用光纤器件,使系统更牢固.该系统的特点是发射脉冲能量低20uJ、重复频率高20KHz、小型化.(18×106个脉冲累加)它对近地面4.7Km高度内的探测信噪比在10∶1以上.光电倍增管的暗计数2×105/s限制了系统探测距离的增加.吸收倍增分离的InGaAs/Si雪崩光电二极管将会改善雷达的性能.

NEAR INFRARED MICRO PULSE LIDAR OF PROFILING ATOMOSPHERIC CO2

um-wave length, fiber-based micro pulse lidar of profiling atmospheric CO 2 was designed, The performance of this lidar was simulated. The transmitter of micro pulse lidar is based on semiconductor laser plus erbium-doped fiber amplifier with a saturated output power of 37dBm. The receiver employs photon counter and near infrared photomultiplier tube with quantum efficiency of 1%. A polarization-independent fiber-optic circulator is used as the transmit-receive switch. The system utilizes fiber devices for almost all components, e.g. wavelength-division-multiplexers/demultiplexers, isolator,filter,coupler, which make the system robust. Characteristic of this lidar is micro pulse energy 20uJ, high repetition rate of 20kHz and miniaturization. Signal simulations indicate that signal-to-noise ratio below 4.7km is more than 10∶1(18×106 pulse).Anode dark count of 2×105 /s limits the system performance. New InGaAs/Si APD with separate absorption and multiplication region will improve the lidar performance.