光电振荡器是一种采用光电结合方式的新型微波频率源,其利用光学长时储能,可以实现极低相位噪声的信号输出。文章研究了光纤中散射噪声对光电振荡器相位噪声的影响,重点介绍了基于相位调制等效展宽激光线宽,抑制布里渊散射噪声架构,通过理论公式推导以及实验验证,表明了上述架构可极大改善光电振荡器的相位噪声。实验中采用调制频率为50MHz、调制幅度为3.1的相位调制信号对激光线宽进行等效展宽,得到在10GHz频率下为-157.3dBc/Hz@10kHz的极低相位噪声信号输出。
相位调制 激光线宽 极低相噪 光电振荡器 phase modulation laser line-width ultra-low phase noise optoelectronic oscillator
中国科学院 苏州纳米技术与纳米仿生研究所,苏州 215123
基于外差相干检测的随机相位调制连续波激光测距具有灵敏度高、对背景噪声容忍度高等优点,但传统的解调方法都是基于序列移位相乘和傅里叶变换,需要消耗大量计算资源和计算时间。提出并验证了一种针对随机相位调制连续波激光测距的快速解调方法,通过对回波外差信号进行傅里叶变换得到多普勒频移,解调出目标速度信息,然后通过数字下变频获得回波信号的正交分量,最后利用傅里叶变换在频域实现伪随机调制序列与回波信号的循环卷积,得到目标的位置信息。在原理验证实验中,使用长度为2 047的11阶伪随机二进制序列,调制速率为40 MHz,利用快速解调方法从回波信号中成功恢复了目标位置和速度,并在光纤中实现了2.7 m的距离分辨率。
激光测距 相位调制 相干探测 伪随机码 Laser ranging Phase modulation Coherent detection Pseudo-random code
激光与光电子学进展
2023, 60(17): 1712001
激光与光电子学进展
2023, 60(15): 1500001
光学学报
2023, 43(16): 1623007
深圳大学 物理与光电工程学院,广东 深圳 518060
金属卤化物钙钛矿(MHP)作为一种新兴的半导体材料,目前已在光电应用中表现出优异的性能。其中,基于MHP的发光二极管(PeLED)发展迅猛,红光和绿光器件的效率已达到商用水平。然而,蓝光PeLED 的效率还远落后于红、绿光器件,这在很大程度上阻碍了 PeLED 在全彩显示领域中的应用。本文通过调节混合卤素阴离子的比例以及准二维钙钛矿组分来实现基于维度调制的准二维蓝色PeLED制备。首先,我们采用在 CsPbBr3∶PEABr 准二维钙钛矿中添加苯乙基氯化胺(PEACl)逐步替换苯乙基溴化胺(PEABr),实现了发光峰从502 nm到476 nm的可调制发射。然而,随着PEACl的增加,薄膜中的缺陷及n = 1低维相逐渐增多,导致器件效率降低。我们将溴化胍(GABr)引入到CsPbBr3∶PEACl 准二维钙钛矿中,n = 1低维相得到了显著的抑制,这有利于激子能量的转移,最终蓝光范围内准二维PeLED性能得到了显著提升。本工作为实现高效蓝光 PeLED 提供了新的思路。
钙钛矿发光二极管 维度调制 蓝光 PEACl掺杂 GABr掺杂 perovskite light-emitting diode phase modulation blue emission PEACl doping GABr doping
光学学报
2023, 43(14): 1426001
光学学报
2023, 43(13): 1326001

1 中北大学仪器与电子学院,山西 太原 030051
2 中北大学山西省光电信息与仪器工程技术研究中心,山西 太原 030051
3 中北大学前沿交叉科学研究院,山西 太原 030051
Overview: Overview: Photoelastic modulator, a high-quality thermo-mechanical coupling device composed of isotropic elastic optical crystal and piezoelectric crystal, is widely used in polarization measurement, spectral measurement, and many other fields. A high-voltage resonant circuit is adopted to generate the periodically changing high voltage amplitude, which is applied to both ends of the piezoelectric crystal to drive the photoelastic modulator to perform forced telescopic vibration, thus generating periodic birefringence. Although the quality factor of the photoelastic modulator is as high as 103, the photoelastic crystal in the photoelastic modulator will vibrate in length under the action of the piezoelectric crystal when driven by the high voltage. In addition, there will be thermal dissipation caused by dielectric loss and mechanical loss, some of which exchange heat with the environment, and the rest will raise the temperature of the photoelastic modulator itself. When the heat exchange between the photoelastic modulator and the external environment is happened before the heat balance, the resonant frequency will be changed, which will lead to the reduction of the modulator driving efficiency and the instability of the modulation amplitude. Standing from the perspective of mechanical point, the system can be equivalent to the vibration model of a damped spring-mass system. The system is an underdamped second-order system, and the modulator can also be equivalent to a RLC series resonant circuit from the electrical perspective. Therefore, when the temperature of the modulator changes, its electrical parameters and resonat will also vary. Therefore, this paper first analyzes the resonant frequency characteristics of the photoelastic modulator from the perspective of electricity, and establishes the equivalent circuit model of the photoelastic modulator and the composite resonant network model with the high-voltage resonant drive circuit. Meanwhile, the resonant network is analyzed, and the results show that when the phoyoelastic is in the resonant state, the modulator impedance and the inductance voltage amplitude of the high-voltage resonant circuit are both the smallest. Therefore, this paper designs a control and test system based on field programmable gate array (FPGA) by combining the above mentioned characteristic and applying the amplitude and frequency characteristics of the resonant network. FPGA completes the measurement of the inductance voltage amplitude and the demodulation of the photoelastic modulation signal through the digital phase-locked amplifier. After obtaining the inductance voltage amplitude, the real-time tracking of the minimum value of the inductance voltage amplitude can be obtained by FPGA, so that the tracking of the resonant frequency of the photoelastic modulator can be realized. By demodulating the modulated signal, the calibration optical path system of the photoelastic modulator is also capable of measuring the modulation amplitude of the modulator. Finally, this paper successfully builds the test system, and conducts the frequency sweep test to verify the feasibility of the resonance tracking system. The resonance tracking tests on the modulator are implemented at room temperature - 20℃ & 80℃ respectively. The results show that the test meets the requirements, and the maximum standard deviation of modulation amplitude is lower than 0.83% rad.
弹光调制器 频率跟踪 相位调制幅度 幅频特性 photoelastic modulator frequency tracking phase modulation amplitude amplitude-frequency characteristics