Jeon Min Yong, Zhang Jun, Chen Zhongping
Beckman Laser Institute, University of California, Irvine, Irvine, California 92612, USA.
Opt Express. 2008 Mar 17;16(6):3727-37. doi: 10.1364/oe.16.003727.
We present characteristics of a wavelength swept laser with a scanning fiber Fabry-Perot filter at 1300 nm. We investigate the dependence of the scanning frequencies in the swept laser. In conventional wavelength swept lasers, the relative intensity of the laser output decreases significantly as the scanning frequency increases. The peak wavelength of the output spectrum is red-shifted due to the nonlinear frequency downshifting in the semiconductor optical amplifier (SOA). In the Fourier domain mode-locked (FDML) wavelength swept laser, we investigate transient intensity profiles and the full width at half maximum in response to the injection currents and detuning of the scanning frequency. The degradation of the scanning range of the swept laser is caused by the deviation from the scanning frequency at 45.6 kHz. In addition, transient intensity profiles show significant asymmetric behavior in response to the detuned frequencies. Finally, the axial resolution and sensitivity as a function of imaging depth are analyzed for both forward and backward scans. With the FDML laser, the detection sensitivity up to 102 dB is achieved for the backward scans. The backward scans exhibit higher axial resolution and sensitivity than the forward scan.
我们展示了一种在1300 nm波长处带有扫描光纤法布里-珀罗滤波器的扫频激光器的特性。我们研究了扫频激光器中扫描频率的依赖性。在传统的扫频激光器中，随着扫描频率的增加，激光输出的相对强度会显著降低。由于半导体光放大器（SOA）中的非线性频率下移，输出光谱的峰值波长会发生红移。在傅里叶域锁模（FDML）扫频激光器中，我们研究了瞬态强度分布以及响应注入电流和扫描频率失谐时的半高全宽。扫频激光器扫描范围的退化是由偏离45.6 kHz的扫描频率引起的。此外，瞬态强度分布在响应失谐频率时表现出明显的不对称行为。最后，针对正向和反向扫描，分析了轴向分辨率和灵敏度作为成像深度的函数。使用FDML激光器，反向扫描可实现高达102 dB的检测灵敏度。反向扫描比正向扫描表现出更高的轴向分辨率和灵敏度。
