Zolnacz Kinga, Urbanczyk Waclaw
Opt Express. 2022 Jan 17;30(2):926-938. doi: 10.1364/OE.445283.
We present an effective method for free-space selective excitation of different combinations of LP and LP polarization modes in a birefringent optical fiber using a Wollaston prism, rotatable polarizer, and achromatic half-wave plate. The method is minimally wavelength-dependent and can be used for high-power sources. The relative coupling efficiencies of different modes can be continuously tuned and the suppression rate of the unwanted modes with respect to the targeted mode exceeds 20 dB. We present input system configurations that allow for the excitation of different individual modes and groups of modes and estimate the maximum coupling efficiencies based on numerical simulations. As example applications, we show the generation of Raman sidebands in different modes, gain tunability of intermodal four-wave mixing, and broadband conversion of a supercontinuum light beam from the fundamental to the LP mode.
我们提出了一种有效的方法，可利用沃拉斯顿棱镜、可旋转偏振器和消色差半波片，在双折射光纤中对LP和LP偏振模式的不同组合进行自由空间选择性激发。该方法对波长的依赖性极小，可用于高功率光源。不同模式的相对耦合效率可连续调节，且不需要的模式相对于目标模式的抑制率超过20 dB。我们给出了允许激发不同单个模式和模式组的输入系统配置，并基于数值模拟估计了最大耦合效率。作为示例应用，我们展示了不同模式下拉曼边带的产生、模式间四波混频的增益可调性以及超连续光束从基模到LP模式的宽带转换。
