Efficient Second Harmonic Generation in 3D Nonlinear Optical-Lattice-Like Cladding Waveguide Splitters by Femtosecond Laser Inscription.
Efficient Second Harmonic Generation in 3D Nonlinear Optical-Lattice-Like Cladding Waveguide Splitters by Femtosecond Laser Inscription.
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通过飞秒激光刻印在 3D 非线性光学晶格包层波导分路器中高效产生二次谐波
DOI：
10.1038/srep22310
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发表时间：
2016-02-29
影响因子：
4.6
通讯作者：
Chen F
中科院分区：
文献类型：
--
作者：
Nie W;Jia Y;Vázquez de Aldana JR;Chen F
具有分束功能的集成光子器件具有广泛的应用前景。通过飞秒激光直写制备的类光学晶格包层波导结构，可以通过轨道限制的折射率分布来设计光的传播，实现定制的输出光束分布。本文报道了在非线性KTP晶体中制备三维激光写入光学晶格结构，实现1 × 4分束。通过这些非线性波导分束器结构的绿色光的二次谐波产生（SHG）为紧凑的可见激光发射器件提供了能力。利用基波（@1064 nm）与二次谐波（@532 nm）的II型相位匹配，通过这种三维分束器实现了倍频。在1064 nm连续波基波长泵浦光下，测量了532 nm的导波倍频，波导分束器的最大功率分别为0.65 mW和0.48 mW（对于相应的直通道波导为0.67 mW和0.51 mW），对应于大约~14.3%/W和13.9%/W的SH转换效率（对于相应的直通道波导，分别为11.2%/W、11.3%/W）。该工作为在单片芯片上制作具有分束功能的紧凑集成非线性光子器件奠定了基础。
Integrated photonic devices with beam splitting function are intriguing for a broad range of photonic applications. Through optical-lattice-like cladding waveguide structures fabricated by direct femtosecond laser writing, the light propagation can be engineered via the track-confined refractive index profiles, achieving tailored output beam distributions. In this work, we report on the fabrication of 3D laser-written optical-lattice-like structures in a nonlinear KTP crystal to implement 1 × 4 beam splitting. Second harmonic generation (SHG) of green light through these nonlinear waveguide beam splitter structures provides the capability for the compact visible laser emitting devices. With Type II phase matching of the fundamental wavelength (@ 1064 nm) to second harmonic waves (@ 532 nm), the frequency doubling has been achieved through this three-dimensional beam splitter. Under 1064-nm continuous-wave fundamental-wavelength pump beam, guided-wave SHG at 532 nm are measured with the maximum power of 0.65 mW and 0.48 mW for waveguide splitters (0.67 mW and 0.51 mW for corresponding straight channel waveguides), corresponding to a SH conversion efficiency of approximately ~14.3%/W and 13.9%/W (11.2%/W, 11.3%/W for corresponding straight channel waveguides), respectively. This work paves a way to fabricate compact integrated nonlinear photonic devices in a single chip with beam dividing functions.