A waveguide-based combiner that can combine an infrared laser beam with primary color (red, green, and blue) laser beams is proposed and analyzed using a simulation based on the beam propagation method. The combiner comprises four single-mode waveguides for individual light inputs and four directional couplers to change the light transmission path. Introducing the characteristic symmetrical arrangement of these waveguides and couplers results in an excellent performance for the four-color (red–green–blue–infrared) waveguide-based combiner. The symmetrical arrangement essentially reduces the combiner size without degrading the combining efficiency even though an additional combining color is added. The total length of the combiner is only 2.5 mm, in spite of the fact that the simulated combining efficiency averaged over the red, green, blue, and infrared colors is as high as 94%. In addition, a combining efficiency of more than 80% is obtained over a wide wavelength region of 35 nm. The effect of the polarization difference on the combining efficiency is negligible, i.e., almost within ± 1%. The analysis of the combining efficiency dependence on the gap width of the directional coupler composing the combiner indicates a large fabrication tolerance for process condition fluctuations. The proposed four-color (red–green–blue–infrared) combiner is expected to expand the functionality of compact laser beam scanner-based displays.

提出了一种基于波导的组合器，该组合器可以将红外激光束与原色（红色、绿色和蓝色）激光束组合，并使用基于光束传播方法的仿真进行分析。该组合器包括四个用于单独光输入的单模波导和四个用于改变光传输路径的定向耦合器。引入这些波导和耦合器的特征对称排列可以为基于四色（红-绿-蓝-红外）波导的组合器带来出色的性能。即使添加了额外的组合颜色，对称布置也基本上减小了组合器的尺寸，而不会降低组合效率。组合器的总长度仅为 2.5 毫米，尽管模拟的组合效率在红色、绿色、蓝色、红外颜色高达94%。此外，在 35 nm 的宽波长范围内获得了超过 80% 的组合效率。偏振差对组合效率的影响可以忽略不计，即几乎在±1%以内。对组合效率对组成组合器的定向耦合器间隙宽度的分析表明，工艺条件波动的制造公差很大。所提出的四色（红-绿-蓝-红外）组合器有望扩展基于激光束扫描仪的紧凑型显示器的功能。对组合效率对组成组合器的定向耦合器间隙宽度的分析表明，工艺条件波动的制造公差很大。所提出的四色（红-绿-蓝-红外）组合器有望扩展基于激光束扫描仪的紧凑型显示器的功能。对组合效率对组成组合器的定向耦合器间隙宽度的分析表明，工艺条件波动的制造公差很大。所提出的四色（红-绿-蓝-红外）组合器有望扩展基于激光束扫描仪的紧凑型显示器的功能。