In wavelength division multiplexing schemes, splitters must be used to combine and separate different wavelengths. Conventional splitters are fairly large with footprints in hundreds to thousands of square microns, and experimentally demonstrated multimode-interference-based and inverse-designed ultracompact splitters operate with only two channels and large channel spacing (>100 nm). Here we inverse design and experimentally demonstrate a three-channel wavelength demultiplexer with 40 nm spacing (1500, 1540, and 1580 nm) with a footprint of 24.75 μm². The splitter has a simulated peak insertion loss of −1.55 dB with under −15 dB crosstalk and a measured peak insertion loss of −2.29 dB with under −10.7 dB crosstalk.

中文翻译：

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紧凑型片上窄带三通道波长解复用器的逆向设计和演示

在波分复用方案中，必须使用分离器来组合和分离不同的波长。常规分离器相当大，占地面积达数百至数千平方微米，并且通过实验证明，基于多模干扰和反设计的超紧凑型分离器仅在两个通道和较大的通道间距（> 100 nm）下运行。在这里，我们反设计和实验证明用40纳米的间隔（1500，1540，1580和纳米）具有24.75微米的覆盖区的三信道波长分波器²。该分路器在−15 dB串扰下具有−1.55 dB的模拟峰值插入损耗，而在−10.7 dB串扰下具有−2.29 dB的测量峰值插入损耗。