新型小尺寸窄带偏振分光器在光纤通信中的应用

在光纤通信中，为了在不改变调制波长范围的基础上仍能实现更多数据通道的波分复用，设计了一种新型的小尺寸窄带偏振分光器，用于对现有的数据通信网络进行扩容以及提高光信号的信噪比。在该分光器上蒸镀了两种新设计的膜系，一层是窄带滤光膜，另一层是偏振分光膜。采用TFCalc软件仿真，设计结果中窄带滤光膜的带宽约为0.4 nm，偏振分光膜在1 530～1 560 nm范围内对p光的通透性能优于99.8%。基于以上膜系设计在BK7光学玻璃上实际制备两组膜系，实验采用Agilent 8164-A型光波测量系统对经过膜后的光进行光谱分析。结果显示，窄带滤光膜的实际带宽优于0.4 nm，增益平坦度小于-0.05 dB，相比现有常见的0.8 nm滤光膜具有更窄的带宽，可以实现在调制波长范围不变的条件下增大波分复用的数据通道总量。偏振滤光膜的实际p光透光率为99.6%，相比仿真值略低，但仍优于设计要求，相比传统分光器的光信号强度保留效果更好，具有更高的信噪比。综上所述，该分光器具有更好的应用价值和实用意义。

Research and Application of Narrowband Polarizing Beam Splitter in the Optical Fiber Communication

In fiber-optic communications,in order to achieve more data channels in the wavelength division multiplexing (WDM) system without changing the modulation wavelength range,a new type of small-sized narrowband polarizing beam splitter was designed.It can be used for data communication network expansion and improve the Signal to Noise Ratio (SNR)of the optical signal.Two kinds new film system designed were deposited on the polarizing beam splitter.One layer is narrowband filter film, while the other layer is polarizing beam splitter film.TFCalc software was used for simulation analysis,and the results shown that the bandwidth of the narrowband filter film was about 0.4 nm,and the permeability of p light from the polarizing beam splitter film was better than 99.8% in the range of 1 530~1 560 nm.Based on the above film system design,two groups film system was made on BK7 optical glass.In the experiment,light through film was spectral analysis with Agilent 8164-A type op-tical measuring instrument.Experimental results show that the actual bandwidth of the narrowband filter film is better than 0.4 nm,gain flatness is not less than -0.05 dB.It has a narrower bandwidth compared to the existing common 0.8 nm filter film, and it can be realized to increase the amount of data channels in the wavelength division multiplexing system with the same modu-lation wavelength range.Actual transmittance of p light was 9 9.6% through polarizing filter film,and it’s slightly lower than the simulated values,but it remains better than the design requirements.Compared to conventional polarizing beam splitter,its optical signal was stronger,and it has a higher SNR.In summary,the polarizing beam splitter has better application value and practical significance.