Update README.md

README.md

@@ -53,7 +53,7 @@ In general, we consider [MLPs](experiments/mlp) and [CNNs](experiments/cnn).  Fo
 If you find this work or the associated paper useful, it can be cited as below.
 
     @article{guo2019aonn,
-      title={End-to-end optical backpropagation for training neural networks},
+      title={Backpropagation through nonlinear units for all-optical training of neural networks},
       author={Guo, Xianxin and Barrett, Thomas D and Whang, Zhiming M and Lvovsky, AI},
       journal={arXiv preprint arXiv:1912.12256},
       year={2019}