High coupling efficiency and low signal light loss (2 + 1) × 1 coupler
*
Chen Xiao
a)
, Xiao Qi-Rong
b)
, Jin Guang-Yong
a)
, Yan Ping
b)
, Gong Ma-Li
b)†
Photograph of a real (2 + 1) × 1 coupler.