Theoretical and numerical analyses of waveguide branches in a photonic crys
tal are presented. Conditions for: perfect transmission and zero reflection
are discussed. Based upon these conditions, numerical simulations of elect
romagnetic-wave propagation in photonic crystals are performed to identify
structures with near-complete transmission. (C) 2001 Optical Society of Ame
rica OCIS codes: 130.1750, 130.2790, 230,7370, 230.1360.