A dual-channel directional coupler has κ = 4 cm−1, α = 0.6 cm−1, and Δβ = 0. What length should it be to produce a 3 dB power divider? If that length is doubled, what fraction of the input power is in...

A dual-channel directional coupler has κ = 4 cm−1, α = 0.6 cm−1, and Δβ =

0. What length should it be to produce a 3 dB power divider? If that length is

doubled, what fraction of the input power is in each channel at the output?