A prism coupler with index np = 2.2 is used to observe the modes of a waveguide as shown below. The light source is a He-Ne laser with λ0 = 6328 A. If ˚ the light from a particular mode is seen at an...

A prism coupler with index np = 2.2 is used to observe the modes of a waveguide as shown below. The light source is a He-Ne laser with λ0 = 6328 A. If ˚

the light from a particular mode is seen at an angle of 26.43◦ with the normal

to the prism surface, what is the propagation constant β for that mode?