hello, just a question : When light strikes a surface from a lower index of refraction to a higher index of refraction, the light wave undergoes a phase shift of pi radians. When light comes from a higher index of refraction to a lower index of refraction, there is no phase shift. so why do we have a phase shift (phi 1 and phi 2 ) ?
In a waveguide there is always a phase shift between incident and reflected wave. This phase shift depends on refractive indexes and the incident angle. If the waveguide is not symmetric the phase shifts are different at each boundary. To calculate the phase shift take a look at my other video about Fresnel equations.
By introducing the normalized frequency You wrote that this is only for TE modes. And next, so by cut-off frequency, You said that this for TE and TM modes. So where is the border between "only for TE" and "for TM too"
Normalized frequency is defining the waveguide. The cutoff frequency in a symmetric waveguide is the same for TE and TM modes. In an asymmetric waveguide these frequencies are different. Cutoff frequency is derived directly from characteristic equation for b=0. Characteristic equations for TE and TM modes are different due to different phase shifts durning reflection at the boundary between the core and cladding.
Wow well explained, thanks !
thank you so much for these videos, they're so informative.
Thanks 🙂
hello, just a question :
When light strikes a surface from a lower index of refraction to a higher index of refraction, the light wave undergoes a phase shift of pi radians. When light comes from a higher index of refraction to a lower index of refraction, there is no phase shift.
so why do we have a phase shift (phi 1 and phi 2 ) ?
In a waveguide there is always a phase shift between incident and reflected wave. This phase shift depends on refractive indexes and the incident angle. If the waveguide is not symmetric the phase shifts are different at each boundary. To calculate the phase shift take a look at my other video about Fresnel equations.
@@SalaScience great thank you !
I still confuse how to calculate the angle. could you give me an example how to calculate angle in fundamental mode?
Could you give me the reference for the phase shift equation?
By introducing the normalized frequency You wrote that this is only for TE modes. And next, so by cut-off frequency, You said that this for TE and TM modes. So where is the border between "only for TE" and "for TM too"
Normalized frequency is defining the waveguide. The cutoff frequency in a symmetric waveguide is the same for TE and TM modes. In an asymmetric waveguide these frequencies are different. Cutoff frequency is derived directly from characteristic equation for b=0. Characteristic equations for TE and TM modes are different due to different phase shifts durning reflection at the boundary between the core and cladding.