This is achieved through the use of and DC Blocking Capacitors . The inductor allows DC to pass while blocking high-frequency AC signals, effectively isolating the DC supply from the RF path.
In standard G.652 fiber, light travels through the glass core via total internal reflection. The cladding has a lower refractive index. When you bend the fiber, the angle of incidence changes. If the bend is too tight, the light breaches the cladding and escapes. 4x-fbb