For suitable power confinement of fundamental mode, the normalized frequency v should be maintained in the range 1.5 to 2.4 m and the fractional index difference must be linearly increased as a square function while the core diameter is linearly reduced to keep v constant. This confinement is achieved by?

• A. Increasing level of silica doping in fiber core
• B. Increasing level of germanium doping in fiber core
• C. Decreasing level of silica germanium in fiber core
• D. Decreasing level of silica doping in fiber core