The birefringence is the difference between the refractive index of a fiber in a direction at parallel to the fiber axis and in a direction at right angles. It is caused by asymmetric core shape for the two axes, and majorly one of the manufacturing imperfections. It helps in controlling polarization property inside the fiber.
Inevitable manufacturing imperfections in optical fiber leads to birefringence, which is one cause of pulse broadening in fiber-optic communications. Such imperfections can be geometrical (lack of circular symmetry), due to stress applied to the optical fiber and/or due to bending of the fiber.
To convert Celsius to kelvin, we need to know the formula. Kelvin = Celsius + 273.15. Now, we can figure out how many degrees kelvin -12 degrees Celsius is.
Thermal energy is defined as the total kinetic energy of all particles in an object. Even though the cup of water has a higher temperature, the bathtub has more thermal energy because it contains much more mass of water compared to the cup.