The correct answer is False.
An intensity modulation optical source is required for many applications that involve optical fiber transmission. This is because the intensity of the light signal is what carries the information in optical fiber communications. The intensity of the light signal can be modulated to encode information, such as digital data or analog signals.
There are a few exceptions to this rule. For example, in some cases, a phase modulation optical source can be used instead of an intensity modulation optical source. However, these cases are relatively rare.
In general, an intensity modulation optical source is required for most applications that involve optical fiber transmission.