This disclosure concerns methods for transmitting a signal in an optical
system. In one example, the method begins when an optical signal is
generated. Then, the optical signal is manipulated such that the optical
signal defines a substantially annular intensity profile, where power of
the optical signal varies in the intensity profile. Finally, the optical
signal is launched into an input face of an optical fiber such that a
predetermined part of the intensity profile of the optical signal is
located proximate an optical axis associated with the optical fiber.