Patent ID: 7289698

Claim:
A multimode fiber system comprising: a transmitter for transmitting an optical signal; a receiver for receiving said optical signal; and at least one mode filter that is coupled between said receiver and said transmitter and passes only a specific set of fiber modes from said transmitter to be received by said receiver, said at least one mode filter comprises a tapered core section that includes a double taper configuration joined at the narrowest regions and in which each end of the two tapers has dimensions compatible with the fiber at that end, wherein said double taper configuration includes at least two tapered regions where one of said at least two tapered regions receives said optical signal and tapers down said optical signal to a single mode condition and another of said tapered regions is expanded to match the mode of the fiber at that end, said at least two tapered regions are directly coupled to each other so as increase the bandwidth of said multimode fiber.