公开(公告)号：JP2001356233A

公开(公告)日：2001-12-26

申请号：JP2001147224

申请日：2001-05-17

Applicant: LUCENT TECHNOLOGIES INC

Inventor： GOLOWICH STEVEN EUGENE ,  JONES SEAN L ,  RITGER ALBERT JOHN ,  THORNBURG K SCOTT JR

IPC: C03B37/012 ,  G02B6/02 ,  G02B6/16

Abstract: PROBLEM TO BE SOLVED: To provide a device and a method to improve the band width of a multimode optical fiber so as to obtain a multimode optical fiber having improved band width and differential mode delay characteristics. SOLUTION: The embodiment of the invention includes an optical fiber preform (30) and a multimode optical fiber drawn from the preform and showing improved characteristics of the excess initiation band width without decreasing the conventional laser initiation band width characteristics. The optical fiber preform has a core region (34) having refractive index with specified differential mode delay which includes a first part belonging to the lower mode operating similar to the conventional one, and a second part belonging to the upper mode different from conventional operation so as to improve the excess initiation band width in a certain operating window without giving adverse influences on the laser initiation band width characteristics in the same and other operating windows. The structure of the preform optimized for the operation at 850 nm is constituted in such a manner that the differential mode delay specific to the preform a 1300 nm increases at the beginning similar to the conventional one and becomes horizontal with a value of nearly 0 in the upper modes and that the differential mode delay specific to the preform at 850 nm keeps horizontal with a value of nearly 0 similar to the conventional one and decreases in the upper modes.