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.

公开(公告)号：JP2001220168A

公开(公告)日：2001-08-14

申请号：JP2000348887

申请日：2000-11-16

Applicant: LUCENT TECHNOLOGIES INC

Inventor： DIGIOVANNI DAVID JOHN ,  GOLOWICH STEVEN EUGENE ,  JONES SEAN L ,  REED WILLIAM ALFRED

IPC: C03B37/01 ,  C03B37/012 ,  C03B37/018 ,  C03B37/027 ,  C03B37/075 ,  G02B6/02 ,  G02B6/028 ,  G02B6/10 ,  G02B6/18

Abstract: PROBLEM TO BE SOLVED: To provide a method for manufacturing multimode silica-based optical fiber and to provide fiber manufactured by this method. SOLUTION: The method for manufacturing the multimode optical fiber of wide range silica-base contains provision of noncircular preform and drawing of fiber of chiral structure from the preform. The noncircular preform can be manufactured by maintaining the inside of a tubular preform under reduced pressure during at least a part of breaking and consequently obtaining a noncircular core and a cladding. The noncircular preform can be also manufactured by removing proper parts of the preform (by grinding or by plasma etching, for example) and obtaining a circular core and a noncircular cladding. The chiral structure is given to the fiber, for example, by twisting the fiber alternately in a clockwise direction and in an anticlockwise direction with respect to the preform during drawing of the fiber.

公开(公告)号：CA2323351A1

公开(公告)日：2001-05-16

申请号：CA2323351

申请日：2000-10-17

Applicant: LUCENT TECHNOLOGIES INC

Inventor： REED WILLIAM ALFRED ,  JONES SEAN L ,  GOLOWICH STEVEN EUGENE ,  DIGIOVANNI DAVID JOHN

IPC: C03B37/01 ,  C03B37/012 ,  C03B37/018 ,  C03B37/027 ,  C03B37/075 ,  G02B6/02 ,  G02B6/028 ,  G02B6/18

Abstract: Our method of making high bandwidth silica-based multimode optical fibe r comprises provision of a non-circular preform, and drawing fiber of chiral structure from the preform. The non-circular preform can be made by maintaining the inside of the tubular preform under reduced pressure during at least part of the collapse, resulting in a non-circular core and cladding. It can also be made by remova l (e.g., by grinding or plasma etching) of appropriate portions of the preform, resulting in a circular core and non-circular cladding. In the latter case, fiber is drawn at a relatively high temperature such that, due to surface tension, the cladding assumes substantially circular shape and the core assumes a non-circular shape. The chiral structure is imposed on the fiber in any appropriate way, e.g., by twisting during fiber drawing the fiber alternately in clockwise and couterclockwise sense relative to the preform.