Multimode optical fiber systems with adjustable chromatic modal dispersion compensation

摘要

Multimode optical fiber systems with adjustable chromatic modal dispersion compensation are disclosed, wherein the system includes a VCSEL light source and primary and secondary optically coupled multimode optical fibers. Because the VCSEL light source has a wavelength spectrum that radially varies, its use with the primary multimode optical fiber creates chromatic modal dispersion that reduces bandwidth. The compensating multimode optical fiber is designed to have a difference in alpha parameter relative to the primary multimode optical fiber of −0.1≦Δα≦−0.9. This serves to create a modal delay opposite to the chromatic modal dispersion. The compensation is achieved by using a select length of the compensating multimode optical fiber optically coupled to an output end of the primary multimode optical fiber. The compensating multimode optical fiber can be configured to be bend insensitive.

主权项

1. A method of compensating a primary multimode optical fiber having a chromatic dispersion D, an alpha parameter α40, and a length L1 for chromatic modal dispersion that arises from using the primary multimode optical fiber with a VCSEL light source having transverse modes of different wavelengths, the method comprising:
measuring a center-wavelength difference Δλmax-c for the VCSEL light source, wherein Δλmax-c≦1 nm; calculating a maximum delay difference Δt due to chromatic modal dispersion in the primary multimode optical fiber based on Δλmax-c, the chromatic dispersion D and the length L1; determining a maximum relative delay Δτmax imparted by a compensating multimode optical fiber having an alpha value α60 and a maximum relative refractive index Δ0; determining a length L2 of the compensating multimode optical fiber based on the maximum delay difference Δt and the maximum relative delay Δτmax; and optically coupling the compensating multimode optical fiber of length L2 to the primary multimode optical fiber.