Exemplary embodiments of the present invention provide for methods to launch data signals from single mode fiber optic cable into legacy multimode fiber optic cable. In one exemplary embodiment, a single mode fiber is offset slightly from the axis of a multimode fiber, thus only exciting the outer mode of the multimode fiber. In an alternate exemplary embodiment, a core portion of the single mode fiber is exposed, heated, and fused with a cladding portion of the multimode fiber. In yet another alternate exemplary embodiment, various lenses can be used to collimate and focus light signals from single mode fibers into multimode fibers, and vice versa. In these exemplary embodiments, the transmitted light signals can be in the range of from 1470 to about 1610 nm with, for example, a 20 nm channel separation. Other wavelengths and channel separations are also possible.

The present invention relates to lensed fiber stub assemblies and optical and optoelectronic packages including them. The fiber stub assemblies include a section of lensed fiber having a lensed end having a lens face, and a distal end having an endface, a lens alignment ferrule affixed to and holding the lensed end of the lensed fiber, and a package attachment ferrule having a distal endface and an exterior surface, the package attachment ferrule affixed to and holding the distal end of the lensed fiber. The lensed fiber stub assemblies of the present invention allow for hermetic packaging of optical and optoelectronic devices, good manufacturing throughput, facile package connectorization, acceptable device thermal performance, and ease of alignment in the packaging process.

In an optical transmission system, a lens converges an optical signal outputted from a light emission element. The optical signal having passed .through the lens enters a multi-mode fiber (MMF). A vertex of the lens and an input plane of the MMF are at a distance. The distance is set to a value which is not equal to the distance from the vertex to a focal point of the lens. As a result, a lowcost optical transmission system can be provided in which the influence of mode dispersion is reduced.

A multimode fiber optical fiber transmission system includes an improved configuration for launching a single mode long wavelength transmission signal into existing multimode optical fiber networks. More specifically, the invention utilizes new single mode long wavelength VCSEL devices to realize a novel transmitter/transceiver for multimode fiber links where offset launch with controlled mode conditioning is achieved without the use of a mode conditioning patchcord, and in some embodiments, without the use of any collecting or focusing elements.

A multimode fiber optical fiber transmission system includes an improved configuration for launching a single mode long wavelength transmission signal into existing multimode optical fiber networks. More specifically, the invention utilizes new single mode long wavelength VCSEL devices to realize a novel transmitter/transceiver for multimode fiber links where offset launch with controlled mode conditioning is achieved without the use of a mode conditioning patchcord, and in some embodiments, without the use of any collecting or focusing elements.