Optical coupler with mode-mixing refractive microparticles

DETAILED DESCRIPTION FIG.
1 illustrates one embodiment of an optical coupler that is utilized as an optical splitter with optical source 101 transmitting light through optical mixing core 102 to optical fibers 104.
Optical mixing core 102 fills cladding structure 103 such that optical fibers 102 are embedded in optical mixing core 102.
Optical source 101 and heat sink 105 are attached to the optical splitter.
In accordance with the invention, a small concentration of refractive particles has been added to the suspension material of optical mixing core 102.
These particles have a typical dimension of 10 to 500 microns and will be hereafter be referred to as microparticles.
As light is transmitted by optical source 101 into optical mixing core 102 toward optical fibers 104, the light is bent slightly by various microparticles and, as a result, is coupled into higher order modes over the distance between optical source 101 and optical fibers 104.
The coupling of the light into higher order modes results in a uniform mode power distribution being applied to optical fibers 104.
It is well known in the art that a uniform mode power distribution in a large, high numerical aperture, step index waveguide results in a uniform power distribution across the aperture of the waveguide.
In this embodiment, optical source 101 is advantageously an optical laser; however, there could be a plurality of optical sources utilized in place of optical source 101.
To understand the manner in which the refractive microparticles cause light to be bent resulting in higher order modes, consider FIG.
2 which illustrates three rays of light striking a single microparticle (illustrated as a sphere) and being refracted.
FIG.
2 illustrates only a two-dimensional representation of the effects that an individual microparticle has within optical mixing core 102 of FIG.
1.
For discussion purposes, microparticle 200 is assumed to have a refractive index of 1.
46 and is suspended in a material having a refractive index of 1.
40