Most developments in data transfer techniques are incremental by nature and the goal of increasing total
capacity in optical communications and networking requires new concepts for basic transmission media. The
transmission data rates can only be enhanced by introducing new modulation and multiplexing techniques. In
this paper different single mode tapered fiber waveguides are used to design a Spatial Multiplexer Unit (SMU)
for a novel optical fiber multiplexing technique called the Spatial Domain Multiplexing (SDM) that allows co-propagation
of two or more channels of exactly same wavelength without interfering with each other. This paper
also presents a CAD model for the SMU and then compares the output beam profiles from different single mode
tapered fibers to determine the optimum geometry for the SMU. Finally experimental and simulated beam
profiles for the SMU are presented.
Spatial Domain Multiplexing (SDM) is a novel technique in optical fiber communications. Single mode fibers are used
to launch Gaussian beams of the same wavelength into a multimode step index fiber at specific angles. Based on the
launch angle, the channel follows a helical path. The helical trajectory is explained with the help of vortex theory. The
electromagnetic wave based vortex formation and propagation is mathematically modeled for multiple channels and the
results are compared against experimental and simulated data. The modeled output intensity is analyzed to show a
relationship between launch angle and the electric field intensity.
Spatial Domain Multiplexing (SDM) is a novel technique that allows co-propagation of two or more optical
communication channels of the same wavelengths over a single strand of optical fiber cable by maintaining spatial
separation between the channels. Spatial multiplexer known as the beam combiner module (BCM) supports helical
propagation of light to ensure spatial separation between the channels. It is inserted at the input end of the system. Spatial
de-multiplexing is achieved by a unit named beam separator module (BSM). This unit is inserted at the receiving end of
the system and it routes the optical energy from individual channels to dedicated receivers. Spatially multiplexed
channels exhibit negligible crosstalk. The bandwidth of the fiber optic systems employing SDM technique increases by
multiple folds. CAD model of a beam combiner module for a two channel system using commercially available
simulation tools is presented here. Simulated beam profile of the output is compared to the experimental data.