Optical time-division multiplexing using picosecond solitons in a terahertz optical asymmetric demultiplexer

Abstract

The performance of a terahertz optical asymmetric demultiplexer (TOAD) operating with an ordinary fiber and with a dispersion decreasing fiber (DDF) and dispersion increasing fiber (DIF) configurations, for three length of fiber ( ξ=π/2, 2π and 5π) and using soliton and quasi-soliton laser profile for the control pulse, was studied. The numerical simulations shows that the increase of the fiber length lead to the decrease of the power for the first and second demultiplexed pulses and lead to a broadening of these pulses, with exception to the TOAD operating with the DDF fiber. For the TOAD operating with a basic telecommunication fiber one see that the increase of the power of the control power lead to a strong compression of the demultiplexed pulse. One can also conclude that operating the TOAD with one soliton period ( ξ=π/2) one has compression of the demultiplexed pulse. For higher length (four and 10 soliton periods) one start having broadening of the switched pulses. Operating the TOAD using a DDF fiber one can say that the control power ( P CTL1) necessary to demultiplex the signal pulse is always lower compared with the TOAD with the normal telecommunication fiber. This is a strong suggestion that the use of the DDF fiber will allow the use of less control power. One can also say that P CTL1 is always higher for the soliton profile compared with the quasi-soliton profile. It was also observed that the compression factor for the demultiplexed pulse ( C 1) is between 2 and 3 for all the lengths of the TOAD and considering the soliton and quasi-soliton profile for the control pulse. When operating the TOAD using a DIF fiber it was observed that P CTL1 for the DIF TOAD is always lower compared with the TOAD with the normal telecommunication fiber (with exception to the ξ=5π fiber in the soliton profile), however the power values are higher when compared with the DDF TOAD. It was also observed that the compression factor C 1 is showing compression ( C 1∼2.2) for shorter length of fiber ξ=π/2 considering the soliton and quasi-soliton, profile for the control pulse. For higher lengths of fiber the compression factor is showing broadening of the demultiplexed pulse (with exception to the ξ=5π fiber in the soliton profile). Our simulations considering the TOAD operating with a DDF and DIF with a linear profile conclude that it is possible to operate the TOAD with lower control power using a DDF fiber setup. For this device the demultiplexed pulses will present a compression on time duration and will be insensitive to the time profile of the control pulse.