Mode-division multiplexing in fibre-optic communications based on orbital angular momentum

Abstract

The possibility of using optical vortices with different values of topological charge l, and hence with different values of the orbital angular momentum (OAM), for mode-division multiplexing in optical fibres is here investigated. Two OAM modes with l equal to 0 and 1, respectively, are multiplexed in a few-mode fibre and then demultiplexed after a fibre propagation of 200 m. Such modes are spatially separated at the two output ports of a Mach–Zehnder interferometer with mutually 90°-rotated Dove prisms in the two arms. It is also shown how to generalize this demultiplexing scheme, which is all-optical, passive and in principle without splitting losses, in order to deal with a higher number of vortices propagating in the fibre. Therefore the proposed mode-division multiplexing technique based on OAM modes is very promising for increasing the capacity of fibre-optic transmission systems in an energy-saving efficient way, without the high power consumption of modal demultiplexing exploiting real-time electronic post-processing.

Representation and Evolution of the Angular Momentum of the Light

“…This means that a beam carrying an orbital angular momentum reverses its handedness and acquires a phase shift l2 after a Dove prism. It is worthwhile to remark that this dependence of the phase shift on both the angle of rotation of the Dove prism and the orbital angular momentum value at the entrance allows for exploiting interferometric schemes based on rotated Dove prisms for demultiplexing beams with different values of orbital angular momentum [19]- [21]. More in detail, considering a balanced Mach-Zehnder interferometer with two Dove prisms mutually rotated of an angle in the two respective arms, it is possible to separate two different orbital angular momentum modes with 2Ál equal to an odd multiple of , at the two output ports of the interferometer.…”

Survey and Evaluation of Space Division Multiplexing: From Technologies to Optical Networks

“…An upcoming technology that could contribute in the new era of SDM is the so called Vortex Fiber for OAM multiplexing [9], [44]- [48]. Optical vortices are light beams In Eq.…”

“…Recent SDM research has focused on fibers supporting multiple cores, multiple elements, few LP modes (the fundamental linear polarized propagation modes of light inside the fiber) or even modes carrying Orbital Angular Momentum (OAM) [9]. Despite the recent extensive SDM research, no single study exists on both quantitatively evaluating these technologies, and correlating network system requirements with SDM technologies performance.…”

Performance analysis of communication links based on VCSEL and silicon photonics technology for high-capacity data-intensive scenario

“…Choosing a suitable subset of propagation constants, independent signals can travel on different propagation modes [4,5]. In the last years, some mode multiplexing and demultiplexing techniques have been experimentally validated [6]. However, MDM technique is still far from integration into commercial products.…”