Design and Performance of 1×8 Core Selective Switch Supporting 15 Cores Per Port Using Bundle of Three 5-Core Fibers

Abstract

A core-selective switch (CSS) is a key building block for a port modular spatial cross-connect where an optical signal launched into any core in the input multi-core fiber (MCF) can be switched to a core that has the same core identifier of any output MCF. One way to increase the core count in a CSS is to use several MCFs as a bundle and collimate/demultiplex beams emitted from it all at once using a single microlens. In this paper, we report a 1×8 CSS prototype based on a bundle of three 5-core fibers (5-CFs), which supports 15 cores per port, demonstrating the feasibility of a high core count CSS through MCF bundling. The CSS prototype exhibits insertion loss of less than 4.8 dB, and polarization dependent loss of less than 0.5 dB over an ultrawide wavelength range of 1480 nm to 1630 nm. The inter-core crosstalk (XT) characteristics as a function of the wavelength are thoroughly investigated. We show that the intra 5-CF XT imparted to the center core from the other four outer cores in the same 5-CF is less than -52 dB and the inter 5-CF XT from cores in the other 5-CFs in the same bundle is less than -64 dB, which are sufficiently low values for practical networks. No OSNR penalty in the 100-Gb/s spatial channel was observed when ten 100-Gb/s DP-QPSK WDM signals in the C-band were simultaneously routed by the bundled 5-CF 1×8 CSS prototype.

Enabling technologies for flexible and scalable spatial cross-connects

“…So far, a 1×8 CSS supporting a five-core fiber (5-CF) per port was prototyped using a MEMS mirror array, which exhibits low insertion loss and low polarization dependent loss over a 1480-nm to 1630-nm wavelength range [6]. One way to increase the core count per port in a CSS is to use several MCFs as a bundle and collimate/demultiplex beams emitted from it all at once using a single microlens [7].…”

“…Figure 3(a) shows a photo of nine 5-CF bundles arranged in a 3×3 orthogonal array at a 750-µm pitch [7]. They are constructed by forming 27 holes with a 125-μm diameter on a silicon substrate and inserting 5-CFs with 125-μm cladding into the substrate while adjusting the core rotational position.…”

Spatial Mode-Multiplexed Light Source Using Angularly-Multiplexed Volume Holograms

“…To support such MCF or MMF transmissions, various elemental technologies have been developed, such as multicore/few-mode Er-doped fiber (EDF) [6], [7], multi-core connecter [8], [9], fan-in/fan-out (FIFO) [10], mode multiplexer/demultiplexer [11]- [16], multi-input multi-output (MIMO) DSP [17], [18], spatial switch [19], [20] and so on. The SDM transceiver is also essential to achieve SDM transmission.…”