40 Gb/s Data Transmission Over a 1-m-Long Multimode Polymer Spiral Waveguide for Board-Level Optical Interconnects

Abstract

Optical interconnects have attracted considerable attention for use in short-reach communication links within high-performance electronic systems, such as data centers, supercomputers, and data storage systems. Multimode polymer waveguides, in particular, constitute an attractive technology for use in board-level interconnects as they can be cost-effectively integrated onto standard PCBs and allow system assembly with relaxed alignment tolerances. However, their highly multimoded nature raises important concerns about their bandwidth limitations and their potential to support very high on-board data rates. In this paper, we report record error-free (BER < 10 −12 ) 40 Gb/s data transmission over a 1-m-long multimode polymer spiral waveguide and present thorough studies on the waveguide bandwidth performance. The frequency response of the waveguide is investigated under a wide range of launch conditions and in the presence of input spatial offsets, which are expected to be highly-likely in real-world systems. A robust bandwidth performance is observed with a bandwidth-length product of at least 35 GHz×m for all launch conditions studied. The reported results clearly demonstrate the potential of this technology for use in board-level interconnects, and indicate that data rates of at least 40 Gb/s are feasible over waveguide lengths of 1 m. Index Terms-Board-level optical interconnects, multimode waveguides, polymer waveguides, waveguide bandwidth. I. INTRODUCTIONO PTICAL technologies have attracted considerable interest in recent years for use in short-reach communication links. Conventional copper-based interconnection technologies struggle to keep up with the ever increasing demand for interconnection bandwidth in high-performance electronic systems, such as data centres, supercomputers and data storage systems [1]-[3]. The inherent disadvantages of copper-based interconnects when operating at high data rates, such as electromagnetic interference (EMI), limited bandwidth and large power consumption,

High-bandwidth and low-loss multimode polymer waveguides and waveguide components for high-speed board-level optical interconnects

“…As a result, important questions arise on the potential of this waveguide technology to support such high data rates because of their highly-multimoded nature. To address this issue, we have recently demonstrated 25 Gb/s [23] and 40 Gb/s [24] data transmission over 1.4 m and 1 m long spiral waveguides respectively, and we have presented bandwidth studies based on frequency response measurements on long spiral waveguides under different launch conditions [25]. The frequency response studies have shown that these waveguides exhibit bandwidth-length products (BLP) > 35 GHz×m, while the data transmission experiments have demonstrated that, for 40 Gb/s data transmission, power rather than bandwidth is the limiting factor in the maximum reach of these waveguide links.…”

Thermal Reflow Engineered Cylindrical Polymer Waveguides for Optical Interconnects

“…Nowadays, optical polymer based photonic integrated circuits (PICs) are highly demanded by optoelectronic applications [1][2][3]. They offer transparency in visible and near-IR, wide tunability for particular applications, low-cost fabrication and simple packaging [4].…”

Dispersion studies on multimode polymer spiral waveguides for board-level optical interconnects

“…Directly-modulated 850 nm VCSELs operating at 64 Gb/s have been recently demonstrated [3]. We have recently presented thorough bandwidth studies on a 1 m long polymer multimode spiral waveguide using frequency domain (S21) measurements, and we have demonstrated a bandwidthlength product of at least 35 GHz×m [4]. However, we haven't been able to determine the actual bandwidth of these waveguides due to the limitations in the active components and instruments.…”