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We present a wavelength-tunable band-pass filter composed of multi-stage cascaded asymmetric Mach-Zehnder interferometers. The fabricated seven and eight-stage filters exhibit full tunability in the C-band, and 3 dB on-chip loss, and 0.27 nm (33 GHz), 0.14 nm (18 GHz) bandwidth respectively.
The continued increase in Internet traffic, particularly in metro networks, is spurring wide deployment of optical networking technologies for wavelength routing. In metro networks, the number of nodes traversed can be very large and hence the optical filtering penalty incurred in the ROADM/OXC nodes can be critical as it degrades fiber frequency utilization. This presentation elucidates how grouped...
Recently, multilevel-modulation formats such as quadrature phase shift keying and 16-ary quadrature amplitude modulation are being introduced into optical communication systems. Since such signal forms are susceptible to laser phase instability, it is important to identify the linewidth of lasers used in such systems. As a measurement technology, the self-heterodyne method is widely deployed [1]....
With the advent of new network services including cloud computing and big-data-related business, intra-datacentre traffic is growing at the rate of 23% a year [1]. To process such a large amount of traffic cost-effectively, optical circuit switches with high port count need to be deployed in intra-datacentre networks [2]. So far, we proposed optical-circuit-switch architecture suitable for intra-datacentre...
We propose a highly reliable and large-scale OXC architecture that consists of MxM WSSs. The proposed scheme can drastically reduce the annual downtime of optical paths stemming from WSS failures while retaining excellent cost-effectiveness.
We propose a novel network architecture that enables intra- and inter-datacenter converged flow management. By adopting our proposed single large-scale optical circuit switch, intra- and inter-datacenter traffic can be transported without any blocking.
Dynamic control of coarse/fine granular routing optical networks is proposed. The routing scheme exploits virtual direct links, which enhances fiber frequency utilization and eliminates the need to control intermediate nodes. Its effectiveness is numerically verified.
We fabricate an optical tunable filter for gridless signal drop in ROADMs. Its effectiveness is confirmed by experiments on 10-Gbaud intensity-modulated signals with 50-GHz spacing and 32-Gbaud dual-polarization QPSK and 16QAM signals with 33.3-GHz spacing.
We present a novel networking concept and a control algorithm that attains link and node cost reduction simultaneously. The proposal can be implemented using existing hardware technologies, OXCs/ROADMs that utilize LCOS WSSs, and an enhanced control algorithm, Grouped Routing scheme, that is aware of the subsystem modular OXC configuration. Numerical experiments demonstrate that the spectral efficiency...
We propose a fast and large-scale optical circuit-switch architecture for intra-datacenter applications. A 1,440×1,440 optical switch is designed and tested with 180-wavelength signals in the full C band; the worst switching time is 498 microseconds.
Hardware scale analysis shows that flexible waveband routing OXCs can substantially reduce the numbers of WSSs and EDFAs. Transmission experiments on developed prototype that adopts monolithic arrayed DC type matrix switches verify their technical feasibility.
We present a novel dynamic optical path control algorithm for Grouped Routing that can greatly enhance fiber frequency utilization. Careful grooming is shown to effectively mitigate the routing penalty even with dynamic optical path control.
We fabricated and characterized a polarization-independent tunable band-pass filter, composed of a four-stage Si-wire asymmetric Mach-Zehnder interferometer. The filter exhibited full tunability in the C-band, 2.2 nm bandwidth, and 2 dB on-chip loss.
We propose highly reliable and cost-effective large-scale OXC architecture. By placing protection WSSs in each subsystem, the proposed OXC can substantially improve the total system reliability cost-effectively. The annual failure time of a network can be greatly reduced with a small number of additional WSSs.
We experimentally demonstrate a 2,160×2,160 optical circuit switch with a switching time of less than 500 μs, aiming at fast and non-hierarchical intra-datacenter interconnection. The switch comprises delivery-and-coupling switches and wavelength-routing switches based on AWGs. We implemented twin 1×135 AWGs on a monolithic PLC chip.
We investigate the effectiveness of coarse and fine granular hybrid optical-path routing networks implemented with virtual direct links. Numerical and experimental evaluations show that our network control scheme can substantially improve the product of spectral efficiency and hop count compared to present single-granular networks.
We provide a guideline on the size of the MxM WSS needed to create future scalable OXCs. Analyses show that 10×10 WSSs can create an OXC that is scalable to 40×40 with marginal routing-performance offset.
A new OXC configuration that yields hitless port-count expansion to meet traffic growth at minimum cost is presented. Numerical experiments verify the node configuration offers almost complete routing capability even though it uses small-degree WSSs.
We proposed a novel elastic optical network architecture employing Grouped Routing that enhances frequency utilization. With a developed network design algorithm, necessary fiber number was further reduced +20% compared with conventional elastic optical path network.
Intra-datacenter traffic is growing more than 20% a year. In typical datacenters, a large number of top-of-rack switches are interconnected via multi-tier electrical switches. The electrical switches necessitate power-consuming optical-to-electrical (OE) and electrical-to-optical (EO) conversion. In addition, the power consumption increases with the growing traffic. To overcome this problem, optical...
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