Relaxed Dimensional Tolerance Whispering Gallery Microbends

Williams, Kevin

doi:10.1109/jlt.2011.2150198

Cited by 17 publications

(9 citation statements)

References 35 publications

(28 reference statements)

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“…Critical dimension variations may be expected to become increasingly important with circuit scaling. Potentially important advances include the use of whispering gallery regimen waveguiding for reproducible, low-radius microbends 67 , precision-fabricated, low-loss de/multiplexers, low-reflection splitters, and manufacturable polarisation controllers 68 . Deep-UV lithography can enable both tighter dimensional control and also lower loss, lower crosstalk de/ multiplexer components that will be important for wavelengthselective architectures.…”

Section: Discussionmentioning

confidence: 99%

Integrated optical switch matrices for packet data networks

Stabile

Albores-Mejia

Rohit³

et al. 2016

Microsyst Nanoeng

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Integrated circuit technologies are enabling intelligent, chip-based, optical packet switch matrices. Rapid real-time reconfigurability at the photonic layer using integrated circuit technologies is expected to enable cost-effective, energy-efficient, and transparent data communications. InP integrated photonic circuits offer high-performance amplifiers, switches, modulators, detectors, and de/multiplexers in the same wafer-scale processes. The complexity of these circuits has been transformed as the process technologies have matured, enabling component counts to increase to many hundreds per chip. Active-passive monolithic integration has enabled switching matrices with up to 480 components, connecting 16 inputs to 16 outputs. Integrated switching matrices route data streams of hundreds of gigabits per second. Multi-path and packet time-scale switching have been demonstrated in the laboratory to route between multiple fibre connections. Wavelength-granularity routing and monitoring is realised inside the chip. In this paper, we review the current status in InP integrated photonics for optical switch matrices, paying particular attention to the additional on-chip functions that become feasible with active component integration. We highlight the opportunities for introducing intelligence at the physical layer and explore the requirements and opportunities for cost-effective, scalable switching.Keywords: large-scale integration; optical switching devices; optoelectronics; photonic integrated circuits In turn, this is leading to unsustainable energy usage and an increasing complexity in network control 2-4 . Optical packet routing and switching technologies offer the prospect of highly efficient networking that is attuned to packet-based traffic flows 4 . However, to date the underlying photonic hardware has not proved sufficiently scalable, and the physical layer performance has been impeded by the analogue nature of the underlying photonic components.Photonic switch matrices and wavelength-selective switches already provide energy-efficient connectivity at the highest bandwidths for circuit-provisioned time-scales. The optical switching engines that are now being deployed in telecom networks and data centre networks are based on slow (millisecond) circuitswitching technologies that leverage micro-electro-mechanical systems (MEMS) 5,6 and liquid crystal on silicon 7,8 switch elements. 3D MEMS systems now allow for connectivity between many hundreds of fibre connections 9,10 . The combination of broadband photonic switches and wavelength-selective diffractive optical elements offers even higher connectivity. However, the use of surface normal micro-optics introduces considerable assembly complexity as the connectivity scales. The switching speeds do not support packet-based traffic at the optical layer.Planar photonic integrated circuits have long held the promise of high-speed broadband connectivity with mass-manufactureable microchips 11 , but only recently has the technology

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Section: Discussionmentioning

confidence: 99%

Integrated optical switch matrices for packet data networks

Stabile

Albores-Mejia

Rohit³

et al. 2016

Microsyst Nanoeng

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“…Microbend waveguide width variations of 100 nm lead to loss variations of only 0.01 dB in the whispering gallery regime [28]. Losses of only 0.2 dB/180°have been estimated from fabricated circuits and simulations alike [27,28]. By controlling the sidewall verticality, polarization conversion of down to −25 dB∕180°is predicted [28].…”

Section: Microbendsmentioning

confidence: 98%

“…Simulations show that bend radii of down to even a few micrometers may be feasible. Microbend waveguide width variations of 100 nm lead to loss variations of only 0.01 dB in the whispering gallery regime [28]. Losses of only 0.2 dB/180°have been estimated from fabricated circuits and simulations alike [27,28].…”

Section: Microbendsmentioning

confidence: 99%

InP photonic circuits using generic integration [Invited]

Williams¹,

Bente²,

Heiss³

et al. 2015

Photon. Res.

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DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement:

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“…Figure 2 shows a schematic cross-section for the waveguide types in the processed wafer, highlighting the depth of the etches relative to the light green optical confinement layers. The deepest etches are used for the low-radius 20 µm microbends [47]. Deep-etched, high side-wall verticality, 1.5 µm-wide waveguides are used for moderate-radius 100 µm curved-waveguides, the power splitters and the arrayed waveguides in the cyclic routers.…”

Section: Monolithic Switch Matrix Fabricationmentioning

confidence: 99%

Advances in integrated photonic circuits for packet-switched interconnection

Williams

2014

Optical Interconnects XIV

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Sustained increases in capacity and connectivity are needed to overcome congestion in a range of broadband communication network nodes. Packet routing and switching in the electronic domain are leading to unsustainable energy-and bandwidth-densities, motivating research into hybrid solutions: optical switching engines are introduced for massive-bandwidth data transport while the electronic domain is clocked at more modest GHz rates to manage routing. Commercially-deployed optical switching engines using MEMS technologies are unwieldy and too slow to reconfigure for future packet-based networking. Optoelectronic packet-compliant switch technologies have been demonstrated as laboratory prototypes, but they have so far mostly used discretely pigtailed components, which are impractical for control plane development and product assembly.Integrated photonics has long held the promise of reduced hardware complexity and may be the critical step towards packet-compliant optical switching engines. Recently a number of laboratories world-wide have prototyped optical switching circuits using monolithic integration technology with up to several hundreds of integrated optical components per chip. Our own work has focused on multi-input to multi-output switching matrices. Recently we have demonstrated 8×8×8λ space and wavelength selective switches using gated cyclic routers and 16×16 broadband switching chips using monolithic multi-stage networks. We now operate these advanced circuits with custom control planes implemented with FPGAs to explore real time packet routing in multi-wavelength, multi-port test-beds. We review our contributions in the context of state of the art photonic integrated circuit technology and packet optical switching hardware demonstrations. INTEGRATED PHOTONIC PACKET SWITCHESPhotonics switching technologies can be broadly classed in terms of wavelength operations. Photonic space switches route massive bandwidth signals independently of signal wavelength and number of multiplexed wavelength channels. Wavelength selective switches operate on multiplexed data streams to re-route fine granularity streams at the wavelength scale. The third class of photonic switch technologies enables the changing of carrier wavelengths at the photonic layer, offering considerable system level flexibility. Photonic and wavelength selective switches are already deployed in telecommunications networks, offering network flexibility advantage within tight cost and energy constraints [1][2][3][4]. Performing these functions at the photonic layer avoids the high energy costs and delays associated with opto-electronic conversions and electronic de/serialisations. The highest connectivity circuits have been based on low loss and high connectivity 3-D MEMS switching engines, but these are inherently free-space systems and require complex, precision assembly. Connectivity can already extend to many hundreds and thousands of connections, but there are concerns about the scaling properties in term of equipment cost, modularity and size....

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Relaxed Dimensional Tolerance Whispering Gallery Microbends

Cited by 17 publications

References 35 publications

Integrated optical switch matrices for packet data networks

Integrated optical switch matrices for packet data networks

InP photonic circuits using generic integration [Invited]

Advances in integrated photonic circuits for packet-switched interconnection

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