An Optical Content Addressable Memory Cell for Address Look-Up at 10 Gb/s

Pitris, Stelios; Vagionas, Christos; Maniotis, Pavlos; Kanellos, George T.; Pleros, Nikos

doi:10.1109/lpt.2016.2572299

Cited by 17 publications

(12 citation statements)

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“…Within this frame, our most recent research efforts have been aligned towards overcoming the frequency barrier set by electronic memories by realizing CAM-and RAM-based configurations completely in the optical domain [25][26][27][54][55][56][57][58][59]. The first all-optical B-CAM cell demonstrations was recently reported based on a monolithically integrated SOA-MZI-based FF with speed capabilities of up to 10 Gb s −1 [56] achieving a large leap in the speed of memory content addressing operations; it was later followed by a series of significant achievements [54][55][56][57][58][59] also advancing the scalability [57] and architectural complexity by introducing all-optical T-CAM cell configurations [55] and realizing optical CAM ML [59] architectures. While optical CAM cells have reached 10 Gb s −1 operation, optical RAM cells have been limited to speeds less than 5 GHz [56].…”

Section: Architecture Of An Optical Al Tablementioning

confidence: 99%

“…The first all-optical B-CAM cell demonstrations was recently reported based on a monolithically integrated SOA-MZI-based FF with speed capabilities of up to 10 Gb s −1 [56] achieving a large leap in the speed of memory content addressing operations; it was later followed by a series of significant achievements [54][55][56][57][58][59] also advancing the scalability [57] and architectural complexity by introducing all-optical T-CAM cell configurations [55] and realizing optical CAM ML [59] architectures. While optical CAM cells have reached 10 Gb s −1 operation, optical RAM cells have been limited to speeds less than 5 GHz [56]. Drawing from this separate operational speeds demonstrated for RAM cells and CAM cells so far, we are here developing a novel RAM cell architecture that exceeds for the first time the 5 GHz barrier of electronics, achieving an operation of 10 Gb s −1 , which combined with our most recent work on 10 Gb s −1 multi-bit optical CAM MLs [59], now holds for the first time the verified credentials for 10 Gb s −1 AL functionalities directly in the optical domain.…”

Section: Architecture Of An Optical Al Tablementioning

confidence: 99%

“…The first optical Β-CAM cell was presented in 2016, successfully providing comparison and write operation at 10 Gb s −1 [56], thus improving the speed capabilities offered by its electronic counterparts [16][17][18] from a MHz to GHz regime while holding high-speed credentials to enable further speed enhancements. The demonstrated B-CAM cell was based on monolithically integrated FF for the fast storing element together with a hybrid SOA-MZI XOR-based logic gate serving for the fast comparison between the stored bit and the search bit.…”

Section: Optical Cams and ML Architectures For Fast Al Tablesmentioning

confidence: 99%

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Optical memory architectures for fast routing address look-up (AL) table operation

et al. 2019

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Today, the increasing demand for fast routing processes has turned the address look-up (AL) operation into one of the main critical performance operations in modern optical networks, since it conventionally relies on slow-performing AL tables. Specifically, AL memory tables are comprised of content addressable memories (CAMs) for storing a known route of the forwarding information base of the router, and random access memories (RAMs) for storing the respective output port for this route. They thus allow for a one-cycle search operation of a packet's destination address, yet they typically operate at speeds well below 1 GHz, in contrast with the vastly increasing optical line rates. In this paper, we present our overall vision towards light-based optical AL memory functionalities that may facilitate faster router AL operations, as the means to replace slow-performing electronic counterparts. In order to achieve this, we report on the development of a novel optical RAM cell architecture that performs for the first time with a speed of up to 10 Gb s −1 , as well as our latest works on multi-bit 10 Gb s −1 optical CAM cell architectures. Specifically, the proposed optical RAM cell exploits a semiconductor optical amplifier-Mach-Zehnder interferometer in a push-pull configuration and deep saturation regime, doubling the speed of prior optical RAM cell configurations. Errorfree write/read operation is demonstrated with a peak power penalty of 6.2 dB and 0.4 dB, respectively. Next, we present the recent progress on optical CAM cell architectures, starting with an experimental demonstration of a 2-bit optical CAM match-line architecture that achieves an exact bitwise search operation of an incoming 2-bit destination address at 10 Gb s −1 , while the analysis is also extended to a numerical evaluation of a multi-cell 4-bit CAM-based row architecture with wavelength division multiplexed outputs for fast parallel memory operations at speeds of up to 4×20 Gb s −1 . Finally, we present a comparative study between electronic and optical RAMs and CAMs in terms of energy and speed and discuss the further challenges towards our vision. entries, even causing the depletion of the remaining IPv4 address space and leading to the advent of an IPv6 protocol with a quadrupled need for address look-up (AL) requirements [5]. This increasing need for faster routing functionalities, including AL, which also requires fast hardware memories to perform fast look-up of the packet's destination address immediately upon its arrival and across the forwarding information base (FIB) of the router.On the path to speeding up hardware memory and lower latency times when fetching data, state-of-the-art highly performing electronic static random access memory (RAM) cell technology has managed to achieve operation up to 5 GHz [6][7][8]. However, RAMs are inherently limited in fast AL as, owing to the address-based fetching of data, they would require multiple sequential random access to the memory and consecutive searches of the desired content. As a re...

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Section: Architecture Of An Optical Al Tablementioning

confidence: 99%

Section: Architecture Of An Optical Al Tablementioning

confidence: 99%

Section: Optical Cams and ML Architectures For Fast Al Tablesmentioning

confidence: 99%

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Optical memory architectures for fast routing address look-up (AL) table operation

et al. 2019

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“…In this regime, some preliminary first steps, stemming from our group, have managed to develop the first photonic alternative CAM-based elements [50,51], which is the main focus of this paper. More specifically, in Section 2, we initially discuss the architectures and main functional building blocks of electronic AL memories, followed by the development of monolithic photonic integration for optical FFs and RAM memories on a monolithic InP platform [33,39] in Section 3.…”

Section: Introductionmentioning

confidence: 99%

“…More specifically, in Section 2, we initially discuss the architectures and main functional building blocks of electronic AL memories, followed by the development of monolithic photonic integration for optical FFs and RAM memories on a monolithic InP platform [33,39] in Section 3. In Section 4, we present the first experimental proof-of-principle of an all-optical Binary CAM (B-CAM) cell architecture at 10 Gb/s [50]. This architecture is later extended in a more advanced all-optical (T-CAM configuration in Section 4, directly supporting, for the first time, a wildcard bit operation of a logical "X" value in the optical domain [51].…”

Section: Introductionmentioning

confidence: 99%

Integrated Optical Content Addressable Memories (CAM) and Optical Random Access Memories (RAM) for Ultra-Fast Address Look-Up Operations

et al. 2017

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Electronic Content Addressable Memories (CAM) implement Address Look-Up (AL) table functionalities of network routers; however, they typically operate in the MHz regime, turning AL into a critical network bottleneck. In this communication, we demonstrate the first steps towards developing optical CAM alternatives to enable a re-engineering of AL memories. Firstly, we report on the photonic integration of Semiconductor Optical Amplifier-Mach Zehnder Interferometer (SOA-MZI)-based optical Flip-Flop and Random Access Memories on a monolithic InP platform, capable of storing the binary prefix-address data-bits and the outgoing port information for next hop routing, respectively. Subsequently the first optical Binary CAM cell (B-CAM) is experimentally demonstrated, comprising an InP Flip-Flop and a SOA-MZI Exclusive OR (XOR) gate for fast search operations through an XOR-based bit comparison, yielding an error-free 10 Gb/s operation. This is later extended via physical layer simulations in an optical Ternary-CAM (T-CAM) cell and a 4-bit Matchline (ML) configuration, supporting a third state of the "logical X" value towards wildcard bits of network subnet masks. The proposed functional CAM and Random Access Memories (RAM) sub-circuits may facilitate light-based Address Look-Up tables supporting search operations at 10 Gb/s and beyond, paving the way towards minimizing the disparity with the frantic optical transmission linerates, and fast re-configurability through multiple simultaneous Wavelength Division Multiplexed (WDM) memory access requests.

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All-optical ternary-content addressable memory (T-CAM) cell and row architectures for address lookup at 20 Gb/s

Maniotis

Pleros

2017

Opt Quant Electron

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An Optical Content Addressable Memory Cell for Address Look-Up at 10 Gb/s

Cited by 17 publications

References 18 publications

Optical memory architectures for fast routing address look-up (AL) table operation

Optical memory architectures for fast routing address look-up (AL) table operation

Integrated Optical Content Addressable Memories (CAM) and Optical Random Access Memories (RAM) for Ultra-Fast Address Look-Up Operations

All-optical ternary-content addressable memory (T-CAM) cell and row architectures for address lookup at 20 Gb/s

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