Optical Static RAM Cell

Applied Optics, 2009

A semiconductor optical amplifier-based all-optical read-only memory (ROM) is successfully demonstrated through simulations using a one-level simplification method optimized for optical logic circuits. Design details are presented, and advantages are discussed in comparison with an all-optical ROMemploying decoder. We demonstrate that eight characters can be stored at each address in the American Standard Code for Information Interchange.

IEEE Photonics Technology Letters, 2012

The authors demonstrate a novel all-optical T-flip-flop (TFF) layout utilizing a single optical latching element that comprises an integrated semiconductor optical amplifier and Mach-Zehnder inteferometer and a feedback loop. Experimental proof-of-concept verification is presented at 8 Mb/s using off-the-shelf bulk components and a fiber-based feedback implementation. The proposed TFF architecture requires the minimum number of active components and just a single toggling signal as input. Its simple circuit design is amenable with photonic integration and holds the credentials for operation at multi-Gb/s speeds.

Journal of the Optical Society of Korea, 2008

Optics Letters, 2007

We report the operation of an all-optical set-reset (SR) flip-flop based on vertical cavity semiconductor optical amplifiers (VCSOAs). This flip-flop is cascadable, has low optical switching power ͑ϳ10 W͒, and has the potential to be integrated on a small footprint ͑ϳ100 m 2 ͒. The flip-flop is composed of two cross-coupled electrically pumped VCSOA inverters and uses the principles of cross-gain modulation, polarization gain anisotropy, and highly nonlinear gain characteristics to achieve flip-flop functionality. We believe that, when integrated on chip, this type of all-optical flip-flop opens new prospects for implementing all-optical fast memories and timing regeneration circuits.

An all-optical flip-flop memory with separate set and reset inputs is presented. The flipflop is formed from two coupled polarization switches that are operated by utilizing the nonlinear polarization rotation in semiconductor optical amplifiers. The concept of the system is explained and experimental results are presented, demonstrating that a contrast ratio of over 20 dB between output states and a switching power of less than −3 dBm can be obtained. The all-optical flip-flop can be utilized in all-optical packet switches.

IEEE Photonics Technology Letters, 2000

By exploiting three coupled semiconductor optical amplifier (SOA) fiber ring lasers, a compact, integratable, and polarization-independent three-state all-optical memory is demonstrated, with 40-dB extinction ratio for each state. Dynamic flip-flop operation between states is also demonstrated with switching pulse energy of 13.6 nJ. Due to the broad bandwidth of SOA gain spectrum, the wavelength range of set pulses is large. Finally, the transition behavior of state switching is investigated.

Applied Sciences, 2017

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.

IEEE Journal of Selected Topics in Quantum Electronics, 2000

All-optical digital circuits based on loop memories are demonstrated. These circuits are a variable optical buffer, an optical random access memory, an optical shift register, and an optical linear feedback shift register. Buffers are employed in network nodes to solve the contentions without loosing information. Shift registers are used for error detection and correction techniques. Linear feedback shift registers are employed for generation of pseudo-random bit sequences, data scrambling, and encryption/decryption of information in secure communication systems. Since the role of optical processing is gradually increasing within the communication systems, the possibility to store information directly in the optical domain can lead to a systems simplification and to a performance improvement. In order to make the schemes suitable for practical applications, optical integration is necessary. The use of semiconductor optical amplifier as gain element into the memory loop allows all the proposed schemes to be integrated.

Optics Communications, 2008

An all-optical regenerative memory device using a single loop mirror and a semiconductor optical amplifier is experimentally demonstrated. This configuration has potential for a low power all-optical stable memory device with non-inverting characteristics where packets are stored through continuously injecting the regenerated data back into the loop.

IEEE Photonics Journal, 2013

An optical RAM row access gate followed by a column address selector for wavelength-division-multiplexing (WDM)-formatted words employing a single semiconductor optical amplifierVMach-Zehnder interferometer (SOA-MZI) is presented. RAM row access is performed by the SOA-MZI that grants random access to a 4-bit WDM-formatted optical word employing multiwavelength cross-phase-modulation (XPM) phenomena, whereas column decoding is carried out in a completely passive way using arrayed waveguide grating. Proof-of-concept experimental verification for both positive and negative logic access is demonstrated for 4 Â 10 Gb/s optical words, showing error-free operation with only 0.4-dBpeak-power penalty and requiring a power value of 25 mW/Gb/s.