Ultra-fast Optical Signal Processing For Digital Communications Using All-Optical Nonlinear Interactions In Semiconductor Optical Waveguides

In optical communications, clock recovery, optical time demultiplexing, and 3R regeneration are known as optical signal processing. Ultra-fast optical signal processing techniques are mandatory in future high-speed network and transmission systems to allow effective use of the large optical fiber bandwidth and the light speed capabilities.

One solution is all-optical signal processing that avoids the bottleneck of slow electronics. All-optical modulation can be achieved through nonlinearties in semiconductor waveguides like EAM or SOA. Those waveguides have fast and strong nonlinearties that are appropriate for ultra-fast processing. In addition, semiconductors require reasonable optical power to operate and they can be integrated with other semiconductor devices.

In this work, we demonstrated a several new techniques for optical signal processing, such as ultrafast optical clock recovery. We use the fast and nonlinear time-dependent loss / gain saturation in EAM / SOA to perform all-optical timing extraction. This in turn is used for optical clock recovery from data rates up to 160 Gbit / s. Simulation results shows that the technique has a potential to recover optical clock up to 640 Gbit / s. Also we demonstrated all-optical logic AND gate using nonlinear transmission of EAM. The gate shows successful operation at 10 Gbit / s with a 2 ^ 31-1 PRBS data and it has potential for higher speeds. We also demonstrated optical time division demultiplexing from 40 Gbit / s with simultaneous clock recovery using cross-absorption saturation inside a single EAM. The system shows an error free operation using a 2 ^ 31-1 PRBS.

Also, it shows successful operation with burst-mode data propagating in a fiber-optic recirculating loop up to a distance of 10,000 Km. The optical 3R regeneration is also demonstrated at 10 Gbit / s using a single EAM. The all-optical timing extraction inside EAM is used for retiming, while the nonlinear transmission of EAM is used for reshaping. Meanwhile, wavelength conversion and re-amplification are performed at the same time. FWM is well known by its ultrafast operation and has been widely investigated by other groups in SOA's and optical fibers. Here, we showed that FWM in EAM has unique characteristics, like wide detuning range and enhancement of conversion efficiency with reverse bias. Also, we demonstrated FWM demultiplexing from 80 Gbit / s with simultaneous clock recovery using co-propagation inside a single EAM.
Source: University of Maryland
Author: Awad, Ehab

Download Project

For more information contact us via Studentstrainer@gmail.com. Caring is sharing, show your caring to us by sharing our post in social sites and keep like us,,,

Benzocyclobutene Microring Resonators Electronics project

Wavelength division multiplexing (WDM) at optical carrier frequencies offers more capacity and flexibility of fiber networks and upgrades conventional point-to-point fiber-optic transmission links to multiuser networks for the demand of high-speed network systems.

The microring resonator, which has been seen in action in many photonic devices, is ideal for WDM applications in realization of narrow bandwidth with a wide free spectral range. In this research, microring resonators are fabricated in benzocyclobutene (BCB), a popular polymer in photonics and electronics applications. First, the single-mode BCB undercut-cladding waveguides were designed to reduce bending loss.

BCB microring resonators were fabricated based on those principles. BCB single-microring devices were demonstrated as add-drop filters and notch filters with a negative coupling gap. Not only are the microring resonators compact (as small as 5 μm in radius) for photonic VLSI, they also exhibit a high out-of-band rejection (~ 30 dB), high extinction as well as a high finesse (~ 285).

In addition, BCB lattices consisting of over one hundred microring resonators were fabricated and demonstrated as bandstop filters. The lattices, despite the large number of resonators, exhibit an extremely low propagation loss. Finally, optical bistability and the field-enhanced all-optical nonlinear switching were demonstrated in BCB microring devices.
Source: University of Maryland
Author: Chen, Wei-Yen

Download this project

For more information contact us via Studentstrainer@gmail.com. Caring is sharing, show your caring to us by sharing our post in social sites and keep like us,,,

Low Energy Wake-up Logic Electronics project

 Wake-up logic is responsible for informing instructions in the Window that are waiting to execute, about the availability of their input operands. The conventional method of wake-up consumes a significant percentage of the Instruction Window energy. Reducing the wake-up energy also addresses the Instruction Window hot spot problem caused due to the high power density of the Instruction Window.

In this work, we investigate the energy and power savings of a low complexity scheme that stores the dependence relations between instructions in an array and uses this array to simplify the wake-up. We then present a new wake-up scheme that further reduces the wake-up energy by using a smaller table to store dependence relations and dynamically allocates dependence slots to only those instructions that have dependents in the Window. Our approach leads to savings of up to 50% in wake-up energy and 15% in the Instruction Window power with a very slight decrease in IPC. Also, both the schemes are more scalable than the conventional wake-up scheme with increasing Instruction Window size and Issue Width.
Source: University of Maryland
Author: Kakaraparthi, Himabindu

For more information contact us via Studentstrainer@gmail.com. Caring is sharing, show your caring to us by sharing our post in social sites and keep like us,,,