Rapidly Tunable Microring Filters for Optical Add-Drop (Project Report CIAN2-1-Y5)

This was a project under the Thrust 2 “Subsystem Integration and Silicon Nanophotonics” of the NSF-funded Center. The goal of this research was to design, fabricate and test microchip-scale silicon photonic components for optical WDM (wavelength division multiplexed) add/drop functionality in access and data networks. This chip was intended for use in a campus ring network.

PR34 The Case for Programmable Front-End Devices for Disaggregated Optical Networks Using Silicon Photonics (1525090-Y4)

We have studied how short-distance, wavelength division multiplexed optical communication networks can be improved by enabling programmability and user-defined tunability in the optical front-ends using silicon photonics. Summary of a Project Outcomes report of research funded by the U.S. National Science Foundation under Project Number 1525090 (Year 4).

High Dynamic Range Variable Optical Attenuation (Project Report CIAN2-1-Y5)

The goal of this project was to design silicon photonic components for optical WDM (wavelength division multiplexed) add/drop functionality in access and data networks. One of the key functionalities that was required by the campus networking testbed was to control the optical power levels in the WDM network of each channel without requiring separate components. This was most easily achieved by integrating the Variable Optical Attenuator (VOA) functionality together with the add-drop functionality on the same photonic chips.

Protection Scheme for a Wavelength-Division-Multiplexed Passive Optical Network Based on Reconfigurable Optical Amplifiers

This paper demonstrates a wavelength-division-multiplexed passive optical network (WDM-PON) scheme based on novel reconfigurable optical amplifiers (ROAs). The measured switching characteristics of the ROA3 constructed with a 2 × 2 crossbar optical switch and a four-port reversible optical circulator (OC) and a conventional EDFA can meet the requirements of most network management and surveillance. The self-made four-port reversible OC’s response time is less than 2 ms, and its insertion losses are about 1 dB or less for all the transmission paths and switching states. An optimal design of ROAs is proposed and evaluated for bidirectional optical amplifier protection, in which ROA3 has an EDF length of 7.5 m long with a 1480 nm pump laser and possesses a backward or forward pumping configuration with the corresponding pump power of 200 mW or 50 mW. We verified the scheme’s feasibility through a simulation of WDM-PON systems with 40 downstream and upstream channels. This scheme enables the intelligent protection switching in practical operation scenarios for high-capacity multi-wavelength networks.

On the Impact of Probabilistic Shaping on Fiber Nonlinearities

This paper addresses probabilistic shaping (PS) which has been a latest key technique to approach capacity of fiber-optic channels. We investigate the impact of PS on nonlinear interference (NLI), including self channel interference (SCI), cross channel interference (XCI), and multi channel interference (MCI) for a polarization multiplexed 16*ary quadrature amplitude modulation format in a wavelength division multiplexed (WDM) system. To this end, we consider performing PS in two scenarios: (i) Solely on the channel of interest and (ii) over all C-band WDM channels of a fiber-optic link by analyzing the effective signal to noise ratio and symbol error rate. It is demonstrated that using the enhanced Gaussian noise model with merely 10% overhead in the first scenario, the applied PS scheme increases the SCI and the total experienced NLI by about 19.23%, and 6.6%, respectively. Interestingly, despite enhancing the NLI in this scenario, the simulated PS technique leads to about 47.6% increase in the transmission reach. In the second scenario, the numerical results show increase of the SCI, XCI, and total NLI around 19.8%, 23.34%, and 20.2%, respectively, but resulting in an increase of 32.3% in the transmission reach.<br>

On the Impact of Probabilistic Shaping on Fiber Nonlinearities

This paper addresses probabilistic shaping (PS) which has been a latest key technique to approach capacity of fiber-optic channels. We investigate the impact of PS on nonlinear interference (NLI), including self channel interference (SCI), cross channel interference (XCI), and multi channel interference (MCI) for a polarization multiplexed 16*ary quadrature amplitude modulation format in a wavelength division multiplexed (WDM) system. To this end, we consider performing PS in two scenarios: (i) Solely on the channel of interest and (ii) over all C-band WDM channels of a fiber-optic link by analyzing the effective signal to noise ratio and symbol error rate. It is demonstrated that using the enhanced Gaussian noise model with merely 10% overhead in the first scenario, the applied PS scheme increases the SCI and the total experienced NLI by about 19.23%, and 6.6%, respectively. Interestingly, despite enhancing the NLI in this scenario, the simulated PS technique leads to about 47.6% increase in the transmission reach. In the second scenario, the numerical results show increase of the SCI, XCI, and total NLI around 19.8%, 23.34%, and 20.2%, respectively, but resulting in an increase of 32.3% in the transmission reach.<br>

Research on Next Generation Fiber Optical Amplifiers and Their Evaluation in Dense Communication Systems

In recent years, the information technology sector has developed rapidly and there has been a rapid increase in the amount of information transmitted. The demand for larger telecommunication network capacities is growing, therefore it is necessary to increase the number of channels and transmission speed in wavelength division multiplexed transmission systems. Various optical amplifiers can be used to compensate for the attenuation of the accumulated signal (over a wide wavelength range). The Doctoral Thesis did research on the use of EDFA, Raman, FOPA and combined optical amplifiers in wavelength division multiplexing systems. In the work, special emphasis is placed on erbium and ytterbium alloy fibers with the study of computer modeling of optical amplifiers in cladding pumping technology.