Performance Optimization of AOWCs Task 1: All-Optical Wavelength Converter (AOWC) Performance Optimization of AOWCs Vikrant Lal, Milan L. Mašanović, Daniel J. Blumenthal

Summary of Work Modeling and Simulation of InP based AOWC to accurately estimate and design various performance metrics Physics based modeling of optical processes in Quantum Well devices Developed a Quantum Well Gain and Index model, and detailed rate equation based Dynamic SOA model Issues Need to improve noise modeling in the SOA Need to include temperature dependent effects in a more detailed manner

Gain Model Compute Strained Quantum Well Band Structure k.p theory based band computation Gain curves vs. Carrier density are computed Spontaneous emission factor and index change are also computed

Gain and Spontaneous Emission Spectra QW gain vs. Wavelength at different Sheet Carrier Densities N (1e12 cm-2) Spontaneous emission at different Sheet Carrier Densities N (1e12 cm-2)

Carrier Induced Index Change Carrier induced Index change computed for modeling XPM Free carrier Index change Index change due to gain spectra change through Kramers-Kronig relation

Dynamic behavior of SOAs N(z,t),g(z,t),n(z,t) Psignal Multi-section model Device Carrier Density : N(z,t) Device Gain : g(z,t) Device Index : n(z,t) ASE noise : PASE(t) Each section is modeled based on the Coupled Rate equations Psignal Pnoise_f Pnoise_b zi Ni(t) ni(t) gi(t) Pisignal(t) Pi+1signal(t) Pinoise_b(t) Pi+1noise_f(t) Pi+1noise_b(t) Pinoise_f(t)

Simulating Device Operation Input SOA SGDBR SOA1 SOA2 SGDBR Wavelength Output Power (XGM) Inverted Phase (XPM) Non-Inverted

Device Operation (2.5Ghz NRZ)

Current Device Operation Limits 5Ghz NRZ

Increasing device operating speed Signal power Carrier Lifetime is approximately given by The parameters that we can control to reduce lifetime are Confinement factor Signal Power (mW) Carrier Lifetime (ps)

Effect of SGDBR power Increasing Input CW power can help reduce Carrier Lifetime

Effect of Confinement factor Increasing Modal Confinement factor has greater effect on Carrier lifetime

Increasing device operating speed Signal power Carrier Lifetime Eye at 5Gbps with increased Power and Confinement

Future Design Improvements Increased SGDBR Power SOA at SGDBR output before going into MZI Increased confinement and lower waveguide width Centered Quantum Well, Buried Heterostructure design offers us these advantages Quantum Well Intermixing offers an excellent platform for integration of such structures 1480nm Pumping to reduce carrier lifetime On board 1480 source could be used to bring down carrier lifetime in the SOAs Again, QWI could allow monolithic integration of 1480 and 1550nm sources

Future Work Analyze device operation to understand how to better reduce carrier lifetime Improve the noise model to accurately simulate noise characteristics of the wavelength conversion process Run full dynamic simulations of the AOWC, that agree with experimental results and trends Further simulate the effect of different design parameters on the operation to help improve device design.