TY - CHAP
T1 - Refractive index contributions to phase shifting in InP based 30 GHz bandwidth n-i-n mach-zehnder modulators
AU - O'Callaghan, James R.
AU - Roycroft, Brendan
AU - Guo, Wei Hua
AU - Lu, Q. Y.
AU - Daunt, Chris
AU - Donegan, John
AU - Peters, Frank H.
AU - Corbett, Brian
PY - 2011
Y1 - 2011
N2 - We present a n-i-n based Mach - Zehnder Modulator with a 30 GHz small signal modulation bandwidth. Fabry-Perot fringes from a straight waveguide structure were investigated as a function of voltage showing a strong positive index shift, which on first sight appears to follow the absolute value of current rather than voltage. However, the refractive index increases with bias, so cannot be a carrier density effect and heating is excluded due to the high bandwidth. Refractive index shifts were measured for both TE and TM polarizations, thereby eliminating the Pockels effect as the major contributing mechanism for index change. From the above considerations of positive index shift and polarization insensitivity we deduce that the dominant mechanism is the second order Quantum Confined Stark Effect, which is quite polarization insensitive at about 100 meV below the bandgap, and that the current does not have a significant contribution to device performance.
AB - We present a n-i-n based Mach - Zehnder Modulator with a 30 GHz small signal modulation bandwidth. Fabry-Perot fringes from a straight waveguide structure were investigated as a function of voltage showing a strong positive index shift, which on first sight appears to follow the absolute value of current rather than voltage. However, the refractive index increases with bias, so cannot be a carrier density effect and heating is excluded due to the high bandwidth. Refractive index shifts were measured for both TE and TM polarizations, thereby eliminating the Pockels effect as the major contributing mechanism for index change. From the above considerations of positive index shift and polarization insensitivity we deduce that the dominant mechanism is the second order Quantum Confined Stark Effect, which is quite polarization insensitive at about 100 meV below the bandgap, and that the current does not have a significant contribution to device performance.
UR - https://www.scopus.com/pages/publications/84858187828
M3 - Chapter
AN - SCOPUS:84858187828
SN - 9781457717536
T3 - Conference Proceedings - International Conference on Indium Phosphide and Related Materials
BT - 2011 Compound Semiconductor Week and 23rd International Conference on Indium Phosphide and Related Materials, CSW/IPRM 2011
T2 - 2011 Compound Semiconductor Week and 23rd International Conference on Indium Phosphide and Related Materials, CSW/IPRM 2011
Y2 - 22 May 2011 through 26 May 2011
ER -