Henry H. Yaffe

Polarization-independent silica-on-silicon Mach-Zehnder interferometers

The birefringence induced by compressive strain in silica waveguides on silicon substrates is compensated with a silicon nitride patch placed below the core. We demonstrate Mach-Zehnder interferometers with polarization-independent spectral response, including a compensated Mach-Zehnder interferometer suitable for stabilization of multiple laser sources in a dense wavelength division multiplexed fiber optic communication network. Furthermore, we show how silicon nitride can also be used to compensate polarization dependent losses. Polarization independence achieved with a silicon nitride patch is applicable to a wide variety of other devices such as arrayed waveguide grating multiplexers and Bragg reflectors. >

Experimental Determination of System Outage Probability Due to First-Order and Second-Order PMD

In this paper, a polarization-mode dispersion (PMD) tolerance testing procedure for transponders and transmission systems is described. This method exploits programmable PMD sources for testing the first- and second-order joint probability density function to estimate the total PMD network outage. Experimental data show that first-order-only PMD testing is insufficient to quantify the tolerance of a transponder and may falsely underestimate network outage

Polarization independent Silica-on-Silicon waveguide devices

Silica-on-silicon (SiO2/Si) waveguide devices show great promise for practical integrated optical circuits. One of the challenges of this technology is to overcome the intrinsic strain birefringence which causes polarization dependent response. A number of methods have been suggested and demonstrated to achieve polarization independent response[1-4]. We present a novel method for achieving polarization independence in SiO2/Si waveguide devices by placing a thin patch of silicon nitride (Si3N4) under the waveguide core to achieve polarization independence in Mach-Zehnder interferometers (MZIs) and for compensation of polarization dependent loss (PDL). Our method requires an additional photolithography step but does not but does not require active tuning and is applicable to a wide variety of SiC2/Si waveguide devices.