Wavelength conversion using a nonlinear optical loop mirror (NOLM) is investigated. Our interest is in considering nonreturn-to-zero (NRZ) and return-to-zero (RZ) signals with a high-duty ratio resulting in a nonlinear phase shift of the counterpropagating wave that is not negligible and reduces the extinction ratio considerably compared to signals with a low-duty ratio. It is shown how the NOLM can be used for high-duty signals anyhow by configuring/adjusting the NOLM, particularly the polarization controller inserted in the loop. This paper gives a mathematical description of the NOLM utilizing the Jones calculus and considers different ways of adjusting the polarization controller. The nonlinear phase shifts are calculated and a reasonable confinement for the walk-off is given. Furthermore, the probability density function of the extinction ratio depending on the duty ratio of the control signal and the configuration of the NOLM for either parallel or orthogonal polarizations of the counterpropagating signal waves is derived and evaluated for some exemplary parameters.

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The continuous implementation of novel technological advances in optical lithography is pushing the technology to ever smaller feature sizes. For instance, it is now well recognized that the 45nm node will be executed using state-of-the-art ArF (193nm) hyper-NA immersion-lithography. Nevertheless, a substantial effort will be necessary to make imaging enhancement techniques like hyper-NA immersion technology, polarized illumination or sophisticated illumination modes routinely available for production environments.In order to support these trends, more stringent demands need to be placed on the lithographic optics. Although this holds for both the illumination unit and the projection lens, this paper will focus on the latter module. Today, projection lens aberrations are well controlled and their lithographic impact is understood. With the advent of imaging enhancement techniques such as hyper-NA immersion lithography and the implementation of polarized illumination, a clear description and control of the state of polarization throughout the complete optical system is required.Before polarization was used to enhance imaging, the imaging properties at each field position of the lens could be fully characterized by 2 pupil maps: a phase map and a transmission map. For polarized imaging, these two maps are replaced by a 2x2 complex Jones matrix for each point in the pupil. Although such a pupil of Jones matrices (short: Jones pupil) allows for a full and accurate description of the physical imaging, it seems to lack transparency towards direct visualization and lithographic imaging relevance.In this paper we will present a comprehensive method to decompose the Jones pupils into quantities that represent a clear physical interpretation and we will study the relevance of these quantities for the imaging properties of lithography lenses.

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Integrated optical TM-pass polarizers operating at wavelengths around X =1.5 pm have been realized by introducing proton exchanged regions adjacent to a Ti-indiffused waveguide on X-cut, Y -propagating lithium niobate. Structural investigations of the proton exchanged regions have been carried out by raster electron microscope and optical methods, in order to characterize the index profile created by the proton exchange. Several polarizers with different geometries of the proton exchanged regions have been analysed numerically by employing the beam propagation method (BPM) and the finite element method (FEM). The device performance is shown to depend strongly on the geometrical shape of the outer boundaries of the proton exchanged regions and on their distance to the channel waveguide. Experimental results are given for several samples with different gaps between the optical waveguide and the proton exchanged regions as well as for different annealing times. For a proper device design a TE-extinction of -26 dB and a TM-excess loss of only 1.2 dB have been obtained experimentally.