Birefringence compensation in double-core optical waveguides

A new concept for birefringence compensation in planar optical waveguides applying a double-core structure is introduced. It is demonstrated on waveguides fabricated in silicon oxynitride technology for applications in optical telecommunicatio

Characterization of optical third-order non-linearities by prism coupling and pulse shape analysis on a ps timescale

Materials with an intensity dependent index of refraction and absorption coefficient¿third-order optical non-linear (ONL) effects¿offer the possibility of all-optical signal processing. Prism coupling is a well-known tool to investigate the intensity dependent refractive index, however, such experiments are often obscured by thermal effects. To avoid these we have studied the influence of the ONL effects on the shape of 70 ps pulses in non-linear prism coupling. The full width at half maximum (FWHM) of the in and out coupled pulses is compared simultaneously with the FWHM of the pulses of a reference beam. By measuring at various angles of incidence around that for optimal coupling it is possible to measure the sign and value of the change in both the refractive index and absorption coefficient. As a function of the coupling angle, the first leads to an asymmetric line shape for the ratio of the two FWHMs mentioned above, whereas the second leads to a symmetric one. From a comparison of simulations with experimental data, the values of the non-linear constants can be derived

Response of a Fabry-Perot to short pulses

The pulse shape deformation of 80 ps Gaussian input transmitted through a Fabry-Pérot has been determined experimentally and theoretically as a function of the mirror spacing. The effect of mirror surface imperfections is discussed and it is shown that for not too large imperfections there is a strong influence on the transmitted pulse energy whereas the transmitted pulse shape remains almost unaffected

Design and implementation of an electro-optical backplane with pluggable in-plane connectors

The design, implementation and characterisation of an electro-optical backplane and an active pluggable in-plane optical connector technology is presented. The connection architecture adopted allows line cards to be mated to and unmated from a passive electro-optical backplane with embedded polymeric waveguides. The active connectors incorporate a photonics interface operating at 850 nm and a mechanism to passively align the interface to the optical waveguides embedded in the backplane. A demonstration platform has been constructed to assess the viability of embedded electro-optical backplane technology in dense data storage systems. The demonstration platform includes four switch cards, which connect both optically and electronically to the electro-optical backplane in a chassis. These switch cards are controlled by a single board computer across a Compact PCI bus on the backplane. The electrooptical backplane is comprised of copper layers for power and low speed bus communication and one polymeric optical layer, wherein waveguides have been patterned by a direct laser writing scheme. The optical waveguide design includes densely arrayed multimode waveguides with a centre to centre pitch of 250μm between adjacent channels, multiple cascaded waveguide bends, non-orthogonal crossovers and in-plane connector interfaces. In addition, a novel passive alignment method has been employed to simplify high precision assembly of the optical receptacles on the backplane. The in-plane connector interface is based on a two lens free space coupling solution, which reduces susceptibility to contamination. Successful transfer of 10.3 Gb/s data along multiple waveguides in the electro-optical backplane has been demonstrated and characterised

Birefringence compensation applying double-core waveguiding structures

For application in communication networks, polarization-independent planar optical waveguiding structures are essential, because the polarization state of the optical signal in an optical network is arbitrary. A new concept for polarization-independent waveguides simply adds a thin birefringence-compensating layer, which results in a double-core waveguiding structure. One of the major advantages of the double-core concept is its technological simplicity. The impact of the layer parameters is simulated and the compensating mechanisms are discussed. The feasibility of this concept is demonstrated on waveguides fabricated with silicon oxynitride technology, where the channel birefringence is tuned over a wide range(+1.6×10-3 to -1.1×10-2) by varying the thickness of the birefringence compensating laye

Nonlinear refractive index of erbium-doped Y2O3 integrated-optical waveguides

Self-induced phase modulation in erbium-doped polycrystalline Y203 integrated-optic waveguides is studied by use of a Mach-Zehnder interferometric setup. We determined the wavelength dispersion of the nonlinear refractive index near the 4F912 absorption band and show that it corresponds qualitatively with a Kramers-Kronig analysis. The nonlinear coefficient at 670 nm was determined to be 1.4 x 10-1' m2/W and has an electronic origin with a slow relaxation time of 6 ms