Nonlinear effects in silicon waveguides

In this work, we modelled the nonlinear effects in silicon waveguides which are crucial for many applications, including all-optical signal processing, switching, wavelength conversion. I have developed the model for ultrafast all-optical switching using split-step Fourier method and calculated the nonlinear phase shift due to the Kerr effect and including the nonlinear losses (i.e. two-photon absorption, free carrier absorption and free carrier index)

Investigation of 2d-wh/ts ocdma code stability in systems with soa-based device

This paper investigates for the first time how the implementation of semiconductor optical amplifier (SOA)-based devices in photonic networks can negatively impact the integrity of two-dimensional wavelength-hopping time-spreading (2D-WH/TS) optical code-division multiple access (OCDMA) codes based on multi-wavelength picosecond code carriers. It is demonstrated and confirmed by simulations that the influence of an SOA under driving currents of 50 mA to 250 mA causes a 0.08 to 0.8 nm multi-wavelength picosecond code carriers’ wavelength redshift. The results obtained are then used to calculate the degradation of OCDMA system performance in terms of the probability of error Pe and the decrease in the number of simultaneous users. It is shown that, when the SOA-induced 0.8 nm code carriers redshift becomes equal to the code carries wavelength channel spacing, the (8,53)-OCDMA system performs only as a (7,53)-OCDMA system, and the number of simultaneous users drops from 14 to 10 or 84 to 74 with the forward error correction (FEC) Pe of 10 −9, respectively. The impact of the 0.8 nm redshift is then shown on a (4,53)-OCDMA system, where it causes a drop in the number of simultaneous users from 4 to 3 or 37 to 24 with the FEC Pe of 10 −9, respectively

Temperature insensitive waveguide interferometer based on subwavelength gratings

We present a design for a temperature insensitive Mach-Zehnder interferometer in which temperature compensating segment is achieved through tailored subwavelength gratings. By engineering the thermal response and the relative length of this segment, an overall temperature insensitivity below ±4pm/ºK is predicted for 100nm bandwidth around 1550nm

Design of an athermal interferometer based on tailored subwavelength metamaterials for on-chip microspectrometry

Temperature dependence is one of the main challenges of the silicon-on-insulator platform due to the large thermo-optic coefficient of its core material. In this work, to the best of our knowledge, we propose a design of an all-passive athermal silicon-on-insulator Mach-Zehnder interferometer (MZI) with the minimal temperature sensitivity reported to date. The MZI’s temperature compensation was achieved by optimizing the relative length of its wire and subwavelength arms and by tailoring the thermal response of the subwavelength structure. Simulations of the device performance showed that the overall temperature sensitivity of 7.5 pm/K could be achieved over a 100 nm spectral range near the 1550 nm region

Technique for the measurement of picosecond optical pulses using a non-linear fiber loop mirror and an optical power meter

A method for measuring picosecond pulse width by using only fiber components and optical power meters is presented. We have shown that the output power splitting ratio of a non-linear fiber loop mirror can be used to extract the full-width half maximum of the optical pulse, assuming a known slowly varying envelope shape and internal phase structure. Theoretical evaluation was carried out using both self-phase and cross-phase modulation approaches, with the latter showing a twofold sensitivity increase, as expected. In the experimental validation, pulses from an actively fiber mode-locked laser at the repetition rate of 10 GHz were incrementally temporally dispersed by using SMF–28 fiber, and then successfully measured over a pulse width range of 2–10 ps, with a resolution of 0.25 ps. This range can be easily extended from 0.25 to 40 ps by selecting different physical setup parameters

Temperature Insensitive Waveguide Interferometer Based on Subwavelength GratingsTemperature Insensitive Waveguide Interferometer Based on Subwavelength Gratings

IEEE British and Irish Conference on Optics and Photonics, IET Savoy London, December 11 - 13 201

Technique for the measurement of picosecond optical pulses using a non-linear fiber loop mirror and an optical power meter

A method for measuring picosecond pulse width by using only fiber components and optical power meters is presented. We have shown that the output power splitting ratio of a non-linear fiber loop mirror can be used to extract the full-width half maximum of the optical pulse, assuming a known slowly varying envelope shape and internal phase structure. Theoretical evaluation was carried out using both self-phase and cross-phase modulation approaches, with the latter showing a twofold sensitivity increase, as expected. In the experimental validation, pulses from an actively fiber mode-locked laser at the repetition rate of 10 GHz were incrementally temporally dispersed by using SMF–28 fiber, and then successfully measured over a pulse width range of 2–10 ps, with a resolution of 0.25 ps. This range can be easily extended from 0.25 to 40 ps by selecting different physical setup parameters.</p