Abstract: A grating coupler is disclosed. The grating coupler comprises a grating formed in a waveguide formed in a silicon layer of a silicon on insulator photonic component. The grating has a series of sequentially arranged grating elements i, each comprising an alternating etched trench section having a length Le and an etch depth e, and an unetched tooth section having a length L0. Each grating element has a total length of ?i and a fill factor Fi. The fill factor Fi of each grating element varies across the grating coupler according to an apodization function dependent on the location of the grating element. The total length of each grating element ?i varies across the grating coupler such that the effective refractive index of each grating element causes the Bragg condition to be satisfied for all of the grating elements of the grating.

Abstract: It is disclosed an optical device for trapping a particle immersed in a fluid. The device of the invention comprises a light source and a probe for guiding and outputting the radiation received from the source. According to the invention, the guided radiation has an intensity distribution having intensity maximum placed at a non-zero distance from the probe longitudinal axis and having rotational symmetry about the longitudinal axis. Further, according to the invention, the intensity maximum is reflected at the interface between probe and fluid, and then it is output by the probe so that it creates a stable equilibrium point wherein the particle is trapped.

Abstract: The device and method are based on tapping off a predetermined line signal fraction and inputting it, together with a continuous pumping radiation, to a resonant cavity which comprises a non-linear wave guide. The value of the pumping wavelength is related to the wavelength of the line signal pulses to produce therewith a four-wave mixing (FWM) effect in the non-linear wave guide. In travelling the non-linear wave guide, a clone signal is generated by FWM effect which duplicates the pulse sequence of the line signal at a clone wavelength. By adjusting the length of the resonant cavity such that, in inputting the line signal, each of its pulses will come in at exactly a pulse of the clone signal which is being circulated within the cavity, a clone signal can be circulated within the resonant cavity whose pulse sequence represents the optical clock signal sought.