Three-dimensional broadband polymer optical waveguide switch matrix.

A 1 x 4 3D broadband polymer optical waveguide switch matrix is demonstrated. The fabricated device, which contains four vertically coupled thermo-optic switches, has a compact construction (only 9 mm in length) and a power consumption of 45 mW. Compared with the corresponding planar ones, this 3D switch matrix has two distinct features.

Fiber-Bragg-grating force sensor based on a wavelength-switching actively mode-locked erbium-doped fiber laser.

A fiber-Bragg-grating (FBG) transverse-force sensor based on a wavelength-switching actively mode-locked erbium-doped fiber laser is proposed, in which a FBG is used as both the sensing element and the wavelength-selection element of the laser. When a force is applied to the FBG, the induced birefringence in the FBG causes the laser to emit pulses at two close wavelengths, whose separation is proportional to the applied force. To suppress the interference between the two wavelengths, the laser is made to emit at the two wavelengths alternately by use of a polarization-switching technique.

Generation of picosecond pulses at five close wavelengths by use of a self-seeded Fabry-Perot laser diode and a spectrum-split fiber Bragg grating.

We have demonstrated simultaneous generation of stable picosecond laser pulses at five close wavelengths at a pulse repetition rate of approximately 2 GHz by using a self-seeding configuration that consisted of a gain-switched Fabry-Perot laser diode (FPLD) with an external cavity formed by a tunable spectrum-split fiber Bragg grating (FBG). The FBG selected only one of the modes of the FPLD and, at the same time, filtered the selected FPLD mode such that the reflection from the FBG, tapped with a directional coupler, provided an output of dual-wavelength pulses and the transmission through the FBG provided an output of three-wavelength pulses. We could change the intensities and the wavelength separations of the pulses by adjusting the modulating radio frequency and the temperature of the FPLD and the separation of the FBG reflection peaks.