Nokia Corporation

Modulight Oy

Optoelectronics Research Center, Tampere University of Technology

Reflekron Ltd.

Reflekron Oy

Nokia Siemens Networks Oy

Epicrystals Oy

Ampliconyx Oy

Oleg Okhotnikov

Mircea Guina

Anatoly Borisovich Grudinin

Tomi Jouhti

Valery Filippov

Markus Pessa

Yuriy Chamorovskiy

A section of active optical fiber () which comprises an active core (), an inner cladding layer () and an outer cladding layer (). The diameter of said core) and the thickness of said inner cladding () change gradually along the length of said section of active optical fiber (). This forms tapered longitudinal profile enabling a continuous mode conversion process along the length of the section of fiber (). The method for fabricating a section of tapered active optical fiber comprises the steps of fabricating a preform for drawing active optical fiber from said preform, installing said preform into a drawing tower, drawing optical fiber in said drawing tower and altering at least one of the two parameters including the take-off preform speed and the take-up fiber speed during drawing of the optical fiber.

Active optical fiber and method for fabricating an active optical fiber

A design of a semiconductor saturable absorber that offers a convenient and reliable way to control/decrease the recovery time of the absorption. The absorption recovery time is controlled during the epitaxial growth by using lattice-mismatched layer(s) to induce dislocations, and implicitly non-radiative recombination centers within the nonlinear absorbing region. These lattice reformation layer(s) are interposed between the distributed Bragg reflector and the nonlinear absorption region, containing quantum-wells, quantum-dots or bulk semiconductor material. The thickness and composition of the lattice reformation layer(s) is an instrumental to control the amount of non-radiative recombination centers used to trap the optically excited carriers generated in the absorption region.

Semiconductor saturable absorber reflector and method to fabricate thereof

A method to stabilize the repetition rate in a passive harmonic mode-locked fiber laser employing semiconductor saturable absorbers. The pulse organization is accomplished by electrically modulating the amplifier pump source that in turn optically modulates the saturable loss of semiconductor absorber. Due to an efficient modulation mechanism of the cavity loss, the method can be used to generate an actively mode-lock pulse train.

Method for organizing a mode-locked pulse train by pump modulation

The invention relates to an optically pumped multilayered modulator having surface-normal geometry. The multilayer structure comprises an absorber section through which an optical signal () to be modulated is coupled from an input () to an output (). The multilayer structure further comprises control means for supplying a control signal for controlling the transmission characteristics of the absorber section. The control signal is generated by an in-plane waveguide-type laser integrated monolithically with the saturable absorption region. The in-plane control laser includes waveguide regions () and multiple-quantum-well layers () used as a gain medium. The laser beam is adapted to travel through the absorber section in order to modulate the transmission characteristics of the absorber section.

Optical modulator

Growing community of inventors

Tampere, Finland

Oleg Okhotnikov