Abstract: Example embodiments relate to lasers that include loop resonators. One example laser includes a loop resonator forming a closed loop light path. The loop resonator includes an optical gain medium configured to lase. The loop resonator is configured to, during lasing, present a pair of modes: a mode of light propagating in a clockwise direction in the closed loop light path of the loop resonator (termed CW mode) and a mode of light propagating in a counter-clockwise direction in the closed loop light path of the loop resonator (termed CCW mode). The laser also includes a first light output configured to output laser light from the laser. Additionally, the laser includes an optical power modulating unit. The optical power modulation unit is configured to modulate an optical power of the CW mode of the loop resonator and an optical power of the CCW mode of the loop resonator.

Abstract: A hybrid laser for generating radiation includes an optical passive material and an optical active material. The laser includes a first optical waveguide and optical laser components with reflectors in the optical passive material. The first optical waveguide is adapted for coupling out radiation from the hybrid laser. The laser also includes a second optical waveguide defined in the optical active material. The optical laser components include reflectors defining a cavity and furthermore are adapted for providing laser cavity confinement in the first optical waveguide and the second optical waveguide. The second optical waveguide thereby is positioned at least partly over the first optical waveguide so that an evanescent coupling interface is defined between the second optical waveguide and the first optical waveguide and the evanescent coupling interface is positioned within the laser cavity.

Abstract: A method is provided for all-optical regeneration of intensity modulated optical signals. A DFB laser diode is selected such that it has a gain bandwidth comprising the signal wavelength, the signal wavelength being outside the stopband of the DFB laser diode. Furthermore, the DFB laser diode is selected such that it can have a bistable amplification characteristic for the signal wavelength showing a hysteresis with an ascending branch and a descending branch, the ascending branch located at a higher input power level than the descending branch. The DFB laser diode is driven such that it operates in the bistable amplification regime, the descending branch of the hysteresis curve located at an input power level above the lower power level of the optical signal pulses and the ascending branch of the hysteresis curve located at an input power level below the upper power level of the optical signal pulses.

Abstract: A hybrid laser for generating radiation includes an optical passive material and an optical active material. The laser includes a first optical waveguide and optical laser components with reflectors in the optical passive material. The first optical waveguide is adapted for coupling out radiation from the hybrid laser. The laser also includes a second optical waveguide defined in the optical active material. The optical laser components include reflectors defining a cavity and furthermore are adapted for providing laser cavity confinement in the first optical waveguide and the second optical waveguide. The second optical waveguide thereby is positioned at least partly over the first optical waveguide so that an evanescent coupling interface is defined between the second optical waveguide and the first optical waveguide and the evanescent coupling interface is positioned within the laser cavity.

Abstract: A method is provided for all-optical regeneration of intensity modulated optical signals. A DFB laser diode is selected such that it has a gain bandwidth comprising the signal wavelength, the signal wavelength being outside the stopband of the DFB laser diode. Furthermore, the DFB laser diode is selected such that it can have a bistable amplification characteristic for the signal wavelength showing a hysteresis with an ascending branch and a descending branch, the ascending branch located at a higher input power level than the descending branch. The DFB laser diode is driven such that it operates in the bistable amplification regime, the descending branch of the hysteresis curve located at an input power level above the lower power level of the optical signal pulses and the ascending branch of the hysteresis curve located at an input power level below the upper power level of the optical signal pulses.

Abstract: A widely tunable laser structure with at least two different sampled or superstructure gratings is provided. The widely tunable laser only requires as much tuning currents as gratings. In the case of two gratings, two tuning currents, instead of 3 tuning currents in a typical laser, are needed. Alternatively, the laser structure can be denoted a sampled or superstructure grating tunable laser with wide tunability characteristics, with a limited amount of needed tuning parameters, e.g., two currents.

Abstract: The present invention provides a cross-connect switching device and a method of cross-connect switching of Nf * N1 channels to one of a plurality of output lines of the switching device, Nf * N1 being equal or greater than four. The device and method includes three basic elements: 1) a partial demultiplexer for partially demultiplexing the channels on its input lines into groups of channels and individual channels; 2) a space switch for switching groups of channels en bloc; and 3) a combiner unit for combining individual channels onto one of the output lines of the cross-connect switching device. The cross-connect switching device according to the present invention may be combined with similar or dissimilar switching devices to form a larger switching device.

Abstract: A widely tunable laser structure with at least two different sampled or superstructure gratings is provided. The widely tunable laser only requires as much tuning currents as gratings. In the case of two gratings, two tuning currents, instead of 3 tuning currents in a typical laser, are needed. Alternatively, the laser structure can be denoted a sampled or superstructure grating tunable laser with wide tunability characteristics, with a limited amount of needed tuning parameters, e.g., two currents.

Abstract: The present invention related to a method and apparatus for controlling a laser structure, comprising at least an amplifying section, a phase section, a first reflection section, a first facet, emitting a substantial part of the electromagnetic radiation generated by the laser structure, and a second facet, injection means for injecting current in the phase section, injection means for injecting current in the reflection section, the method including the steps of determining a first value by measuring the power output at the first facet, determining a second value by measuring the power output at the second facet, determining a third value depending on the first value and the second value, determining a plurality of values for currents for controlling the laser structure from at least the third value, wherein the determining being based on a step of optimizing the third value, and injecting the currents with the determined current values via the injection means.

Abstract: An optical decision circuit, based on gain clamped semiconductor optical amplifiers, is disclosed. This optical decision circuit can be used for 2R signal regeneration in optical communication systems. By adding a clock signal to the input of said optical decision circuit, said circuit is also suited for 3R regeneration. Such a circuit can easily be implemented as an integrated circuit or an OEIC.