Abstract: The invention shows a transmission system with a transmitter function, a transmitting fiber and a receiver function where the transmitter function comprising lightsources (1), modulators (2) and a multiplexer (3), and the receiver comprising at least a demultiplexer (5), filters and electrical receivers where the channels for left side filtering are modulated with modulators with a negative chirp and for right side filtering with modulators with positive chirp.

Abstract: It is an object of the present invention to provide a method for processing optical signals showing real improvement for the transmission of optical signals over long distance at high bit rate but without implying to high costs. This is achieved by the use of a new modulation format (BL-FSK) based on the generation of a frequency modulated signal. It is obtained by driving an electro-optical modulator (e.g. LiNbO3) with a 1-bit delay pre-coded signal (or some other differential pre-coding) in a similar way as for generating DPSK. But unlike for DPSK, it is advantageously make use of the bandwidth limitation of the electrical and electro-optical components, chosen close to a half of the bit rate (B). A ramp-electrical signal is generated that produces the FSK modulation. As a direct consequence of such modulation, a higher spectral efficiency and a lower cost construction of the transmitter is achieved.

Abstract: A frequency allocation scheme for optical channels transmitted via a WDM transmission line with alternating left side and right side filtering for adjacent channels, with alternating channel spacing of A and B, where A<B, and with two sets of channels orthogonally polarized.

Abstract: The invention shows a frequency allocation scheme for optical channels transmitted via a WDM transmission line with alternating left side and right side filtering for adjacent channels, with alternating channel spacing of A and B, where A<B, and two sets of channels orthogonally polarized.

Abstract: The invention shows a transmission system with a transmitter function, a transmitting fiber and a receiver function where the transmitter function comprising lightsources (1), modulators (2) and a multiplexer (3), and the receiver comprising at least a demultiplexer (5), filters and electrical receivers where the channels for left side filtering are modulated with modulators with a negative chirp and for right side filtering with modulators with positive chirp.

Abstract: An integrated optoelectronic semiconductor component is presented, which can equally process light signals of any polarization direction. Such semiconductor components are used for digital optical telecommunications. The semiconductor component has active (A) and passive (B) waveguide sections, which comprise a number of semiconductor layers (SP) with so-called multiple quantum well structures. The semiconductor layers (SP) are deposited by a process known as selective area growth (SAG). A portion of the semiconductor layers has a lattice constant which is smaller than the lattice constant of a substrate (SUB). This creates a biaxial tensile strain in these layers. The tensile strain is optimized in the active waveguide sections (A) to attain polarization independence. Furthermore a process is described whereby such a semiconductor component can be manufactured.

Abstract: A semiconductor device is operated as an optical filter. The semiconductor device has a substrate and a monolithically integrated branched waveguide structure disposed above the substrate, portions of the waveguide structure being divided into a plurality of regions by troughs, one of the regions being a branching region. Light is radiated into the waveguide structure at an end face of one of the regions and currents that are smaller than respective laser threshold currents of the regions flow through the regions, including the branching region, perpendicular to a propagation direction of light through the waveguide.

Abstract: A semiconductor laser is provided monolithically integrated on a substrate and has a cavity layer extending above a plane that is coplanar with a base surface of the substrate, is branched and includes a plurality of separately controllable regions. The laser is operated by changing charge carrier density in at least one of the regions so that it emits light at one of a first wavelength and a second wavelength in correspondence with the charge carrier density change.

Abstract: An interferometric semiconductor laser includes a cavity in the form of a Y and at east three individually actuatable active segments. A central segment couples together the individually actuatable active segments. The central segment is an active or passive segment that acts as a beam divider. The arrangement of the segments forms two resonator paths which contain at least one common active segment. At least one resonator path includes an active segment that does not belong to the other resonator path. In the absence of, or with the same actuation of the active segments, the optical path length of one resonator path differs from the optical path length of the other resonator path.

Abstract: A semiconductor laser that is monolithically integrated on a substrate and whose cavity has a branched structure that is simply contiguous in a topological sense, and which includes a plurality of regions that enclose the cavity, is operated as a mode-locked semiconductor laser, with an alternating current flowing through at least one region in addition to a direct current. The frequency of the alternating current is related to the reciprocal of the round-trip time or an integral multiple of this reciprocal of light pulses generated by the alternating current in the semiconductor laser.

Abstract: An optical device includes a semiconductor laser monolithically integrated on a substrate having a branched cavity extending above a plane that is coplanar with a base surface of the substrate, and an adjustable optical power light source for radiating light into the cavity of the semiconductor laser thereby controlling the operation of the semiconductor laser optically.

Abstract: In the commonly used methods for the coating of opto-electronic components, especially of semiconductor lasers, the layer thickness of a layer that is to be deposited is measured optically. The optical signal is converted into an electrical one with which the coating is controlled.The invention relates to the purely electrical interpretation of the high frequency component of the electrical noise power of an opto-electronic component (3) when a direct current passes through it. From the noise power, a controlling computer (10) derives a signal for control of the layer thickness; this is fed into a coating apparatus (14) of a coating reactor (2) which has a reacting chamber (1) containing the component (3) to be coated.