Abstract: The present invention relates to a method of and arrangement for determining non-linear behavior of a device (40) under test, wherein the device (40) is excited by a test signal on relevant device terminals under different termination conditions and the emitted signals at the fundamental and harmonic frequencies are measured at the relevant device terminals. Then, calibration measurements taken on calibration standards of known impedance and linearity are performed to derive parameters needed to correct the raw data read by the measurement for cable loss and delay and for non-linear behavior of the measurement system. Finally, non-linear scattering or admittance parameters are extracted from the error corrected measurements taken at different excitation and termination conditions. Thereby, the non-linear behavior can be more accurately characterized, modeled and understood.

Abstract: The invention relates to an optoelectronic device (1) with a laser amplifier (3) at one side of which are present in the radiation path in that order: a lens (8), a polarization-changing element (17), and a mirror (9) which together with the element (17) forms an orthogonal reflector. Both the radiation to be amplified and the amplified radiation issue from the device at the other side of the amplifier (3). Such a device (1) has a very low sensitivity to the polarization of the radiation to be amplified and is particularly suitable for use at very high bit rates.A disadvantage of the known device is that its efficiency is not particularly high and not well reproducible.According to the invention, the lens (8) comprises a magnifying lens (8), and the mirror (9) is present substantially in the image plane of the magnifying lens (8). As a result, the alignment of the amplifier (3) with respect to the lens (8) is much less critical, so that the efficiency is higher and more reproducible.

Abstract: The invention relates to an optical unit (17) for synchronizing clock signals. The unit (17) comprises at least two ring lasers (1', 1"), each ring laser (1', 1") generating a repetitive optical pattern at a different repetition frequency f.sub.i. The repetition frequency of at least one of the ring lasers (1', 1") is variable. The unit (17) comprises detection means (19) adapted to simultaneously receive the optical patterns from two ring lasers (1', 1") to be synchronized with each other and to compare these patterns. The ring laser, whose repetition frequency is variable, is controllable on the basis of a signal from the detection means, by which the optical path length of this laser is changed. The invention also relates to a high-frequency carrier transmission system comprising an optical unit as described hereinbefore.

Abstract: An optical unit for multiplying the frequency of a clock signal includes at least two series-arranged ring lasers. Each ring laser has a different resonance frequency f.sub.i. The unit has an input for receiving a signal, for example, a low-frequency electric signal for modulating one of the ring lasers. The repetition frequency of at least one of the ring lasers is variable by adapting the optical path length of the resonator.

Abstract: The invention relates to an optoelectronic device with a module comprising a holder with an amplifier and on either side thereof a lens and a glass fiber which can be aligned relative to the amplifier. The module also comprises two monitor diodes. A disadvantage of the known device is that the lenses cannot be easily aligned relative to the amplifier, and the monitor diodes cannot be easily connected electrically. The use of a spherical lenses also poses a problem. In a device according to the invention, the monitor diodes are so positioned that they are capable of detecting radiation reflected at the outside of the lenses instead of radiation refracted and reflected within the lenses, while the radiation-sensitive surfaces of the monitor diodes are positioned such that they receive more radiation from one lens than from the other lens.

Abstract: A semiconductor diode laser amplifier (100) includes an active layer (4) which is situated between two cladding layers (1A, (3,6)) and in which a strip-shaped active region is present which is bounded in longitudinal direction by two end faces (7,8) which are practically perpendicular to the active region and are provided each with an antireflection layer (71,81).The amplification ripple of such a laser amplifier (100) is comparatively high, in particular when radiation of different wavelengths is present in the laser (100), such as the TE and TM portions of the radiation to be amplified.

Abstract: Optoelectric device having a coupling between a semiconductor diode laser component, such as an amplifier or modulator, and two optical glass fibres. The optoelectronic device has an optoelectronic module comprising a first holder with a semiconductor diode laser component and provided on either side of the component with a second holder comprising a plate with an opening and a lens holder in which a lens is present. The module also comprises a third holder for an optical glass fibre aligned with the component on either side of the component. The second holder comprises a bush which is connected to the plate and within which the lens holder is fastened to the plate, while the bush is provided with at least one opening, near the plate.

Abstract: The invention relates to a III-V laser (amplifier) with an active region (4A) which encloses a small angle with the end faces (50, 51), is separated therefrom by a preferably current-blocking cladding layer (5) and has a tapering end (40) of which a first side face (42) coincides with a side face (42) of the remainder of the strip-shaped active region (4A), while a second side face (43) thereof encloses an acute angle with the perpendicular to the end faces (50, 51). Such a laser has an amplification ripple, which is undesirable. In a laser according to the invention, the second side face (43) of the tapering portion (40) encloses an angle with the perpendicular to the end face (50, 51) which lies between 0.degree. and 30.degree., preferably between 0.degree. and 10.degree., and which is preferably approximately 0.degree.. The laser according to the invention has a particularly low reflection, as a result of which said amplification ripple is absent or at least very small.

Abstract: An optoelectronic device with an optoelectronic module containing a semiconductor diode laser device and, in the radiation path (S) on either side of the semiconductor diode laser device, in that order, a first lens, an optical component, in particular an optical isolator, a second lens, and an optical glass fiber. The second lens and the glass fiber are arranged in a sub-module. The optical component is present in the sub-module and the first lens outside it, and the module is provided with means for fastening the sub-module to the module at an adjustable angle relative to the radiation path. Said means preferably comprise a membrane and radially adjustable clamping means.

Abstract: An optoelectronic semiconductor device with at least one laser and two mutually parallel, strip-shaped active regions, whose ends are optically coupled at one side, is a very suitable radiation source or amplifier, for example as a tunable radiation source. More than one kind of radiation is often present in such a device, whereas it is desirable for only one kind of radiation to pass through a gate of the device. To achieve this in prior devices, an additional component, such as a filter or isolator, is necessary.

Abstract: Optical amplifier which utilizes a solid-state laser as an amplifying element. In the optical amplifier, according to the invention, a linearity improvement is achieved by feeding the solid-state laser from a voltage source rather than from a current source, as is customary.

Abstract: An optical amplifier with a semiconductor body includes a layer structure grown on a substrate, with an active layer between two cladding layers, and a strip-shaped amplification region bounded by two end faces of low reflection which form the input and output faces for the radiation to be amplified. The active layer has a number of quantum well (QW) layers with direct band transition, and separated by barrier layers of a different semiconductor material, a first portion of the QW layers being under tensile stress. Another portion of the layers forming part of the active layer is under compressive stress. Owing to the compressive stress present locally in the amplification region, the TE-mode is more strongly amplified there than the TM-mode, while in the tensile portion of the amplification region the TM-mode is more strongly amplified than the TE-mode. This results in a polarization-insensitive amplifier with higher stress and thus with a large amplification at a relatively low current.