Telefonaktiebolaget Lm Ericsson (publ)

Syntune Ab

Finisar Sweden Ab

Ii-vi Delaware, Inc.

Per O Granestrand

Jan-Olof Wesstrom

Jan-Olof Wesström

Dave Adams

David Adams

Lennart Lundqvist

Martin Anders Isak Stattin

Staffan David Hellström

Stefan Hammerfeldt

Jan-OLof Wesstrom

Stefan Bjurshagen

Åsa Björkström

Per Johan Olof Svensson

Armand Vatsel

Johan Berg

Ove B Andersson

A laser device includes front and back DBRs and an interferometer. The front DBR is coupled to a front DBR electrode. The front DBR forms a first tunable multi-peak lasing filter. The back DBR is coupled to a back DBR electrode. The back DBR forms a second tunable multi-peak lasing filter. The interferometer part is coupled between the front DBR and the back DBR. The interferometer part includes first and second waveguide combiners and first and second interferometer waveguides coupled therebetween. The first waveguide combiner couples the interferometer part to the back DBR. The second waveguide combiner couples the interferometer part to the front DBR. The first interferometer waveguide is coupled to an interferometer electrode. The interferometer forms a third tunable multi-peak lasing filter.

Tunable semiconductor laser device

An optical device comprises a light input, a light modulating means and a light output. The optical device further comprises an optical amplification device arranged to amplify light travelling between said light modulating means and said output. The optical amplification device comprises first and second serially connected post SOA (Semiconductor Optical Amplifier) units, each comprising at least one respective serially connected post SOA segment, which device is arranged to vary a light amplification by varying respective SOA bias voltages across said post SOA segments. A total SOA length of the first post SOA unit is relatively longer than a total SOA length of the second post SOA unit, which is relatively shorter. The optical device is arranged to, during operation using a particular operation program, always keep respective SOA bias voltages across each of the post SOA segments of the first post SOA unit at +0.5 V or more.

Optical device and method for controlling such a device

A waveguide for the extraction of light at low levels of reflection arranged to guide light from an electro-optical component on a chip to a facet on the chip for extraction includes a first part and a second part. The first part () is extended, the second part () includes a surface (JK) through which the light exits from the waveguide (). A non-adiabatic longitudinal section (GHLM) is located after the first part () but before the surface (JK) in the direction of propagation of the light, and the surface (JK) forms in the plane of the chip a first angle (V) with the optical axis (A) of the first part () that lies between 5 and 80 degrees.

Waveguide for extraction of light at low levels of reflection

Optical waveguiding part (), which waveguiding part is arranged to convey light through an output facet () of the waveguiding part, which waveguiding part comprises a ridge waveguide comprising a semiconductor substrate () and a semiconductor light-conveying ridge, wherein the output facet is set at an angle (&#x3b1;) in relation to a main direction (z) of light along the said waveguide, so that light travelling in the waveguide along said main direction has an angle of incidence towards the facet of between 2&#xb0; and 14&#xb0; and is reflected towards a first side () of the said ridge, wherein the waveguide comprises an MMI (Multi Mode Interferometer) (), arranged to create an output image substantially at the output facet.

Optical waveguiding part

A Mach Zehnder (MZ) modulator () includes a splitter () for splitting incident light in one wave guide () into two modulator arms () of the MZ and a combiner () that combines light from the two arms () into an output mode, where electrodes () are present in connection with the arms () for changing the refractive index in the arms in order to modulate incident light so that the light is amplified or so that an extinction, due to interference between the light in the two arms, takes place. The splitter () is arranged to split incident light equally into the two arms () and a part () of one of the arms () between the electrode () and the combiner () is designed to cause an intentional loss of light in the wave guide (), whereby a desired asymmetry in transmission of the two arms () occurs.

Mach zehnder modulator

A transition part () between two optical waveguides () with different index contrast is characterised in that the transition part () includes a non-adiabatically up-tapered longitudinal section (), and in that the transition () between the two waveguides () is arranged after the up-tapered longitudinal section () as seen along the main direction (L) of propagation of the light. A method of manufacturing the transition part is also described.

Transition device for optical waveguides

An electrooptic device () such as a distributed feed back semiconductor laser or a semiconductor modulator comprises an optical waveguide. A contact layer () is applied to the optical waveguide for conducting electrical current to the device for driving or modulating it. The contact layer is connected to the end of an electrically conducting path () and can have a shape, as seen perpendicularly to the surface of the device, to give an electric resistance between the end of the path and different areas at the optical waveguide which resistance is higher for areas located close to the ends of the device than for areas are located at the central region of the device. The shape can be si-milar to a trapezium having concave oblique sides and is selected so that the resulting varying electrical resistance gives a sub-stantially uniform electrical power or gain inside the optical waveguide, taken in the longitudinal direction of the waveguide.

Distributed feedback laser with varying electrical resistance for uniform gain inside the optical waveguide

An optical device has a back facet () and a front facet (') opposite to each other, and includes a laser () adapted to emit light essentially perpendicular to said back facet; a modulator () having an input end and an output end (), respectively, and adapted to receive and modulate light emitted from said laser and to output modulated light at said modulator output end; and a window region () arranged between said modulator output end and said device front facet, said device being further arranged such that modulated light output from said modulator is transmitted through said window region and is output from said device through said device front facet. The modulator is bent such that the modulated light output from said modulator is propagating essentially in a direction (), which is angled (&#x3b1;; &#x3b4;) with respect to the normal (Z;) of said device front facet.

Optical device and fabrication thereof

The present invention relates to a high yield DFB laser with an effective reject selection using criteria on threshold current. The demand for high output power often will require use of lasers with asymmetric power distributions with most of the light power coming out from the front mirror. The laser according to the invention preferably has an as-cleaved back mirror, an AR-coated front mirror and a 90- degree phase shift (wavelength/4) positioned at 43% of the laser length counted from the rear mirror. This type of laser gives a good SM-yield, an advantageous power asymmetry and a possibility to select good lasers using the threshold current as selection parameter.

High yield DFB laser with effective reject selection

The present invention relates to an optical waveguide (,) comprising a transition portion in at least one connection end for connection with an optical component. The transition portion is arranged in such a way that the waveguide at first changes over into a widening portion (,) which in turn changes over into a tooth structure (,), where said tooth structure (,) is intended to be connected to said optical component.

Optical waveguide designed to facilitate connections with optical componentry and fibers

Laser amplifier, an optical system comprising such a laser amplifier and

An X-cut or near Y-cut monocrystalline wafer of electro-optical material forms a substrate of a digital optical switch. Waveguides of LiNbO.sub.3 are diffused into the wafer to form ribbon waveguides such that light propagates in a direction near the Z axis of the wafer. These waveguides form a Y-shape, refractive indices of which are controlled by electrodes formed closely adjacent thereto.

Near Z digital switch

Polarization independent switch or coupler including a directional coupler with extremely relaxed fabrication tolerances. The coupler includes a mono-crystalline wafer of electro-optic material with two closely adjacent light waveguides at an upper surface along with electrodes positioned adjacent the waveguides. The electrodes include a grounded, main electrode formed on one side of the waveguides and four smaller electrodes formed in a line on a side or sides of the waveguides opposite to the main electrode, each of the four smaller electrodes being supplied with a voltage. The electrodes and waveguides can be in a planar or stacked relationship to one another. When the voltages applied to the middle two electrodes have equal values and have like polarity (V.sub.c =V.sub.b) and the voltages applied to the outer electrodes have equal values and like polarity (V.sub.d =V.sub.a), the light travelling in one waveguide is barred from transferring to another waveguide.

Four section optical coupler

Polarization directing optoelectronic coupler on a wafer of doubly refracting material with an optical axis (L1). The coupler has an interaction region (L1) with waveguides (L1) and an electrode means. The interaction region (L1) is divided into two sections with a central electrode and two outer electrodes in each section. Voltage sources are connected to the electrodes and generate electrical fields through the waveguides. The electrical field between the outer electrodes has in each section the same direction in both waveguides and achieves an .DELTA.H modulation. The electrical field between the central electrode and outer electrodes has mutually reverse direction in both waveguides in the sections and achieves a .DELTA..beta. modulation. For an arbitrarily polarized lightwave both the crossover state and the bar state can be achieved for both the TE and TM modes or one of its oscillation modes can be crossed over and the other of its oscillation modes can be coupled straight through. The directional coupler can be driven at low voltages and the required manufacturing accuracy is relatively low.

Method of disposing a polarization directing optoelectronic coupler and

The present invention relates to optical repeaters in a two-way optical line link, e.g. one included in a teletransmission system. The optical repeaters are implemented such as to provide a system which, inter alia in fault localizing, utilizes the line link transmission capacity optimally by completely optical through-connection of signals on the optical fibre cables. In fault localizing, one repeater at a time is checked, by an end terminal in the link transmitting a test signal including an address for selecting a repeater for testing and a test pattern. An optical amplifier amplifies the test signal in every repeater through which the signal passes, and when it reaches the repeater indicated by the address, a control circuit controls an optical switch such that the test signal is switched (loop connected) and is returned to the transmitting terminal where fault analysis takes place.

Growing community of inventors

Tyreso, Sweden

Per O Granestrand