Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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 (4) is extended, the second part (5) includes a surface (JK) through which the light exits from the waveguide (1). A non-adiabatic longitudinal section (GHLM) is located after the first part (4) 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 (V1) with the optical axis (A) of the first part (4) that lies between 5 and 80 degrees.

Abstract: Optical waveguiding part (300), which waveguiding part is arranged to convey light through an output facet (30) of the waveguiding part, which waveguiding part comprises a ridge waveguide comprising a semiconductor substrate (320) and a semiconductor light-conveying ridge, wherein the output facet is set at an angle (?) 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° and 14° and is reflected towards a first side (301) of the said ridge, wherein the waveguide comprises an MMI (Multi Mode Interferometer) (310), arranged to create an output image substantially at the output facet.

Abstract: Optical waveguiding part (300), which waveguiding part is arranged to convey light through an output facet (30) of the waveguiding part, which waveguiding part comprises a ridge waveguide comprising a semiconductor substrate (320) and a semiconductor light-conveying ridge, wherein the output facet is set at an angle (?) 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° and 14° and is reflected towards a first side (301) of the said ridge, wherein the waveguide comprises an MMI (Multi Mode Interferometer) (310), arranged to create an output image substantially at the output facet.

Abstract: A Mach Zehnder (MZ) modulator (1) includes a splitter (4) for splitting incident light in one wave guide (3) into two modulator arms (5,6) of the MZ and a combiner (7) that combines light from the two arms (5,6) into an output mode, where electrodes (9,10) are present in connection with the arms (5,6) 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 (4) is arranged to split incident light equally into the two arms (5,6) and a part (11) of one of the arms (5) between the electrode (9) and the combiner (7) is designed to cause an intentional loss of light in the wave guide (5), whereby a desired asymmetry in transmission of the two arms (5,6) occurs.

Abstract: A transition part (1) between two optical waveguides (2,3) with different index contrast is characterised in that the transition part (1) includes a non-adiabatically up-tapered longitudinal section (8), and in that the transition (7) between the two waveguides (2,3) is arranged after the up-tapered longitudinal section (8) as seen along the main direction (L) of propagation of the light. A method of manufacturing the transition part is also described.

Abstract: 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 (4) is extended, the second part (5) includes a surface (JK) through which the light exits from the waveguide (1). A non-adiabatic longitudinal section (GHLM) is located after the first part (4) 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 (V1) with the optical axis (A) of the first part (4) that lies between 5 and 80 degrees.

Abstract: A Mach Zehnder (MZ) modulator (1) includes a splitter (4) for splitting incident light in one wave guide (3) into two modulator arms (5,6) of the MZ and a combiner (7) that combines light from the two arms (5,6) into an output mode, where electrodes (9,10) are present in connection with the arms (5,6) 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 (4) is arranged to split incident light equally into the two arms (5,6) and a part (11) of one of the arms (5) between the electrode (9) and the combiner (7) is designed to cause an intentional loss of light in the wave guide (5), whereby a desired asymmetry in transmission of the two arms (5,6) occurs.

Abstract: A transition part (1) between two optical waveguides (2,3) with different index contrast is characterised in that the transition part (1) includes a non-adiabatically up-tapered longitudinal section (8), and in that the transition (7) between the two waveguides (2,3) is arranged after the up-tapered longitudinal section (8) as seen along the main direction (L) of propagation of the light. A method of manufacturing the transition part is also described.

Abstract: An electrooptic device (1) such as a distributed feed back semiconductor laser or a semiconductor modulator comprises an optical waveguide. A contact layer (11) 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 (3) 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.

Abstract: An optical device has a back facet (27) and a front facet (29; 29?) opposite to each other, and includes a laser (23) adapted to emit light essentially perpendicular to said back facet; a modulator (25; 51; 55) having an input end and an output end (35; 53; 57), 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 (33) 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 (34), which is angled (?; ?) with respect to the normal (Z; 71) of said device front facet.

Abstract: An electrooptic device (1) such as a distributed feed back semiconductor laser or a semiconductor modulator comprises an optical waveguide. A contact layer (11) 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 (3) 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 hither 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 similar to a trapezium having concave oblique sides and is elected 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.

Abstract: An optical device has a back facet (27) and a front facet (29; 29′) opposite to each other, and includes a laser (23) adapted to emit light essentially perpendicular to said back facet; a modulator (25; 51; 55) having an input end and an output end (35; 53; 57), 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 (33) 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 (34), which is angled (&agr;; &dgr;) with respect to the normal (Z; 71) of said device front facet.

Abstract: A laser amplifier, an optical system comprising such a laser amplifier and a method of forming such a laser amplifier for obtaining polarization independent amplification over a large wavelength region. The optical amplifier comprises an active region that is formed on a semiconductor substrate (6). The active layer has been formed through growing of quantum well layers (13, 14, 15, 16) alternating with barrier layers (12). The well layers comprise well layers of a first type (14, 15, 16) having tensile strain together with or without well layers of a second type having compressive strain (13). At least one of the well layers of one type (16) has been grown to a different width and/or with a different material composition than the other well layers of the same type (14, 15).