Abstract: According to an example aspect of the present invention, there is provided a photonic integrated circuit, comprising: a waveguide with an end having a tilted surface for reflecting light with a total internal reflection (TIR) mirror, and a functional surface for interacting with the light reflected by the TIR mirror, wherein the functional surface is directly deposited on to an antireflection coating on the waveguide. According to another aspect of the present invention there is provided a method for manufacturing a photonic integrated circuit.

Abstract: An optical assembly for realizing horizontal and vertical spot-size conversion to couple light from a thin waveguide to a thick waveguide is disclosed. The assembly comprises at least one first thin waveguide with a first section having a first optical mode field and a horizontal spot-size expansion section providing spot-size conversion for a first horizontal dimension of said first optical mode field of a light beam propagating in said first waveguide, and at least one second thick waveguide with a second section having a second optical mode field and a horizontal spot-size reduction section providing spot-size conversion for a second horizontal dimension of said second optical mode field of a light beam propagating in said second waveguide.

Abstract: The invention concerns a polarization rotator, comprising a first waveguide layer containing at least a first waveguide, said first waveguide having an input end and an output end, a second waveguide layer having at least a second waveguide, said second waveguide having an input end and an output end, and at least a first vertical mirror element arranged at the end of at least one of said waveguides to couple light between the output end of the first waveguide and the input end of the second waveguide. The optical axis of said first or second waveguide which has the vertical mirror element at its end is rotated in its waveguide layer at a first angle in order to induce rotation of polarization of light coupled between said first and second waveguides with an amount that corresponds to said first angle.

Abstract: The invention concerns a polarization rotator. The inventive polarization rotator comprises an optical coupler comprising a waveguide having at one first end at least a first port configured as an input port for polarized light and a second port configured as an output port for reflected polarized light, said waveguide having a second end opposite to said first end. It further comprises a birefringent waveplate having on one side a reflective surface, which waveplate is arranged to receive light from said second end of said waveguide and to reflect light transmitted out from said coupler back into said coupler. According to the invention, the waveplate is further configured to cause said birefringent material to rotate the polarization of said reflected light, which amount of rotation depends on an angle of rotation of said birefringent waveplate with respect to said optical coupler.

Abstract: The invention relates to devices and methods for polarization splitting, where a first optical coupler having at least one input port which receives an input light beam, and at least two output ports at which said light beam, is split into at least a first and a second arms at a first end of said arms. At least one total internal reflection mirror is coupled to the second arm for inducing polarization-dependent phase shifts to the light beam propagating in the second arm, and a polarization-dependent phase difference between the second and the first arm. A second optical coupler having input ports is coupled to the second and opposite ends of the arms. The second coupler has at least one first output port at which light is coupled from said arms, so that the polarization-dependent phase shift of the at least one total internal reflection mirror causes polarization-dependent coupling of light from said input port to said output port.

Abstract: An optical assembly for realizing horizontal and vertical spot-size conversion to couple light from a thin waveguide to a thick waveguide is disclosed. The assembly comprises at least one first thin waveguide with a first section having a first optical mode field and a horizontal spot-size expansion section providing spot-size conversion for a first horizontal dimension of said first optical mode field of a light beam propagating in said first waveguide, and at least one second thick waveguide with a second section having a second optical mode field and a horizontal spot-size reduction section providing spot-size conversion for a second horizontal dimension of said second optical mode field of a light beam propagating in said second waveguide.

Abstract: The invention relates to optical waveguide components, such as Faraday rotators and their manufacture Faraday rotators based on silicon waveguides are provided, where the waveguide has folded or wound sections that are parallel to an externally applied magnetic field.

Abstract: The invention concerns a polarization rotator, comprising a first waveguide layer containing at least a first waveguide, said first waveguide having an input end and an output end, a second waveguide layer having at least a second waveguide, said second waveguide having an input end and an output end, and at least a first vertical mirror element arranged at the end of at least one of said waveguides to couple light between the output end of the first waveguide and the input end of the second waveguide. The optical axis of said first or second waveguide which has the vertical mirror element at its end is rotated in its waveguide layer at a first angle in order to induce rotation of polarization of light coupled between said first and second waveguides with an amount that corresponds to said first angle.

Abstract: The invention concerns a polarization rotator. The inventive polarization rotator comprises an optical coupler comprising a waveguide having at one first end at least a first port configured as an input port for polarized light and a second port configured as an output port for reflected polarized light, said waveguide having a second end opposite to said first end. It further comprises a birefringent waveplate having on one side a reflective surface, which waveplate is arranged to receive light from said second end of said waveguide and to reflect light transmitted out from said coupler back into said coupler. According to the invention, the waveplate is further configured to cause said birefringent material to rotate the polarization of said reflected light, which amount of rotation depends on an angle of rotation of said birefringent waveplate with respect to said optical coupler.

Abstract: The invention relates to devices and methods for polarization splitting, where a first optical coupler having at least one input port which receives an input light beam, and at least two output ports at which said light beam, is split into at least a first and a second arms at a first end of said arms. At least one total internal reflection mirror is coupled to the second arm for inducing polarization-dependent phase shifts to the light beam propagating in the second arm, and a polarization-dependent phase difference between the second and the first arm. A second optical coupler having input ports is coupled to the second and opposite ends of the arms. The second coupler has at least one first output port at which light is coupled from said arms, so that the polarization-dependent phase shift of the at least one total internal reflection mirror causes polarization-dependent coupling of light from said input port to said output port.

Abstract: The invention relates to photonic circuits, in particular to photonic circuits where light is escalated transferred between optical waveguides which are coupled to photonic devices. A first waveguide on a silicon substrate is provided having a first thickness and a first refractive index. A tapered second waveguide having a second thickness less than the first thickness and a second refractive index higher than said first refractive index is deposited on the first waveguide. At least one layer of an optically active material comprising a photonic device is deposited on the first waveguide adjacent to the second waveguide. The photonic device is interfaced with the wide end of the tapered second waveguide to provide an optical coupling, and the opposite narrow end of the tapered second waveguide is interfaced on top of the first waveguide to provide adiabatic light transfer between said first and second waveguides.

Abstract: According to an example aspect of the present invention, there is provided a method for integrating photonic circuits comprising optical waveguides, where a smaller chip with at least one first photonic circuit is aligned and bonded on top of a larger chip having at least one second photonic circuit in order to couple light between optical waveguides on each chip, wherein optical coupling between the waveguides on said chips occurs from a single side of said smaller chip.

Abstract: The invention relates to optical waveguide components, such as Faraday rotators and their manufacture Faraday rotators based on silicon waveguides are provided, where the waveguide has folded or wound sections that are parallel to an externally applied magnetic field.

Abstract: The invention relates to photonic circuits, in particular to photonic circuits where light is escalated transferred between optical waveguides which are coupled to photonic devices. A first waveguide on a silicon substrate is provided having a first thickness and a first refractive index. A tapered second waveguide having a second thickness less than the first thickness and a second refractive index higher than said first refractive index is deposited on the first waveguide. At least one layer of an optically active material comprising a photonic device is deposited on the first waveguide adjacent to the second waveguide. The photonic device is interfaced with the wide end of the tapered second waveguide to provide an optical coupling, and the opposite narrow end of the tapered second waveguide is interfaced on top of the first waveguide to provide adiabatic light transfer between said first and second waveguides.

Abstract: An optical multi-mode HIC (high index contrast) waveguide (102, 104, 201, 301) for transporting electromagnetic radiation in the optical waveband, the waveguide comprising a guiding core portion (204) with higher refractive index, and cladding portion (206) with substantially lower refractive index configured to at least partially surround the light guiding core in the transverse direction to facilitate confining the propagating radiation within the core, the waveguide being configured to support multiple optical modes of the propagating radiation, wherein the waveguide incorporates a bent waveguide section (202) having bend curvature that is configured to at least gradually, preferably substantially continuously, increase towards a maximum curvature of said section from a section end.

Abstract: An optical multi-mode HIC (high index contrast) waveguide (102, 104, 201, 301) for transporting electromagnetic radiation in the optical waveband, the waveguide comprising a guiding core portion (204) with higher refractive index, and cladding portion (206) with substantially lower refractive index configured to at least partially surround the light guiding core in the transverse direction to facilitate confining the propagating radiation within the core, the wave-guide being configured to support multiple optical modes of the propagating radiation, wherein the waveguide incorporates a bent waveguide section (202) having bend. curvature that is configured to at least gradually, preferably substantially continuously, increase towards a maximum curvature of said section from a section end.

Abstract: A VCSEL (Vertical Cavity Surface Emitting Laser) structure (1), wherein at least one cross-section of the VCSEL structure perpendicular to the optical axis (2) of the VCSEL structure comprises a mode selecting shape (10) promoting output of the fundamental transverse mode of the resonator while suppressing output of the higher modes. According to the present invention, the mode selecting shape (10) comprises a longitudinal portion (101) being directed past the optical axis (2) and having a one-sided broadening (102) forming a central area (103) around the optical axis, the geometry of the mode selecting shape being chosen to concentrate the fundamental mode in the central area while guiding the possible higher modes away from the optical axis through the longitudinal portion.

Abstract: The present invention concerns an optical fiber acting as a slab-coupled waveguide. The optical fiber has a cross-section comprising a core (1), which is two dimensional and responsible for the horizontal confinement of the fiber's fundamental mode. A slab (2) is placed in the vicinity of the core (1). The slab (2) extends substantially in a plane, acts as a mode sink for the core, and is at least three times wider than the core (1). A cladding (3) surrounds the core (1) and the slab (2). The cladding (3) is made of one or several materials with refractive indices lower than the core and slab materials. The core (1), slab (2) and cladding (3) and any other protective or supportive structures attached to them form an overall structure that determines the mechanical properties of the fiber. The cross-section of the fiber is formed to make the fiber significantly more flexible in the direction perpendicular to the plane of the slab than in the plane of the slab.

Abstract: A structure comprises an inner strip waveguide (1) and an outer rib waveguide (2) on a common substrate. The thicker inner waveguide (1) is patterned into an inner core layer (3). The thinner outer waveguide (2) is patterned into an outer core layer (4). The inner and outer waveguides are separated by a gap (5) being less than 500 nm. The structure forms an adiabatic coupler. In the method, the first (inner) waveguide (1) is patterned into the thicker inner core layer (3) by etching trenches (8). A thinner outer silicon layer (4) is attached on top of the inner-core layer (3) and the first waveguide (1) to form an outer core layer (4). The second (outer) waveguide (2) is patterned into the outer core layer (4).

Abstract: A method for controlling an optoelectronic component that includes two waveguides. The refractive index of the first waveguide is changed periodically with a first control signal, the amplitude of which is changed between a first amplitude level and higher second amplitude level. The refractive index of the second waveguide is changed periodically with a second control signal, the amplitude of which is changed between the aforementioned first amplitude level and a lower third amplitude level. When the control signals are on their common first amplitude level, the refractive indices of the waveguides are equal and the phase difference between them is zero. When the first control signal is on the second amplitude level and the second control signal on the third amplitude level, the refractive indices of the waveguides are unequal so that their mutual phase difference has a predetermined target value.