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 waveguide, which is part of an integrated optical circuit is arranged onto a planar substrate, and has a core section propagating light to a direction of propagation. The waveguide is a conversion waveguide between a ridge-type waveguide and a strip waveguide. In the conversion waveguide, the core section is made of the one and same material so that the cross-section of the core section transverse to the direction of propagation of light is two-step from both edges. The conversion waveguide has two layers of different widths so that the height of the first layer is equal to the height of the ridge of the ridge-type waveguide, and the height of the second layer is equal to the height of the base part of the ridge-type waveguide.

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.

Abstract: A waveguide, which is part of an integrated optical circuit is arranged onto a planar substrate, and has a core section propagating light to a direction of propagation. The waveguide is a conversion waveguide between a ridge-type waveguide and a strip waveguide. In the conversion waveguide, the core section is made of the one and same material so that the cross-section of the core section transverse to the direction of propagation of light is two-step from both edges. The conversion waveguide has two layers of different widths so that the height of the first layer is equal to the height of the ridge of the ridge-type waveguide, and the height of the second layer is equal to the height of the base part of the ridge-type waveguide.