Abstract:
An optical device comprises a semiconductor structure including first and second ridge waveguides, each waveguide comprising a ridge extending across a surface of the semiconductor structure. The ridge of the first waveguide has a first height above a first region of the surface, and the ridge of the second waveguide has a second, greater, height above a second region of the surface. The semiconductor structure includes a multimode interference (MMI) region situated between the first and second ridge waveguides, which provides a transition between them. At least a part of the MMI region is tapered in width and/or at least a part of the first and/or second ridge waveguide is tapered in width in a direction extending away from the MMI region.
Abstract:
An optical device (1000) comprises a multi-mode interference (MMI) region (912), a single optical input (908), a single optical output (910), a first electrode (1010) associated with the MMI device and a second electrode (902) located or a face (914) of a semiconductor substrate (906) opposite another face on which the MMI region (912) is formed, the first electrode (1010) and the second electrode (902) being arranged to apply an electric field to the MMI region (912), thereby to cause absorption of light propagating through the MMI device. The device may be operated as an optical attenuator or an optical electro-absorption modulator (EAM). The MMI region allows the spreading of light coupled through the input (908) within the MMI region (912), thus decreasing the optical power absorption per unit area in the device and improving thereby the thermal dissipation.
Abstract:
A monolithically integrated optoelectronic component comprises a substrate (48) , and at least three optoelectronic sub-devices (41, 42, 43) integrated within a semiconductor layer on the substrate (48) . Each of the sub-devices (41, 42, 43) has an upper conductor (44) and a lower conductor (45, 46) separated by a common active region (49) , and two of the sub-devices (41, 43) are electrically coupled to a conducting semiconductor sub- layer (47) within the semiconductor layer by their upper or lower conductors. Electrical isolation zones (54, 55, 56) are provided for electrically isolating a further one of the sub-devices (42) from the semiconductor sub-layer (47) and from the coupled conductors of the sub-devices (41, 43) , and for electrically isolating the other conductors of the sub-devices (41, 43) from one another. The combined use of such electrical isolation zones enables more complex electrical connection schemes to be used than has previously been possible with conventional integrated optoelectronic components. Such electrical connection schemes can be independent of the physical ordering of the sub-devices on the substrate which is of course of significance in terms of the optical path through the sub-devices.
Abstract:
An opto-electronic device comprises a waveguide (3) along which light may propagate and an electrode (7) associated with the waveguide and arranged to apply a variable electric field thereto. The waveguide includes one or more active regions (10) in which variations in the electric field applied by the electrode to the waveguide cause variations in absorption of the light, and one or more passive regions (9) in which variations in the electric field applied by the electrode to the waveguide cause substantially no variations in any absorption of the light. Relative proportions of the waveguide that comprise the active and passive regions vary along at least part of the length of the waveguide.
Abstract:
A monolithically integrated electroabsorption modulated laser having a ridge waveguide structure, has lateral ion implantation. The integrated device has a laser section and a modulator section. The modulator section has ion implanted regions adjacent to the waveguide ridge. The implanted regions penetrate through the top cladding layer to reduce capacitance within the intrinsic active core of the reverse biased modulator and allow a shallow etched ridge waveguide structure to be used for the modulator. The device provides good optical coupling, efficient manufacturing, and good high power performance.
Abstract:
An electro-optic modulator having a continuously adjustable chirp is provided. Optical signals input into the electro-optic modulator are divided into portions which are phase modulated in opposite senses, one portion imparted with a positive chirp and the other with a negative chirp. Variable couplers are used to adjust (by way of adjusting their coupling ratios) the amount of power allocated between the optical signals contributing to the positive chirp and the power of signals contributing to the negative chirp so that when the optical signals are combined an optical signal with an adjustable chirp is produced.
Abstract:
An optical device comprises a semiconductor structure including first and second ridge waveguides, each waveguide comprising a ridge extending across a surface of the semiconductor structure. The ridge of the first waveguide has a first height above a first region of the surface, and the ridge of the second waveguide has a second, greater, height above a second region of the surface. The semiconductor structure includes a multimode interference (MMI) region situated between the first and second ridge waveguides, which provides a transition between them. At least a part of the MMI region is tapered in width and/or at least a part of the first and/or second ridge waveguide is tapered in width in a direction extending away from the MMI region.
Abstract:
An electro-optic modulator having a continuously adjustable chirp is provided. Optical signals input into the electro-optic modulator are divided into portions which are phase modulated in opposite senses, one portion imparted with a positive chirp and the other with a negative chirp. Variable couplers are used to adjust (by way of adjusting their coupling ratios) the amount of power allocated between the optical signals contributing to the positive chirp and the power of signals contributing to the negative chirp so that when the optical signals are combined an optical signal with an adjustable chirp is produced.