35 results about "Rib waveguides" patented technology

A tapered rib waveguide tapering from a large, multi-mode optical waveguide to a smaller, single-mode optical waveguide, the tapered rib waveguide comprising two portions (4,5) formed of the same material: a lower portion (4) which tapers laterally from the large waveguide to the smaller waveguide and an upper portion (5) formed on the lower portion (4), which tapers to a point (or other form of termination), the dimensions of the two portions (4,5) being such that substantially all of a fundamental mode propagated in the large multi-mode waveguide is coupled to the smaller, single-mode waveguide.

High speed optical modulators can be made of a reverse biased lateral PN diode formed in a silicon rib optical waveguide disposed on a SOI or other silicon based substrate. A PN junction is formed at the boundary of the P and N doped regions. The depletion region at the PN junction overlaps with the center of a guided optical mode propagating through the waveguide. Electrically modulating a reverse biased lateral PN diode causes a phase shift in an optical wave propagating through the waveguide. Prior art forward biased PN and PIN diode modulators have been relatively low speed devices.

A light coupler between an optical fiber (6) and a waveguide is made on a semiconductor-on-insulator substrate (1), this substrate (1) comprising a thin layer of semiconducting material in which the waveguide is made. The coupler comprises a light injector (5) and an adiabatic collector (4) made up with an inverted nanotip formed from the thin layer of semiconducting material. The injector (5) is formed on the insulator (3) and has a face (7) for receiving an end of the optical fiber (6). The adiabatic collector (4) has a cross-section which increases from a first end located on the side of said end of the optical fiber (6) right up to a second end which is connected to the waveguide, the injector (5) covering the adiabatic collector (4) and having a rib waveguide shape.

An integrated optical circuit for use in a fibre optic gyroscope which senses rotation rates by determining a phase shift due to the Sagnac Effect between light beams travelling around an optical fibre sensing loop (4) in opposite directions, the circuit being provided on a silicon-on-insulator chip comprising a layer of silicon separated from a substrate by an insulating layer, the circuit comprising: rib waveguides (11) formed in the silicon layer for receiving light from a light source (2) and transmitting light to a light detector (3), fibre optic connectors (9) in the form of grooves etched in the silicon layer for receiving the respective ends of the optical fibre sensing loop (4); rib waveguides (11) formed in the silicon layer for transmitting light to and from said fibre optic connectors (9) so as to direct light beams in opposite directions around the sensing loop (4) and receive light beams returning therefrom, phase determining means and (13,17,31) integrated in silicon layer for determining a phase shift between the light beams returning from the sensing loop (4).

High speed optical modulators can be made of a lateral PN diode formed in a strip loaded optical waveguide on a SOI or other silicon based substrate. A PN junction is formed at the boundary of the P and N doped regions. The depletion region at the PN junction overlaps with the center of a guided optical mode propagating through the waveguide. Electrically modulating a lateral PN diode causes a phase shift in an optical wave propagating through the waveguide. Due to differences in fabrication methods, forming strip loaded waveguides with consistent properties for use in PN diode optical modulators is much easier than fabricating similar rib waveguides.

A method and system for waveguide mode filters are disclosed and may include processing optical signals of a fundamental mode and higher-order modes by filtering the higher-order modes in rib waveguides in a photonic chip. The higher-order modes may be filtered utilizing doped regions and/or patterns in one or more slab sections in the rib waveguides. The patterns may be periodic or aperiodic along the rib waveguides. The higher-order modes may be filtered utilizing varying widths of slab sections, or doped, patterned, and/or salicided ridges on the slab sections in the rib waveguides. The higher-order modes may be attenuated by scattering and/or absorbing the modes. The chip may comprise a CMOS photonic chip.

A low loss coupling arrangement between a slab/strip waveguide and a rib waveguide in an optical waveguiding structure formed on a silicon-on-insulator (SOI) platform utilizes tapered sections at the input and/or output of the rib waveguide to reduce loss. Optical reflections are reduced by using silicon tapers (either vertical tapers, horizontal tapers, or two-dimensional tapers) that gradually transition the effective index seen by an optical signal propagating along the slab/strip waveguide and subsequently into and out of the rib waveguide. Loss can be further reduced by using adiabatically contoured silicon regions at the input and output of the rib waveguide to reduce mode mismatch between the slab/strip waveguide and rib waveguide. In a preferred embodiment, concatenated tapered and adiabatic sections can be used to provide for reduced optical reflection loss and reduced optical mode mismatch.

An optical device is disclosed which includes a single-mode waveguide (700) which supports a first optical mode in a first region and a second optical mode in a second region. The waveguide includes a guiding layer (703) having at least one wing (750) extended outwardly from the guiding layer (703). The guiding layer (703) may desirably have a rib waveguide (706, 707) cross sectional shape at the wings. The wings (750) decrease in width along the length of the guiding layer to convert a rib waveguide mode at the wings to a channel waveguide mode.

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).

An optical waveguide element includes: a rib waveguide and a pair of slab portions including a first slab portion and a second slab portion connected to both sides of the rib portion so as to sandwich the rib portion. The rib portion has a cross-sectional dimension which allows the propagation of a fundamental mode and a higher order mode in a predetermined single polarization state, and has a first P-type semiconductor and a first N-type semiconductor forming a PN junction, the first slab portion has a second P-type semiconductor and a P-type conductor connected to each other, the second P-type semiconductor is connected to the first P-type semiconductor of the rib portion, the second slab portion has a second N-type semiconductor and an N-type conductor connected to each other, and the second N-type semiconductor is connected to the first N-type semiconductor of the rib portion.

The invention concerns a guided wave spatial filter (300) for receiving input radiation and outputting corresponding filtered output radiation, the filter comprising first and second waveguide sections (30, L3, L5) connected in series, the sections: (a) mutually matched for transmitting fundamental mode radiation components present in the input radiation therethrough to provide the output radiation; and (b) mutually mismatched for hindering higher-order mode radiation components present in the input radiation from propagating therethrough and contributing to the output radiation. The spatial filter (300) is implemented using rib waveguides (30) for the sections with associated relatively deeply and relatively shallowly etched structures (20, 310, 320) for imparting to the sections their radiation mode filtration characteristics. The spatial filter according to the invention can be incorporated into optical splitters and optical modulators to enhance their performance and desensitise them to higher-order mode radiation injected thereinto.

Methods and systems for a silicon-based optical phase modulator with high modal overlap are disclosed and may include, in an optical modulator having a rib waveguide in which a cross-shaped depletion region separates four alternately doped sections: receiving an optical signal at one end of the optical modulator, modulating the received optical signal by applying a modulating voltage, and communicating a modulated optical signal out of an opposite end of the modulator. The modulator may be in a silicon photonically-enabled integrated circuit which may be in a complementary-metal oxide semiconductor (CMOS) die. An optical mode may be centered on the cross-shaped depletion region. The four alternately doped sections may include: a shallow depth p-region, a shallow depth n-region, a deep p-region, and a deep n-region. The shallow depth p-region may be electrically coupled to the deep p-region periodically along the length of the modulator.

Provided are a polarization beam splitter and an optical device with high productivity. A polarization beam splitter (PBS) according to an exemplary embodiment of the present invention includes: a demultiplexer (11) that is formed of a rib waveguide (50) and demultiplexes input light into first input light and second input light; a multiplexer (14) that is formed of the rib waveguide (50) and multiplexes the first input light and the second input light that are obtained by demultiplexing the input light by the demultiplexer (11); a first arm waveguide (12) that is formed of a channel waveguide (51) and guides the first input light to the multiplexer (11); and a second arm waveguide (13) that is formed of the channel waveguide (51), generates a phase difference in the first input light propagating through the first arm waveguide, and guides the second input light to the multiplexer (14).

A waveguide optoelectronic device comprising a rib waveguide region, and method of manufacturing a rib waveguide region, the rib waveguide region having: a base of a first material, and a ridge extending from the base, at least a portion of the ridge being formed from a chosen semiconductor material which is different from the material of the base wherein the silicon base includes a first slab region at a first side of the ridge and a second slab region at a second side of the ridge; and wherein: a first doped region extends along: the first slab region and along a first sidewall of the ridge,the first sidewall contacting the first slab region; and a second doped region extends along: the second slab region and along a second sidewall of ridge, the second sidewall contacting the second slab region.

The disclosure discloses a polarization rotator and a polarization stabilizer. The polarization rotator includes a rib waveguide. The rib waveguide includes: a slab portion; and a ridge portion, whichis disposed along a surface of the slab portion. The slab portion has a first slab region whose width, as measured in a direction perpendicular to a guiding direction of the waveguide, increases froma first slab width to a second slab width along a first length, and the ridge portion has a first ridge region whose width, as measured in the same direction as the slab widths, decreases from a first ridge width to a second ridge width along the same first length; such that the rotator is configured to rotate the polarization of light during its transmission through the rib waveguide.