70 results about "Ridge waveguides" patented technology

The present application relates to a kind of on-chip photo-thermal gas sensor and on-chip photo-thermal gas sensor assembly, the refractive index of the upper waveguide material layer of sensor ridge waveguide layer is greater than the refractive index of lower waveguide material layer, can support TM mode pump light and TE mode probe light simultaneously. That is, both high absorption of pump light and weak influence of probe light on the gas to be measured are considered, and the detection accuracy of the gas is improved. Moreover, a simpler waveguide structure is used, and the waveguide preparation process is simple, and the waveguide loss is relatively low. Compared with the photo-thermal interference method in optical fiber sensing, the interaction between pump light and the gas to be measured is greatly improved, the length of the detection waveguide is greatly shortened while ensuring high sensitivity, and the device size can be reduced to micrometer level. In addition, the waveguide structure of the on-chip photo-thermal gas sensor disclosed in the present application is prepared from chalcogenide glass, which has more obvious advantages for gas detection in the mid-infrared waveband.

The invention relates to the technical field of optical communication, and provides a polarization separation rotator and optical communication equipment. The polarization separation rotator comprises an input coupling waveguide, a ridge waveguide and a separation waveguide, and the input coupling waveguide, the ridge waveguide and the separation waveguide are sequentially arranged in the light propagation direction; the input coupling waveguide is used for coupling an input optical signal to the ridge waveguide, and the input optical signal comprises two polarization modes; the vertical section of the ridge waveguide is in a step shape to form a vertical asymmetric structure, and the vertical section is perpendicular to the light propagation direction. And the separation waveguide is used for separating the optical signals in the two polarization modes so as to respectively transmit the optical signals to different output ports. According to the polarization separation rotator provided by the invention, the defects that the size is difficult to further reduce and the polarization extinction ratio is reduced in the prior art are overcome, efficient polarization mode hybridization is realized by increasing the asymmetry in the vertical direction, and miniaturization of the polarization separation rotator is facilitated.

A waveguide for an optical modulator system includes multiple tapered portions, or regions, designed to couple a CMBH laser light source to a ridge modulator. Using a waveguide with different tapered portions, transmission efficiency between the CMBH light source and the ridge modulator is improved, thus allowing the optical modulator to be used in high-speed applications. Waveguide described herein may include tapered portions in which, along a single direction, include one portion that tapers to a reduced width while another portion tapers to an increased width.

The invention discloses a mid-infrared laser based on three-device on-chip integration and a preparation method thereof, relates to the crossing field of a semiconductor laser technology and an optical communication technology, and solves the problem that the existing quantum cascade laser QCL technology cannot give consideration to both high modulation rate and high power. An intermediate infrared laser comprises a QCL unit, an EAM unit and an SOA unit which are sequentially arranged on a substrate. The substrate comprises a semi-insulating InP (Indium Phosphate); the QCL unit, the EAM unit and the SOA unit share the same ridge-shaped waveguide structure and grow through epitaxy butt joint. The method provided by the invention is suitable for a mid-infrared band space communication scene with high requirements on the laser modulation rate, the output power and the single-mode stability.

The utility model discloses a composite multimode waveguide structure, which belongs to the technical field of optoelectronic devices and comprises a plasmon unit made of a metal material or a material with a negative real part dielectric function. The plasmon unit is structurally characterized by comprising nanoparticles, nanowires, nanopore arrays or gradient structures; the dielectric waveguide is made of a semiconductor material with a high refractive index, and the dielectric waveguide is designed to be one of a strip-shaped waveguide, a ridge-shaped waveguide or a slit waveguide; and the substrate layer is located below the plasmon unit and the dielectric waveguide and comprises at least one low-refractive-index supporting layer, and the material system of the low-refractive-index supporting layer is one of an oxide material, a nitride material, a fluoride material or a composite substrate structure. According to the scheme, the contradiction of a plasma device and silicon photonics among mode degree of freedom, loss and process compatibility is solved.

A dual-polarized four-ridge horn antenna disclosed by the present invention comprises a horn section and a waveguide section, the horn section comprises a horn shell and four ridges which are located in the horn shell and have the same structure, the four ridges form a cross-shaped structure, two ridges located on the same straight line are a pair, two feeder lines are configured in the waveguide section, and the waveguide section is provided with two feed lines. The two feeder lines respectively excite the pair of ridges at the same time, so that dual polarization is realized. The two pairs of ridges are excited at the same time to realize two polarization directions at the same time, and low-frequency cut-off wavelength is effectively reduced and high-frequency cut-off wavelength is improved by means of smooth transition of the ridge waveguides, so that the bandwidth of the horn antenna is widened.

The invention provides a visible light modulator which is small in size and capable of high-speed driving at low voltage. An optical modulator (1) is provided with: a substrate (2); an optical waveguide layer (3) comprising lithium niobate in which a plurality of MZ-type waveguides including first and second ridge waveguides that propagate visible light are arranged in parallel; a signal electrode having an interaction portion disposed along the MZ-type waveguide; the optical modulator includes a first ridge waveguide, a second ridge waveguide, a signal electrode disposed above the first ridge waveguide, a first ground electrode disposed above the second ridge waveguide, and signal electrode lead-out portions (62R-3, 62B-3, 62G-3) connecting the signal electrode and a pad disposed at an end edge portion (S3), and a second ground electrode disposed above the first ridge waveguide and the second ridge waveguide, the signal electrode lead-out portions (62R-3, 62B-3, 62G-3) connecting the signal electrode and the pad disposed at the end edge portion (S3). And a light multiplexing unit (40) that is disposed downstream of the Mach-Zehnder waveguide and multiplexes the plurality of visible light, in which the first ground electrode, the second ground electrode, and the signal electrode lead-out unit are disposed at positions that do not overlap the light multiplexing unit in plan view.

A silicon-phase change material hetero-integrated waveguide structure includes a silicon flat plate layer and a phase change material deposited on the silicon flat plate layer. A non-volatile waveguide phase shifter includes a base layer, a hetero-integrated waveguide structure and a silicon waveguide mode spot conversion structure fixed on the base layer, two ends of the hetero-integrated waveguide structure are symmetrically connected to the silicon waveguide mode spot conversion structure; the silicon waveguide mode spot conversion structure includes two silicon waveguides with narrow-to-wide and an ridge waveguide with wide-to-narrow arranged in axial symmetry; an aluminum oxide film is covered on the phase change material, a single-layer graphene is on the aluminum oxide film, and a metal layer is on the single-layer graphene, the metal layer includes two metal electrodes. The single-layer graphene forms ohmic contact with the metal electrodes, current passes through the graphene to generate heat, the heat is conducted through the aluminum oxide film below the single-layer graphene to provide heat required for phase change of the low-loss phase change material. The phase shifter has the advantages of compact structure, low insertion loss, small driving voltage, low phase change power consumption, non-volatile phase adjustment, etc. and can be used as a core optical path regulation device in an integrated optoelectronic chip.

The invention provides a broadband horizontal polarization waveguide slot antenna array, which comprises a radiation slot layer, a slot coupling layer, a feed network layer and a standard waveguide interface, and is characterized in that the radiation slot layer is provided with 16 independent ridge waveguides, 16 V-shaped slots are cut on each ridge waveguide, each ridge waveguide is blocked by three cavity isolation walls to form four ridge waveguide sections, and each cavity isolation wall is provided with one V-shaped slot. Four V-shaped slots are distributed on each ridge waveguide section, 64 I-shaped coupling slots are formed in the slot coupling layer, the I-shaped coupling slots are located under the ridge waveguide sections, and the feed network layer adopts a flattened narrow-edge ridge waveguide design. Comprising a five-order one-to-two ridge waveguide power divider, a ridge waveguide-to-common waveguide converter, a multi-branch waveguide impedance transformer and an E-plane T-shaped joint. The antenna has the beneficial effects that the antenna is light in weight and low in profile; the antenna bandwidth is improved; the antenna structure is simple.

A silicon modulator with lateral capacitance structure includes, from bottom to top, substrate (3), dielectric layer (2), ridge waveguide (10), capacitive dielectric layer (20), first transparent electrode (108), second transparent electrode (101), first contact metal (130), second contact metal (131), third contact metal (132), fourth contact metal (133), and upper cladding layer (4). Ridge waveguide (10) includes PN junction, P-doped region (105), N-doped region (102), P+ region (106), P++ region (107), N+ region (103), and N++ region (104). First transparent electrode (108) is arranged on upper left side of capacitive dielectric layer (20), and together with capacitive dielectric layer (20), P-doped region (105), P+ region (106), and P++ region (107), forms P-region lateral capacitance structure. Second transparent electrode (101) is arranged on upper right side of capacitive dielectric layer (20), and together with capacitor dielectric layer (20), N-doped region (102), N+ region (103), and N++ region (104), forms N-region lateral capacitance structure. Silicon modulator bandwidth is enhanced according to the technical solution.

The application discloses a photonic device, a cross waveguide and a waveguide layer thereof. The waveguide layer comprises a flat plate sublayer, a first waveguide and a second waveguide intersecting with the first waveguide, wherein the first waveguide and the second waveguide are both ridge waveguides; the first waveguide and the second waveguide are arranged on the flat plate sublayer, and the flat plate sublayer, the first waveguide and the second waveguide are integrally formed. The application solves the technical problem of fast loss of the ridge waveguide in the related art.

The application relates to the technical field of lasers, and provides a structure and a manufacturing method of an electro-absorption modulation laser chip. The electro-absorption modulation laser chip is composed of a laser region 1, an isolation region 2 and a modulation region 3 which are coupled in sequence, and specifically, the laser region 1, the isolation region 2 and the modulation region 3 have respective ridge waveguide structures; wherein the quantum well width under the ridge waveguide structure of the modulation region 3 is larger than the quantum well width under the ridge waveguide structure of the laser region 1 by a preset value. In the application, the ridge waveguide process is adopted, the growth of an iron-doped buried layer is not needed, the failure phenomenon caused by the epitaxial steps and the iron-doped buried growth is reduced, and the application has the advantages of high yield and low cost.

The application discloses an active flat-plate-passive ridge structure gain waveguide and a preparation method thereof. The scheme can break through the strong light field limitation, significantly increase the mode field area, and fully utilize the low-loss transmission characteristics of the ridge waveguide structure by limiting the injected ions in the active flat-plate area and guiding light only in the ridge. Moreover, the structure has excellent process friendliness and preparation economy. The two preparation technologies provided by the application are completely based on mature semiconductor planar processes, do not need to introduce complex and expensive special equipment or steps, and can be realized through core steps such as single patterning etching, thin film growth, polishing and thinning and ion implantation. The process flow is greatly simplified, which means that the preparation process has higher process tolerance and production yield and lower preparation cost. The preparation process can realize rapid large-scale production relying on the existing semiconductor manufacturing line and provide a feasible process solution for the industrialization of integrated photonic devices.

The invention discloses an ultra-compact reconfigurable light beam splitter based on reverse design, and the device comprises a multimode interference coupler which is realized based on a ridge waveguide and comprises a phase change material region, an N-type doped silicon waveguide and a P-type doped silicon waveguide, and the N-type doped silicon waveguide and the P-type doped silicon waveguide are arranged at the two sides of the phase change material region. The phase change material region is arranged on the ridge of the ridge waveguide and is obtained through reverse design; the metal electrode is used for applying voltage to the N-type doped silicon waveguide and the P-type doped silicon waveguide on the two sides of the phase change material area, so that the phase state of the phase change material in the phase change material area is changed; and the conical input waveguide and the conical output waveguide are arranged at the input end and the output end of the multimode interference coupler. The fixed light beam splitting mode of a traditional device is broken through, the light beam splitter integrates the optical regulation and control characteristics of the phase change material and the degree of freedom of a reversely designed structure, and an innovative solution with high dynamic range, low insertion loss and chip-level integration is provided for an optical interconnection system.

The present disclosure provides a mode spot converter and a preparation method thereof, which are used for directly coupling an optical fiber and a photoelectric detector chip. The mode spot converter comprises a substrate, a ridge waveguide formed on the substrate, and the ridge waveguide comprises a ridge single-mode waveguide, a tapered ridge waveguide and a widened ridge waveguide connected in sequence along a direction parallel to the surface of the substrate. The widened ridge waveguide is used for connecting an optical fiber and matching the mode field of the optical fiber. The tapered ridge waveguide is used for amplifying and concentrating the mode spot of the light wave output by the optical fiber. The ridge single-mode waveguide is used for coupling the light wave after mode spot conversion to the photoelectric detector chip. The mode spot converter improves the coupling efficiency, accuracy and tolerance, and transmission efficiency, greatly reduces the loss of directly coupling a single-mode optical fiber and a ridge single-mode waveguide, and has high compact integration and low packaging cost.

The invention relates to an integrated photonic circuit (10) comprising at least one waveguide (12) for guiding light and at least one coupling device (14) for coupling light into and / or out of the waveguide (12), wherein the waveguide (12) has at least one end (16) for coupling light in and / or out, wherein the waveguide (12) has a taper section (18) at its end (16), wherein the taper section (18) extends at least partially, in particular completely, in a longitudinal direction (11), wherein the waveguide (12) is designed to taper along the taper section (18) towards the end (16) of the waveguide (12), wherein the taper section (18) has a first section (20) in which the waveguide (12) is designed as a ridge waveguide, wherein the taper section (18) has a second section (22) adjoining the first section (20), in which the waveguide (12) is designed as a strip waveguide, wherein the coupling device (14) at least partially covers the taper section (18), in particular the second section (22), in particular wherein the coupling device (14) is designed to taper at least partially, in particular completely, in the longitudinal direction (11) towards the end (16) of the waveguide (12). The invention also relates to a kit consisting of at least one such integrated photonic circuit and at least one optical fiber (36).

The application discloses a waveguide device structure manufacturing method and a waveguide device structure, and relates to the technical field of waveguide device structures. The method comprises the following steps: forming a waveguide layer and a hard mask on a substrate; etching the waveguide layer through the hard mask to form a ridge-shaped waveguide pattern; using a first fluorine-containing free radical, a first nitrogen-containing free radical and a first oxygen-containing free radical to perform first processing on a first sidewall of the ridge-shaped waveguide pattern with the hard mask to remove a first protruding part; using a second nitrogen-containing free radical and a second oxygen-containing free radical to perform second processing on the first sidewall to perform surface passivation protection; the first processing and the second processing are alternately cycled for multiple times to reduce the surface roughness of the first sidewall; after the hard mask is removed, using a first hydrogen-containing free radical and a hydroxyl-containing free radical to perform third processing on the first sidewall to remove a second protruding part, and the surface roughness of the first sidewall is further reduced. The application can significantly improve the smoothness of the surface of the ridge-shaped waveguide pattern, thereby improving the key performance of the device.

The utility model relates to the technical field of semiconductor lasers, in particular to a semiconductor laser chip, which comprises a substrate, a growth buffer layer, a lower waveguide layer, an active layer, an upper waveguide layer, an upper cladding and a cover layer which are sequentially stacked from bottom to top in the longitudinal direction, a plurality of current injection regions with different widths and a plurality of ion injection regions with different widths are arranged in the transverse direction of the semiconductor laser chip; a plurality of current injection regions are distributed between the two ion injection regions on the two sides; the ion implantation region penetrates through the cover layer and a part of the upper cladding layer in the longitudinal direction; forming a ridge waveguide structure on the cover layer; processing the ridge waveguide structure through ion implantation to form a lateral chirp electric injection modulation ridge waveguide structure; the chirp electric injection structure formed by the utility model can regulate and control each order mode from the aspects of gain and loss, so that the loss of a high-order mode is greater than that of a fundamental mode, and finally, the effects of reducing the output of the high-order mode, reducing the divergence angle and improving the beam quality of a far field are achieved.

The application provides a broadband slot scattering flat panel antenna applied to the field of communication systems. The antenna comprises, from top to bottom, a radome, a radiation slot layer, a coupling cavity layer and an H-T type broadband ridge waveguide feed network layer; the radiation slot layer comprises a radiation cavity, the bottom of the radiation cavity is provided with a plurality of radiation slots arranged uniformly and at intervals, and a radiation metal ridge is arranged between two adjacent rows of radiation slots; the coupling cavity layer comprises a plurality of coupling cavities, each coupling cavity corresponds to an antenna unit, each antenna unit comprises four radiation slots, the bottom center of each coupling cavity is connected with a ridge waveguide through a coupling slot, and the coupling slot is located on one side of the center of the wide side of the ridge waveguide; the H-T type broadband ridge waveguide feed network layer is internally provided with an H-T type broadband ridge waveguide feed network composed of a plurality of ridge waveguides, and a taper pin type power distribution is adopted to perform amplitude and phase weighting on input excitation signals so as to radiate out through the radiation slots. The antenna has an ultra-low profile, a lightweight design and higher radiation efficiency.

The invention provides a laser device, and relates to the technical field of optics, the laser device comprises a substrate, and the substrate comprises a first surface and a second surface which are opposite to each other; the heterojunction is arranged on the first surface; the plurality of gratings are arranged on one side, far away from the substrate, of the heterojunction; the plurality of gratings are arranged in sequence along a first direction parallel to the first surface, and the distance between every two adjacent gratings is increased in sequence; the ridge waveguides are arranged on the sides, away from the substrate, of the gratings; in the first direction, the width of the ridge waveguide increases in the second direction parallel to the first surface, and the second direction intersects with the first direction. The first electrode is arranged on the second surface, and the second electrode is arranged on the side, away from the substrate, of the ridge waveguide. A continuously-distributed Bragg wavelength pool is formed through a plurality of gratings with sequentially increased intervals and ridge waveguides with increased widths, light with different wavelengths is reflected or refracted at different positions, and the structure basis for achieving spectrum broadening and reducing coherence is provided.

This invention discloses a millimeter-wave ultra-wideband gapped waveguide mechanical synchronous phase-shifting feed device with anisotropic pulse width modulation, belonging to the field of microwave and millimeter-wave antenna technology. The device includes a stacked top cover plate, an intermediate layer, a fixed base plate, and a movable base plate. Fixed and movable pins are arranged alternately to form four rectangular waveguide channels. When the movable base plate is translated, the width of the first channel decreases to achieve phase lead, while the width of the remaining channels increases to achieve phase delay, forming anisotropic pulse width modulation offset to counteract nonlinear phase disturbances. The intermediate layer integrates stepped transitions, cross-shaped transition ridges, and oblique ridge waveguides to achieve cross-layer broadband coupling and path compensation. The power divider is loaded with capacitive grooves and inductive steps, and the second stage uses asymmetric steps and tuning pillars to achieve tapered distribution. An electromagnetic bandgap structure is provided at the gap to suppress leakage. This invention achieves compact, low-error multi-channel synchronous phase shifting in the 32-42 GHz frequency band.

Embodiments of the present application relate to the technical field of electronic devices, and provide a waveguide antenna, a waveguide antenna assembly, a radio frequency apparatus, a radar, and an electronic device, capable of achieving transmission of a signal between a waveguide antenna and a chip without an additional conversion structure, thereby greatly reducing structural complexity and production costs. The waveguide antenna comprises multiple waveguide interfaces arranged in an array, adjacent waveguide interfaces being orthogonally arranged. Each waveguide interface comprises a single ridged waveguide port, the single ridged waveguide port being used for transmitting a radio frequency signal radiated and / or received by the waveguide antenna.

This application discloses a waveguide structure for a semiconductor laser, relating to the field of semiconductor manufacturing technology. The waveguide structure of the semiconductor laser of this application includes a substrate, a lower confinement layer, a quantum well, an upper confinement layer, and a ridge forming layer. The lower confinement layer is disposed on the substrate; the quantum well is disposed on the lower confinement layer; the upper confinement layer is disposed on the quantum well; and the ridge forming layer is disposed on the upper confinement layer. The ridge forming layer includes etched trenches and ridge waveguides; wherein the top width of the etched trenches is 0.5-5 μm. Therefore, this application achieves coupling of higher-order modes by reducing the width of the etched trenches, increasing the loss of higher-order modes, thereby suppressing the lasing of higher-order modes and ensuring the stability of the fundamental mode lasing.

The embodiment of the invention relates to the technical field of electronic devices, provides a waveguide antenna, a waveguide antenna assembly, a radio frequency device, a radar and electronic equipment, and can realize signal transmission between the waveguide antenna and a chip without arranging an additional conversion structure, thereby greatly reducing the structural complexity and the production cost. The waveguide antenna comprises a plurality of waveguide interfaces arranged in an array, and the adjacent waveguide interfaces are orthogonally arranged; the waveguide interface comprises a single ridge-shaped waveguide port, and the single ridge-shaped waveguide port is used for transmitting radio frequency signals radiated and / or received by the waveguide antenna.

The invention discloses a semiconductor laser-based heterogeneous integrated coupling structure and a preparation method thereof, and belongs to the technical field of optoelectronic integrated devices. The heterogeneous integrated coupling structure comprises a chip and a laser; the chip is provided with a bonding groove, a silicon nitride conical waveguide and a silicon nitride single-mode waveguide, and the wide end of the silicon nitride conical waveguide is connected with the silicon nitride single-mode straight waveguide; the laser includes a contact layer, a ridge waveguide, a first tapered waveguide, and a second tapered waveguide. According to the invention, a double-layer tapered waveguide structure composed of a first tapered waveguide and a second tapered waveguide is designed, a silicon nitride tapered waveguide and a silicon nitride single-mode waveguide are arranged on a chip, and the second tapered waveguide and the silicon nitride tapered waveguide are optically interconnected in a vertical coupling manner; the problem of mode adaptation of an existing laser and a silicon nitride chip can be effectively solved, efficient on-chip coupling of heterogeneous integration of the laser is achieved, and the coupling efficiency of the heterogeneous integration coupling structure is improved.

The invention relates to a CW-DFB laser epitaxial structure and a preparation method thereof, the epitaxial structure comprises a composite divergence angle layer design of a first N-InGaAsP divergence angle layer, a second N-InGaAsP divergence angle layer, a first P-InGaAsP divergence angle layer and a second P-InGaAsP divergence angle layer, carriers can be accurately constrained in a quantum well active region, a light field offset n region is regulated and controlled at the same time, and the light field offset n region is regulated and controlled. And internal loss is reduced. A multi-layer alternating structure of an N-InP buffer layer and an N-InGaAsP divergence angle layer is arranged in a basic structure, a multi-layer alternating structure of a P-InP buffer layer and a P-InGaAsP divergence angle layer is designed on a ridge waveguide, and the material component difference (InP and InGaAsP) of the buffer layer and the divergence angle layer can form a specific refractive index gradient. According to the multi-layer alternating structure, the propagation path of light in the vertical direction can be accurately adjusted in a regional manner, the symmetry of light beams is improved, and the divergence angle can be controlled within 20 degrees under the condition of multiple quantum wells, so that the overall optimization of the power and divergence angle performance of the CW-DFB laser is realized.

A mid-infrared laser based on on-chip integration of three devices and its fabrication method is disclosed, involving the intersection of semiconductor laser technology and optical communication technology. This invention alleviates the problem of the existing quantum cascaded laser (QCL) technology being unable to simultaneously achieve high modulation rate and high power. The mid-infrared laser includes a QCL unit, an EAM unit, and an SOA unit sequentially disposed on a substrate; the substrate comprises semi-insulating InP; the QCL unit, EAM unit, and SOA unit share the same ridge waveguide structure and are grown through epitaxial docking. The method described in this invention is applicable to mid-infrared band space communication scenarios with high requirements for laser modulation rate, output power, and single-mode stability.

This invention relates to the field of semiconductor laser technology, and more particularly to a semiconductor laser with switchable spectral width. The laser includes a mesa and a ridge waveguide located in the middle of the mesa. From bottom to top, the mesa includes an N-type electrode layer, a substrate layer, an N-type cladding layer, an N-type waveguide layer, an active layer, and a P-type waveguide layer. The ridge waveguide is located at the upper middle part of the P-type waveguide layer and, from bottom to top, includes a P-type cladding layer, a P-type capping layer, and a P-type electrode. The two sides of the ridge waveguide are insulating layers, and a periodic electrode is included on the insulating layer on one side of the ridge waveguide. When a current is applied to the periodic electrode, frequency selectivity can be achieved by modulating the optical field distributed within the periodic electrode region, thus narrowing the laser spectral width. When no current is applied to the periodic electrode, the laser oscillates at the front and rear cavity surfaces and exhibits broadband lasing characteristics. This invention also provides a method for fabricating a semiconductor laser with switchable spectral width.

The application discloses a lithium niobate thin film modulator based on upper and lower layer traveling wave electrodes, which comprises a substrate, a silicon oxide layer and a lithium niobate thin film, the silicon oxide layer is located on one side of the substrate, and the lithium niobate thin film is located on the side of the silicon oxide layer away from the substrate, and the lithium niobate thin film is provided with a plurality of protruding ridge-shaped waveguide structures; the ridge-shaped waveguide structure comprises a first modulation arm and a second modulation arm, and the first modulation arm and the second modulation arm are provided with a silicon oxide cover layer on the side away from the silicon oxide layer; the silicon oxide cover layer is provided with a GSG traveling wave electrode and a plurality of upper and lower layer electrodes on the side away from the lithium niobate thin film. The lithium niobate thin film modulator based on upper and lower layer traveling wave electrodes can effectively solve the problems of impedance mismatch, large electric signal reflection, large microwave loss and the like, and improve the modulator bandwidth.

A photonic device has a waveguide, such as a ridge waveguide, defined by a waveguide etch, an etched facet defined by a facet etch and having an optical coupling region optically coupled to the waveguide, and a fiducial mark configured for alignment of an optical component, such as a photonic integrated circuit, to the optical coupling region. The fiducial mark has a first portion defined by at least a part of the waveguide etch and a second portion defined by at least a part of the facet etch. The first portion has an elongate broken bar shape that extends lengthwise along a direction parallel to the waveguide's propagation direction at the optical coupling region. The second portion includes an elongate shape that extends lengthwise orthogonally with respect to its etch depth and with respect to the waveguide's propagation direction at the optical coupling region.