摘要:
A wafer-level testing arrangement for opto-electronic devices formed in a silicon-on-insulator (SOI) wafer structure utilizes a single opto-electronic testing element to perform both optical and electrical testing. Beam steering optics may be formed on the testing element and used to facilitate the coupling between optical probe signals and optical coupling elements (e.g., prism couplers, gratings) formed on the top surface of the SOI structure. The optical test signals are thereafter directed into optical waveguides formed in the top layer of the SOI structure. The opto-electronic testing element also comprises a plurality of electrical test pins that are positioned to contact a plurality of bondpad test sites on the opto-electronic device and perform electrical testing operations. The optical test signal results may be converted into electrical representations within the SOI structure and thus returned to the testing element as electrical signals.
摘要:
An SOI-based opto-electronic structure includes various electronic components disposed with their associated optical components within a single SOI layer, forming a monolithic arrangement. EMI/EMC shielding is provided by forming a metallized outer layer on the surface of an external prism coupler that interfaces with the SOI layer, the metallized layer including transparent apertures to allow an optical signal to be coupled into and out of the SOI layer. The opposing surface of the prism coupler may also be coated with a metallic material to provide additional shielding. Further, metallic shielding plates may be formed on the SOI structure itself, overlying the locations of EMI-sensitive electronics. All of these metallic layers are ultimately coupled to an external ground plane to isolate the structure and provide the necessary shielding.
摘要:
A planar optical isolator is formed within the silicon surface layer of an SOI structure. A forward-directed signal is applied to an input waveguiding section of the isolator and thereafter propagates through a non-reciprocal waveguide coupling region into an output waveguide section. A rearward-directed signal enters via the output waveguide section and is thereafter coupled into the non-reciprocal waveguide structure, where the geometry of the structure functions to couple only a small amount of the reflected signal into the input waveguide section. In one embodiment, the non-reciprocal structure comprises an N-way directional coupler (with one output waveguide, one input waveguide and N-1 isolating waveguides). In another embodiment, the non-reciprocal structure comprises a waveguide expansion region including a tapered, mode-matching portion coupled to the output waveguide and an enlarged, non-mode matching portion coupled to the input waveguide such that a majority of a reflected signal will be mismatched with respect to the input waveguide section. By cascading a number of such planar SOI-based structures, increased isolation can be achieved—advantageously within a monolithic arrangement.
摘要:
An ECL laser structure utilizes an SOI-based grating structure coupled to the external gain medium to provide lasing activity. In contrast to conventional Bragg grating structures, the grating utilized in the ECL of the present invention is laterally displaced (i.e., offset) from the waveguide (in most cases, a rib or strip waveguide) comprising the laser cavity. The grating is formed in an area with higher contrast ratio between materials (silicon and oxide) and thus requires a lesser amount of optical energy to reflect the selected wavelength, and can easily be formed using well-known CMOS fabrication processes. The pitch of the grating (i.e., the spacing between adjacent grating elements) and the refractive index values of the grating materials determine the reflected wavelength (also referred to as the “center wavelength”). A thermally conductive strip is disposed alongside the grating to adjust/tune the center wavelength of the grating, where the application of an electric current to the thermally conductive strip will heat the strip and transfer this heat to the grating. The change of temperature of the grating will modify the refractive indexes of the grating materials and as a result change its center wavelength.
摘要:
An SOI-based photonic bandgap (PBG) electro-optic device utilizes a patterned PBG structure to define a two-dimensional waveguide within an active waveguiding region of the SOI electro-optic device. The inclusion of the PBG columnar arrays within the SOI structure results in providing extremely tight lateral confinement of the optical mode within the waveguiding structure, thus significantly reducing the optical loss. By virtue of including the PBG structure, the associated electrical contacts may be placed in closer proximity to the active region without affecting the optical performance, thus increasing the switching speed of the electro-optic device. The overall device size, capacitance and resistance are also reduced as a consequence of using PBGs for lateral mode confinement.
摘要:
An arrangement for providing optical crossovers between waveguides formed in an SOI-based structure utilize a patterned geometry in the SOI structure that is selected to reduce the effects of crosstalk in the area where the signals overlap. Preferably, the optical signals are fixed to propagate along orthogonal directions (or are of different wavelengths) to minimize the effects of crosstalk. The geometry of the SOI structure is patterned to include predetermined tapers and/or reflecting surfaces to direct/shape the propagating optical signals. The patterned waveguide regions within the optical crossover region may be formed to include overlying polysilicon segments to further shape the propagating beams and improve the coupling efficiency of the crossover arrangement.
摘要:
A silicon-based IR photodetector is formed within a silicon-on-insulator (SOI) structure by placing a metallic strip (preferably, a silicide) over a portion of an optical waveguide formed within a planar silicon surface layer (i.e., “planar SOI layer”) of the SOI structure, the planar SOI layer comprising a thickness of less than one micron. Room temperature operation of the photodetector is accomplished as a result of the relatively low dark current associated with the SOI-based structure and the ability to use a relatively small surface area silicide strip to collect the photocurrent. The planar SOI layer may be doped, and the geometry of the silicide strip may be modified, as desired, to achieve improved results over prior art silicon-based photodetectors.
摘要:
An arrangement for providing optical crossovers between waveguides formed in an SOI-based structure utilize a patterned geometry in the SOI structure that is selected to reduce the effects of crosstalk in the area where the signals overlap. Preferably, the optical signals are fixed to propagate along orthogonal directions (or are of different wavelengths) to minimize the effects of crosstalk. The geometry of the SOI structure is patterned to include predetermined tapers and/or reflecting surfaces to direct/shape the propagating optical signals. The patterned waveguide regions within the optical crossover region may be formed to include overlying polysilicon segments to further shape the propagating beams and improve the coupling efficiency of the crossover arrangement.
摘要:
An arrangement for providing optical crossovers between waveguides formed in an SOI-based structure utilize a patterned geometry in the SOI structure that is selected to reduce the effects of crosstalk in the area where the signals overlap. Preferably, the optical signals are fixed to propagate along orthogonal directions (or are of different wavelengths) to minimize the effects of crosstalk. The geometry of the SOI structure is patterned to include predetermined tapers and/or reflecting surfaces to direct/shape the propagating optical signals. The patterned waveguide regions within the optical crossover region may be formed to include overlying polysilicon segments to further shape the propagating beams and improve the coupling efficiency of the crossover arrangement.
摘要:
An SOI-based photonic bandgap (PBG) electro-optic device utilizes a patterned PBG structure to define a two-dimensional waveguide within an active waveguiding region of the SOI electro-optic device. The inclusion of the PBG columnar arrays within the SOI structure results in providing extremely tight lateral confinement of the optical mode within the waveguiding structure, thus significantly reducing the optical loss. By virtue of including the PBG structure, the associated electrical contacts may be placed in closer proximity to the active region without affecting the optical performance, thus increasing the switching speed of the electro-optic device. The overall device size, capacitance and resistance are also reduced as a consequence of using PBGs for lateral mode confinement.