Abstract: Various embodiments of a coplanar waveguide (CPW) transmission line as well as a silicon-based electro-optic (E-O) modulator comprising the CPW transmission line are described. The CPW transmission line has a curved or winding shape. The silicon-based E-O modulator includes a rib optical waveguide, a beam splitter, a beam combiner, and a CPW transmission line that exhibits the winding shape. At least one of the two optical arms of the rib optical waveguide alternately and periodically extends through a first groove and a second groove of the CPW transmission line. The plurality of active sections of the rib optical waveguide are evenly distributed on both sides of the CPW transmission line to suppress undesired transmission modes. An increased length of transmission path of the rib optical waveguide is also avoided or minimized, thereby reducing the transmission speed mismatch of the E-O modulator, which is essential for achieving high-speed operation.

Abstract: Various embodiments of a monolithic avalanche photodiode (APD) are described, which may be fabricated on a silicon-on-insulator substrate. The monolithic APD includes an optical waveguide that guides an incident light to an active region of the APD. An optical coupler is integrally formed with the optical waveguide to capture the incident light. The monolithic APD also includes an optical reflector to reflect a portion of the incident light that is not readily captured by the optical coupler back to the optical coupler for further capturing. The active region includes an absorption layer for converting the incident light into a photocurrent, an epitaxial structure for amplifying the photocurrent by avalanche multiplication, as well as a pair of electrical conductors for conducting the amplified photocurrent.

Abstract: Various embodiments of a photodetector having a reflector are described. The photodetector includes a waveguide layer disposed on top of a substrate, an avalanche multiplication detection region disposed on top of the waveguide layer, and a reflector disposed adjacent to a rear surface of the waveguide layer. The waveguide layer includes a narrower input section and a wider detection section concatenated with the input section. The waveguide layer may also include a tapering section having a changing width that follows the detection section. The reflector may be a one-dimensional photonic crystal, a two-dimensional photonic crystal, or a bulk material. A careful design of the reflector and the waveguide layer of the photodetector is helpful in achieving a high responsivity and a high operation speed at the same time.

Abstract: Various embodiments of a coplanar waveguide (CPW) transmission line as well as a silicon-based electro-optic (E-O) modulator comprising the CPW transmission line are described. The CPW transmission line has a curved or winding shape. The silicon-based E-O modulator includes a rib optical waveguide, a beam splitter, a beam combiner, and a CPW transmission line that exhibits the winding shape. At least one of the two optical arms of the rib optical waveguide alternately and periodically extends through a first groove and a second groove of the CPW transmission line. The plurality of active sections of the rib optical waveguide are evenly distributed on both sides of the CPW transmission line to suppress undesired transmission modes. An increased length of transmission path of the rib optical waveguide is also avoided or minimized, thereby reducing the transmission speed mismatch of the E-O modulator, which is essential for achieving high-speed operation.

Abstract: Various embodiments of a monolithic electro-optical (E-O) modulator are described. The monolithic E-O modulator includes an active region comprising a plurality of p-n junction diodes, as well as a modulation electrode and a bias electrode that extend through the active region. The monolithic E-O modulator further includes a resistor-capacitor-bias-capacitor (RCBC) electrode structure configured to receive an electrical modulation signal, a direct-current (DC) bias voltage and a power supply voltage. Specifically, the RCBC electrode structure includes a resistor coupled to the modulation electrode and two capacitors each coupled to a respective end of the bias electrode. Beneficially, the RCBC electrode structure enables the p-n junction diodes to be biased independently from a DC level of the electrical modulation signal.

Abstract: Various embodiments of a monolithic electro-optical (E-O) modulator are described, which may be fabricated on a silicon-on-insulator substrate. The monolithic E-O modulator includes an optical waveguide that allows an optical signal to propagate therein. The monolithic E-O modulator also includes a comb-shaped transmission line for conducting an electrical modulation signal that modulates the optical signal. The comb-shaped transmission line includes electrical conductors running in parallel with the optical waveguide. At least one of the conductors includes recesses or thin slots that form the conductor into a shape having a plurality of teeth, like a comb. The comb-shaped transmission line can be engineered to realize a close matching between a propagation velocity of the optical signal along the optical waveguide and a group velocity of the electrical modulation signal along the comb-shaped transmission line, which helps to achieve a high operating speed of the monolithic E-O modulator.

Abstract: Various embodiments of a photonic integrated circuit (PIC) are described herein. A PIC, functioning as a coherent receiver, may include optical components such as an optical coupler, a directional coupler, a beam splitter, a polarizing beam rotator-splitter, a variable optical attenuator, a monitor photodiode, 90-degree hybrid mixer, and a waveguide photodiode. The PIC may also include electrical components such as an electrode, a capacitor, a resistor and a Zener diode.

Abstract: Various embodiments of a monolithic electro-optical (E-O) modulator are described, which may be fabricated on a silicon-on-insulator substrate. The monolithic E-O modulator includes an optical waveguide that allows an optical signal to propagate therein. The monolithic E-O modulator also includes a comb-shaped transmission line for conducting an electrical modulation signal that modulates the optical signal. The comb-shaped transmission line includes electrical conductors running in parallel with the optical waveguide. At least one of the conductors includes recesses or thin slots that form the conductor into a shape having a plurality of teeth, like a comb. The comb-shaped transmission line can be engineered to realize a close matching between a propagation velocity of the optical signal along the optical waveguide and a group velocity of the electrical modulation signal along the comb-shaped transmission line, which helps to achieve a high operating speed of the monolithic E-O modulator.

Abstract: Various embodiments of a monolithic avalanche photodiode (APD) are described, which may be fabricated on a silicon-on-insulator substrate. The monolithic APD includes an optical waveguide that guides an incident light to an active region of the APD. An optical coupler is integrally formed with the optical waveguide to capture the incident light. The monolithic APD also includes an optical reflector to reflect a portion of the incident light that is not readily captured by the optical coupler back to the optical coupler for further capturing. The active region includes an absorption layer for converting the incident light into a photocurrent, an epitaxial structure for amplifying the photocurrent by avalanche multiplication, as well as a pair of electrical conductors for conducting the amplified photocurrent.

Abstract: Various embodiments of a photonic integrated circuit (PIC) are described herein. A PIC, functioning as a coherent receiver, may include optical components such as an optical coupler, a directional coupler, a beam splitter, a polarizing beam rotator-splitter, a variable optical attenuator, a monitor photodiode, 90-degree hybrid mixer, and a waveguide photodiode. The PIC may also include electrical components such as an electrode, a capacitor, a resistor and a Zener diode.

Abstract: Various embodiments of a monolithic electro-optical (E-O) modulator are described herein. The monolithic E-O modulator may include a phase shifter having a suspended structure. The suspended structure may be realized by partially or completely removing silicon material underneath the active area of the phase shifter to form a void in the bulk silicon substrate supporting the phase shifter. The suspended structure may be utilized to result in a lower radio-frequency loss and an effective group refractive index of the phase shifter that is closer to the refractive index of silicon waveguides or optical fibers, both advantageous to enhancing the performance of the E-O modulator such as a higher operating bandwidth.

Abstract: Various embodiments of a monolithic electro-optical (E-O) modulator are described. The monolithic E-O modulator includes an active region comprising a plurality of p-n junction diodes, as well as a modulation electrode and a bias electrode that extend through the active region. The monolithic E-O modulator further includes a resistor-capacitor-bias-capacitor (RCBC) electrode structure configured to receive an electrical modulation signal, a direct-current (DC) bias voltage and a power supply voltage. Specifically, the RCBC electrode structure includes a resistor coupled to the modulation electrode and two capacitors each coupled to a respective end of the bias electrode. Beneficially, the RCBC electrode structure enables the p-n junction diodes to be biased independently from a DC level of the electrical modulation signal.

Abstract: Various embodiments of a photonic integrated circuit (PIC) are described herein. A PIC, functioning as a coherent receiver, may include optical components such as an optical coupler, a directional coupler, a beam splitter, a polarizing beam rotator-splitter, a variable optical attenuator, a monitor photodiode, 90-degree hybrid mixer, and a waveguide photodiode. The PIC may also include electrical components such as an electrode, a capacitor, a resistor and a Zener diode.

Abstract: Various embodiments of a fully integrated avalanche photodiode receiver and manufacturing method thereof are described herein. A photonic device includes a silicon-on-insulator (SOI) substrate with a buried oxide (BOX) layer therein, an avalanche photodiode integrated with the SOI substrate, a capacitor integrated with the SOI substrate, a resistor integrated with the SOI substrate, and silicon passive waveguides as well as bonding pads integrated with the SOI substrate.

Abstract: Various embodiments of a monolithic electro-optical (E-O) modulator are described herein. The monolithic E-O modulator may include a phase shifter having a suspended structure. The suspended structure may be realized by partially or completely removing silicon material underneath the active area of the phase shifter to form a void in the bulk silicon substrate supporting the phase shifter. The suspended structure may be utilized to result in a lower radio-frequency loss and an effective group refractive index of the phase shifter that is closer to the refractive index of silicon waveguides or optical fibers, both advantageous to enhancing the performance of the E-O modulator such as a higher operating bandwidth.

Abstract: Various embodiments of a compensated photonic device structure and fabrication method thereof are described herein. A photonic device may include a silicon-on-insulator (SOI) substrate with a buried oxide (BOX) layer therein, a Si waveguide and an n-type contact layer formed on the BOX layer, a Si multiplication layer disposed on the n-type contact layer, a p-type Si charge layer disposed on the Si multiplication layer, a germanium (Ge) absorption layer disposed on the p-type Si charge layer, a p-type contact layer disposed on the Ge absorption layer, and a metal layer disposed on the p-type contact layer. A compensated region may be formed between the p-type Si charge layer and the Ge absorption layer with a portion of the compensated region in the p-type Si charge layer and another portion of the compensated region in the Ge absorption layer.

Abstract: Various embodiments of a photonic integrated circuit (PIC) are described herein. A PIC, functioning as a coherent receiver, may include optical components such as an optical coupler, a directional coupler, a beam splitter, a polarizing beam rotator-splitter, a variable optical attenuator, a monitor photodiode, 90-degree hybrid mixer, and a waveguide photodiode. The PIC may also include electrical components such as an electrode, a capacitor, a resistor and a Zener diode.

Abstract: Various embodiments of a fully integrated avalanche photodiode receiver and manufacturing method thereof are described herein. A photonic device includes a silicon-on-insulator (SOI) substrate with a buried oxide (BOX) layer therein, an avalanche photodiode integrated with the SOI substrate, a capacitor integrated with the SOI substrate, a resistor integrated with the SOI substrate, and silicon passive waveguides as well as bonding pads integrated with the SOI substrate.

Abstract: A method of fabricating an integrated structure for MEMS device and semiconductor device comprises steps of: providing a substrate having a transistor thereon in a semiconductor device region and a first MEMS component thereon in a MEMS region; performing a interconnect process on the substrate in the semiconductor device region to form a plurality of first dielectric layers, at least a conductive plug and at least a conductive layer in the first dielectric layers; forming a plurality of second dielectric layers and an etch stopping device in the second dielectric layers on the substrate in a etch stopping device region; forming a plurality of third dielectric layers and at least a second MEMS component in the third dielectric layers on the substrate in the MEMS region; and performing an etching process to remove the third dielectric layers in the MEMS region.

Abstract: An optical coupler structure may include a substrate, a waveguide section and an anchored cantilever section. The substrate may include a main body and a sub-pillar structure formed on the main body. The waveguide section may be disposed on the substrate, and may include a core waveguide of a first material surrounded by a cladding layer of a second material. The anchored cantilever section may be disposed on the sub-pillar structure on the substrate, which may be configured to support the cantilever section and separate the cantilever section from the main body of the substrate. The anchored cantilever section may include a multi-stage inverse taper core waveguide and a cladding layer, of the second material, which surrounds the multi-stage inverse taper core waveguide.