Abstract: A monolithically integrated electro-absorption modulated laser (EML) fabricated with Multi-Guide Vertical Integration (MGVI) comprises a first optical waveguide, defining a laser and a laterally tapered vertical optical coupler (taper), and a second optical waveguide, comprising an electro-absorption modulator (EAM). The epitaxial layer stack for the DFB laser comprises a balancing layer, comprising a higher index material, e.g. a quaternary composition, positioned above or below the DFB grating of the DFB laser. In combination with the design of the taper, the balancing layer allows for efficient control of laser mode confinement, distributed feedback coupling and control of optical mode transfer between the DFB laser waveguide and the EAM waveguide. Example EML structures are fabricated with III-V semiconductor materials, such an InP-based materials system. Optionally, the EML is monolithically integrated with driver and control electronics, e.g. comprising InP HBTs.

Abstract: An electro-photonic integrated circuit, an optical system comprising an electro-photonic circuit, and a method of operating each. The electro-photonic integrated circuit comprises a distributed EAM comprising a one or more EAM portions optically coupled to generate a modulated optical output from an optical input; a distributed driver comprising a one or more driver portions for receiving a drive signal input for the EAM from an electrical input; the distributed EAM being electrically coupled to the distributed driver; wherein the modulated optical output is based on the optical input and the electrical input to implement equalization. For example, a propagation delay and a gain of the optical input and/or electrical input are combined to provide desired signal characteristics. The electrical propagation delay and optical propagation delay may be matched, or be adjusted, e.g. to provide a mismatch for optimization of both a characteristic impedance and a bandwidth of the distributed EAM.

Abstract: An electro-photonic integrated circuit, an optical system comprising an electro-photonic circuit, and a method of operating each. The electro-photonic integrated circuit comprises a distributed EAM comprising a one or more EAM portions optically coupled to generate a modulated optical output from an optical input; a distributed driver comprising a one or more driver portions for receiving a drive signal input for the EAM from an electrical input; the distributed EAM being electrically coupled to the distributed driver; wherein the modulated optical output is based on the optical input and the electrical input to implement equalization. For example, a propagation delay and a gain of the optical input and/or electrical input are combined to provide desired signal characteristics. The electrical propagation delay and optical propagation delay may be matched, or be adjusted, e.g. to provide a mismatch for optimization of both a characteristic impedance and a bandwidth of the distributed EAM.

Abstract: A waveguide (WG)-device configured to modulate light and comprising a p type material, an i-type material and an n-type materials (a PIN waveguide), the waveguide device comprising: a semi-insulating (SI) indium phosphide (InP) substrate; an epitaxial layer stack formed on the SI:InP substrate structured to form the PIN waveguide, the epitaxial layer stack comprising: an n-layer structure and a p-layer structure; an i-region comprising optical material having an operational wavelength range located between the n-layer structure and the p-layer structure; the n-layer structure and the p-layer structure providing a mode-shaping functionality configured to optical confine one or more modes of an optical signal configured to propagate through the i-region; wherein the mode-shaping functionality includes providing a mode-extending functionality in at least one of the n-layer structure and the p-layer structure.

Abstract: An optical receiver comprises monolithically integrated components comprising a demultiplexer (DEMUX), a plurality of waveguide photodiodes (WG-PD) and a plurality of transimpedance amplifiers (TIA). Each TIA comprises InP heterojunction bipolar transistors (HBT) fabricated from a first plurality of layers of an epitaxial layer stack grown on a SI: InP substrate; each WG-PD is fabricated from a second plurality of layers of the epitaxial layer stack, overlying the first plurality of layers. The DEMUX is fabricated from photonics layers of the epitaxial stack; outputs of the DEMUX may be laterally or vertically coupled to each WG-PD. This design approach enables cost-effective fabrication of a monolithically integrated DEMUX with multiple PIN-TIAs for DWM applications. Also disclosed in an optical transmitter wherein a plurality of electro-absorption modulators (EAM), EAM Drivers, and a Multiplexer (MUX) are monolithically integrated for WDM applications.

Abstract: An electro-optic device comprising a waveguide (WG)-device configured as an electro-absorption modulator (EAM) and electronics comprising an EAM driver. The electro-optic device comprising: a semi-insulating (SI) indium phosphide (InP) substrate; an epitaxial layer stack formed on the SI:InP substrate comprising a first plurality of semiconductor layers forming InP heterojunction bipolar transistors of the electronics and a second plurality of semiconductor layers structured to form a PIN waveguide of the EAM, the PIN waveguide comprising: an n-layer structure and a p-layer structure; an i-region comprising optical material located between the n-layer structure and the p-layer structure; the n-layer structure and the p-layer structure configured to optical confine one or more modes of an optical signal configured to propagate through the i-region; and at least one of the n-layer structure and the p-layer structure comprises a mode extending layer.

Abstract: A waveguide (WG)-device comprising a p type material, an i-type material and an n-type materials (a PIN waveguide), the waveguide device comprising: a semi-insulating (SI) indium phosphide (InP) substrate; an epitaxial layer stack formed on the SI:InP substrate structured to form the PIN waveguide, the epitaxial layer stack comprising: an n-layer structure and a p-layer structure; an i-region comprising optical material having an operational wavelength range located between the n-layer structure and the p-layer structure; the n-layer structure and the p-layer structure providing a mode-shaping functionality configured to optical confine one or more modes of an optical signal configured to propagate through the i-region; wherein the mode-shaping functionality includes providing a mode-extending functionality in at least one of the n-layer structure and the p-layer structure.

Abstract: An electro-optic device comprising-a waveguide (WG)-device configured as an electro-absorption modulator (EAM) and electronics comprising an EAM driver. The electro-optic device comprising: a semi-insulating (SI) indium phosphide (InP) substrate; an epitaxial layer stack formed on the SI:InP substrate comprising a first plurality of semiconductor layers forming InP heterojunction bipolar transistors of the electronics and a second plurality semiconductor layers structured to form a PIN waveguide of the EAM the PIN waveguide comprising: an n-layer structure and a p-layer structure; an i-region comprising optical material located between the n-layer structure and the p-layer structure; the n-layer structure and the p-layer structure configured to optical confine one or more modes of an optical signal configured to propagate through the i-region; and at least one of the n-layer structure and the p-layer structure comprises a mode extending layer.

Abstract: Device topologies for monolithic electro-photonic integrated circuits comprising optical transmitters and receivers are disclosed, wherein each transmitter comprises a first electro-absorption modulator (EAM) waveguide and EAM driver electronics and each receiver comprises a waveguide photodiode, which may be a second EAM waveguide, and a transimpedance amplifier (TIA); and an optical input port for coupling an external laser to each of the transmitters, or an on-chip laser. Monolithic integration of photonics and electronics on a single chip with compact form factor provides reduced interconnect path lengths between the EAMs and the electronics compared to discrete electronics. Tx optical output ports and Rx optical input ports may be interleaved, or banked, along a first (beachfront) edge of the chip with a port-to-port spacing of ?350 ?m.

Abstract: A transistor comprising a plurality of semiconductor layers arranged to form a base, an emitter and a collector wherein the emitter is of a first semiconductor material and comprises an emitter ledge being made from a material which is selectively etchable relative to the emitter or base material to produce the emitter ledge that is lattice matched.

Abstract: A dispersion compensation structure for use in an optical network to compensate for transmission-based dispersion of a light signal, wherein the dispersion compensation structure comprises an array of dispersion compensation elements having an AI-generated arrangement configured to compensate for transmission-based dispersion to one or more channels of the light signal and to generate an output having a spectrum that is substantially matching a pre-transmission spectrum for the or each channel.

Abstract: Electro-absorption modulators (EAM) and monolithically integrated electro-absorption modulated lasers (EML) and methods of fabrication are disclosed. Vertically stacked waveguides for a distributed feedback (DFB) laser, an electro-absorption modulator (EAM) and a passive output waveguide are vertically integrated, and the DFB laser, EAM and output waveguide are optically coupled using laterally tapered vertical optical couplers. Laterally tapered vertical optical couplers provide an alternative to conventional butt-coupling of a laser and EAM, offering improved reliability for high power operation over extended lifetimes. The EML may comprise monolithically integrated electronic circuitry, e.g., driver and control electronics for the DFB laser and EAM. Beneficially, integrated EAM driver and control circuitry comprises a high-speed electro-optical control loop for very high-speed linearization and temperature compensation, e.g.

Abstract: Monolithically integrated electro-absorption modulated lasers (EML) and methods of fabrication are disclosed. Vertically stacked optical waveguides for a laser, such as a distributed feedback (DFB) laser, and an electro-absorption modulator (EAM) are vertically integrated, and the laser and EAM are optically coupled using a laterally tapered vertical optical coupler. A passive output waveguide may be provided. Laterally tapered vertical optical couplers provide an alternative to conventional butt-coupling of a laser and EAM, offering improved reliability for high power operation over extended lifetimes. The EML may comprise monolithically integrated electronic circuitry, e.g., driver and control electronics for the laser and EAM. Beneficially, integrated EAM driver and control circuitry comprises a high-speed electro-optical control loop for very high-speed linearization and temperature compensation, e.g.

Abstract: Electro-absorption modulators (EAM) and monolithically integrated electro-absorption modulated lasers (EML) and methods of fabrication are disclosed. Vertically stacked waveguides for a distributed feedback (DFB) laser, an electro-absorption modulator (EAM) and a passive output waveguide are vertically integrated, and the DFB laser, EAM and output waveguide are optically coupled using laterally tapered vertical optical couplers. Laterally tapered vertical optical couplers provide an alternative to conventional butt-coupling of a laser and EAM, offering improved reliability for high power operation over extended lifetimes. The EML may comprise monolithically integrated electronic circuitry, e.g., driver and control electronics for the DFB laser and EAM. Beneficially, integrated EAM driver and control circuitry comprises a high-speed electro-optical control loop for very high-speed linearization and temperature compensation, e.g.

Abstract: Electro-absorption modulators (EAM) and monolithically integrated electro-absorption modulated lasers (EML) and methods of fabrication are disclosed. Vertically stacked waveguides for a distributed feedback (DFB) laser, an electro-absorption modulator (EAM) and a passive output waveguide are vertically integrated, and the DFB laser, EAM and output waveguide are optically coupled using laterally tapered vertical optical couplers. Laterally tapered vertical optical couplers provides an alternative to conventional butt-coupling of a laser and EAM, offering improved reliability for high power operation over extended lifetimes. Optionally, the EML comprises monolithically integrated electronic circuitry, e.g., driver and control electronics for the DFB laser and EAM. Beneficially, integrated EAM driver and control circuitry comprises a high-speed electro-optical control loop for very high-speed linearization and temperature compensation, e.g.

Abstract: An optical receiver comprises a monolithically integrated photodiode (PD) and transimpedance amplifier (TIA). The TIA comprises InP heterojunction bipolar transistors (HBT) fabricated from a first plurality of layers of an epitaxial layer stack grown on a SI:InP substrate; the PD may be a pin PD fabricated from a second plurality of layers of the epitaxial layer stack, overlying the first plurality of layers. The p-contact of the PIN is directly connected to the input of the TIA to reduce PIN capacitance CPIN. The TIA capacitance CTIA may be matched to CPIN. The PD may be a vertical PIN with a top facet window or a waveguide PD with a lateral facet window. Device parameters comprising a device area, device capacitance CPIN+CTIA; and feedback resistance RF of the TIA are optimized to performance specifications comprising a specified sensitivity and responsivity at an operational wavelength. This design approach enables cost-effective fabrication of integrated PIN-TIA.

Abstract: Electro-photonic integrated circuits comprising optical transmitters and receivers are disclosed, wherein a monolithically integrated electro-absorption modulated laser (EML) is operable bidirectionally, in a transmitter mode and in a receiver mode. Vertically stacked waveguides are provided for a laser and an electro-absorption modulator (EAM). The laser and EAM are optically coupled using a laterally tapered vertical optical coupler. The EML comprises monolithically integrated electronic circuitry, e.g., driver and control electronics for the driving the laser and EAM as an EML, in transmitter mode. The electronic circuitry comprises a transimpedance amplifier (TIA). The EAM has first and second parts that can be 10 independently biased. In receiver mode, the laser current is reduced to close to the threshold, and a first part of the EAM is biased to absorb residual laser light, and the second part of the EAM acts as a photodiode receiver to provide a photocurrent to the TIA.

Abstract: An optical receiver comprises a variable optical attenuator (VOA), a photodiode (PD) which may be a pin-PD or an APD, a transimpedance amplifier (TIA), and a feedback/control circuit for adjusting a bias voltage of the VOA in response to an optical input signal level, to provide an attenuated optical output signal to the PD having a narrower dynamic range. Providing signal level adjustment in the optical domain mitigates the requirement for a TIA with a large dynamic range and provides for fast switching. The optical receiver may comprise a waveguide configuration, wherein a first electro-absorption modulator (EAM) is operable as the VOA and a second EAM is operable as the photodiode. A monolithically integrated electro-photonic circuit comprising the VOA, PD, TIA and feedback/control circuit may be provided using InP-based semiconductor materials.

Abstract: An optical receiver comprises a monolithically integrated pin photodiode (PIN) and transimpedance amplifier (TIA). The TIA comprises InP heterojunction bipolar transistors (HBT) fabricated from a first plurality of layers of an epitaxial layer stack grown on a SI:InP substrate; the PIN is fabricated from a second plurality of layers of the epitaxial layer stack. The p-contact of the PIN is directly connected to the input of the TIA to reduce PIN capacitance CPIN. The TIA capacitance CTIA may be matched to CPIN. Device parameters comprising: a thickness of the absorption layer, window area, and an optional mirror thickness of the PIN; device capacitance CPIN+CTIA; and feedback resistance RF of the TIA; are optimized to performance specifications comprising a specified sensitivity and responsivity at an operational wavelength. This design approach enables cost-effective fabrication an integrated PIN-TIA, for applications such as a 1577 nm receiver for an ONU for 10G-PON.

Abstract: A burst-mode optical receiver for an optical line terminal (OLT) of a passive optical network (PON) comprises a variable optical attenuator (VOA), a photodiode (PD) which may be a pin-PD or an APD, a transimpedance amplifier (TIA), and a feedback/control circuit for adjusting a bias voltage of the VOA in response to a burst-mode optical input signal level, to provide an attenuated optical output signal to the PD having a narrower dynamic range. Providing signal level adjustment in the optical domain mitigates the requirement for a burst-mode TIA with a large dynamic range and provides for fast switching. The burst-mode optical receiver may comprise a waveguide configuration, wherein a first electro-absorption modulator (EAM) is operable as the VOA and a second EAM is operable as the photodiode. A monolithically integrated electro-photonic circuit comprising the VOA, PD, TIA and feedback/control circuit may be provided using InP-based semiconductor materials.