Abstract: A FEC enhanced system for an optical transport or communication network that includes an optical transmitter that has a transmitter photonic integrated circuit (TxPIC) chip having an integrated circuit comprising an array of modulated sources providing a plurality of optical modulated channel signals comprising digital bit data streams where each signal is at a wavelength on a wavelength grid. The modulated channel signal outputs from the modulated sources are provided to an integrated multiplexer in the circuit to provide a WDM output signal at a circuit output. At least one FEC encoder is coupled to the modulated sources to encode error-correcting code containing redundant information of the data bit stream for each channel signal. An optical receiver in the network includes a receiver photonic integrated circuit (RxPIC) chip having an integrated circuit comprising an input to a demultiplexer and an array of photodetectors coupled to outputs of the demultiplexer.

Abstract: Disclosed is a method of adjusting a center channel wavelength of a group of channel wavelengths from of a plurality of modulated sources, integrated in a photonic integrated circuit (PIC), relative to the center of a wavelength passband of an optical combiner, such as an arrayed waveguide array (AWG), also integrated in the photonic integrated circuit (PIC) and optically coupled to outputs from the modulated sources.

Abstract: An optical transmitter comprises a monolithic transmitter photonic integrated circuit (TxPIC) chip that includes an array of modulated sources formed on the PIC chip and having different operating wavelengths approximating a standardized wavelength grid and providing signal outputs of different wavelengths. A wavelength selective combiner is formed on the PIC chip having a wavelength grid passband response approximating the wavelength grid of the standardized wavelength grid. The signal outputs of the modulated sources optically coupled to inputs of the wavelength selective combiner to produce a combined signal output from the combiner. A first wavelength tuning element coupled to each of the modulated sources and a second wavelength tuning element coupled to the wavelength selective combiner. A wavelength monitoring unit is coupled to the wavelength selective combiner to sample the combined signal output.

Abstract: A method and apparatus operates an array of laser sources as an integrated array on a single substrate or as integrated in an optical transmitter photonic integrated circuit (TxPIC) maintaining the emission wavelengths of such integrated laser sources at their targeted emission wavelengths or at least to more approximate their desired respective emission wavelengths. Wavelength changing elements may accompany the laser sources to bring about the change in their operational or emission wavelength to be corrected to or toward the desired or target emission wavelength. The wavelength changing elements may be comprise of temperature changing elements, current and voltage changing elements or bandgap changing elements.

Abstract: A method of operating an array of integrated laser sources formed as an integrated array on a single substrate in a photonic integrated circuit (PIC) where the laser sources are designed for operation at different targeted emission wavelengths which, in toto, at least approximate a grid of spatial emission wavelengths. A first wavelength tuning element is associated with each laser source and is adjusted over time so that each laser source maintains its targeted emission wavelength. As an alternative, the drive current to each laser source may be initially set so that each laser source operates at its targeted emission wavelength. Thereafter, adjustments to retune the laser sources to their targeted emission wavelengths are accomplished by the first wavelength tuning elements. The outputs of the laser sources may be combined via an optical combiner to produce a single combined output from the PIC.

Abstract: The extraction efficiency of a light emitting device can be improved by making the absorbing device layers as thin as possible. The internal quantum efficiency decreases as the device layers become thinner. An optimal active layer thickness balances both effects. An AlGaInP LED includes a substrate and device layers including an AlGaInP lower confining layer of a first conductivity type, an AlGaInP active region of a second conductivity type, and an AlGaInP upper confining layer of a second conductivity type. The absorbance of the active region is at least one fifth of the total absorbance in the light-emitting device. The device optionally includes at least one set-back layers of AlGaInP interposing one of confining layer and active region. The p-type upper confining layer may be doped with oxygen improve the reliability.

Abstract: An active semiconductor device, such as, buried heterostructure semiconductor lasers, LEDs, modulators, photodiodes, heterojunction bipolar transistors, field effect transistors or other active devices, comprise a plurality of semiconductor layers formed on a substrate with one of the layers being an active region. A current channel is formed through this active region defined by current blocking layers formed on adjacent sides of a designated active region channel where the blocking layers substantially confine the current through the channel. The blocking layers are characterized by being an aluminum-containing Group III–V compound, i.e., an Al-III–V layer, intentionally doped with oxygen from an oxide source. Also, wet oxide process or a deposited oxide source may be used to laterally form a native oxide of the Al-III–V layer. An example of a material system for this invention useful at optical telecommunication wavelengths is InGaAsP/InP where the Al-III–V layer comprises InAlAs:O or InAlAs:O:Fe.

Abstract: An optical waveguide device, power coupler, a star coupler, a MMI coupler, an arrayed waveguide grating (AWG) or an Echelle grating, having at least one free space region with a plurality of optical waveguides coupled as inputs and separated by channels having a angled bottom portion, the channels monotonically decreasing in size or shape in a direction toward the free space region and optically coupling with adjacent waveguides at the interface region between the optical waveguides and the free space region so that insertion loss at the interface region is substantially reduced.

Abstract: A monolithic transmitter photonic integrated circuit (TxPIC) chip comprises an array of modulated sources formed on the PIC chip and having different operating wavelengths according to a standardized wavelength grid and providing signal outputs of different wavelengths. Pluralities of wavelength tuning elements are integrated on the chip, one associated with each of the modulated sources. An optical combiner is formed on the PIC chip and the signal outputs of the modulated sources are optically coupled to one or more inputs of the optical combiner and provided as a combined channel signal output from the combiner. The wavelength tuning elements provide for tuning the operating wavelength of the respective modulated sources to be approximate or to be chirped to the standardized wavelength grid. The wavelength tuning elements are temperature changing elements, current and voltage changing elements or bandgap changing elements.

Abstract: A method of tuning optical components integrated on a monolithic chip, such as an optical transmitter photonic integrated circuit (TxPIC), is disclosed where a group of first optical components are each fabricated to have an operating wavelength approximating a wavelength on a standardized or predetermined wavelength grid and are each included with a local wavelength tuning component also integrated in the chip. Each of the first optical components is wavelength tuned through their local wavelength tuning component to achieve a closer wavelength response that approximates their wavelength on the wavelength grid.

Abstract: A method and apparatus operates an array of laser sources as an integrated array on a single substrate or as integrated in an optical transmitter photonic integrated circuit (TxPIC) maintaining the emission wavelengths of such integrated laser sources at their targeted emission wavelengths or at least to more approximate their desired respective emission wavelengths. Wavelength changing elements may accompany the laser sources to bring about the change in their operational or emission wavelength to be corrected to or toward the desired or target emission wavelength. The wavelength changing elements may be comprise of temperature changing elements, current and voltage changing elements or bandgap changing elements.

Abstract: An optical probe and a method for testing an optical chip or device, such as an photonic integrated circuit (PIC), to provide for testing of such devices or circuits while they are still in their in-wafer form and is accomplished by using a an optical probe for interrogation of the circuit where an access is provided in the wafer to one or more of such in-wafer devices or circuits. As one example, the interrogation may be an interrogation beam provided at the access input to the in-wafer device or circuit. As another example, the interrogation may be an optical pickup from the access input to the in-wafer device or circuit.

Abstract: A method of operating an array of laser sources integrated as an array in a single monolithic chip where the steps include designing the laser sources to have different target emission wavelengths so that together they form a spectral emission wavelength grid, coupling outputs from the laser sources to an array of gain/loss elements also integrated on the single monolithic chip, one each receiving the output from a respective laser source; and adjusting the outputs with the gain/loss elements so that the power levels across the laser source array are substantially uniform.

Abstract: A photonic integrated circuit (PIC) comprises a plurality of integrated optically coupled components formed in a surface of the PIC and a passivating layer overlies at least a portion of the PIC surface. The overlying passivating layer comprises a material selected from the group consisting of BCB, ZnS and ZnSe. Also, when the circuits are PIC chips are die in the semiconductor wafer, a plurality of linear cleave streets are formed in a wafer passivation layer where a pattern of the cleave streets define separate PIC chips in the wafer for their subsequent singulation from the wafer.

Abstract: The Group III–V quaternary, InAlGaAs is employed as a waveguide layer in optical components, such as In-P based array waveguide gratings (AWGs), avalanche photodiodes (APDs) or other optical components that contain a waveguide core in the InP regime. The deployment of InAlGaAs waveguides provides for high uniform photoluminescent (PL) emission wavelength across the wafer for InAlGaAs waveguides as compared to InGaAsP waveguides as now commonly employed in such optical devices or components. The use of an InAlGaAs waveguide core has particular utility when deployed in a photonic integrated circuit (PIC) such as an AWG with a plurality of outputs optically integrated with a plurality of photodetectors, such as APDs which are exemplified in this disclosure. In lieu of an InAlGaAs waveguide, combination layers of InGaAs/InAlAs, InGaAs/InAlGaAs or InAlAs/InAlGaAs may be employed or stacks of such layers to form the waveguides in the PIC chip.

Abstract: Cleaved grooves, also referred to herein as “cleave streets”, are formed exclusively in a wafer passivation layer overlaying a wafer to provide for correctly aligned and sharp cleaves prior to singulation of the wafer into separate die or chips.

Abstract: A method for reducing insertion loss in a transition region between a plurality of input or output waveguides to a free space coupler region in a photonic integrated circuit (PIC) includes the steps of forming a passivation layer over the waveguides and region and forming the passivation overlayer such that it monotonically increases in thickness through the transition region to the free space coupler region.

Abstract: A photonic integrated circuit that includes a plurality of active and passive components on a substrate where one of the components is an optical combiner/decombiner having at least one free space coupler region and a plurality of longitudinal ridge waveguides each extending in the circuit from a first region of the waveguide and coupled at a second region of the waveguide at the free space coupler region. A first dielectric layer formed over the ridge waveguides and the free space coupler region. The first dielectric layer monotonically increases in cross-sectional thickness from the waveguide first region to the second region to reduce signal insertion losses in transitioning from the ridge waveguides to the free space coupler region. The first dielectric layer may be covered with a second passivation layer. The first dielectric layer may be SiOx, SiNx or SixONy and the second passivation layer may be BCB, ZnS or ZnSe.

Abstract: Disclosed is a method of adjusting a center channel wavelength of a group of channel wavelengths from of a plurality of modulated sources, integrated in a photonic integrated circuit (PIC), relative to the center of a wavelength passband of an optical combiner, such as an arrayed waveguide array (AWG), also integrated in the photonic integrated circuit (PIC) and optically coupled to outputs from the modulated sources.

Abstract: An InP-based photonic integrated circuit (PIC) includes an optical passive element in the circuit with no bias current applied to such an element. A passivation cladding layer overlies a surface of the optical passive element where the passivation layer comprises benzocyclobutene polymer or BCB.