A quantum cascade laser includes a first and a second mesa waveguides disposed on a substrate, a first electrode, a second electrode, and a current blocking region disposed burying the first and second mesa waveguides. The first and second mesa waveguides extend in a first direction. The first and second mesa waveguides are arranged apart from each other by a distance in a second direction intersecting with the first direction. The current blocking region has a first portion disposed between the first and second mesa waveguides and a second portion disposed on the first portion. The end of the first electrode and the end of the second electrode are facing each other in the second direction. The second portion protrudes from a reference plane which includes a surface of the end of the first electrode and extends in the first and second directions.

An apparatus, and related method, relates generally to a fiber-optic sensing system. In such a system, fiber-optic sensors are in a rosette or rosette-like pattern. An optical circulator is coupled to receive a light signal from a broadband light source, to provide the light signal to the fiber-optic sensors, and to receive a returned optical signal from the fiber-optic sensors. A spectral engine is coupled to the optical circulator to receive the returned optical signal and configured to provide an output signal.

A quantum-cascade laser element includes: an embedding layer including a first portion formed on a side surface of a ridge portion, and a second portion extending from an edge portion of the first portion along a width direction of a semiconductor substrate; and a metal layer formed at least on a top surface of the ridge portion and on the first portion. A surface of the first portion has a first inclined surface inclined with respect to the side surface to go away from the side surface as going away from the semiconductor substrate, and a second inclined surface located opposite to the semiconductor substrate with respect to the first inclined surface and inclined with respect to a center line to approach the center line as going away from the semiconductor substrate. The metal layer extends over the first inclined surface and the second inclined surface.

A device includes: a mesa stripe structure comprising a semiconductor in a stripe shape extending in a first direction, with first and second portions spaced apart in the first direction, and a third portion between the first and second portions; and an electrode pattern including a first electrode overlapping with the first portion but not overlapping with the second portion, and a second electrode overlapping with the second portion but not overlapping with the first portion. The first and second electrodes are separated. The electrode pattern comprises a metal in a shape of not overlapping with the third portion. The electrode pattern includes an adjacent area not overlapping with the mesa stripe structure. The adjacent area is next to the third portion in a second direction orthogonal to the first direction, and is on a semiconductor layer continuous to the mesa stripe structure.

A non-etched gap is introduced along the length of an integrated Bragg grating with etched grooves such that the coupling coefficient, K, of the grating is reduced by the non-etched gap. In this way, multiple grating K values may be defined within a photonic integrated circuit using a single lithography and etch step. Additionally, the non-etched gap width may be varied along the length of a single grating to implement a chirped grating.

Wavelength division multiplexing (WDM) has enabled telecommunication service providers to provide multiple independent multi-gigabit channels on one optical fiber. To meet demands for improved performance, increased integration, reduced footprint, reduced power consumption, increased flexibility, re-configurability, and lower cost monolithic optical circuit technologies and microelectromechanical systems (MEMS) have become increasingly important. However, further integration via microoptoelectromechanical systems (MOEMS) of monolithically integrated optical waveguides upon a MEMS provide further integration opportunities and functionality options. Such MOEMS may include MOEMS mirrors and optical waveguides capable of deflection under electronic control. In contrast to MEMS devices where the MEMS is simply used to switch between two positions the state of MOEMS becomes important in all transition positions. Improvements to the design and implementation of such MOEMS mirrors, deformable MOEMS waveguides, and optical waveguide technologies supporting MOEMS devices are presented where monolithically integrated optical waveguides are directly supported, moved and/or deformed by a MEMS.

Wavelength division multiplexing (WDM) has enabled telecommunication service providers to provide multiple independent multi-gigabit channels on one optical fiber. To meet demands for improved performance, increased integration, reduced footprint, reduced power consumption, increased flexibility, re-configurability, and lower cost monolithic optical circuit technologies and microelectromechanical systems (MEMS) have become increasingly important. However, further integration via microoptoelectromechanical systems (MOEMS) of monolithically integrated optical waveguides upon a MEMS provide further integration opportunities and functionality options. Such MOEMS may include MOEMS mirrors and optical waveguides capable of deflection under electronic control. In contrast to MEMS devices where the MEMS is simply used to switch between two positions the state of MOEMS becomes important in all transition positions. Improvements to the design and implementation of such MOEMS mirrors, deformable MOEMS waveguides, and optical waveguide technologies supporting MOEMS devices are presented where monolithically integrated optical waveguides are directly supported, moved and/or deformed by a MEMS.

Methods for driving a tunable laser with integrated tuning elements are disclosed. The methods can include modulating the tuning current and laser injection current such that the laser emission wavelength and output power are independently controllable. In some examples, the tuning current and laser injection current are modulated simultaneously and a wider tuning range can result. In some examples, one or both of these currents is sinusoidally modulated. In some examples, a constant output power can be achieved while tuning the emission wavelength. In some examples, the output power and tuning can follow a linear relationship. In some examples, injection current and tuning element drive waveforms necessary to achieve targeted output power and tuning waveforms can be achieved through optimization based on goodness of fit values between the targeted and actual output power and tuning waveforms.

Methods for driving a tunable laser with integrated tuning elements are disclosed. The methods can include modulating the tuning current and laser injection current such that the laser emission wavelength and output power are independently controllable. In some examples, the tuning current and laser injection current are modulated simultaneously and a wider tuning range can result. In some examples, one or both of these currents is sinusoidally modulated. In some examples, a constant output power can be achieved while tuning the emission wavelength. In some examples, the output power and tuning can follow a linear relationship. In some examples, injection current and tuning element drive waveforms necessary to achieve targeted output power and tuning waveforms can be achieved through optimization based on goodness of fit values between the targeted and actual output power and tuning waveforms.

A vertical cavity surface emitting laser (VCSEL) has first and second electrical contacts, and an optical resonator. The optical resonator has first and second distributed Bragg reflectors (DBRs), an active layer, a distributed heterojunction bipolar phototransistor (DHBP), and an optical guide. The DHBP has a collector layer, light sensitive layer; a base layer; and an emitter layer. There is an optical coupling between the active layer and the DHBP for providing an active carrier confinement by the DHBP. The optical guide guides an optical mode within the optical resonator during operation. The optical guide is outside a current flow which can be provided by the first and second electrical contacts during operation of the VCSEL. The optical guide is outside a layer sequence between the first and second electrical contacts in the vertical direction of the VCSEL. The optical guide has an oxide aperture arranged in the second DBR.