A Distributed Feedback Laser comprises a layer stack comprising a p-layer, an n-layer which are arranged so as to form an pn-junction having an active layer in between. Within the layer stack, an index coupled grating layer or a grating layer is arranged which comprises a first, a second, and a third grating portion. The first, the second, and the third grating portions are asymmetrically arranged along a lateral dimension of the layer stack, wherein the second grating portion is formed without a grating structure.

A tunable laser device includes a laser structure and a plurality of individually addressable, separated contact stripes disposed on the laser structure. The laser structure includes a substrate, an active portion disposed on the substrate, and a chirped distributed feedback (DFB) grating disposed on the active portion. The active portion includes at least top and bottom contact layers and a gain medium.

A two-dimensional photonic-crystal surface-emitting laser 10 includes: a two-dimensional photonic crystal (two-dimensional photonic crystal layer 12) including a plate-shaped base body 121 having a predetermined size in which modified refractive index areas 122 whose refractive index differs from the base body are periodically arranged in a two-dimensional pattern; an active layer 11 provided on one side of the two-dimensional photonic crystal; and first and second electrodes 15 and 16 facing each other across the two-dimensional photonic crystal and the active layer 11, for supplying an electric current to the active layer 11. The modified refractive index areas 122 are provided in such a manner that the in-plane occupancy of those areas 122 in the base body 121 decreases, or the lattice constant for those areas 122 increases, in the direction from an outer edge toward the center of a current passage region 21 which is a region where the electric current passes through the two-dimensional photonic crystal. With this configuration, a stable laser oscillation can be obtained even when a temperature distribution which is lower at the outer edge and higher at the center of the current passage region is formed within the two-dimensional photonic crystal.

A two-dimensional photonic crystal including a plate-shaped base body in which modified refractive index areas differs from the base body are periodically arranged in a two-dimensional pattern; an active layer provided on one side of the two-dimensional photonic crystal; and first and second electrodes facing each other across the two-dimensional photonic crystal and the active layer, for supplying an electric current to the active layer. The modified refractive index areas are provided in the in-plane occupancy of areas in the base body increases, or the lattice constant for those areas decreases, in the direction from an outer edge toward the center of a current passage region where the electric current passes through the two-dimensional photonic crystal. A stable laser oscillation can be obtained when temperature distribution is lower at the outer edge and higher at the center of the current passage region is formed within the two-dimensional photonic crystal.

An optical semiconductor device includes a chassis that has an external wall, a feedthrough that penetrates the external wall of the chassis and has a projection portion projecting toward outside of the chassis from the external wall, a connection terminal that is electrically connected to a component mounted in the chassis and is on the projection portion of the feedthrough, a first temperature detector that is on an external face of the external wall of the chassis and detects a temperature of the chassis, and a flexible substrate of which an end is connected to the connection terminal and of which a portion spaced from the end is connected to the first temperature detector, wherein the first temperature detector is between the external wall and the flexible substrate.

A light detection and ranging (LIDAR) system may include a laser source configured to emit one or more optical beams; a scanning optical system configured to scan the one or more optical beams over a scene and capture reflections of the one or more optical beams from the scene; a measurement system configured to divide the scene into a plurality of pixels, the measurement system comprising a detector configured to detect a return signal from multiple pixels of the plurality of pixels as the one or more optical beams are scanned across the scene, and a data processor configured to perform data processing from the return signal from the multiple pixels to determine a range and/or range rate for each pixel of the scene.

Frequency modulated lasers, LIDAR systems, and methods of controlling laser are disclosed. A laser source emits an optical beam having an optical frequency that changes in response to a signal applied to an input of the laser source. A laser driver that generates the signal applied to the input to cause the optical frequency to vary in accordance with a periodic frequency versus time function. The laser driver generates the signal for a current period of the periodic frequency versus time function based, at least in part, on optical frequency versus time measurements of one or more prior periods of the periodic frequency versus time function.

A compact, wavelength-stabilized laser source is provided by utilizing a specialty gain element (i.e., formed to include a curved waveguide topology), where a separate wavelength stabilization component (for example, a fiber Bragg grating (FBG)) is used one of the mirrors for the laser cavity. That is, the FBG takes the place of the physical front facet of the gain element, and functions to define the laser cavity in the first instance, while also utilizing the grating structure to impart the desired wavelength stability to the output from the packaged laser source. As a result, the FBG is disposed within the same package used to house the gain element and provides a wavelength-stabilized laser source in a compact form.

A quantum cascade laser may include a substrate, and a semiconductor layer adjacent the substrate and defining an active region. The active region may have an elongate shape extending laterally across the substrate and having first and second lowest injector states with an energy spacing greater than 20 meV. In some embodiments, the active region may have a thickness less than or equal to 1.3 m and a length greater than or equal to 20 m. The quantum cascade laser may also include an optical grating adjacent the active region and configured to emit a continuous wave laser output through the substrate. The optical grating may include a curved grating pattern.

A tunable laser device includes a laser structure and a plurality of individually addressable, separated contact stripes disposed on the laser structure. The laser structure includes a substrate, an active portion disposed on the substrate, and a chirped distributed feedback (DFB) grating disposed on the active portion. The active portion includes at least top and bottom contact layers and a gain medium.