In a first embodiment, an external cavity tunable laser, comprising a silicon photonics circuit comprising one or more resonators having one or more p-i-n junctions; wherein a voltage is applied to one or more of the p-i-n junctions. In a second embodiment, a method of operating an external cavity tunable laser, comprising sweeping out free-carriers from a resonator of the tunable laser by applying a voltage to a p-i-n junction of a waveguide of the resonator.

A technique for narrowing a linewidth of a plurality of lines of a coherent comb laser (CCL) concurrently comprises providing a mode-locked semiconductor coherent comb laser (CCL) adapted to output of at least 4 mode-locked lines; tapping a fraction of a power from the CCL from the laser cavity to form a tapped beam; propagating the tapped beam to an attenuator to produce an attenuated beam; and reinserting the attenuated beam into the laser cavity, where the reinserted beam has a power less than 10% of a power of the tapped beam. The reinsertion allows the CCL to be operated to output the mode-locked lines, each with a linewidth of less than 80% of the original linewidth. By propagating the tapped and attenuated beams on a solid waveguide, and ensuring that the secondary cavity is polarization maintaining, improved stability of the linewidth narrowing is ensured.

A technique for narrowing a linewidth of a plurality of lines of a coherent comb laser (CCL) concurrently comprises providing a mode-locked semiconductor coherent comb laser (CCL) adapted to output of at least 4 mode-locked lines; tapping a fraction of a power from the CCL from the laser cavity to form a tapped beam; propagating the tapped beam to an attenuator to produce an attenuated beam; and reinserting the attenuated beam into the laser cavity, where the reinserted beam has a power less than 10% of a power of the tapped beam. The reinsertion allows the CCL to be operated to output the mode-locked lines, each with a linewidth of less than 80% of the original linewidth. By propagating the tapped and attenuated beams on a solid waveguide, and ensuring that the secondary cavity is polarization maintaining, improved stability of the linewidth narrowing is ensured.

The present invention relates to an optical time domain reflectometer using, as a optical source, a polymer wavelength tunable laser which tunes the wavelength of an optical signal by using polymer grating. The optical time domain reflectometer of the present invention tunes the wavelength of a polymer wavelength tunable laser that outputs a constant optical signal and inspects cutting, reflection, and damage of an optical line by separating an optical signal returning from the optical line by an optical filter having a specific central wavelength. Since a optical source having a constant light intensity is used, the present invention has an effect of reducing the nonlinear effect generated in an optical line.

A quantum dot comb laser includes a body defining a lasing cavity and an extension defining an external cavity, the FSR of the lasing cavity being an inverse of an integer multiple of the FSR of the external cavity.

A diagnostic system is provided with a plurality of semiconductor light emitters, each configured to generate an optical beam, and a beam combiner to generate a multiplexed optical beam. An optical fiber or waveguide communicates at least a portion of the multiplexed optical beam to form an output beam, wherein the output beam is pulsed. A filter, coupled to at least one of a lens and a mirror to receive at least a portion of the output beam, forms an output light. A beam splitter splits the light into a sample arm and a reference arm and directs at least a portion of the sample arm light to a sample. A detection system is configured to receive from the sample at least a portion of reflected sample light, to generate a sample detector output, and to use a lock-in technique with the pulsed output beam.

A quantum dot comb laser includes a body defining a lasing cavity and an extension defining an external cavity, the FSR of the lasing cavity being an inverse of an integer multiple of the FSR of the external cavity.

A distributed feedback (DFB) laser outputting a predetermined wavelength of laser light includes a quantum well active layer positioned between a p-type cladding layer and an n-type cladding layer in thickness direction. The DFB laser includes a separate confinement heterostructure layer positioned between the quantum well active layer and then-type cladding layer. The DFB laser includes an electric-field-distribution-control layer positioned between the separate confinement heterostructure layer and then-type cladding layer and configured by at least two semiconductor layers having band gap energy greater than band gap energy of a barrier layer constituting the quantum well active layer. The DFB laser has a function to select a specific wavelength by returning a specific wavelength in the wavelength-variable laser.

An image sensing device that includes a lens housing; a bulk lens system coupled to the lens housing and configured to receive light from the surrounding environment and focus the received light to a focal plane, the bulk lens system comprising a first lens, a second lens, and a third lens mounted in the lens housing; wherein the first lens, the second lens, or the first lens and the second lens are plastic; and wherein the third lens is glass; an array of photosensors configured to receive light from the bulk lens system and detect reflected portions of the light pulses that are reflected from the objects in the surrounding environment; and a mount that mechanically couples the lens housing with the array of photosensors, wherein the lens housing, the bulk lens system, and the mount are configured to passively focus light from the bulk lens system onto the array of photosensors over a temperature range.

A light ranging system including a housing; a shaft defining an axis of rotation; a first circuit board assembly disposed within and coupled to the housing in a fixed relationship such that the first circuit board assembly is aligned along a first plane perpendicular to the axis of rotation, the first circuit board assembly including a plurality of first circuit elements disposed on a first circuit board; a second circuit board assembly spaced apart from the first circuit board assembly within the housing in a second plane parallel to the first plane and rotationally coupled to the shaft such that the second circuit board assembly rotates about the axis of rotation, the second circuit board assembly including a plurality of second circuit elements disposed on a second circuit board and aligned with and configured to function in wireless cooperation with at least one of the first plurality of circuit elements; and a light ranging device electrically connected to and coupled to rotate with the second circuit board assembly, the light ranging device configured to transmit light pulses to objects in a surrounding environment, to detect reflected portions of the light pulses that are reflected from the objects in the surrounding environment, and to compute ranging data based on the reflected portion of the light pulses.