A heterodyne starring array active imager for producing an image. The imager comprises a light source intermittently illuminating a scene and an array of light collecting sites imaging the scene, each one comprising: a coupling component optically coupling scene light into a first waveguide and a local oscillator light coupled into a second waveguide. The first and second waveguides coupled to a third waveguide such that the scene light and local oscillator light propagate into the third waveguide. A square law photo detector associated with each light collecting site receives the merged light for heterodyning the scene light and the local oscillator light. Components receive and process the heterodyned light from the photo detectors to produce a frame signal for each light collecting site. A read-out device produces an array signal responsive to the frame signal from each light collecting site.

A tunable laser has a first mirror, a second mirror, a gain medium, and a directional coupler. The first mirror and the second mirror form an optical resonator. The gain medium and the directional coupler are, at least partially, in an optical path of the optical resonator. The first mirror and the second mirror comprise binary super gratings. Both the first mirror and the second mirror have high reflectivity. The directional coupler provides an output coupler for the tunable laser.

A heterodyne starring array active imager for producing an image. The imager comprises a light source intermittently illuminating a scene and an array of light collecting sites imaging the scene, each one comprising: a coupling component optically coupling scene light into a first waveguide and a local oscillator light coupled into a second waveguide. The first and second waveguides coupled to a third waveguide such that the scene light and local oscillator light propagate into the third waveguide. A square law photo detector associated with each light collecting site receives the merged light for heterodyning the scene light and the local oscillator light. Components receive and process the heterodyned light from the photo detectors to produce a frame signal for each light collecting site. A read-out device produces an array signal responsive to the frame signal from each light collecting site.

A distributed reflector (DR) laser may include a distributed feedback (DFB) region and a distributed Bragg reflector (DBR). The DFB region may have a length in a range from 30 micrometers (m) to 100 m and may include a DFB grating with a first kappa in a range from 100 cm.sup.1 to 150 cm.sup.1. The DBR region may be coupled end to end with the DFB region and may have a length in a range from 30-300 m. The DBR region may include a DBR grating with a second kappa in a range from 150 cm.sup.1 to 200 cm.sup.1. The DR laser may additionally include a lasing mode and a p-p resonance frequency. The lasing mode may be at a long wavelength side of a peak of a DBR reflection profile of the DBR region. The p-p resonance frequency may be less than or equal to 70 GHz.

The present invention includes an optical waveguide with a grating and a method of making the same for increasing the effectiveness of the grating. In one example, the grating is at least partially covered by a liner layer disposed on at least a portion of a grating; and a cover layer disposed on the liner layer, wherein a first material selected for the core and ridges and a second material selected for the liner layer are selected to provide a difference in the index of refraction between the first and second material that is sufficient to provide a contrast therebetween.

The present invention includes an optical waveguide with a grating and a method of making the same for increasing the effectiveness of the grating. In one example, the grating is at least partially covered by a liner layer disposed on at least a portion of a grating; and a cover layer disposed on the liner layer, wherein a first material selected for the core and ridges and a second material selected for the liner layer are selected to provide a difference in the index of refraction between the first and second material that is sufficient to provide a contrast therebetween.

In various example embodiments, hybrid waveguide devices are disclosed based on a silicon nitride waveguide conformally coated with a tellurium oxide layer. A tellurium oxide layer is deposited over a silicon nitride waveguide such that the tellurium oxide layer forms a conformal layer that inherits the underlying shape of the silicon nitride waveguide, thereby forming a conformal raised region above the silicon nitride waveguide, while also forming planar regions that extend laterally from the silicon nitride waveguide. The present example hybrid waveguide structures enable the formation of a guided single mode that extends from the raised region of the tellurium oxide layer that resides above the silicon nitride waveguide into the silicon nitride waveguide, and the dimensions of the structure may be selected such that a majority of the optical mode is confined within the tellurium oxide layer, at least over a portion of the infrared region.

A distributed reflector (DR) laser may include a distributed feedback (DFB) region and a distributed Bragg reflector (DBR). The DFB region may have a length in a range from 30 micrometers (m) to 100 m and may include a DFB grating with a first kappa in a range from 100 cm.sup.1 to 150 cm.sup.1. The DBR region may be coupled end to end with the DFB region and may have a length in a range from 30-300 m. The DBR region may include a DBR grating with a second kappa in a range from 150 cm.sup.1 to 200 cm.sup.1. The DR laser may additionally include a lasing mode and a p-p resonance frequency. The lasing mode may be at a long wavelength side of a peak of a DBR reflection profile of the DBR region. The p-p resonance frequency may be less than or equal to 70 GHz.

Examples of the present invention include integrated erbium-doped waveguide lasers designed for silicon photonic systems. In some examples, these lasers include laser cavities defined by distributed Bragg reflectors (DBRs) formed in silicon nitride-based waveguides. These DBRs may include grating features defined by wafer-scale immersion lithography, with an upper layer of erbium-doped aluminum oxide deposited as the final step in the fabrication process. The resulting inverted ridge-waveguide yields high optical intensity overlap with the active medium for both the 980 nm pump (89%) and 1.5 m laser (87%) wavelengths with a pump-laser intensity overlap of over 93%. The output powers can be 5 mW or higher and show lasing at widely-spaced wavelengths within both the C- and L-bands of the erbium gain spectrum (1536, 1561 and 1596 nm).

A method of fabricating an acousto-optic waveguide that includes a waveguide cladding surrounding an optical core is disclosed. The method comprises providing a wafer substrate; depositing an initial amount of a first material over an upper surface of the wafer substrate to form a partial cladding layer; depositing a second material over the partial cladding layer to form an optical layer; removing portions of the second material of the optical layer to expose portions of the partial cladding layer and form an optical core comprising the remaining second material; and depositing an additional amount of the first material over the optical core and the exposed portions of the partial cladding layer to form a full cladding layer that surrounds the optical core. A relative concentration of components of the first material is adjusted to provide Brillouin gain spectral position control of the waveguide cladding to tune the acousto-optic waveguide.