Photodigm Inc.

Other

Jacob Meyer Hammer

Gary Alan Evans

Jay Bernard Kirk

Laser diodes are formed with an outcoupling grating between two separate distributed Bragg reflectors. The devices have gain regions located between the reflector gratings for pumping the active region. The outcoupling grating couples light out of the waveguide normal to the surface if the grating spacings are equal to an integer number of wavelengths of the light within the cavity. If the gratings are not such an integer number, the light is coupled out of the cavity off the normal.

Grating&#x2014;outcoupled surface-emitting lasers

An exemplary optical isolator, such as a magnetic-semiconductor composite optical isolator, and method for making the same, is provided that includes a semiconductor waveguide and a magnetic-semiconductor composite layer. The semiconductor waveguide includes a guide layer, a first clad layer and a second clad layer. The guide layer includes one or more layers with a first end, a second end, a top, and a bottom, the guide layer allows a light wave incident the first end of the guide layer to propagate in a positive propagation direction, and allows a light wave incident the second end of the guide layer to propagate in a negative propagation direction. The first clad layer and the second clad layer are provided, respectively, relative to the bottom and the top of the guide layer, and the second clad layer has a thickness to allow an optical field penetration through the second clad layer. The magnetic-semiconductor composite layer is provided in the presence of a magnetic field oriented in a desired direction and is positioned relative the second clad layer and at a thickness and index of refraction to receive the optical field penetration through the second clad layer and to attenuate a light wave that propagates in the negative propagation direction more than the attenuation of a light wave that propagates in the positive propagation direction. The magnetic-semiconductor composite optical isolator may be integrated with a semiconductor laser, such as on the same semiconductor substrate.

Ferromagnetic-semiconductor composite isolator and method

Grating-outcoupled surface-emitting lasers

A band-stop wavelength filter and TE-TM mode selector made using an absorptive layer on an optical waveguide is provided. At the correct thickness, refractive index, absorptive loss, and location of the absorptive layer, a relatively high fraction of guided-mode intensity flows in the absorptive layer for one polarization mode. A much smaller fraction flows for the perpendicular polarization mode and for wavelengths on both sides of the design center. The result is a broad-band-stop filter for the selected polarization mode. This device is capable of strong discrimination between TE and TM modes over a very broad bandwidth.

Wavelength filter and polarizer

An exemplary optical isolator, which may use a magnetic-composite material made of a ferromagnetic-composite, and method for making the same are provided. The optical isolator may include a core, a cladding, and a magnetic-composite material. The core is operable to allow a light wave incident a first end to propagate to a second end to define a positive propagation direction, and to allow a light wave incident the second end to propagate to the first end to define a negative propagation direction. The cladding is positioned relative the core and includes a thinned segment of the cladding with a cladding thickness operable to allow an optical field penetration through the thinned segment of the cladding by a light wave that propagates either in the positive or negative propagation direction. The thinned segment has a length that extends relative to a portion of the core. The magnetic-composite material is provided in the presence of a magnetic field, such as a static magnetic field, in a direction perpendicular to the positive propagation direction of the core, and is positioned relative the thinned segment to receive the optical field penetration through the thinned segment. The magnetic-composite material having a thickness and an index of refraction to attenuate a light wave that propagates in the portion of the core in the negative propagation direction more than the attenuation of a light wave that propagates in the portion of the core in the positive propagation direction.

Inline ferromagnetic-composite isolator and method

Two or more laser diodes are combined by crossing their cavities, and the multiple lasers share a common outcoupling aperture. By controlling the quantum wells in the active region, crosstalk between the devices can be eliminated. The multiple devices can also be made to crosstalk, and can be made coherent with respect to one another by mixing enough photons to phase lock the devices.

Multiple grating-outcoupled surface-emitting lasers

An optical device includes a body of a semiconductor material having a waveguide therein along which light flows and means for providing gain to the light. A layer of an amorphous or polycrystalline metallic-ferromagnetic material extends along the waveguide and means, such as a permanent magnet, provides a magnetic field to the metallic-ferromagnetic material layer. This provides an optical isolator of the Faraday rotation type which can be integrated with a variety of material systems including those commonly used to fabricate semiconductor lasers, arrays and amplifiers.

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Annapolis, MD, United States of America

Jacob Meyer Hammer