Abstract: The optical device includes a waveguide positioned on a base and a modulator positioned on the base. The modulator includes a ridge that includes Si1-xGex where x is greater than or equal to 0.4 and less than or equal to 0.8. The modulator is configured to guide a light signal through the modulator such that the light signal contacts the Si1-xGex. A local heater is configured to heat the modulator.

Abstract: A method of forming an optical device includes forming a waveguide mask on a device precursor. The device precursor includes a waveguide positioned on a base. The method also includes forming a facet mask on the device precursor such that at least a portion of the waveguide mask is between the facet mask and the base. The method also includes removing a portion of the base while the facet mask protects a facet of the waveguide. The portion of the base that is removed can be removed such that a recess is defined in the base and/or a shelf is defined on the device precursor. A light source such as an optical fiber or laser can be received in the recess and/or positioned over the shelf such that the light source is optically aligned with the facet of the waveguide.

Abstract: An optical system includes a laser die that includes a gain medium and multiple laser waveguides that are each configured to guide a different laser light signal through the gain medium. Each of the laser waveguides outputs a laser light signal at a wavelength. The laser waveguides are arranged in multiple candidate groups. Each candidate group includes multiple laser waveguides. The wavelength spacing of the laser waveguides is the same or substantially the same in different candidate groups.

Abstract: An optical device includes a waveguide on a base and a taper on the base. The waveguide and the taper are optically aligned such that the taper and the waveguide exchange light signals during operation of the device. The taper is configured to guide the light signals through a taper material and the waveguide is configured to guide the light signals through a waveguide medium. The taper material and the waveguide medium are different materials and/or have different indices of refraction.

Abstract: The laser cavity is positioned on a substrate and includes a cavity waveguide guiding a laser light signal between a gain medium and a partial return device. The partial return device receives the laser light signal from the cavity waveguide and returns a first portion of the laser light signal to the cavity waveguide. The partial return device transmits a second portion of the laser light signal to an output waveguide. The partial return device reflects different wavelengths of the laser light signal at different intensities. Additionally, the partial return device is configured such that when the most intense wavelength of the laser light signal reflected by the partial return device is the same as a wavelength of one of modes of the laser light signal, the mode with the next longest wavelength and the mode with the next shortest wavelength are each reflected by the partial return device at an intensity greater than 80% of the intensity of the most intensely reflected wavelength.

Abstract: A platform taper is formed in an optical chip. A light-transmitting medium is attached to the optical chip after forming the platform taper in the optical chip. An waveguide taper is formed in the light-transmitting medium such that the waveguide taper and the platform taper are aligned so as to form an optical taper on the optical device.

Abstract: A base device has a first waveguide positioned on a first base. The waveguide is at least partially defined by a ridge extending away from the first base. An auxiliary optical device has a second waveguide positioned on a second base. The second optical device is immobilized on the base device such that the second waveguide is between the first base of the first optical device and the second base of the auxiliary device. The first waveguide is optically aligned with the second waveguide such that the first waveguide and second waveguides can exchange optical signals.

Abstract: A wafer includes multiple optical devices. One of the devices includes a waveguide that terminates at a facet that is included in a testing port. Light is injected from a light source into the waveguide through the facet without being reflected between exiting from the light source and entering the facet. The devices are separated from the wafer after the light is injected into the waveguide.

Abstract: The optical device includes a light sensor positioned on a base. The light sensor is configured to receive an input light signal and outputs a passed light signal that includes light from the input light signal. The optical device also includes a return system located on the base. The return system is configured to receive the passed light signal from the light sensor and to return at least a portion of the light from the passed light signal back to the light sensor.

Abstract: A method of forming an optical device includes obtaining a wafer having multiple optical device dies that each includes a waveguide. The method also includes forming a facet on the waveguide of different dies. The method further includes separating the dies from the wafer after forming the facets. The dies are separated from the wafer such that the facets are positioned at an edge of the dies.

Abstract: Forming an optical device includes growing an electro-absorption medium in a variety of different regions on a base of a device precursor. The regions include a component region and the regions are selected so as to achieve a particular chemical composition for the electro-absorption medium included in the component region. An optical component is formed on the device precursor such that the optical component includes at least a portion of the electro-absorption medium from the component region. Light signals are guided through the electro-absorption medium from the component region during operation of the component.

Abstract: The optical includes a waveguide positioned on a base and an optical component positioned on the base. The optical component is a light sensor that includes an active medium or a modulator that includes an active medium. The waveguide is configured to guide a light signal through the component such that the light signal is guided through the active medium. The device includes one or more heat control features selected from the group consisting of: placing one or more thermal conductors over a lateral side of a ridge of the active medium; extending thermal conductors from within the active component to a location outside of the active component, and tapering the ridge of the active medium within the perimeter of the active component.

Abstract: The optical device includes a waveguide positioned on a base and a modulator positioned on the base. The modulator includes a ridge of an electro-absorption medium having a top side and a lateral side. The lateral side is between the top side and the base and the top side has a width. The waveguide is configured to guide a light signal through the modulator such that the light signal is guided through the ridge of electro-absorption medium. A heater is positioned over the lateral side of the electro-absorption medium without being positioned over the entire width of the ridge.

Abstract: Fabricating the mode transformer includes forming a cladding trench in a first light-transmitting medium that is included on a wafer. A lateral cladding is formed in the cladding trench such that the lateral cladding becomes an optical cladding on a lateral side of a first tapered portion of a waveguide. A second light-transmitting medium is formed on the wafer such that a portion of the first light-transmitting medium is between a bottom of the trench and the second light-transmitting medium. The second light-transmitting medium is patterned so as to define a second tapered portion of the waveguide over the first tapered portion of the waveguide.

Abstract: An optical device includes a laser or amplifier positioned on a base. The laser includes a ridge of a gain medium positioned on the base such that the base extends out from under the ridge. The ridge includes a top that connects lateral sides of the ridge. Electronics are configured to drive an electrical current through the ridge such that the electrical current passes through one or more of the lateral sides of the ridge.

Abstract: The optical device includes a waveguide positioned on a base and a modulator positioned on the base. The modulator includes an electro-absorption medium. The waveguide is configured to guide a light signal through the modulator such that the light signal is guided through the electro-absorption medium. A heater is positioned on the electro-absorption medium such that the electro-absorption medium is between the base and the heater.

Abstract: A method of forming an optical device includes forming a waveguide mask on a device precursor. The device precursor includes a waveguide positioned on a base. The method also includes forming a facet mask on the device precursor such that at least a portion of the waveguide mask is between the facet mask and the base. The method also includes removing a portion of the base while the facet mask protects a facet of the waveguide.

Abstract: A method of forming an attenuator on an optical device includes forming a ridge for a waveguide. The ridge is formed in a light-transmitting medium that is positioned on a base. The ridge extends upwards from slab regions of the light-transmitting medium. The method also includes forming trenches in the slab regions of the light-transmitting medium such that the trenches extend through the light-transmitting medium to the base. The trenches are formed such that the ridge is located between the trenches. The method also includes forming a semiconductor in a bottom of each of the trenches and then doping a region of each of the semiconductors.

Abstract: The optical device includes a waveguide positioned on a base and a modulator positioned on the base. The modulator includes a ridge of an electro-absorption medium having a top side and a lateral side. The lateral side is between the top side and the base and the top side has a width. The waveguide is configured to guide a light signal through the modulator such that the light signal is guided through the ridge of electro-absorption medium. A heater is positioned over the lateral side of the electro-absorption medium without being positioned over the entire width of the ridge.

Abstract: The optical device includes an optical modulator positioned on a base. The modulator includes a ridge extending upward from the base. The ridge includes an electro-absorption medium through which light signals are guided. A thermal conductor is positioned so as to conduct thermal energy away from the ridge. The distance between the thermal conductor and the ridge changes along a length of at least a portion of the ridge.