Abstract: The specification describes thermo-optically controlled waveguides where the thermo-optic control is a heater strip precisely aligned to the waveguide core by using the heater strip as an etch mask to define at least part of the core/upper cladding structure. In one embodiment the heater strip mask is larger than the underlying waveguide core so as to produce, on etching, a core surrounded with a minimum of cladding material on the sidewalls of the core, and a confined heat channel between the waveguide core and the heater strip. In a second embodiment the heater strip is used as an etch mask to define a core cladding stack, and a third cladding layer is deposited to clad the sidewalls of the core. In this embodiment, the cladding material in the stack can be optimized for thermal conductivity, and the third cladding material can be optimized for thermo-optic sensitivity.

Abstract: A hybrid integrated optical transmitter comprising a wavelength selectable laser (WSL) source coupled to an optical amplifier/modulator has been realized. Disposed between the optical combiner and the optical amplifier/modulator is an “optical isolator.” The optical isolator includes at least a Faraday rotator and, either solely or in combination with a single polarizer and/or half-wave plate is used to selectively rotate and pass polarized light egressing from the wavelength selectable laser source. Optical isolation is achieved by the egressing radiation from and back reflections incident on the laser source being at two mutually exclusive orthogonal polarization states or by the reflections being totally extinguished. Advantageously, the laser source is unresponsive to orthogonally polarized light, and hence any unwanted back reflections do not substantially affect the operating characteristics of the laser(s).

Abstract: An apparatus for stabilizing the wavelength of light emitted by a laser or light source comprising a divider for dividing a sample of emitted light into a first and second portion; a first photodetector configured to measure an intensity of the first portion and a second photodetector configured to measure an intensity of the second portion, the second photodetector configured to receive the emitted light via an optical frequency discriminator, such as a dielectric coating, wherein the optical frequency discriminator is configured to modify the intensity of the emitted light at the second photodetector as a function of an optical frequency of the emitted light; and a processor configured to maintain a desired level corresponding to a ratio of the intensity measured by the first photodetector and the intensity measured by the second photodetector, so as to provide a feedback control signal to adjust the wavelength of the emitted light.

Abstract: The present invention includes a MZI comprising a pair of folded waveguides disposed between a pair of couplers. Each folded waveguide comprises a pair of segments intersecting at a reflector. The respective reflectors are different distances from the couplers to provide a major portion of the differential path length between the two arms. In a preferred embodiment, the reflectors are polysilicon mirrors and can be formed by etching through the intersecting waveguides and depositing polysilicon. The result is a compact MZI that can be used as a multiwavelength reference for a laser light source on a common silicon optical bench chip.

Abstract: An improved optical assembly includes a platform which mounts a plurality of optical components operating at multiple wavelengths of light. At least one of the optical components is coated with a filter layer which absorbs stray light generated by the other optical components. The filter layer substantially reduces crosstalk in the optical assembly.

Abstract: The invention is a photodetector device and a lightguide circuit incorporating the device. The photodetector device includes a semiconductor region for absorbing light which is incident on an edge surface of the device. The region above the absorbing region is narrow at the edge and fans out in the direction of light propagation in the device.