Abstract: In one aspect, the present invention provides techniques and apparatus for optical characterization of photonic devices and/or circuits. By way of example, the techniques can be used to identify damaged devices in photonic integrated circuits. In some embodiments, thermal imaging is employed as a diagnostic tool for characterizing the devices/circuits under investigation. For example, in one embodiment, integrated cascaded semiconductor amplifiers can be characterized using amplified spontaneous emission from one amplifier as a thermal modulation input to another amplifier. A thermoreflectance image of the second amplifier can reveal flaws, if present. Further, in some embodiments, thermal imaging in conjunction with a total energy model can be employed to characterize the elements of photonic circuits optically and/or to map the optical power distribution throughout the circuits.

Abstract: An embodiment of a method of performing thermoreflectance measurements with an imaging system comprises: reflecting radiation from a number of points in a sample in response to an illuminating radiation while a temperature modulation is applied to the sample; acquiring digital images of the reflected radiation after the reflected radiation passes through an aperture; and deriving a map of relative reflectivity of the sample based on the digital images. At least a portion of the illuminating radiation passes through at least a portion of the sample and is reflected at a change refractive index interface.

Abstract: A non-destructive evaluation system for evaluating an article such as a test sample, the system comprising: a silicon-based CCD camera for obtaining a series of images of the article; first apparatus for receiving the series of images of the article from the silicon-based CCD camera and using a first imaging modality to generate a first data set spatially correlated to the article; second apparatus for receiving the series of images of the article from the silicon-based CCD camera and using a second imaging modality to generate a second data set spatially correlated to the article; and processing apparatus for processing at least one of the first and second data sets so as to evaluate at least one physical characteristic of the article.

Abstract: In one aspect, the present invention provides techniques and apparatus for optical characterization of photonic devices and/or circuits. By way of example, the techniques can be used to identify damaged devices in photonic integrated circuits. In some embodiments, thermal imaging is employed as a diagnostic tool for characterizing the devices/circuits under investigation. For example, in one embodiment, integrated cascaded semiconductor amplifiers can be characterized using amplified spontaneous emission from one amplifier as a thermal modulation input to another amplifier. A thermoreflectance image of the second amplifier can reveal flaws, if present. Further, in some embodiments, thermal imaging in conjunction with a total energy model can be employed to characterize the elements of photonic circuits optically and/or to map the optical power distribution throughout the circuits.

Abstract: An embodiment of a method of performing thermoreflectance measurements with an imaging system comprises: reflecting radiation from a number of points in a sample in response to an illuminating radiation while a temperature modulation is applied to the sample; acquiring digital images of the reflected radiation after the reflected radiation passes through an aperture; and deriving a map of relative reflectivity of the sample based on the digital images. At least a portion of the illuminating radiation passes through at least a portion of the sample and is reflected at a change refractive index interface.

Abstract: The invention is directed to systems and methods of digital signal processing and in particular to systems and methods for measurements of thermoreflectance signals, even when they are smaller than the code width of a digital detector used for detection. For example, in some embodiments, the number of measurements done is selected to be sufficiently large so as to obtain an uncertainty less than the code width of the detector. This allows for obtaining images having an enhanced temperature resolution. The invention is also directed to methods for predicting the uncertainty in measurement of the signal based on one or more noise variables associated with the detection process and the number of measurement iterations.

Abstract: The invention is directed to systems and methods of digital signal processing and in particular to systems and methods for measurements of thermoreflectance signals, even when they are smaller than the code width of a digital detector used for detection. For example, in some embodiments, the number of measurements done is selected to be sufficiently large so as to obtain an uncertainty less than the code width of the detector. This allows for obtaining images having an enhanced temperature resolution. The invention is also directed to methods for predicting the uncertainty in measurement of the signal based on one or more noise variables associated with the detection process and the number of measurement iterations.

Abstract: A laser comprises a first contact to receive an active region control signal, a second contact to receive an optical absorber control signal, and a sandwich of distributed Bragg reflector mirror stacks. Each distributed Bragg reflector mirror stack has an alternate doping with respect to an adjacent distributed Bragg reflector mirror stack. An active region is positioned in the sandwich to provide optical gain in response to the active region control signal. An optical absorber is positioned in the sandwich. The optical absorber has wavelength dependent absorption in response to the optical absorber control signal. The device of the invention may be utilized as an integrated detector, a self-pulsating laser, a high speed intracavity modulator, or an optical pick-up device.