A method for evaluating the optical insertion loss of a mechanical splice joint of two optical fibers with a laser source includes, upon initiation by a user, automatically performing the steps of: checking for ambient light, estimating the level of noise by analyzing an area of a sensor that is not illuminated by external sources and setting a noise threshold, checking self-alignment by taking a foreground image of the joint with the laser source turned on and one with it turned off, subtracting the images to obtain a resultant image, setting all pixels with levels below the noise threshold to zero, selecting a region of interest of the joint, computing a centroid and a width of the resultant image based on the region of interest, estimating a tilt and if the tilt is above a certain threshold, compensating for the tilt, and processing the resultant image.

Examples disclosed herein illustrate systems and methods to determine and evaluate the quality of mechanical splices of optical fibers using insertion loss estimation. In at least some of the disclosed systems and methods, an optical fiber termination system may include a reference fiber coupling a light source and a stub fiber of a fiber optic connector, a digital camera sensor and lens to capture images of scattered light emanating from a portion of the fiber optic connector and a portion of the reference fiber both in a field of view (FOV) of the digital camera sensor, and a processor. The processor may analyze digital images of scatter light emitted from at least a portion of the fiber optic connector and the reference fiber to estimate insertion loss at the fiber optic connector.

A system and method for measuring refractive index inhomogeneity between plates of a Lightguide Optical Element (LOE) uses an innovative measuring technique based on a shearing interferometric technique conventionally used to observe interference and test the collimation of light beams. Another feature of the current implementation is an innovative method for analyzing the characteristics of the generated interferogram to characterize discrepancies between adjacent plates in an LOE.

A mode control system and method for controlling an output mode of a broadband radiation source including a photonic crystal fiber (PCF). The mode control system includes at least one detection unit configured to measure one or more parameters of radiation emitted from the broadband radiation source to generate measurement data, and a processing unit configured to evaluate mode purity of the radiation emitted from the broadband radiation source, from the measurement data. Based on the evaluation, the mode control system is configured to generate a control signal for optimization of one or more pump coupling conditions of the broadband radiation source. The one or more pump coupling conditions relate to the coupling of a pump laser beam with respect to a fiber core of the photonic crystal fiber.

A surface grating coupler for polarization splitting or diverse includes a planar layer and an array of scattering elements arranged in the planar layer at intersections of a first set of concentric elliptical curves crossing with a second set of concentric elliptical curves rotated proximately 90 or 180 degrees to form a two-dimensional (2D) grating. Additionally, the grating coupler includes a first waveguide in double-taper shape and a second waveguide in double-taper shape respectively for split or diverse an incident light into the 2D grating into two output light to two output ports with a same (either TE or TM) polarization mode or one output port with TE polarization mode and another output port with TM polarization mode. The polarization diverse grating coupler is required to test multiple polarization sensitive photonics components and can be used with other single polarization grating coupler via a fiber array to perform wafer-level testing.

An intact semiconductor wafer (wafer) includes a plurality of die. Each die has a top layer including routings of conductive interconnect structures electrically isolated from each other by intervening dielectric material. A top surface of the top layer corresponds to a top surface of the wafer. Below the top layer, each die has a device layer including optical devices and electronic devices. Each die has a cladding layer below the device layer and on a substrate of the wafer. Each die includes a photonic test port within the device layer. For each die, a light transfer region is formed within the intact wafer to extend through the top layer to the photonic test port within the device layer. The light transfer region provides a window for transmission of light into and out of the photonic test port from and to a location on the top surface of the wafer.

Aspects relate to an integrated optical probe card and a system for performing wafer testing of optical micro-electro-mechanical systems (MEMS) structures with an in-plane optical axis. On-wafer optical screening of optical MEMS structures may be performed utilizing one or more micro-optical bench components to redirect light between an out-of-plane direction that is perpendicular to the in-plane optical axis to an in-plane direction that is parallel to the in-plane optical axis to enable testing of the optical MEMS structures with vertical injection of the light.

At various positions in an eye motion box (EMB) an output image from an optical device can be captured and analyzed for detection and evaluation of image propagation via the optical device. Optical testing along a specific axis can evaluate optical engine transfer function uniformity across facet's active area, detect the existence and degree of smearing of a projected image from an optical device, and detect the existence and degree of a white stripes (WS) phenomenon related to scattering and diffraction in the wedge-to-LOE interface. A variety of metrics can be derived for quality control and feedback into the production system, and for disposition of the optical devices.

There are provided methods of inspecting an optical waveguide including inspecting the degree of curvature of a light reflecting surface formed in a core of the optical waveguide, and of manufacturing an optical waveguide using the same. In the method of inspecting an optical waveguide, light enters the core of the optical waveguide via a connection surface in a second end portion of the core, to reflect from light reflecting surfaces in a first end portion of the core and to exit the optical waveguide, and the exiting light is imaged by a camera. Then, the brightness of the exiting light is measured by determining the brightness of the obtained image. The degree of curvature of the light reflecting surfaces decreases as the measurement value of brightness increases. Thus, an optical waveguide having a brightness greater than a reference value has light reflecting surfaces which are nearly flat.

A system for measuring an absorption coefficient of a doped optical fiber may include: a laser source configured to transmit laser light at a selectable wavelength; a single-mode optical fiber including an end configured to splice to the doped optical fiber; two or more multimode fibers at a side of the doped optical fiber, spaced apart along the side of the doped optical fiber, configured to collect spontaneous emissions from the side of the doped optical fiber; and/or a photodiode or power meter connected to the two or more multimode fibers. A method for measuring an absorption coefficient of a doped optical fiber may include: collecting, from a side of the doped optical fiber, an emission spectrum using two or more multimode fibers; and/or calculating the absorption coefficient form using the emission spectrum and McCumber theory.