Structured beams, Bessel beams, Laguerre Gaussian beams, and focused Gaussian are used as a natural waveguide and its group velocity can be subluminal (slower than the speed of light) as compared to a Gaussian beam in free space. A free space dispersion relation for a Bessel beam, i.e., the dependence of its wavenumber on its angular frequency, is outlined from which the Bessel beam's subliminal group velocity is derived. For reasonable conditions a Bessel light beam has associated parameters that allow slowing near a critical frequency. The application of Bessel beams for a natural optical buffer in free space is presented. Optical transitions and selection rules in materials are altered by structured light carrying orbital angular momentum (OAM). Nano antennas are used to enhance the interactions of structured light.

A system and method generates a compensation circuit element for an optical circuit design by receiving an optical circuit design. The optical circuit design includes optical circuit elements and channels optically connecting the optical circuit elements. Further, a first compensation length for a first channel of the channels is determined based on a first measured length parameter of the first channel and a first design length parameter associated with the first channel. A compensation circuit element is determined based on the first compensation length. An updated optical circuit design is determined based on the compensation circuit element.

A process for delaying a useful optical signal (P1) having a wavelength value λ between 0.2 μm and 3 μm, with respect to a reference optical signal (P2) having the same wavelength value λ. The process includes having the useful optical signal propagate along a tapered fiber portion. A length of the tapered fiber portion can be varied using stretching means that are light, less cumbersome and less expensive compared to those necessary for a standard optical fiber. In addition, the delay value which is effective for the useful optical signal can be varied over a wide range. Such process can be useful for interferometry measurements in particular.

An optical delay device includes a multi-mode waveguide for propagating first light through at least a portion of the multi-mode waveguide. The multi-mode waveguide has a first width. The optical delay device also includes a first waveguide having a second width that is less than the first width and a first coupler connected to the multi-mode waveguide and the first waveguide for coupling the first light from the multi-mode waveguide to the first waveguide. The first waveguide includes a first portion connected to the first coupler for receiving the first light from the first coupler; and a second portion connected to the first portion for receiving the first light from the first portion and positioned adjacent to the multi-mode waveguide for coupling of the first light to the multi-mode waveguide as second light so that the second light propagates through at least the portion of the multi-mode waveguide.

A silicon on insulator (SOI) photonic device having a waveguide is provided that includes a mode overlap portion with a topology optimized structure situated below an electrode of the capacitance structure. The device can significantly change a refractive index in a volume of mode overlap depending upon the applied potential to the capacitor and allows for a π phase shift in a modest mode overlap volume. The topology optimized structure has a waveguide and substrate that are partitioned in three dimensions using an extruded projection design. The electrode is a transition metal di-chalcogenide monolayer sheet (2D TMD). The enhanced mode overlay from the topology optimized waveguide portion allows a large reduction in the length of the waveguide with the mode overlap to achieve the needed phase shift for a photonic device.

An optically controlled switch includes a substrate integrated waveguide (SIW) including: a first port and a second port, the first port and the second port being located at ends of the SIW to input and output an electromagnetic wave; and a shorting via electrically connected to a bottom layer of the SIW and separated from a top layer of the SIW by a dielectric gap. The optically controlled switch includes: a photoconductive element located on the top layer of the SIW and electrically connected to the shorting via and the top layer of the SIW, the photoconductive element being configured to have a dielectric state and a conductor state depending on a state of a controlling light flux; and a cutoff waveguide formed around the dielectric gap and the photoconductive element, and configured to provide control of the photoconductive element from a light source and block parasitic radiation.

A disclosed optical device includes a first waveguide disposed between a branching portion and a multiplexing portion on a semiconductor substrate, and a second waveguide disposed between the branching portion and the multiplexing portion, the second waveguide being longer than the first waveguide. In the optical device, an optical confinement effect of the first waveguide is greater than an optical confinement effect of the second waveguide, the first waveguide has a curvature with a first curvature radius (Rs), the second waveguide has a curvature with a second curvature radius (Rl), and the first curvature radius is smaller than the second curvature radius.

Disclosed herein are configurations for few-mode fiber optical endoscope systems employing distal optics and few-mode, double-clad or other optical fiber wherein the systems directing an optical beam to a sample via the optical fiber; collecting light backscattered from the sample; direct the backscattered light to a detector via the optical fiber; and detect the backscattered light; wherein the directed optical beam is single mode and the collected light is one or more higher order modes.

A self-equalizing photo-detector (SEPD) includes, in part, a multitude of optical splitters and photo detectors, and at least one optical delay element. The first optical splitter splits an optical signal into second and third optical signals. The optical delay element delays the second optical signal to generate a fourth optical signal. The second optical splitter splits a signal representative of the fourth optical signal to generate fifth and sixth optical signals. The first photo detector receives the third optical signal via a first optical path, has an anode terminal coupled to an output terminal of the detector and a cathode terminal coupled to a first supply voltage. The second photo detector receives the sixth optical signal via a second optical path, has an anode terminal coupled to a second supply voltage and a cathode terminal coupled to the output terminal of the detector.

An optical true time delay (TTD) control device for controllably alters the transit time of an optical beam traveling through the device by using the tip & tilt capability of MEMS MMAs to control the entrance and exit angles to a reflection cavity to coarsely control the path length and transit time and the piston capability to fine tune the path length and transit time. The reflection cavity can be configured in one, two or three dimensions with or without an optically transparent solid medium and using additional MEMS MMAs to provide controllable mirror surfaces within the cavity to enhance dynamic range and tenability. The input MEMS MMA may be “segmented” to re-direct a plurality of channel optical beams from the cavity at the same or different exit angles. The segments may be coated with different AR coatings to provide channel optical beams at different wavelengths.