30results about How to "Linewidth also decrease" patented technology

A partially coherent Optical Time Domain Reflectometry (OTDR) apparatus has a light source comprising a directly modulated semiconductor Distributed FeedBack (DFB) laser diode for transmitting partially coherent light pulses along a monomode optical fibre. Light Rayleigh backscattered from the light pulses as they travel along the optical fibre is output from the end of the fibre into which the light pulses are transmitted to a Fibre Bragg Grating (FBG) filter. The FBG filter reduces the supectral width of light received at a photodetector. In one embodiment, the supectral width of the FBG filter is around one fifth of the supectral width of the light pulse after it has travelled around 1 km along the optical fibre. As a consequence of reducing the supectral width of the light received at the photodetector, the FBG filter increases the temporal coherence of the light. So, the FBG filter can ensure that the detected light is sufficiently coherent that a temporal supeckle pattern can be detected at the photodetector. At the same time, the light traveling in the optical fibre can be relatively supectrally broad so that non-linear effects in the optical fibre, such as Brillouin scattering, can be reduced.

A new lithographic process comprises reducing the linewidth of an image while maintaining the lithographic process window, and using this process to fabricate pitch split structures comprising nm order (e.g., about 22 nm) node semiconductor devices. The process comprises applying a lithographic resist layer on a surface of a substrate and patterning and developing the lithographic resist layer to form a nm order node image having an initial line width. Overcoating the nm order node image with an acidic polymer produces an acidic polymer coated image. Heating the acidic polymer coated image gives a heat treated coating on the image, the heating being conducted at a temperature and for a time sufficient to reduce the initial linewidth to a subsequent narrowed linewidth. Developing the heated treated coating removes it from the image resulting in a free-standing trimmed lithographic feature on the substrate. Optionally repeating the foregoing steps further reduces the linewidth of the narrowed line. The invention also comprises a product produced by this process.

An electron beam (EB) lithography method using a new material is provided. The method includes forming a thin layer using a Pb-based material; and patterning the thin layer by partially volatilizing the thin layer by irradiating electron beams. In this method, the thin layer formed of the Pb-based material is patterned using e-beams so that the linewidth of patterns formed on the thin layer can be greatly reduced.

An FM LIDAR system is described that includes a frequency modulated LIDAR system that incorporates a laser source that is optically coupled to a whispering gallery mode optical resonator. Light from the laser that is coupled into the whispering gallery mode optical resonator is coupled back out as a returning counterpropagating wave having a frequency characteristic of a whispering gallery mode of the optical resonator. This returning wave is used to reduce the linewidth of the source laser by optical injection. Modulation of the optical properties of the whispering gallery mode optical resonator results in modulation of the frequency of the frequencies supported by whispering gallery modes of the resonator, and provides a method for producing highly linear and reproducible optical chirps that are highly suited for use in a LIDAR system. Methods of using such an FM LIDAR system and vehicle assisting systems that incorporate such FM LIDAR systems are also described.

An etching process is described. A material layer having a bottom anti-reflection coating (BARC) and a patterned photoresist layer thereon is provided. An etching step is performed to the BARC using the patterned photoresist layer as a mask. A cleaning step is performed to remove the polymer formed on the surface of the patterned photoresist layer. Thereafter, another etching step is performed to the material layer using the patterned photoresist layer as a mask.

Provided is a surface plasmon resonance sensor including: a part of delivering light by which a signal beam is incident to generate an evanescent field; and a part of exciting surface plasmon for exciting surface plasmons by the generated evanescent field and giving rise to a surface plasmon resonance, wherein a dielectric waveguide layer is inserted between metal layers of the part of exciting surface plasmon, and surface plasmon resonance properties are changed by an object to be analyzed.

Stimulated Brillouin scattering (SBS) limits the maximum power in fiber lasers with narrow linewidths. SBS occurs when the power exceeds a threshold proportional to the beam area divided by the effective fiber length. The fiber lasers disclosed here operate with higher SBS power thresholds (and hence higher maximum powers at kilohertz-class linewidths) than other fiber lasers thanks to several techniques. These techniques include using high-absorption gain fibers, operating the laser with low pump absorption (e.g., ≤80%), reducing the length of un-pumped gain fiber at the fiber output, foregoing a delivery fiber at the output, foregoing a cladding light stripper at the output, using free-space dichroic mirrors to separate signal light from unabsorbed pump light, and using cascaded gain fibers with non-overlapping Stokes shifts. The upstream gain fiber has high absorption and a larger diameter for high gain, and subsequent gain fiber has a smaller diameter to improve beam quality.

A low noise, single mode laser includes a semiconductor gain element generating light and having a highly reflective first end forming a first end of a laser cavity. The gain element may be monolithically or discretely integrated with, or distinct from, and coupled to a waveguide comprised of a low loss material with a refractive index ‘n’ greater than 3. The waveguide includes a Bragg grating forming the second end of the laser cavity. A cavity phase control section may be provided between the gain element and the Bragg grating. Two photodetector monitors provide a feedback signal for locking the light from the gain element to a specific wavelength on the Bragg grating reflection spectrum by varying at least one of the cavity phase control section and the gain element bias current. The Bragg grating may have a physical length larger than 10 mm and that occupies at least 50% of the optical length of the external cavity.

A Vertical External Cavity Surface Emitting Laser (VECSEL) system is provided. The VECSEL system includes a laser device including an active layer in which laser light is generated by pumping and a reflector reflecting the laser light generated in the active layer; an optical element that forms a cavity together with the reflector of the laser device and reduces a line width of laser light; and a SHG (Second Harmonic Generation) device that is disposed between the laser device and the optical element and doubles the frequency of laser light.

An apparatus for an atomic clock includes first and second distinctive substrates, each having at least a planar surface substantially parallel therebetween. The apparatus also includes a medium having particles capable of undergoing energetic transition between at least two energy levels, said medium being located in the space defined between the planar surfaces. It further includes a magnetic device arranged to the first substrate and generating at least in the volume of the medium a predetermined static magnetic field B the direction of which is substantially parallel or perpendicular to the planar surfaces and an excitation device arranged to the second substrate and generating an excitation magnetic field H at, at least an excitation frequency, the direction of said excitation magnetic field H in the volume of the medium being substantially orthogonal to said direction of the static magnetic field B.

The present disclosure provides methods and apparatus to improve the dynamic coherent length of a sweep velocity-locked laser pulse generator (SV-LLPG) in an all-electronic fashion. A digital SV-LLPG is disclosed with two operation modes, i.e., unidirectional and bidirectional sweep modes; self-adaptive and time-dependent loop parameters (gain and location of poles / zeros); and, self-adaptive initial input curve. High frequency locking architectures, both single-side band (SSB) modulation method and direct phase measurement method, are provided to suppress the linewidth, or improve the coherent length, of the swept laser. A combination of high and low frequency locking, or a combination of multiple architectures disclosed in this invention, is utilized to achieve a higher level of linewidth reduction. The enhanced laser coherence extends the measurement range by at least one order of magnitude for applications including frequency-modulated continuous wave (FMCW) light detection and ranging (LiDAR) and optical fiber distributed sensing applications.