Abstract: Various embodiments disclose an electronic circuit for an electrochemical gas sensor. The electronic circuit comprises a first switching element electrically coupled to a reference terminal of the electrochemical gas sensor and a ground voltage terminal. Further, the electronic circuit comprises a second switching element electrically coupled to a sensing terminal of the electrochemical gas sensor and the ground voltage terminal. In an instance in which the electrochemical gas sensor is powered OFF, the first switching element and the second switching element are configured to electrically couple the reference terminal and the sensing terminal to the ground voltage terminal such that current generated when the sensing electrode and the target gas react while the electrochemical gas sensor is powered OFF flows to the ground voltage terminal and the potential of the reference terminal and the sensing terminal remain the equal.

Abstract: A modulator and a capacitor are integrated on a semiconductor substrate for modulating a laser beam. Integrating the capacitor on the substrate reduces parasitic inductance for high-speed optical communication.

Abstract: The present disclosure belongs to the field of petroleum exploration and development and, in particular, relates to a system and a method for analyzing while-drilling rock fragments in oil and gas field. The system includes a sample preparation mold and a sample scanning apparatus; the mold is configured to quickly batch prepare fragments into scanning ready samples; the apparatus is portable and configured for batch scanning and analyzing the samples, and having the capabilities of anti-vibration, temperature control, dust prevention, and adaptability to a harsh well site environment; the method includes a scanning step where surface images, elements and mineral types of rock can be rapidly quantitatively analyzed, and lithologies thereof can be identified; the method also includes the analysis step in which rock's elastic parameters and target zone of the vertical well are determined, and geosteering and design of staged fracturing of horizontal well can be provided.

Abstract: A waveguide mode expander couples a smaller optical mode in a semiconductor waveguide to a larger optical mode in an optical fiber. The waveguide mode expander comprises a shoulder and a ridge. In some embodiments, the ridge of the waveguide mode expander has a plurality of stages, the plurality of stages having different widths at a given cross section.

Abstract: The present invention includes an optical waveguide with a grating and a method of making the same for increasing the effectiveness of the grating. In one example, the grating is at least partially covered by a liner layer disposed on at least a portion of a grating; and a cover layer disposed on the liner layer, wherein a first material selected for the core and ridges and a second material selected for the liner layer are selected to provide a difference in the index of refraction between the first and second material that is sufficient to provide a contrast therebetween.

Abstract: The present invention includes an optical waveguide with a grating and a method of making the same for increasing the effectiveness of the grating. In one example, the grating is at least partially covered by a liner layer disposed on at least a portion of a grating; and a cover layer disposed on the liner layer, wherein a first material selected for the core and ridges and a second material selected for the liner layer are selected to provide a difference in the index of refraction between the first and second material that is sufficient to provide a contrast therebetween.

Abstract: Systems, methods, and software can be used to provide reminding information. In some aspect, a special event is determined to occur. In response to determining that the special event occurs, a network type currently used by a device is acquired. Historical network usage information corresponding to the network type is determined. The network type and a traffic usage situation is outputted based on the historical usage information.

Abstract: A tunable laser has a first mirror, a second mirror, a gain medium, and a directional coupler. The first mirror and the second mirror form an optical resonator. The gain medium and the directional coupler are, at least partially, in an optical path of the optical resonator. The first mirror and the second mirror comprise binary super gratings. Both the first mirror and the second mirror have high reflectivity. The directional coupler provides an output coupler for the tunable laser.

Abstract: A method, apparatus, and terminal for obtaining a route are provided, including techniques and related apparatus for: obtaining, by a terminal, a first moment at which a signal in the terminal disappears and first location information of the terminal at the first moment, and performing dead reckoning starting from the first moment; obtaining, by the terminal, a second moment at which a user sends a distress signal and second location information of the terminal at the second moment, and ending the dead reckoning, to obtain a first dead reckoning curve; and determining, by the terminal, a track of a traveled route based on the first moment, the second moment, the second location information, the first dead reckoning curve, and each moment between the first moment and the second moment.

Abstract: A 400 Gb/s transmitter is integrated on a silicon substrate. The transmitter uses four gain chips, sixteen lasers, four modulators to modulate the sixteen lasers at 25 Gb/s, and four multiplexers to produce four optical outputs. Each optical output can transmit at 100 Gb/s to produce a 400 Gb/s transmitter. Other variations are also described.

Abstract: An optical receiver, used in wavelength-division multiplexing, has multiple photodetectors per channel. The optical receiver comprises a demultiplexer to separate incoming light into different output waveguides, one output waveguide for each channel. A splitter is used in each output waveguide to split each output waveguide into two or more branches. A separate photodetector is coupled with each branch so that two or more photodetectors are used to measure each channel.

Abstract: The present invention includes an optical waveguide with a grating and a method of making the same for increasing the effectiveness of the grating. In one example, the grating is at least partially covered by a liner layer disposed on at least a portion of a grating; and a cover layer disposed on the liner layer, wherein a first material selected for the core and ridges and a second material selected for the liner layer are selected to provide a difference in the index of refraction between the first and second material that is sufficient to provide a contrast therebetween.

Abstract: The present invention includes an optical waveguide with a grating and a method of making the same for increasing the effectiveness of the grating. In one example, the grating is at least partially covered by a liner layer disposed on at least a portion of a grating; and a cover layer disposed on the liner layer, wherein a first material selected for the core and ridges and a second material selected for the liner layer are selected to provide a difference in the index of refraction between the first and second material that is sufficient to provide a contrast therebetween.

Abstract: The present disclosure relates to a genetically engineered strain with high production of uridine and its construction method and application. The strain was constructed as follows: heterologously expressing pyrimidine nucleoside operon sequence pyrBCAKDFE (SEQ ID NO:1) on the genome of E coli prompted by strong promoter Ptrc to reconstruct the pathway of uridine synthesis; overexpressing the autologous prsA gene coding PRPP synthase by integration of another copy of prsA gene promoted by strong promoter Ptrc on the genome; deficiency of uridine kinase, uridine phosphorylase, ribonucleoside hydrolase, homoserine dehydrogenase I and ornithine carbamoyltransferase. When the bacteria was used for producing uridine, 40-67 g/L uridine could be obtained in a 5 L fermentator after fermentation for 40-70 h using the technical scheme provided by the discloure with the maximum productivity of 0.15-0.25 g uridine/g glucose and 1.

Abstract: The present invention includes an optical waveguide with a grating and a method of making the same for increasing the effectiveness of the grating. In one example, the grating is at least partially covered by a liner layer disposed on at least a portion of a grating; and a cover layer disposed on the liner layer, wherein a first material selected for the core and ridges and a second material selected for the liner layer are selected to provide a difference in the index of refraction between the first and second material that is sufficient to provide a contrast therebetween.

Abstract: A positioning method and a mobile device, where the method is applied to the mobile device and includes periodically detecting a status of the mobile device, where the status of the mobile device includes a driving state and a walking state, positioning the mobile device using a first positioning algorithm when detecting that a quantity of times that the driving state consecutively occurs reaches M, where the M is an integer greater than one, and positioning the mobile device using a second positioning algorithm when detecting that a quantity of times that the walking state consecutively occurs reaches N, where the N is an integer greater than one. Hence, the status of the mobile device can be more accurately determined by implementing this technical solution to position the mobile device using a positioning algorithm matching an actual status of the mobile device, thereby improving accuracy of a positioning result.

Abstract: A waveguide mode expander couples a smaller optical mode in a semiconductor waveguide to a larger optical mode in an optical fiber. The waveguide mode expander comprises a shoulder and a ridge. In some embodiments, the ridge of the waveguide mode expander has a plurality of stages, the plurality of stages having different widths at a given cross section.

Abstract: A tunable laser has a first mirror, a second mirror, a gain medium, and a directional coupler. The first mirror and the second mirror form an optical resonator. The gain medium and the directional coupler are, at least partially, in an optical path of the optical resonator. The first mirror and the second mirror comprise binary super gratings. Both the first mirror and the second mirror have high reflectivity. The directional coupler provides an output coupler for the tunable laser.

Abstract: An optical filter for attenuating higher-order modes in an optical waveguide includes a shoulder slab formed of a first material having a first index of refraction and disposed on a second material having a second index of refraction, the first index of refraction being higher than the second index of refraction. The shoulder slab defines a near end having a first width, an intermediate section, adjacent to the first end section, and a far end section, adjacent to the intermediate section and opposite the first end section along a direction of beam propagation. The optical filter also includes a waveguide ridge, formed of the first material and disposed atop the shoulder slab, that traverses the shoulder slab, and is configured to guide light of a fundamental mode along the direction of beam propagation from the near end section to the far end section.

Abstract: An optical filter for attenuating higher-order modes in an optical waveguide includes a shoulder slab formed of a first material having a first index of refraction and disposed on a second material having a second index of refraction, the first index of refraction being higher than the second index of refraction. The shoulder slab defines a near end having a first width, an intermediate section, adjacent to the first end section, and a far end section, adjacent to the intermediate section and opposite the first end section along a direction of beam propagation. The optical filter also includes a waveguide ridge, formed of the first material and disposed atop the shoulder slab, that traverses the shoulder slab, and is configured to guide light of a fundamental mode along the direction of beam propagation from the near end section to the far end section.