Spectrasensors, Inc.

Analytical Specialties, Inc.

Tunable Photonics Corporation

Spectrasensor, Inc,.

Randy Dean May

Alexander Ksendzov

Rex J Fleming

W Stephen Woodward

Ambient temperature for a temperature sensor can be calculated using a mobile temperature sensor system that samples air from the boundary layer around a mobile platform and passes the air through a measurement cell containing two flush-mounted or embedded sensor elements. A common reference voltage can be applied by control circuitry to minimize drift in the sensor element readings and to calculate the ambient temperature.

Mobile temperature sensor

A system and method are disclosed for the detection of water vapor in a natural gas background. The system includes a light source operating in a wavelength range such as, 1.877-1.901 &#x3bc;m, 2.711-2.786 &#x3bc;m, or 920-960 nm, passes through the natural gas to be detected by a detector. In one embodiment, the light source is a tunable diode laser and the moisture level is determined by harmonic spectroscopy. In other embodiments, a VCSEL laser is utilized.

System and method for detecting water vapor within natural gas

The method and system operate to maintain a widely tunable laser (WTL) at a selected transmission wavelength. To lock the WTL to an ITU grid line, a portion of the output beam from the WTL is routed through the etalon to split the beam into a transmission line for detection by an etalon fringe detector. Another portion of the beam is routed directly to a laser wavelength detector to determine the power of the beam. A wavelength-locking controller compares signals from the two detectors and adjusts the temperature of the etalon to align the wavelength of one of the transmission lines of the etalon with the wavelength of the output beam, then controls the WTL in a feedback loop to lock the laser to the etalon line. The wavelength-locking controller thereafter monitors the temperature of the etalon and keeps the temperature constant to prevent any wavelength drift attributable to the etalon.

Laser wavelength locker

The amount of water vapor in natural gas at different levels, including at levels below 10 ppmv, is measured by directing a light from a quantum cascade laser at a frequency in the 5.01 to 5.03 micron or the 5.07 to 50.9 micron wavelength range through natural gas containing water vapor. A detector is configured to detect the intensity of light transmitted through the natural gas from the laser; and an analyzer is coupled to the detector for determining the level of water vapor in the natural gas.

System and method for measuring water vapor in natural gas

A system and method can detect ethylene oxide in a sample of gas, such as air. The system includes a light source operating at a wavelength where molecules typically found within air absorb light at a substantially lower level than ethylene oxide molecules. Exemplary wavelengths are in the range of approximately 1.6&#x2013;2.2 &#x3bc;m, and in particular at 1.6 &#x3bc;m, 1.645 &#x3bc;m, 1.692 &#x3bc;m, 2.195 &#x3bc;m, 2.2 &#x3bc;m, 2.216 &#x3bc;m, passes through the sample of gas to be detected by a detector. In one variation, the light source is a tunable diode laser or a VCSEL and the ethylene oxide level is determined using harmonic spectroscopy.

Technique for detecting ethylene oxide in air

A system and method are disclosed for the detection of water vapor in a natural gas background. The system includes a light source operating in a wavelength range such as, 1.877&#x2013;1.901 &#x3bc;m, 2.711&#x2013;2.786 &#x3bc;m, or 920&#x2013;960 nm, passes through the natural gas to be detected by a detector. In one embodiment, the light source is a tunable diode laser and the moisture level is determined by harmonic spectroscopy. In other embodiments, a VCSEL laser is utilized.

The method and system operate to calibrate a transmission laser of the dense wavelength division multiplexer (DWDM) and to lock the laser to a selected transmission wavelength. In one example, the transmission laser is a widely tunable laser (WTL) to be tuned to one of a set of International Telecommunications Union (ITU) transmission grid lines for transmission through an optic fiber. To lock the WTL to an ITU grid line, a portion of the output beam from the WTL is routed through the etalon to split the beam into a set of transmission lines for detection by a detector. Another portion of the beam is routed directly to another detector. A wavelength-locking controller compares signals from the two detectors and adjusts the temperature of the etalon to align the wavelength of one of the transmission lines of the etalon with the wavelength of the output beam, then controls the WTL in a feedback loop to lock the laser to the etalon line. The wavelength-locking controller thereafter monitors the temperature of the etalon and keeps the temperature constant to prevent any wavelength drift in the etalon. In one example, the etalon is a silicon etalon configured to have finesse of about 20 and to provide a free spectral range of about 8 GHz. With these parameters, the system is able to lock the wavelength of the WTL to within a precision of about 0.2 GHz.

Method and system for locking transmission wavelengths for lasers in a dense wavelength division multiplexer

The method and system operate to calibrate a transmission laser of the dense wavelength division multiplexer (DWDM) and to lock the laser to a selected transmission wavelength. In one example, the transmission laser is a widely tunable laser (WTL) to be tuned to one of a set of International Telecommunications Union (ITU) transmission grid lines for transmission through an optic fiber. To lock the WTL to an ITU grid line, a portion of the output beam from the WTL is routed through the etalon to split the beam into a set of transmission lines for detection by an etalon fringe detector. Another portion of the beam is routed directly to a laser wavelength detector. A wavelength-locking controller compares signals from the two detectors and adjusts the temperature of the etalon to align the wavelength of one of the transmission lines of the etalon with the wavelength of the output beam, then controls the WTL in a feedback loop to lock the laser to the etalon line. The wavelength-locking controller thereafter monitors the temperature of the etalon and keeps the temperature constant to prevent any wavelength drift in the etalon. In one example, the optical components are aligned so that laser wavelength detector receives a portion of the laser beam directly from the laser so that phase characteristics of the laser beam are not affected by an intervening beamsplitter thereby permitting improved wavelength locking. In another embodiment, an etalon chirp filter is provided for reducing or eliminating optical frequency chirp, regardless of the particular ITU channel being used for transmission.

Technique for filtering chirp from optical signals

A semiconductor laser is provided having a cavity including a gain chip, a Mach-Zehnder wide tuning port, and a ring resonator mirror. Optical signals generated by the gain chip propagate through the Mach-Zehnder wide tuning port and into the ring resonator mirror where the optical signals are reflected back through the Mach-Zehnder wide tuning port to the gain chip. The ring resonator is configured to reflect only those optical signals back into the laser cavity having wavelengths within a set of sharp peaks and the laser cavity therefore can resonate only within one of the sharp peaks. The ring resonator mirror is heated to adjust its dimensions so as to maintain one of the sharp peaks at a selected emission wavelength. As optical signals reflected from the ring resonator pass through the Mach-Zehnder wide tuning port, the signals are split between two channels of differing lengths resulting in optical interference. The optical interference limits the ability of the laser cavity to resonate at wavelengths other than near the center of a single broad peak determined by the relative lengths of the two channels. The Mach-Zehnder wide tuning port is heated to vary the relative lengths of the two channels so as to maintain the single broad peak at the selected transmission wavelength. In this manner, the laser cavity is controlled to resonate substantially only at the selected wavelength. Resonance at the other sharp resonance peaks permitted by the ring resonator is significantly reduced, thereby significantly reducing transmission sidebands generated by the laser.

Tunable semiconductor laser having cavity with ring resonator mirror and mach-zehnder interferometer

Wavelength locker on optical bench and method of manufacture

A system and method are disclosed for the detection of water vapor in a natural gas background. The system includes a light source operating in the 1.877-1.901 &mgr;m wavelength range passes through the natural gas to be detected by a detector. In one embodiment, the light source is a tunable diode laser and the moisture level is determined by harmonic spectroscopy.

System and method for water vapor detection in natural gas

The semiconductor laser has a resonance cavity composed of a gain chip, a Mach-Zehnder wide tuning port, and a wavelength-selective mirror component formed either as a ring resonator or a reflective Fabry-Perot etalon. Optical signals generated by the gain chip propagate through the wide tuning port and into the wavelength-selective mirror component and are then reflected back to the gain chip. The wavelength-selective mirror component is configured to reflect only those optical signals having wavelengths within a set of sharp peaks so that the laser cavity resonates only within the sharp peaks. The wavelength-selective mirror component is heated to adjust internal dimensions to maintain one of the sharp peaks at a selected emission wavelength. As optical signals pass through the wide tuning port, the signals are split between two channels of differing lengths resulting in optical interference. The optical interference limits the ability of the laser cavity to resonate at wavelengths other than near the center of a single broad peak determined by the relative lengths of the two channels. The wide tuning port is heated to vary the relative lengths of the two channels to maintain the single broad peak at the selected transmission wavelength. In this manner, the laser cavity is controlled to resonate substantially only at the single selected wavelength. Resonance at any of the other wavelengths reflected by the wavelength-selective mirror component is greatly limited, thereby significantly reducing transmission sidebands generated by the laser. Specific implementations of the ring resonator mirror and the reflective etalon are described.

Tunable semiconductor laser having cavity with wavelength selective mirror and Mach-Zehnder interferometer

A total temperature probe with a complimentary sensor cavity for measuring multiple properties of a fluid flowing rapidly through the probe. The probe includes a sensor housing for diverting a portion of the rapidly flowing fluid into a primary flow path. A sample chamber within the probe houses a total temperature probe and is configured to divert a portion of the rapidly flowing fluid from a primary flowpath. An ancillary chamber adjacent to the sample chamber is configured to house an additional sensor and to divert a portion of the rapidly flowing fluid from the sample chamber. In some embodiments, the ancillary chamber diverts fluid directly from the rapidly flowing fluid. Preferably, the sensor housed within the ancillary chamber measures the water vapor level within the rapidly flowing fluid.

Growing community of inventors

Montrose, CA, United States of America

Randy Dean May