Abstract: A multi-function sight port door includes a sensor mount attached at an aperture within the sight port door. A sensor is mounted to the sensor mount and configured to monitor the interior of a heater that the multi-function sight port door is mounted to. The multi-function sight port door is also configured to open to allow visual inspection of the interior of the heater while the sensor is mounted thereto. The multi-function sight port may be configured to allow for one or more of X-axis, Y-axis, Z-axis, tilt, roll, and yaw positioning of the sensor as mounted to the sight port door. The sensor may be a temperature sensor, pressure sensor, flame scanner, gas analyzer, optical-based sensor, thermal imager, thermal camera, or laser-based analyzer.

Abstract: Systems for measuring a concentration of a target species include a first and second tunable diode laser generating laser light at a respective first and second wavelength each corresponding to respective absorption lines of the target species. A first optical fiber is optically coupled to the first tunable diode laser, and does not support a fundamental mode at the second wavelength. A second optical fiber is coupled to the second tunable diode laser and does not support a fundamental mode at the first wavelength. A fiber bundle includes respective distal ends of the first and second optical fibers, which are stripped of their respective coatings and arranged with their claddings adjacent to each other. A pitch head is configured to project respective optical beams from the fiber bundle through a measurement zone. A catch head located across the measurement zone receives the projected beams and directs them to a sensor.