Abstract: Methods of, and systems for, detecting an airborne material. In a first preferred embodiment, a method is provided that includes deploying a cloud of optical sensors, illuminating at least a portion of the cloud with a flare, and detecting the cloud using the illumination provided by the flare. Preferably, the illumination is in the infrared, near infrared, or visible spectral range. Also, the sensors can be porous silicon sensors for measuring the concentration of either a chemical or biological agent. Moreover, the method may include deploying the flare while remaining concealed. Preferably, the spectrum of the flare is compared with the spectrum from the cloud of sensors.

Abstract: A fiber optic transceiver module, having built-in test capability and a low physical profile that meets mil spec requirements, comprises a housing. The housing comprises an optical fiber having an angled end that defines an acute angle relative to the longitudinal axis of the optical fiber, an optical source for emitting an optical signal which is reflected by the angled end of the optical fiber and propagated along the optical fiber, and an optical detector for receiving a return optical signal transmitted through the angled end of the optical fiber in response to reflection from a discontinuity in the optical fiber. The acute angle may be 48 degrees, causing a desired portion of the signal emitted from the optical source to be propagated along the optical fiber and to cause a desired portion of the return optical signal to be transmitted through the angled end to a photodetector.

Abstract: Opto-electronic array modules using a Vertical Cavity Surface Emitting Laser (VCSEL) and photodiode arrays have polished fiber end face angles varying from a 45 degree angle to attenuate the amount of light entering the fiber in order to eliminate saturation of the opto-electronic receiver in a fiber optic transceiver system. Varying angles may be used when coupling light between the fiber and an active device to adjust the attenuation.