Abstract: Low data rate, low power, bi-directional transmissions may be provided over existing physical communication media (e.g., coaxial cables) using a portable network communications module and in the presence of higher bandwidth, higher power primary signals currently being transmitted over the communication media. The low data rate, low power, bi-directional transmissions may be accomplished using spread-spectrum modulated signals that are positioned in frequency relative to the primary signals, such that the low data rate, low power transmissions occur without detectable interference with the primary signals, which include multiplexed narrowband modulated signals. The primary signals may be modulated using quadrature amplitude modulation (QAM) and multiplexed using orthogonal frequency division multiplexing (OFDM) and the spread-spectrum modulated signals may be chirp spread spectrum (CSS) modulated signals modulated using Gaussian frequency shift keying (GFSK).

Abstract: A modular laser assembly has a laser-fiber housing comprising a semiconductor laser optically coupled to an end of an optical fiber, the laser-fiber housing having electrical leads electrically coupled to the laser and extending from a front face of the laser-fiber housing; a mounting platform comprising laser interfacing circuitry and contacts electrically coupled thereto, an opening for receiving the laser-fiber housing wherein when said laser-fiber housing is mounted to the mounting platform the electrical leads are proximate and may be electrically coupled to the contacts, and a plurality of pins electrically coupled to said interfacing circuitry and extending laterally from opposing sides of the mounting platform; and a temperature controlling element for mounting to and controlling the temperature of the laser-fiber housing.

Abstract: A fiber-photodetector coupling apparatus and method for coupling a fiber to a photodetector. A photodetector is mounted on one surface of the platform, with its active region facing an opening in the platform. A fiber inserted into the opening from the opposite surface of the platform is secured in said opening so that its output optical signal is directed onto the active region of the photodetector.