Abstract: An electronic module for use as a subsea electronic module (SEM) for an underwater fluid extraction well, as provided. An example of such an SEM includes a plurality of substantially planar electronics cards to operate devices in the SEM. The cards are arranged in a stack such that major faces of each card are oriented substantially parallel to, and coaxial with, major faces of the other cards in the stack. The SEM also includes a substantially planar switch card orientated relative to the stack such that its major faces are oriented substantially parallel to a main axis of the stack and orthogonal to the orientation of the major faces of the electronics cards within the stack. The switch card includes a first Ethernet switch blade configured to control traffic on a LAN area network and a second Ethernet switch blade configured to control traffic on a second LAN.

Abstract: A high-resolution fiber laser sensor for measuring a quantity to be measured M has a pumping light source, a fiber laser and a detection/evaluating unit. The fiber laser has: a birefringent first end reflector, a second end reflector, a laser-amplifying fiber, a sensor fiber and a mode coupling. The laser-amplifying fiber, the sensor fiber and the mode coupling are arranged between the end reflectors. In the fiber laser, light is capable of propagating in two optical states which are orthogonal to one another due to their polarization and/or their transversal space structure. The orthogonal optical states can be coupled to one another by the mode coupling. In the fiber laser, a number of longitudinal modes are capable of oscillating in each of the two optical states. In the sensor fiber a change in the birefringence for the two orthogonal optical states can be achieved by interaction of the quantity to be measured with the sensor fiber.

Abstract: A high-resolution fiber laser sensor for measuring a quantity to be measured M has a pumping light source (2), a fiber laser (1) and a detection/evaluating unit (3). The fiber laser (1) has: a birefringent first end reflector (11), a second end reflector (12), a laser-amplifying fiber (13), a sensor fiber (14) and a means for mode coupling (15). The laser-amplifying fiber (13), the sensor fiber (14) and the means for mode coupling (15) are arranged between the end reflectors (11, 12). In the fiber laser (1), light is capable of propagating in two optical states (x, y; LP?01, LP?11) which are orthogonal to one another due to their polarization and/or their transversal space structure. The orthogonal optical states (x, y; LP?01, LP?11) can be coupled to one another by the means for mode coupling (15). In the fiber laser (1), a number of longitudinal modes (LMxp, LMxp+1 . . . , LMyq, LMyq+1 . . . ; LM01p, LM01p+1 . . . , LM11q, LM11q+1 . . .