Abstract: A semiconductor laser amplifier includes both a waveguide layer and an active layer. In use, an optical wave in the active layer interacts with the waveguiding layer to reduce the polarisation sensitivity of the amplifier. A short, thick active layer is not required, typical dimensions being 250 or 500 .mu.m long, by 0.2 .mu.m high. The mesa is typically about 2 .mu.m wide, but may be wider.

Abstract: In a semiconductor buried heterostructure laser having a mesa (2, 3, 4) and confinement layers (5, 6, 7) on a substrate (12), at least the lowermost of the confinement layers (5, 6, 7) is substantially planar up to the mesa. This is achieved by MOVPE growth of InP against lateral surfaces of the mesa (2, 3, 4) which are defined by distinct crystallographic planes of the material of the mesa. In particular (111) B InP planes are used. The laser is particularly for use in the field of optical communications.

Abstract: An assembly secures a pair of rods to a door inner panel and allows linear and lateral movement of the rods relative to the door inner panel. The door inner panel has a keyhole shaped slot including an access portion and a retaining portion. The assembly includes a one-piece flexible rubber rod clip having a rod insulation portion and a tab portion. The rod insulation portion has a pair of oblong bores for receiving the rods for spacing and insulating the rods from the door inner panel. The rod insulation portion has a pair of channels, each channel connecting one of the bores to an outer surface for installing the rods into the bores. The rod insulation portion has a base for engaging the door inner panel. The tab portion has a locking tab spaced from the base of the rod insualtion portion by a trunk.

Abstract: A band rejection filtering arrangement utilizing bandpass filters each terminated by a matched load. A quadrature hybrid circuit divides the input signals and applies them to the bandpass filters. Signals within the rejection band are dissipated by the filters and matched loads, whereas desired signals are reflected. The reflected signals are then combined by the quadrature hybrid circuit to provide the band rejected output. This arrangement is made switchable between an all pass mode and the band rejection mode by providing PIN diodes between the quadrature hybrid circuit and the bandpass filters.

Abstract: A calibration circuit for a solid state electricity meter comprises a plurality of resistors formed on an integrated circuit. The resistors are connected by an on-chip array of electrically controlled switches, such as MOSFETs, to signal processing circuitry driving the meter. The resistors establish variable voltage divider networks which compensate the meter for phase, gain and offset errors distributed in the signal processing circuitry. The values of the variable voltage divider network may be established automatically during testing of the meter, by a digital computer, or semi-automatically, by a technician, to establish the "on" and "off" states of the various transistors of the array.

Abstract: A method of calibrating reflectance measuring devices, such as spectrophotometers, that incorporate automatic gain or sensitivity setting capability. According to the method, offset reflectance and reflectance of a secondary reflectance standard for several wavelengths are calculated and stored in a memory of a reflectance measuring device. A secondary standard is mounted in the reflectance measuring device and reflectances at a selected wavelengths from the secondary standard are read prior to measurement of the reflectance of the test sample. The stored offset reflectance and secondary reflectance for the operational wavelength are used to calculate true reflectance of the test sample.