Abstract: A transconductance circuit has an input terminal (VIN) and an output terminal (Out), a first current source (4) having a gate connected to said input terminal (VIN); and a second current source (5), in parallel with said first current source, and having a higher transconductance and a wider dynamic range than the first current source. The current sources are configured so that at a low input voltage only the first current source (4) is on. A voltage drop circuit provides a lower bias voltage for the second current source than for the first current source.

Abstract: A connector receives and grips an optical fiber in registry with an optical element. Pivoting portions are held in default inoperative position by the spring action of molded hinges, at which position two shutter portions meet, so forming a shutter preventing the ingress of dirt to the optical element. As the optical liber is pushed a small distance into the connector, the pivoting portions are caused to pivot a small amount about the hinges, bringing teeth into contact with the outside jacket of the fiber. The bodies of the inserts are forced radially away from the central axis of the connector, so providing a leaf spring force which keeps the teeth engaged with the jacket of the fiber. The shutter portions move out of the way of the fiber and the spring action applies a force to draw the fiber further into the body of the connector.

Abstract: An optical connector includes four main components, namely a clamp; a housing into which the clamp slides; two optical elements, a transmitter and a receiver; and an EMI metal shield surrounding the elements. The clamp has two parallel through holes for receiving fiber terminations, each through-hole having a generally conical mouth for convenient guidance of a fiber termination. Inside of the through-holes there are side resilient clamp members, and there is a single central clamp member. The clamp is of moulded plastics construction, and the clamp members are resilient in the lateral plane. The central clamp member on the other hand has little flexibility and remains essentially static throughout the clamping operation. Each resilient clamping member has a tooth at its end for snap-fitting engagement with the housing at open and closed positions. Fiber terminations are inserted through the clamp mouths and the through-holes and into the sockets of the housing.

Abstract: An optical connector includes four main components, namely a clamp; a housing into which the clamp slides; two optical elements, a transmitter and a receiver; and an EMI metal shield surrounding the elements. The clamp has two parallel through holes for receiving fiber terminations, each through-hole having a generally conical mouth for convenient guidance of a fiber termination. Inside of the through-holes there are side resilient clamp members, and there is a single central clamp member. The clamp is of moulded plastics construction, and the clamp members are resilient in the lateral plane. The central clamp member on the other hand has little flexibility and remains essentially static throughout the clamping operation. Each resilient clamping member has a tooth at its end for snap-fitting engagement with the housing at open and closed positions. Fiber terminations are inserted through the clamp mouths and the through-holes and into the sockets of the housing.

Abstract: An optical assembly has a socket for receiving a fiber termination ferrule. A PIN diode is on a lead frame encapsulated in a transparent body. As a fiber ferrule is pushed into the socket the electronic output from the diode is monitored to determine optimum insertion distance.

Abstract: A green LED has a substrate, a GaN heavily n-doped bottom confining layer, an active region, an upper GaN confinement layer, and a semi-transparent ohmic contact layer. The active region has less than or equal to three highly compressively strained quantum wells. The widths of the quantum wells is less than 3 nm. The active region arrangement provides a short free carrier life-time and hence an increase in the modulation bandwidth of the LED.