Abstract: An optical circuit can include a bidirectional amplifier connected so as to amplify source light prior to emission through an output device such as a telescope as well as amplification of reflected light received by the telescope. Such an optical circuit can be used in laser doppler velocimeter applications as well as other applications. The optical circuit can also include passive splitters or active switches to provide for advantageous multiplexing.

Abstract: An optical circuit can include a bidirectional amplifier connected so as to amplify source light prior to emission through an output device such as a telescope as well as amplification of reflected light received by the telescope. Such an optical circuit can be used in laser doppler velocimeter applications as well as other applications. The optical circuit can also include passive splitters or active switches to provide for advantageous multiplexing.

Abstract: High p-type impurity concentration levels are achieved in Group III nitride semiconductor layers by depositing a nitrogen-rich surface onto a supporting layer while impeding the flow of Group III element reactant. Thereafter, the Group III element source is introduced into the reactor to generate a p-type region having a high impurity concentration. The flow of the reactant from the active nitrogen source is kept below about 300 sccm and the temperature of the reactor is reduced below 1075.degree. C. in order to provide improved surface characteristics.