Abstract: A receiver circuit for receiving a modulated optical signal and for generating a corresponding electrical signal comprises a photodiode (1) for receiving the optical signal and for generating a first modulated electrical signal. An amplification circuit (3) receives the first electrical signal or a signal related thereto via an n stage (where n is an odd-integer) filter network (2) connected between the photodiode (1) and the amplification circuit (3). The output from the amplification circuit is fed to a first equalization amd noise filter (5). The characteristics of the filter network are such that the total thermal noise power output of the first noise filter is substantially minimized.

Abstract: A method of growing semiconductor compounds which are formed from elements of group III with elements of group V by liquid phase epitaxy. A suitable solvent is provided in contact with a source of the compound to be grown, the solution is heated to a predetermined temperature and the solute is allowed to come to equilibrium with the solvent. The solution is then subjected to a rapid, relatively small decrease in temperature to produce supersaturation of the solution. The temperature is then maintained substantially constant and, after a predetermined first period of time at the constant temperature, the solution is brought into contact with a substrate on which the compound is to be grown for a predetermined second period of time.