An infrared collector for use in communications systems. The infrared collector employs a concentrator which concentrates infrared radiation received from some directions more than others. The concentrator is made of a dielectric material which is substantially transparent to infrared radiation and has a shape which is convex above a base plane determined by the top surface of an infrared radiation detector and in which any ray which connects any part of the top surface of the detector to any part of the concentrator above the base plane intersects the surface of the concentrator at an angle less than the critical angle for the material from which concentrator is made. The amount of concentration from a given direction is controlled by the curvature of the collector. The less a portion of the surface is curved, the less infrared radiation normal to the less-curved portion is concentrated. The collector may be used in environments where there is a predominant direction from which infrared noise is received in the collector which is different from the direction from which infrared communications signals are received in the collector.