High-speed avalanche photodiode photoreceivers have been released by the New Focus Div. of Bookham Inc. for use in ultralow-light-level detection. They comprise a high-gain avalanche photodiode, a low-noise amplifier and an internal bias supply in a compact module. A linear amplifier optimizes the noise performance and enhances sensitivity. Typical noise-equivalent power is as low as 0.5 pW/√Hz. The photoreceivers offer adjustable gain with single-ended and differential outputs, a built-in temperature-compensation circuit and 3-dB bandwidth of up to 2 GHz. They operate from a ±15-V supply and do not require a separate high-voltage input.