The 1801-FS-AC Silicon Optical Receiver is a free space, 320 to 1000 nm AC coupled photoreceiver offering a well-balanced combination of gain, bandwidth, and low noise over the 25 kHz to 125 MHz frequency range. Because of its high transimpedance gain and low noise-equivalent power (NEP), it offers the best in sensitivity for signals with rise and fall times as short as 3 ns. This high sensitivity, combined with its high-level output, reduces the effects of downstream noise sources. For mounting it has a 8-32 mounting thread, and we include an M4 metric adaptor and tool. An external ±15 VDC power supply, which must be purchased separately, is required. Power supply cables