We introduce a multichannel optical fiber based detector for photoacoustic imaging. By using in-house produced photodetectors and relative low-cost components from telecommunication industries we were able to reduce the costs for one channel significantly compared to previous setups. The estimated cost for one channel (without sampling device) is below 800 €. The self-made balanced photodetector for 1550 nm achieves a gain of 100 dB, a -3dB bandwidth of 45 MHz and a maximum signal-to-noise-ratio of 48 dB. We present a four channel annular detector array based on optical fiber Mach-Zehnder interferometers. Photoacoustic imaging is demonstrated by measuring photoacoustic signals of a black polyethylene microsphere.