PD-LD Inc. offers multimode laser based fiber optic transceiver modules in convenient industry standard 1×9 style packages. The PTR155 series modules are designed to comply with SONET/SDH 155 Mbps operation over 62.5/125um multimode optical fiber. A 1310 nm (-B35) or 1550nm (-B53) FP laser and an InGaAs PIN photodiode are integrated with a WDM filter to form a bi-directional single fiber optical subassembly (OSA). A LD driver IC that converts differential input LVPECL logic signals into an analog laser driving current drives the laser. The photodiode is connected to a circuit providing post-amplification, quantization, and optical signal detection.