Directly-Modulated 1310 nm Laser TOSA Developed for Seamless Millimeter Wave Radio Over Fiber Transmission

Abstract

[EN] We present for the first time a directly-modulated high-frequency laser transmitter optical subassembly (TOSA) in a commercially-available TO-can packaging working in the 1310 nm band capable of digital transmission at 25 Gb/s and analog transmission up to 25 GHz. We show a step-by-step assembly procedure starting from the TO-can package high-frequency characterization, followed by a bare laser chip analysis and the supporting PCB evaluation to the final TOSA assembly step. We verify the developed TOSA long-term stability by shock and aging tests which had no impact on the TOSA bandwidth or output optical power. We reveal the optimal forward current for digital transmission at 60 mA, and for analog transmission, we operate below the forward current of 40 mA to suppress unwanted laser side modes. We test the TOSA performance by a successful 25 Gb/s on-off keying (OOK) data transmission over a passive optical network with BER of 3.2E-3 and 2.0E-8 for 25 Gb/s, and 10.3 Gb/s, respectively. Finally, we demonstrate analog millimeter wave radio transmission at 25 GHz of a 16-QAM orthogonally frequency division multiplexing (OFDM) signal with 20 MHz bandwidth over a 5 km-long optical fronthaul with a seamless wireless link providing EVM below the 12.5% limit to show real-case scenario performance.