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

We present for the first time a directly-modulated high-frequency laser transmitter optical sub-assembly (TOSA) in a commercially-available TO-can packaging working in the 1310nm band capable of digital transmission at 25Gb/s and analog transmission up to 25GHz. 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 60mA, and for analog transmission, we operate below the forward current of 40mA to suppress unwanted laser side modes. We test the TOSA performance by a successful 25Gb/s on-off keying (OOK) data transmission over a passive optical network with BER of 3.2E-3 and 2.0E-8 for 25Gb/s, and 10.3Gb/s, respectively. Finally, we demonstrate analog millimeter wave radio transmission at 25GHz of a 16-QAM orthogonally frequency division multiplexing (OFDM) signal with 20MHz bandwidth over a 5km-long optical fronthaul with a seamless wireless link providing EVM below the 12.5% limit to show real-case scenario performance.