Characterization of a MOPA system used for underwater optical communication

Abstract

Underwater water optical communication (UWOC) requires high-power laser transmitter with good beam quality for high-rate data modulation. Since master oscillator power amplifier (MOPA) has the characteristic of preserving the property of seed laser (e.g. bandwidth and beam quality), it is expected to resolve the problem. In this paper, we theoretically simulate the large-signal modeling of the amplified laser light and the frequency response of a MOPA system and experimentally amplified 3-mW 1-um light to 145mW. The seed light came from 1064-nm TO-Packaged laser diode and was coupled into HI1060. To satisfy the requirements of the transmitters for UWOC, we used second harmonic generation and got 0.06mW 532-nm laser light. Finally, according to the theoretical analysis of a MOPA system and the electrical response of a laser driver, we chose Manchester Encoding to modulate the amplified 1064-nm laser light and achieved 100-Mbps transmission. The system was error free for 1◊104 bits.