Abstract

The optical Costas loop¹ is one of the candidates to achieve a multigigabit/second optical homodyne receiver in coherent optical communication systems. In our earlier work,² the optical Costas loop experiment was carried out using an external phase adjuster for phase locking the local oscillator laser. However, bit error rate (BER) characteristics of the systems were not investigated because of the wide bandwidth of the lasers. Here, we successfully demonstrate the measurement of BER characteristics of the optical Costas loop system using external phase control, and we clarify receiver sensitivity characteristics vs the bandwidth of external phase control.

© 1992 Optical Society of America