Enhanced broadband semiconductor laser phase conjugate mirrors and optical repeaters

Abstract

SOP is never affected by any phase noise in principle. In the free space channel without such a polarization dependency as in the optical fiber, we can make good use of the SOP of light as a modulation parameter in the coherent optical communication system. If we choose the SOP as a new modulation parameter, it is possible to establish the coherent optical space communication system insensitive to the phase noise. Therefore, our system is very useful in the presence of any phase noise. Figure 1 shows the principle of POLAM system, where the polarization azimuth, X(t), is modulated by an integration of broadband information signal, m(t). In other words, the rotating speed of linear polarization is modulated by the information signal. At the receiver as shown in Fig. 2, after the received optical signal is divided into two orthogonal polarization components, they are optically heterodyne-detected independently. The K