| 摘要 |
PURPOSE:To realize a simple and stable optical transmitter by providing a phase delay means that gives a specified phase delay on the n-th number of output laser beams from the N-number of laser beams and an optical coupling means that couples the N-number of laser beams to one optical transmission line. CONSTITUTION:The input binary signal of a signal source 14 is put into an N-value and at a signal process circuit 15, one of the phase locked laser beams 1-N oscillating with a single vertical and horizontal modes/N is driven corre sponding to its multivalue level, and each of the phase of the output light of the laser beams 1-N is shifted in order by 2pi/N with 1 phase shifters phi1-phiN respectively, that is, the n-th number of phase shifter gives the phase delay of 2pi (n-1)/N and the output light of the phase shifters phi1-approx.=N are coupled to a single mode optical fiber transmission line 13 by an optical coupler 86. Thereby, since the quantity of the phase shift is decided physically, a transmis sion at a pure and stable optical area where no incidental amplitude modulation exists can be realized without using a complicated control circuit. |
