Dp. Wei et al., A novel scheme for optical pulse multiplication using fiber coupler loop-connecting configuration, CZEC J PHYS, 51(2), 2001, pp. 155-162
Connecting an input port and an output port of a single-mode fiber coupler
to form a fiber-loop, and making the time delay of the fiber-loop odd multi
ple of the half-period of the input optical pulse stream, we can obtain a p
ulse stream with multiplying repetition rate at the other output port of th
e coupler. Utilizing three loop-connecting fiber couplers cascaded, a pulse
stream with eight times the repetition rate is achieved.