| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical signal detecting apparatus capable of singly detecting a plurality of kinds of bit sequences in the lump by using one apparatus. <P>SOLUTION: A directional coupler 103 distributes an optical bit sequence 101 in 8 bits subjected to phase modulation and each having a phase of +π/2 or -π/2 for a coding period T into eight, each passes through a delay line group 104 comprising: a delay line connected to a first port and whose length is the longest; and delay lines connected to second and succeeding ports and whose length is sequentially decreased by ncT each, wherein n is a refractive index of an optical waveguide and c is the velocity of light in vacuum, the outputs of the delay line group 104 are given to directional coupler groups 106-1, 106-2, 106-3 whose input and output ports are respectively apart by 4, 2, 1 in terms of bits via phase adjustment means groups 105-1, 105-2, 105-3, respectively, then the directional coupler group 106-3 can output 8 kinds of bit sequences from its separate output ports. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
