Optical RZ signal generator, optical RZ signal generating method, optical time division multiplexer, and optical time division multiplexing method

An optical RZ signal generating method for generating an optical RZ signal by supplying a signal light from a steady-state power laser light source and performing intensity modulation on the basis of electric signals for said signal light using a Mach-Zehnnder optical modulator,

• wherein said electric signals are binary voltage signals and insertion loss of said Mach-Zehnnder optical modulator is preset so as to shift from a first state to a second state other than the first one and then to return to said first state in a logic level transition process of the binary voltage signals.

An optical RZ signal generating method for generating an optical RZ signal by supplying a signal light from a steady-state power laser light source and performing intensity modulation for said signal light by using a Mach-Zehnnder optical modulator having a first phase modulator for modulating a phase of a light on the basis of a first electric signal and a second phase modulator for modulating a phase of a light on the basis of a second electric signal on optical paths,

• wherein said first electric signal and said second electric signal are binary voltage signals and insertion loss of said Mach-Zehnnder optical modulator is preset so as to shift from a first state to a second state other than the first one and then to return to said first state in a logic level transition process of the binary voltage signals.

An optical RZ signal generating method for generating an optical RZ signal by supplying a signal light from a steady-state power laser light source and performing intensity modulation for said signal light by using a Mach-Zehnnder optical modulator having a first phase modulator for modulating a phase of a light on the basis of a first electric signal and a second phase modulator for modulating a phase of a light on the basis of a second electric signal on a first optical path and having a third phase modulator for modulating a phase of a light on the basis of a third electric signal and a fourth phase modulator for modulating a phase of a light on the basis of a fourth electric signal on a second optical path,

• wherein said first electric signal and said third electric signal are a binary voltage signal and its negative-phase binary voltage signal and said second electric signal and said fourth electric signal are a binary voltage signal and its negative-phase binary voltage signal and wherein insertion loss of said Mach-Zehnnder optical modulator is preset so as to shift from a first state to a second state other than the first one and then to return to said first state in a logic level transition process of the binary voltage signals.

An optical time division multiplexing method,

• wherein a signal light is supplied from a steady-state power laser light source to a first to nth (n is an integer of 2 or greater) external intensity modulators connected in series;
• and
• wherein said first to nth external intensity modulators execute intensity modulation during a period corresponding to first to nth time slots on the basis of first to nth electric signals, respectively.