Nec Corporation

Hisakazu Kurita

Hiroyuki Yokoyama

Hirohito Yamada

Shigeru Kawai

Masayuki Shirane

An optical repeater includes an optical splitter for splitting an optical input data pulse stream of wavelength &lgr; into first and second components. The first component is supplied to a first. mode-locked laser diode to produce a first clock pulse stream of wavelength &lgr; which is synchronized to the input data pulse stream. The first clock pulse stream is fed to a second mode-locked laser diode to produce a second clock pulse stream of wavelength &lgr; which is synchronized to the first clock pulse stream. The second clock pulse stream is entered to an optical gate. The second component of the input data from the splitter is amplified sufficiently to control the optical gate to modulate the second clock pulse stream so that the data pulse pattern is impressed on the second clock pulse stream.

Optical repeater using two mode-locked laser diodes for regenerating output pulses of same wavelength as incident optical pulses

A method for measuring the waveform of light is provided, which makes it possible to synchronize easily the phase of sampling light with the phase of target light even if the target light is ultra-high speed pulsed light and is transmitted by way of long transmission channel, and to measure the waveform of target light with sufficient time resolution in real time. The method comprises the steps of: (a) generating sampling light having a pulse width sufficiently narrower than that of the target light from the target light; a repetition frequency of the sampling light having a constant difference with respect to a repetition frequency of the target light; (b) supplying the sampling light and the target light to a nonlinear optical member to generate cross-correlated light between the sampling light and the target light; and (c) measuring waveform of the target light based on the cross-correlated light. Preferably, the step (a) comprises the substeps of (a-1) extracting clock light from the target light; the clock light being synchronized with the target light; (a-2) generating an electrical clock signal from the clock light; (a-3) generating an electrical driving signal in such a way that a constant frequency difference exists between a frequency of she electrical driving signal and that of the electrical clock signal; and (a-4) generating the sampling light based on the electrical driving signal.

Optical measurement of target-light waveform

An optical connector comprises a series of transparent substrates 50-53 including a refraction type lens 10 embedded in the central substrate 50, two beam deflection elements 40 and 41 offset from the optical axis of the lens 10, a light emitting element 20 directly below the beam deflection element 40, and a light detecting element 30 directly above the beam deflection element 41. The lens 10 is designed to have identical meridional and sagittal focal lengths so that meridional and sagittal images of obliique incident beams may be formed on the same spot on the light detecting element 30. Beam of light emitted from the light emitting element 20 are deflected by the beam deflection element 40 and enters the lens 10 obliquely. The beams, passing through the lens 10 and the deflection element 41 are cllimated within a small spot on the light detecting element 30 since the lens 10 has identical meridional and sagittal focal lengths.

Growing community of inventors

Ehime, Japan

Hisakazu Kurita