The present invention is directed to methods and apparatuses for performing temporal scanning using ultra-short pulsewidth lasers in which only minimal (micro-scale) mechanical movement is required. The invention also relates to methods for obtaining high-accuracy timing calibration, on the order of femtoseconds. A dual laser system is disclosed in which the cavity of one or more of the lasers is dithered, by using a piezoelectric element. A Fabry-Perot etalon is used to generate a sequence of timing pulses used in conjunction with a laser beam produced by the laser having the dithered laser cavity. A correlator correlates a laser pulse from one of the lasers with the sequence of timing pulses to produce a calibrated time scale. The methods and apparatuses of the present invention are applicable to many applications requiring rapid scanning and time calibration, including, but not limited to metrology, characterization of charge dynamics in semiconductors, electro-optic testing of ultrafast electronic and optoelectronic devices, optical time domain reflectometry, and electro-optic sampling oscilloscopes.

Scanning temporal ultrafast delay methods and apparatuses therefor

The method of the present invention comprises the steps of providing a nonlinear optical loop mirror comprising a first optical coupler including first and second optical paths directionally coupled to each other, a loop optical path including first and second fibers having different characteristics for connecting the first and second optical paths, and a second optical coupler including a third optical path directionally coupled to the loop optical path; and supplying probe light and input signal light from the first and third optical paths, respectively, and outputting output signal light from the second optical path.

Method, device, and system for waveform shaping of signal light

A medical instrument that comprises: a first-stage optic responsive to a tissue surface of a patient; a spectral separator optically responsive to the first stage optic and having a control input; an imaging sensor optically responsive to the spectral separator and having an image data output; and a diagnostic processor having an image acquisition interface with an input responsive to the imaging sensor and a filter control interface having a control output provided to the control input of the spectral separator.

Multispectral/hyperspectral medical instrument

A reliable optical transmission system with an improved signal control mechanism that avoids abrupt power variations of light beams, thereby preventing optical supervisory channel (OSC) signals from experiencing errors An optical amplifier amplifies main signals under the control of an optical amplifier controller, which spends a first predetermined time to raise the output power of the optical amplifier up to a desired level A pump light source produces a pump beam for injection to a fiber-optic transmission line so as to make it serve as an amplifying medium The pump light source is controlled by a pump light source controller that spends a second predetermined time to raise the pump beam to a desired power level This stepwise start-up process of the amplifier power and pump beam power prevents OSC signals from experiencing abrupt power variations

Optical transmission system

Apparatus for stabilizing an output wavelength of a laser assembly (80), including a plurality of optical elements (88, 92, 97, 96) coupled together so as to form a laser cavity resonating in a single mode dependent upon an optical length of the cavity, and an optical length changer (86) which varies an optical length of at least one of the optical elements so as to vary accordingly the optical length of the cavity. The apparatus further includes a detector (91) which monitors the output of the laser assembly responsive to the variation in the optical length of the at least one of the optical elements. There is also included a stabilizer (93) which responsive to the measured output from the detector supplies a control signal to the optical length changer to control an optical length of at least one of the optical elements, so that the cavity resonates stably at the output wavelength in the single mode.

Laser wavelength stabilization

PROBLEM TO BE SOLVED: To prevent polarization condition from being changed and to improve operational stability by using the components of all a polarization holding type and coupling all of these optical main axes in parallel or perpendicularly. SOLUTION: A pulsed light source 10 which generates SC light pulses, an optical amplifier 11, a nonlinear optical medium 12, an optical band-pass filter 13 and a dispersion compensator 14 are defined as a polarization holding type, all optical axes of each component are coupled in parallel or perpendicular by an optical coupling means 20 of the polarization holding type. In this way, in the case using optical parts of optical fiber structure when respective elements are defined as the polarization holding type, the elements can be structured by ANDA fibers or elliptic core fibers. By this, changes in the polarization condition of output pulses and pulses can be made small for mechanical vibrations and temperature variation, etc. Since the components for controlling the conditions of polarization is unnecessitated the loss of the entire system can be reduced, and the device can be made small in size and low in cost.

Light pulse generating circuit

PURPOSE:To enable high-speed optical modulation only by light signals without electronic circuit of optical modulator by cascade-connecting n-stages of optical modulators and setting the phases of modulated input pulse light so as to vary these phases from each other. CONSTITUTION:Four stages of optical modulators 101 to 104 having optical nonlinear media to which input pulse light of a specified repeating period t and the modulated input pulse light of the repeating period t/m and spectral demultiplexers which remove the output light of the wavelengths of the modulated input pulse light from the output light of the optical nonlinear media and output the modulated output light are cascade-connected and the phases of the modulated input pulse light are so set as to vary from each other. The optical nonlinear media are media to generate four-light wave mixed waves from the input pulse wave and the modulated input pulse light. The pulse light of the specified repeating period t is given the modulated input pulse light of the repeating period t/n and is modulated in the optical nonlinear media. The modulation method includes a induction phase shift type to change the phases or an induction frequency shift type to change frequencies.

Optical modulation device

PROBLEM TO BE SOLVED: To make the eye pattern measurement with high time resolution possible by generating a specific sampling light pulse train of an ultra-short pulse width and low jitter by repetition of low pulses. SOLUTION: The output of a pulse light source 13 is amplified by a first optical amplifier 14-1 and is made incident on an optical gate switch 23. On the other hand, the other of the branched outputs of an oscillator 11 is divided down in frequency to 1/M.N by a frequency dividing circuit 12. An electric pulse generator 22 is driven by the electric signal of the divided down lowfrequency f0 -NΔf, by which the electric pulse trains of the repetitive frequency f0 -NΔf and pulse width 100ps to 1ns are generated. The optical gate switch 23 is driven by matching the timing with the light pulse trains by such electric pulse signals, by which the light pulse train of the repetitive frequency M(f0 --NΔf) is divided down to the light pulse train of the low-repetitive frequency f0 -NΔf. At this time, the electric pulse signals include the jitter, but the frequency dividing is executed without receiving the influence of the jitter by gating the light pulses near the center of the electric pulses.

Optical waveform measuring instrument by light sample

PURPOSE: To embody a full light type time-division multiplex separating circuit which integrally outputs the respective low order group signal channel of time-division multiplex signal light to respectivley different output ports. CONSTITUTION: This separating circuit has an optical amplifier means 8 which amplifiers and outputs the time-division multiplex signal light of a wavelength λs formed by time-division multiplexing of N pieces of the low order group signal channels, a station light emitting source 10 which generates station light emitted pulse trains having wavelengths λ1, λ2,...λN varying from each other in synchronization with the respective low order group signal channels, an optical coupling means 9 of 2×2 which inputs the station light emitted pulse trains to the first input port 9A and branches these pulse trains one to one to two output ports 9C, 9D, an optical Kerr medium 4 which couples the two output ports 9C, 9D of the optical coupling means 9 to each other, an optical multiplexing means 6 which multiplexes the time-division multiple signal light amplified by the station light emitted light pulse trains branched to the one output port 9C of the optical coupling means 9 and inputs the signal light to the optical Kerr medium 4 and an optical demultiplexing means 7 which demultiplexes the station emitted light of the wavelength corresponding to the respective low order group signal channels of the time-division multiple signal light and outputs the demultiplexed light to the ports corresponding to the respective wavelengths.

Full light type time-division light pulse multiplex separating circuit and full light type tdm-wdm conversion circuit and full light type time-division channel drop circuit

PURPOSE:To provide a mode synchronizing laser device in which optical pulses can be generated with a plurality of wavelengths simultaneously. CONSTITUTION:A plurality of optical amplifiers 2-1, 2-2 exhibiting gains, respectively, in a plurality of different spectral regions are disposed in a laser resonator and then a wavelength spreading means 3 imparts refractive indexes, dependent on the wavelength, such that mode synchronizing oscillation conditions are satisfied concurrently for the wavelengths in the plurality of spectral regions.

Saruwatari Masatoshi

Papers

Light pulse generating circuit

Optical modulation device

Optical waveform measuring instrument by light sample

Full light type time-division light pulse multiplex separating circuit and full light type tdm-wdm conversion circuit and full light type time-division channel drop circuit

Mode synchronizing laser device