An all-fiber configuration system and method for generating temporally coherent supercontinuum pulsed emission are provided. The system includes a sequential structure of all-fiber sections including: a fiber laser seed source to produce a seed pulse with given optical properties; a stretching section including an optical fiber to temporally stretch the seed pulse; an amplification section including an active optical fiber, doped with a rare earth element, to amplify the stretched pulse by progressively stimulating radiation of active ions of the doped active optical fiber; a compressing section to temporally compress the amplified pulse; and a spectrum broadening section including an ANDi microstructured fiber that spectrally broadens the compressed pulse by a nonlinear effect of Self Phase Modulation (SPM) while maintaining the temporal coherence of the pulse.

The invention relates to a supercontinuum light source comprising a microstructured optical fiber and a pump light source. The microstructured optical fiber comprises a core and a cladding region surrounding the core, as well as a first fiber length section, a second fiber length section and an intermediate fiber length section between said first and second fiber length sections. The first fiber length section comprises a core with a first characteristic core diameter. The second fiber length section comprises a core with a second characteristic core diameter, smaller than said first characteristic core diameter, where said second characteristic core diameter is substantially constant along said second fiber length section. The intermediate length section of the optical fiber comprises a core which is tapered from said first characteristic core diameter to said second characteristic core diameter over a tapered length.

A system includes a processor communicatively coupled to an Amplifier Stimulated Emission (ASE) source and an optical receiver, wherein the processor is configured to cause transmission of one or more shaped ASE signals, from the ASE source, on an optical fiber, obtain received spectrum of the one or more shaped ASE signals from the optical receiver connected to the optical fiber, and characterize the optical fiber based in part on a nonlinear skirt and/or center dip depth in the received spectrum of the one or more shaped ASE signals. The one or more shaped ASE signals can be formed by the ASE source communicatively coupled to a Wavelength Selective Switch (WSS) that is configured to shape ASE from the ASE source to form the one or more shaped ASE signals with one or two or multiple peaks and with associated frequency.

A method of optimizing the coupling to an optical fiber, including: generating a femtosecond laser pulse; directing a focus of the laser pulse to a longitudinal depth in the region beneath the endface of the optical fiber to generate microvoids; adjusting the intensity of the laser pulse at different depths, such that a refractive index profile is created in the region beneath the endface of the optical fiber.

A femtosecond laser multimodality molecular imaging system includes a near-infrared pulse generation device for providing near-infrared pulses with a central wavelength of 1010 nm to 1100 nm and a spectral width of less than 25 nm. The near-infrared pulses can excite an optical medium with strong nonlinearity to generate the femtosecond laser pulses with ultra-wide spectrum. A pulse measurement compression and control module measures and compensates the accumulated dispersion of the femtosecond laser pulses arriving at the tissue sample, so as to eliminate the time domain broadening effect as much as possible. The obtained shortest pulses can interact with the tissue sample to generate spectral signals from different modalities, thus providing a variety of nonlinear molecular image modalities.

An example all polarization-maintaining, passively mode-locked linear fiber laser oscillator has a linear cavity. A semiconductor saturable absorber mirror (SESAM) is disposed at one end of the linear cavity. A polarization-maintaining gain fiber is operatively associated with the SESAM in the linear cavity, the gain fiber having normal dispersion. A polarization-maintaining undoped fiber is operatively associated with the SESAM in the linear cavity, the undoped fiber having anomalous dispersion. An output coupler is configured to generate laser light output from the linear cavity.

When a soliton and a dispersive pulse propagate in an optical fiber, they can interact via cross-phase modulation, which occurs when one pulse modulates the refractive index experienced by the other pulse. Cross-phase modulation causes each pulse to shift in wavelength by an amount proportional to the time delay between the pulses. Changing the time delay between the pulses changes the wavelength shift of each pulse. This make it possible to produce pulses whose output wavelengths can be tuned over large ranges, e.g. hundreds of nm, in a time as short as the pulse repetition period of the laser (e.g., at rates of megahertz or gigahertz). Such a laser requires no moving parts, providing high reliability. The laser's optical path can be made entirely of optical fiber, providing high efficiency with low size, weight, and power consumption.

A frequency chirp correction method for the photonic time-stretch system comprises acquiring the stretching signal, i.e. acquiring the time-domain data after the time-domain stretching. First, the time-domain data of the stretching signal is Fourier transformed to obtain the spectral distribution. The spectral distribution is then convoluted with the first frequency-domain correction factor, and then multiplied with the second frequency-domain correction factor to obtain the modified frequency spectrum. Finally, the modified frequency spectrum is performed by the inverse Fourier transform to obtain the time-domain signal after the frequency chirp correction.

The present disclosure relates to an optical waveguide system. The system may include a first waveguide having a core-guide and a material portion surrounding and encasing the core-guide. The core-guide enables a core-guide mode for an optical signal travelling through the core-guide. A second waveguide forms a lossy waveguide on an outer surface of the first waveguide. The construction of the second waveguide is such as to achieve a desired coupling between the core-guide mode and the lossy waveguide to control an energy level of the optical signal travelling through the core-guide.

A fiber laser system based in solitonic passive mode-locking, including a laser diode to emit and deliver an optical signal of a first wavelength; a single-fiber laser cavity including a dichroic mirror, a SESAM and a polarization maintaining highly-doped active fiber, to receive the emitted signal and to emit a pulsed optical signal of a second wavelength, generating laser light in the form of mode-locked ultrashort pulses; a unit coupling the laser diode to the single-fiber laser cavity; and an isolator device protecting the cavity from back reflections. The solitonic mode-locked ultrashort pulses are comprised in a range of 100 fs<10 ps with repetition rates of hundreds MHz to tens of GHz.