A pulse transformer for modifying the amplitude and phase of short optical pulses includes a pulse source and an adaptively controlled stretcher or compressor including at least one fiber Bragg grating (FBG) configured to receive pulses from the pulse source and having a first second-order dispersion parameter (D.sub.21). The pulse transformer further includes at least one optical amplifier configured to receive pulses from the FBG and a compressor configured to receive pulses from the at least one optical amplifier. The compressor has a second second-order dispersion parameter (−D.sub.22), an absolute value of the first second-order dispersion parameter (|D.sub.21|) and an absolute value of the second second-order dispersion parameter (|−D.sub.22|) that are substantially equal to one another to within 10%.

A tunable multi-mode laser is configured to generate a multi-mode optical signal at a tuned wavelength. The laser includes a semiconductor optical gain region, a feedback region, and a phase modulation region between the gain and feedback regions. Each of the regions may be monolithically integrated. A feedback loop is coupled to the tunable laser to receive the optical signal and includes at least one delay line. The delay line may also be monolithically integrated. An output of the delay line is fed back to the tunable multi-mode laser in order to provide at least one of self-injection locking and self-phase locked looping for the multi-mode tunable laser. Each of the optical gain region and phase modulation region of the laser is biased by the output of the delay line in order to reduce phase drift of the optical signal.

Examples herein relate to optical systems. In particular, implementations herein relate to an optical system including an optical transmitter configured to transmit optical signals. The optical transmitter includes a first optical source configured to emit light having different wavelengths, a waveguide, and an optical coupler configured to couple the emitted light from the first optical source to the waveguide. The optical transmitter further includes an array of two or more second optical sources coupled to the waveguide, each of the two or more second optical sources configured to be injection locked to a different respective wavelength of the emitted light transmitted via the waveguide from the first optical source. In some implementations, the first optical source is a master comb laser and the two or more second optical sources are slave ring lasers.

A tunable multi-mode laser is configured to generate a multi-mode optical signal at a tuned wavelength. The laser includes a semiconductor optical gain region, a feedback region, and a phase modulation region between the gain and feedback regions. Each of the regions may be monolithically integrated. A feedback loop is coupled to the tunable laser to receive the optical signal and includes at least one delay line. The delay line may also be monolithically integrated. An output of the delay line is fed back to the tunable multi-mode laser in order to provide at least one of self-injection locking and self-phase locked looping for the multi-mode tunable laser. Each of the optical gain region and phase modulation region of the laser is biased by the output of the delay line in order to reduce phase drift of the optical signal.

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.

Examples herein relate to optical systems. In particular, implementations herein relate to an optical system including an optical transmitter configured to transmit optical signals. The optical transmitter includes a first optical source configured to emit light having different wavelengths, a waveguide, and an optical coupler configured to couple the emitted light from the first optical source to the waveguide. The optical transmitter further includes an array of two or more second optical sources coupled to the waveguide, each of the two or more second optical sources configured to be injection locked to a different respective wavelength of the emitted light transmitted via the waveguide from the first optical source. In some implementations, the first optical source is a master comb laser and the two or more second optical sources are slave ring lasers.

A laser-assisted ridge preservation method is performed using a free-running (FR) pulsed neodymium yttrium aluminum garnet (Nd:YAG) laser device. The method includes one or more of photothermally denaturing and vaporizing encapsulated granulomatous tissues with the laser device on all sides of a socket of an extracted tooth, and irradiating the socket with the laser device to form a thrombus. A bone graft material may be placed into the thrombus.

An optical line terminal includes an optical comb generator, N downlink channels D.sub.k, and N uplink-photodetectors PD.sub.k. The optical comb generator is configured to generate a carrier signal having an optical-frequency-comb spectrum and including N optical tones T.sub.k and N optical tones R.sub.k, k={1, 2, . . . , N}. Each of the N downlink channels D.sub.k is optically coupled to the optical comb generator and is configured to generate a respective downlink signal DS.sub.k that includes optical tone T.sub.k modulated by downlink data. Each of the N uplink-photodetectors PD.sub.k is configured to receive a respective one of a plurality of modulated uplink signals US.sub.k, having optical tone R.sub.k as a carrier signal.

An optical frequency comb setup including a semiconductor cascade laser drivable by a laser driver, emitting a laser beam through an end facet of the semiconductor cascade laser with a frequency comb with at least two given individual emission frequencies, repetition frequency, carrier envelope offset frequency shows improved comb stability and/or comb formation and/or comb bandwidth. This is achieved by an external cavity added outside of the cavity of the semiconductor cascade laser, having a reflective element with a mirror surface reflecting the at least two individual emission frequencies being arranged in a relative distance to the end facet allowing to adapt repetition frequency and/or carrier envelope offset frequency and/or the dispersion seen by the light in the optical frequency comb setup.

A laser source for emitting radiation in a given emission spectral band, centered on a given emission angular frequency, the central emission angular frequency is provided. The laser source comprises a laser cavity comprising a gain section having a known frequency dependent Group Delay Dispersion, and a GTI mirror arranged at one end of the gain section, having a known frequency dependent Group Delay Dispersion. The gain section and the GTI mirror are formed into a same laser medium, the laser medium having a known frequency dependent Group Delay Dispersion, and the gain section and the GTI mirror are separated by a gap of predetermined width filled with a dielectric medium thus forming a two parts laser cavity. Further, the GTI GDD at least partly compensates the sum of the Gain GDD and the material GDD in the emission spectral band.