A laser device includes: a substrate formed from material transparent at a laser wavelength; a first reflecting layer to reflect at least some incident radiation at the laser wavelength; a layer including a gain medium for providing stimulated emission of radiation at the laser wavelength, and positioned between the first reflecting layer and the substrate; a second reflecting layer on an opposite side of the substrate from the first reflecting layer to reflect at least some incident radiation at the laser wavelength; a spatial light modulator in an optical cavity comprising the first and second reflecting layers, and comprising an array of elements each corresponding to a different path for radiation in the optical cavity; and a computer controller that, during operation, causes the spatial light modulator to selectively vary an intensity or phase of radiation in the optical cavity to provide variable transverse spatial mode output of the radiation.

A label-free biosensor detection arrangement incorporating an external cavity laser (ECL) includes a tunable lasing element (e.g. an antireflection coated laser diode or semiconductor optical amplifier) and a narrow bandwidth resonant reflectance filter as the wavelength-selective element for the tunable lasing element. A sample is deposited on the surface of the resonant reflectance filter containing a biological material. The wavelength emitted by the external cavity laser is continuously tunable by binding interactions between the biological material and the resonant reflectance filter or adsorption of the biological material present in the sample on resonant reflectance filter. The narrow bandwidth resonance reflectance filter can take the form of photonic crystal (PC), a Bragg stack, or a Brag fiber reflection filter.

A narrow linewidth laser in which an all-optical feedback line-up is used to improve the linewidth from a conventional laser source, such as a laser diode. The feedback line-up comprises an optical device having a controllable unbalanced optical coupler arranged on a cavity input path to couple a source signal from the laser source into the optical cavity, and to couple a seed signal received back from the optical cavity into the laser source. The seed signal has a lower power than the source signal. The unbalanced optical coupler may be an optical isolator arranged to couple the seed signal into the laser source at a power level selected to promote preferential stimulated emission within a narrower linewidth. By controlling the power of seed signal such that only a small portion thereof influences the lasing cavity, the narrowing effect of the preferential stimulated emission can be enhanced.

A narrow linewidth laser in which an all-optical feedback line-up is used to improve the linewidth from a conventional laser source, such as a laser diode. The feedback line-up comprises an optical device having a controllable unbalanced optical coupler arranged on a cavity input path to couple a source signal from the laser source into the optical cavity, and to couple a seed signal received back from the optical cavity into the laser source. The seed signal has a lower power than the source signal. The unbalanced optical coupler may be an optical isolator arranged to couple the seed signal into the laser source at a power level selected to promote preferential stimulated emission within a narrower linewidth. By controlling the power of seed signal such that only a small portion thereof influences the lasing cavity, the narrowing effect of the preferential stimulated emission can be enhanced.

A tunable narrow-linewidth single-frequency linear-polarization laser device comprising a heat sink, a pumping source packaged on the heat sink, a first and second collimating lenses, a laser back cavity mirror, a thermal optical tunable filter, a rare-earth-ion heavily-doped multicomponent glass optical fiber, a super-structure polarization-maintaining fiber grating, a polarization-maintaining optical isolator, a polarization-maintaining optical fiber, and a thermoelectric refrigerating machine. The laser device uses a short and straight single-frequency resonant cavity structure, the heavily-doped and high-gain characteristics of the multicomponent glass optical fiber, a frequency selection role and wavelength tuning function of the thermal optical tunable filter and the superstructure polarization-maintaining fiber grating, and combines a precision temperature adjustment technology, and by means of real-time adjustment of distribution of reflection wavelengths and transmission wavelengths, the laser device changes spectrum peak overlapping positions, so as to implement stable output of wide-tuning-range, extra-narrow-linewidth, high-extinction-ratio and high-output-power continuously tunable single-frequency linear-polarization laser.

A tunable narrow-linewidth single-frequency linear-polarization laser device comprising a heat sink, a pumping source packaged on the heat sink, a first and second collimating lenses, a laser back cavity mirror, a thermal optical tunable filter, a rare-earth-ion heavily-doped multicomponent glass optical fiber, a super-structure polarization-maintaining fiber grating, a polarization-maintaining optical isolator, a polarization-maintaining optical fiber, and a thermoelectric refrigerating machine. The laser device uses a short and straight single-frequency resonant cavity structure, the heavily-doped and high-gain characteristics of the multicomponent glass optical fiber, a frequency selection role and wavelength tuning function of the thermal optical tunable filter and the superstructure polarization-maintaining fiber grating, and combines a precision temperature adjustment technology, and by means of real-time adjustment of distribution of reflection wavelengths and transmission wavelengths, the laser device changes spectrum peak overlapping positions, so as to implement stable output of wide-tuning-range, extra-narrow-linewidth, high-extinction-ratio and high-output-power continuously tunable single-frequency linear-polarization laser.

A technique related to a semiconductor chip is provided. An optical gain chip is attached to a semiconductor substrate. An integrated photonic circuit is on the semiconductor substrate, and the optical gain chip is optically coupled to the integrated photonic circuit thereby forming a laser cavity. The integrated photonic circuit includes an active intra-cavity thermo-optic optical phase tuner element, an intra-cavity optical band-pass filter, and an output coupler band-reflect optical grating filter with passive phase compensation. The active intra-cavity thermo-optic optical phase tuner element, the intra-cavity optical band-pass filter, and the output coupler band-reflect optical grating filter with passive phase compensation are optically coupled together.

A grating for line-narrowing a laser beam that is outputted from a laser apparatus at a wavelength in a vacuum ultraviolet region may include: a grating substrate; a first aluminum metal film formed above the grating substrate, the first aluminum metal film having grooves in a surface thereof; and a first protective film formed by an ALD method above the first aluminum metal film.

A tunable transmission optical filter is optically coupled between a laser section and semiconductor optical amplifier (SOA) section of a tunable laser device. The optical filter may be tuned to provide a high transmission near the lasing peak while suppressing a significant portion of back-propagating amplified spontaneous emission (ASE) of the SOA section. Without the optical filter, the laser output spectrum may develop side lobes of higher intensity after the ASE is amplified and reflected in the forward direction by the laser gain and mirror sections. While lessening the side lobes, the optical filter simultaneously transmits the laser peak for amplification by the SOA section.

A tunable transmission optical filter is optically coupled between a laser section and semiconductor optical amplifier (SOA) section of a tunable laser device. The optical filter may be tuned to provide a high transmission near the lasing peak while suppressing a significant portion of back-propagating amplified spontaneous emission (ASE) of the SOA section. Without the optical filter, the laser output spectrum may develop side lobes of higher intensity after the ASE is amplified and reflected in the forward direction by the laser gain and mirror sections. While lessening the side lobes, the optical filter simultaneously transmits the laser peak for amplification by the SOA section.