An electro-optic modulator (EOM) for altering an optical path length of an optical field is described. The EOM comprises first and second Brewster-angle cut nonlinear crystals having a first and second optical axis. The optical axes are orientated relative to each other such that when an optical field propagates through the nonlinear crystals it experiences no overall deviation. The nonlinear crystals are also arranged to be opposite handed relative to the optical field. The EOM has the advantage that its optical losses are lower when compared with those EOMs known in the art. In addition, the EOM can be inserted into, or removed from, an optical system without any deviation being imparted onto the optical field. This reduces the levels of skill and effort required on the part of an operator. The described method and apparatus for mounting the nonlinear crystals also suppresses problematic piezo-electric resonances within the nonlinear crystals.

An integrated Ti:Sapphire laser device includes a substrate [100], a first waveguide resonator [102] composed of a gain medium integrated onto the substrate in a planar technology configuration, a frequency doubler [104] composed of a second order nonlinear material integrated onto the substrate in a planar technology configuration, and a second waveguide resonator [106] composed of a titanium doped sapphire gain medium integrated onto the substrate in a planar technology configuration.

There is described a device for generating electromagnetic field oscillation in a RF device or cavity. The device generally has a photo-diode configured for receiving a laser pulse train and emitting a first electrical signal based thereon, the first electrical signal having a plurality of frequencies; and a harmonics selector configured to output a second electrical signal having one or more frequency of the first electrical signal, the one or more frequency being selected in a manner for the output to generate the electromagnetic field oscillation in the RF device or cavity.

Embodiments of the disclosure provide a waveguide-confining layer, a photonic integrated circuit (PIC) die with embodiments of a waveguide-confining layer, and methods to form the same. The waveguide-confining layer may include an oxide layer over a buried insulator layer, a silicon-based optical confinement structure embedded within or positioned on the oxide layer, and first and second blocking layers over the oxide layer and separated from each other by a horizontal slot. The first and second blocking layers include a metal or an oxide. A gain medium is positioned on the oxide layer and within the horizontal slot between the first and second blocking layers, and has a lower refractive index than each of the first and second blocking layers. The gain medium is vertically aligned with the silicon-based optical confinement structure, and a portion of the oxide layer separates the gain medium from the silicon-based optical confinement structure.

Provided is a method for producing a crystal fiber which can suppress the occurrence of stress birefringence even while distributing a light emission center so as to concentrate on a cross-sectional middle portion. The method for producing a crystal fiber comprises the steps of: using, as a preform, the crystal fiber comprising a light emission center that volatilizes from a melted portion upon the melting of a crystal, and heating a portion or a plurality of portions of the side of the preform, whereby the portion or the plurality of portions of the preform are melted such that only a given amount of the inside of the portion or the plurality of portions of the preform is not melted, to form the melted portion; and sequentially transferring the melted portion in the longitudinal direction of the preform, and cooling the melted portion, whereby the melted portion is continuously recrystallized to form a recrystallized region.

A method and apparatus for passively synchronising the repetition rate of two or more mode-locked lasers is described. The method and apparatus involve forming a first synchronising optical field (6) by separating a portion of an output field of a first mode-locked laser (2) and thereafter redirecting this synchronising optical field to form a driving signal for a second mode-locked laser (3). Employing these techniques results in systems with timing jitter of less than 1 fs. The method is independent of the wavelength and polarisation at which the mode-locked lasers operate and so is not limited to use with any particular type of mode-locked laser. Since the technique is passive it does not require the employment of electronics, variable time delay paths or additional non-linear optical crystals. Therefore, the method and apparatus are significantly less complex than those known in the art and are not power limited by additional non-linear optical processes. Part of the output (7) of the first mode-locked laser (2) is redirected via a beam splitter (9) and beam steering mirrors (11,12) and a half-wave plate (15) to a polariser (13) in the beam line of the second mode-locked laser (3). The seeding and synchronising signal from the first mode-locked laser (2) may be perpendicularly polarized with respect to the polarization of the second mode-locked laser (3) and may have a different wavelength.

Methods, devices and systems that allow three-dimensional printing of material with high resolution are described. One example system includes a two-photon polymerization (TPP) subsystem including a first light source coupled to an optical fiber positioned to deliver a first laser light to a scanning optical device, and an optical projection subsystem comprising a second light source configured to provide a second light to a digital projection device. A dichroic mirror is positioned to receive light corresponding to the first and the second light source, and an objective lens positioned to provide illumination to a target material for 3D printing. The dichroic mirror is configured to allow light from one of the light sources to pass therethrough to the objective lens, and to allow light corresponding to the other light source to be reflected towards the objective lens to enable simultaneous illumination of the target material.

A laser device includes: a traveling wave type resonator comprising a first mirror and a second mirror; and a laser medium disposed between the first mirror and the second mirror. The first mirror and the second mirror are disposed such that round-trip light that travels in round trips in the resonator has a focus inside the laser medium. The laser device is configured such that: excitation light incident on the resonator is superimposed on the round-trip light at the focus and narrowed to be thinner than the round-trip light, Z.sub.R×α<0.5 is satisfied, where Z.sub.R is a Rayleigh length of the excitation light and α is an absorption coefficient of the laser medium with respect to the excitation light, and a round-trip Gouy phase shift of the resonator has a value excluding 2π×n/m where m is an integer of less than 15 and n is an integer of equal to or less than m.

A method and system for combining two or more optical fields is disclosed. A first continuous-wave high powered output field generated by a solid-state master laser is injected into a first solid state optical amplifier to produce a single output field from the laser system that exhibits a high phase-coherence with the output field of the master laser. The power of the output field equals the sum of powers of the master laser and that generated by the first optical amplifier, while exhibiting similar beams characteristics to that produced by the output field of the master laser i.e. it exhibits low noise, in a single transverse and longitudinal mode Gaussian beam, and has a single polarisation. The laser system is highly scalable in that N optical amplifiers may be located in series with the master laser to provide a single low noise, high power output field.

One illustrative laser disclosed herein includes a gain medium layer having a first width in a transverse direction that is orthogonal to a laser emitting direction of the laser, and an upper light-confining structure positioned above an upper surface of the gain medium layer, wherein the upper light-confining structure has a second width in the transverse direction that is equal to or less than the first width and comprises at least one material having an index of refraction that is at least 2.0. The laser also includes a lower light-confining structure positioned below a lower surface of the gain medium layer, wherein the lower light-confining structure has a third width in the transverse direction that is equal to or less than the first width and comprises at least one material having an index of refraction that is at least 2.0.