A device includes an integrated structure of an input fiber, a first output fiber, an input splitting/combining device, a first output splitting/combining device, an input rotation device, a first output rotation device, a first lens, an isolator core, a second lens, a second output rotation device, a second output splitting/combining device, and a second output fiber. With the integrated structure, the device integrates functions of an optical isolator and an optical splitter. As an optical splitter, input of an optical signal into the input fiber are distributed to the two output fibers for output. As an optical splitter, the device can isolate light in opposite directions and can reduce damage to a light source at the input. In a system, the device can replace two conventional optical isolators and optical splitters and effectively reduce space, simplify the assembly process, and facilitate miniaturization and integration for systems.

Techniques for managing gain equalization error in optical communication systems are provided. For example, a multi-stage gain correction filter may be configured to at least correct gain equalization error produced by filters with insufficient resolution, for example, conventional non-reflective gain correction technology used in the optical communication systems. The multi-stage filter may include at least a broadband gain correction filter to correct gain equalization error in most of the transmission bandwidth and a narrow band gain correction filter to correction error in a narrow region of the bandwidth. One or more of the multi-stage filters may be implemented in the repeaters of the system (which may be referred to as hybrid GFFs) or may be included in a standalone body (which may be referred to as hybrid GEFs).

Disclosed is a device for interaction between a laser beam and a hyperfine energy transition of a chemical species. The device further includes an electro-optic modulator with a single sideband with an input optical waveguide suitable for receiving a source laser beam and an output optical waveguide suitable for generating an output laser beam and an electronic system suitable for generating and applying, simultaneously, a first modulated electrical signal, sin(Ω.sub.1t)) to a first hyperfrequency pulse on a first high-frequency electrode of the electro-optic modulator and, respectively, another modulated electrical signal, cos(Ω.sub.1t)) to the first pulse on another high-frequency electrode of the electro-optic modulator, in such a way as to frequency-switch the output laser beam to a first optical frequency offset from the first pulse with respect to the initial optical frequency.

A hybrid optical amplifier is proposed that includes a preamplifier element formed of single-clad Ho-doped optical fiber and a power amplifier element formed of single-clad Tm-doped (or Tm—Ho co-doped) optical fiber. The preamplifier is used to impart gain to an input signal propagating at a wavelength λ.sub.S in the presence of a first pump beam operating at λ.sub.P1, creating an amplified output over a defined transmission bandwidth. The power amplifier element is disposed at the output of the preamplifier element and provides an additional level of gain to the output of the preamplifier element in the presence of a second pump beam operating at λ.sub.P2. A passband filter may be used between the preamplifier and the power amplifier to ensure that only wavelength components within the defined transmission bandwidth are applied as an output to the power amplifier.

An optical fiber amplifier comprising a first optical fiber, a second optical fiber, a third optical fiber, and an excitation light source, is disclosed. Each optical fiber has cores and a cladding surrounding the cores. The third optical fiber transmits excitation light used for signal amplification in the second optical fiber. A rare-earth element is doped to the second optical fiber that amplifies an optical signal propagating therein by the excitation light. The third optical fiber includes a reduced-diameter portion. A distance between the cores of the third optical fiber in the reduced-diameter portion is shorter than a distance between the cores in other portion of the third optical fiber, and the excitation light entering from the excitation light source to one of the cores of the third optical fiber is mode-coupled with another core of the third optical fiber to distribute the excitation light in the reduced-diameter portion.

In one embodiment, a package includes: a substrate; a photonic integrated circuit (PIC) adapted to the substrate, the PIC including at least one optical circuit, a first plurality of waveguides, a second plurality of waveguides, and a laser to output optical energy via the first plurality of waveguides; and a prism assembly adapted to the substrate to reflect the optical energy output from the first plurality of waveguides to the second plurality of waveguides, the prism assembly including a prism and at least one isolator. Other embodiments are described and claimed.

An optical apparatus and method of using same. The optical apparatus includes a vortex optical isolator including an axis. The vortex optical isolator includes a first amplitude mask defining a first limiting aperture and aligned with the axis. The first limiting aperture includes a first radius. The vortex optical isolator includes a first lens aligned with the axis. The vortex optical isolator includes a vortex phase mask aligned with the axis. The vortex optical isolator includes a second lens aligned with the axis. The vortex optical isolator includes a second amplitude mask defining a second limiting aperture aligned with the axis. The second limiting aperture includes a second radius sufficiently smaller than the first radius so as to block reverse light traveling through the optical apparatus. The apparatus includes a standard light source configured to transmit forward light through the vortex optical isolator.

A semiconductor laser diode light source package includes: a seed light source for outputting signal beams; a pump beam source for outputting pump beams; and at least one mirror for transmitting the signal beams to a core of an output optical fiber and transmitting the pump beams to first cladding of the output optical fiber, wherein the seed light source, the pump beam source, and the at least one mirror are realized in a semiconductor chip, and the output optical fiber is connected to an end terminal of the semiconductor laser diode light source package.

A method and a system are provided to simultaneously generate blue-shifted and red-shifted femtosecond light sources with tunable spectral peak location and bandwidth, by controlling the input condition (chirp/spectrum) of a fiber-optic nonlinear propagation. The system comprises (A) a seed source, (B) a driving current controller to regulate the spectrum of the seed source, (C) a dispersion controller to control the chirp and pulse width of the seed source, (D) a fiber-optic spectral conversion module to shape and broaden the laser spectrum via fiber-optic nonlinear processes, and (E) a spectral selection module to filter out the required wave packets. With the simultaneous uses of the driving current controller and the dispersion controller, the light sources feature continuously tunable spectral peak with (1) a relatively constant output pulse energy or (2) a tunable spectral bandwidth at a specific peak location.

An ultraviolet laser apparatus includes an oscillation-stage laser, an amplifier that amplifies the pulse laser light, and an optical isolator. The optical isolator includes a first Faraday rotator that rotates the polarization direction of the pulse laser light output from the oscillation-stage laser by a first angle in a first rotation direction, a first polarizer so disposed to transmit the pulse laser light that exits out of the first Faraday rotator at normalized transmittance greater than or equal to 0.9, a second Faraday rotator that rotates the polarization direction of the pulse laser light passing through the first polarizer by a second angle in the opposite direction to the first rotation direction, and a second polarizer so disposed to transmit the pulse laser light that exits out of the second Faraday rotator at the normalized transmittance greater than or equal to 0.9.