A depolarizer for a broadband optical source to split the source beam by power, not by polarization state, and route the components into respective light paths. A polarization rotator arranged in one of the light paths rotates the polarization state of that beam component to make it orthogonal to that of the other. The components are then recombined by a combiner and output. A variable optical attenuator is arranged in one of the light paths, which during operation is adjusted by a controller to maintain power equalization between the light paths and hence depolarization performance. The controller receives power measurements from the light paths and from after the combiner via respective sensors. With this feedforward design reminiscent of a Mach-Zehnder interferometer the light from a light source which generates highly polarized light can be depolarized in theory with zero insertion loss and in practice with losses of about 1 dB.

An optical aperture multiplier includes a first optical waveguide (10) having a rectangular cross-section and including partially reflecting surfaces (40) at an oblique angle to a direction of elongation of the waveguide. A second optical waveguide (20), also including partially reflecting surfaces (45) at an oblique angle, is optically coupled with the first optical waveguide (10). An image coupled into the first optical waveguide with an initial direction of propagation at an oblique coupling angle advances by four-fold internal reflection along the first optical waveguide, with a proportion of intensity of the image reflected at the partially reflecting surfaces so as to be coupled into the second optical waveguide, and then propagates through two-fold reflection within the second optical waveguide, with a proportion of intensity of the image reflected at the partially reflecting surfaces so as to be directed outwards from one of the parallel faces as a visible image.

The present invention discloses a device and a method for realizing spectral polarization-independent measurement based on a frequency domain depolarization structure. The device comprises a pump light source module, a depolarization module, an SBS effect generation module and a data acquisition and spectrum reconstruction module. The method comprises: emitting laser light having a fixed polarization state from the pump light source module; the laser light from an output end of the pump light source module passing through the depolarization module to become depolarized light; inputting the depolarized light as pump light into the SBS effect generation module to interact with signal light under test input from the outside into the SBS effect generation module; and after amplifying the signal light under test through the SBS effect generation module, performing data acquisition processing through the data acquisition and spectral reconstruction module and finally obtaining a spectrum of a signal under test. The present invention can eliminate the problems that the acquired spectral information is not accurate, the power measurement is not stable and the like when a spectral measurement device based on an SBS effect measures an input signal light having arbitrary polarization state, and has an important application prospect.

An optical aperture multiplier includes a first optical waveguide (10) having a rectangular cross-section and including partially reflecting surfaces (40) at an oblique angle to a direction of elongation of the waveguide. A second optical waveguide (20), also including partially reflecting surfaces (45) at an oblique angle, is optically coupled with the first optical waveguide (10). An image coupled into the first optical waveguide with an initial direction of propagation at an oblique coupling angle advances by four-fold internal reflection along the first optical waveguide, with a proportion of intensity of the image reflected at the partially reflecting surfaces so as to be coupled into the second optical waveguide, and then propagates through two-fold reflection within the second optical waveguide, with a proportion of intensity of the image reflected at the partially reflecting surfaces so as to be directed outwards from one of the parallel faces as a visible image.

An optical aperture multiplier includes a first optical waveguide (10) having a rectangular cross-section and including partially reflecting surfaces (40) at an oblique angle to a direction of elongation of the waveguide. A second optical waveguide (20), also including partially reflecting surfaces (45) at an oblique angle, is optically coupled with the first optical waveguide (10). An image coupled into the first optical waveguide with an initial direction of propagation at an oblique coupling angle advances by four-fold internal reflection along the first optical waveguide, with a proportion of intensity of the image reflected at the partially reflecting surfaces so as to be coupled into the second optical waveguide, and then propagates through two-fold reflection within the second optical waveguide, with a proportion of intensity of the image reflected at the partially reflecting surfaces so as to be directed outwards from one of the parallel faces as a visible image.

A polarization scrambler based on Faraday magneto-optic effect is disclosed. A polarization control unit (2) is connected between a first rotator unit (1) and a second rotator unit (3). The first rotator unit (1) includes a first optical fiber circle (11) and a first wire coil (12). The second rotator unit (3) includes a second optical fiber circle (31) and a second wire coil (32). ACs with two frequencies f1 and f2 are respectively introduced into the first wire coil (12) and the second wire coil (32), such that the ACs in the two wire coils are changed to control the polarization angle in the two optical fiber circles to independently change within the range of +/90. The polarization control unit (2) can ensure motion trajectories of outputted light polarization pointsare in two orthogonal directions, thus achieving uniform polarization disturbance.

The present invention discloses a device and a method for realizing spectral polarization-independent measurement based on a frequency domain depolarization structure. The device comprises a pump light source module, a depolarization module, an SBS effect generation module and a data acquisition and spectrum reconstruction module. The method comprises: emitting laser light having a fixed polarization state from the pump light source module; the laser light from an output end of the pump light source module passing through the depolarization module to become depolarized light; inputting the depolarized light as pump light into the SBS effect generation module to interact with signal light under test input from the outside into the SBS effect generation module; and after amplifying the signal light under test through the SBS effect generation module, performing data acquisition processing through the data acquisition and spectral reconstruction module and finally obtaining a spectrum of a signal under test. The present invention can eliminate the problems that the acquired spectral information is not accurate, the power measurement is not stable and the like when a spectral measurement device based on an SBS effect measures an input signal light having arbitrary polarization state, and has an important application prospect.

An optical aperture multiplier includes a first optical waveguide (10) having a rectangular cross-section and including partially reflecting surfaces (40) at an oblique angle to a direction of elongation of the waveguide. A second optical waveguide (20), also including partially reflecting surfaces (45) at an oblique angle, is optically coupled with the first optical waveguide (10). An image coupled into the first optical waveguide with an initial direction of propagation at an oblique coupling angle advances by four-fold internal reflection along the first optical waveguide, with a proportion of intensity of the image reflected at the partially reflecting surfaces so as to be coupled into the second optical waveguide, and then propagates through two-fold reflection within the second optical waveguide, with a proportion of intensity of the image reflected at the partially reflecting surfaces so as to be directed outwards from one of the parallel faces as a visible image.

Methods, systems, and apparatus, for optical depolarization. One optical depolarizer includes a light-combining module comprising a birefringent prism, wherein an optic axis of a first crystal of the birefringent prism forms a 90 angle with an optic axis of a second crystal of the birefringent prism; and a depolarization module, wherein the depolarization module is disposed at a light emitting end of the light-combining module, the depolarization module comprising a light splitting component and a light-combining component disposed at an emitting end of the light-splitting component, and a delayer disposed between the light-splitting component and the light-combining component, wherein the delayer is disposed on an emitting optical path of the light-splitting component.

Provided is a low-loss mode scrambler in which a steady mode distribution can be obtained in a short distance and switch to an entire mode distribution state is easy even when incident light is smaller than a numerical aperture of a fiber to be measured in a multimode fiber having a core diameter exceeding several tens of ?m and a numerical aperture of 0.2 or more. One fiber 2 is wound around a plurality of bobbins 3a and 3b having a radius larger than a minimum bending radius of the fiber to form a bundle, and the fiber 2 is twisted by rotating the bobbins 3a and 3b to form a twisted portion 5, whereby it is possible to perform output of a steady mode from light incident on the fiber 2.