Elements info

The beam splitter divides incident light into reflected light and transmitted light. The ratio of reflected light and transmitted light varies depending on the reflectance and transmittance. Usually, 50:50 beam splitters with the same reflectance and transmittance are used.

A polarizing beam splitter divides incident light into P-polarized light and S-polarized light. Here, P-polarization refers to polarization parallel to the plane of incidence, and S-polarization refers to polarization perpendicular to the plane of incidence.

A polarizer passes through a certain amount of polarized light and blocks the light of polarization perpendicular to that light.

The Faraday Rotator rotates the polarization. A Faraday Mirror is an element that connects a mirror to a Faraday rotor that rotates polarized light by 45°. The polarized light rotated by 45° by the Faraday rotor is reflected in the mirror and then further rotated by 45° past the Faraday rotor, leaving the polarized light rotated 90° than the incident polarized light.

A wave plate is a device that phase shifts the polarization state of light between two vertical polarizing components and is called a phase retarder. A wavelength plate that makes the relative phase difference between the two vertical polarizing components π radians is called a half-wave plate, and a wavelength plate that makes π/2 radians is called a quarter-wave plate.

Optical fibers are fibers that are used as a means of transmitting light. A single-mode fiber is called a single-mode fiber because the diameter of the core, the center of light passing through the fiber, is so small that there is only one propagation mode of light. Polarization-maintaining fiber is a type of single-mode fiber, designed to maintain polarization aligned on either fast axis or slow axis unchanged, unlike single-mode fiber that transmits randomly polarized light.

A polarization controller is a device that changes the polarization state of light. It has the same effect as a combination of multiple wave plates on a wire.

An optical circulator is a device that allows light to pass only in certain directions. Light incident on port1 is output only on port2, light incident on port2 is output only on port3, and light incident on port3 is output only on port1.

A phase modulator is a device that changes the phase of light. Applying voltage to the phase modulator induces birefringence, resulting in phase shifts by induced birefringence. An intensity modulator is a device that modulates the intensity of light. As with the phase modulator, applying a voltage induces birefringence, and the induced birefringence causes a phase shift. The light generated by the phase shift is interfered with by a Mach-Zehnder interferometer within the light intensity modulator, which changes the intensity of the light.