摘要:
A polarized light synthesizing apparatus has a lens assembly including a securing member for securing ends of a plurality of optical fibers which can propagate light having different polarization components and a lens for converting the plural kinds of polarization component light emitted from the optical fibers into collimated beams, and a birefringent member for polarization-synthesizing the plural kinds of polarization component light as the same optical axis using a difference in refractive index characteristic between the plural kinds of polarization component light emitted from the lens, thereby largely decreasing a packaging size of the apparatus while keeping functions of a known optical circuit device, a required resistance to light, reliability and readiness of fabrication.
摘要:
A wavelength division multiplexing module capable of multiplexing or demultiplexing a plurality of optical signals having close wavelengths with less crosstalk. The wavelength division multiplexing module includes a housing having a bottom wall, a first side wall, and a second side wall inclined a predetermined angle with respect to the first side wall, and a common port assembly fixed to the bottom wall of the housing so as to emit a collimated beam substantially perpendicular to the first side wall. One or more filter port assemblies are fixed to the first side wall in the condition that the pass wavelength characteristic and optical axis of each assembly have been adjusted. Similarly, one or more filter port assemblies are fixed to the second side wall in the condition that the pass wavelength characteristic and optical axis of each assembly have been adjusted. Each filter port assembly includes an optical film holder rotatable in a hole having a center axis inclined a predetermined angle .theta.1 with respect to the optical axis, and a band-pass filter mounted in the optical film holder so as to be inclined a predetermined angle .theta.2 with respect to a plane normal to the center axis of the hole of the optical film holder.
摘要:
A polarization coupler in which a polarization maintaining fiber is employed and a process of producing such polarization coupler are disclosed. Where the polarization coupler is used, beams of light from two laser diodes can be introduced into a single optical fiber and light for the monitoring can be split from a main signal output. Since minimum components required to realize the function are a rotator, a birefringent plate and two or three polarization maintaining fibers, the polarization coupler is superior in operability in production and is suitable for miniaturization. The branching ratio of light for monitoring can be adjusted by adjustment of the angle of rotation of light by the rotator.
摘要:
An optical apparatus which is reduced in the number of optical devices arranged on a main optical signal transmission path, thereby reducing the size and cost of the device, and which is improved in optical transmission quality. An optical amplifier includes an amplification medium, which is doped with an active material for optical amplification and to which pump light is introduced, for amplifying an optical signal to be output. A reflection-type variable optical attenuator includes a reflecting mirror for reflecting an input light to generate a reflected light, and a magneto-optical crystal arranged in a position where the input and reflected lights pass. The magneto-optical crystal is applied with a magnetic field to induce a Faraday rotation angle therein and thereby vary an attenuation amount of the amplified optical signal, and part of light transmitted through the reflecting mirror is converted, as input monitor light, into an electrical signal.
摘要:
A movable mirror having a mirror surface reflecting a light input from an input fiber collimator is moved in an arrow (1) direction so that the reflection frequency of the input light reflected by an optical filter can be variable. The light is reflected plural times between the mirror surface and the optical filter, directed to a fixed mirror by the mirror surface, reflected by the fixed mirror, and is connected to an output fiber collimator. By moving the movable mirror in parallel, the reflection count of the light between the optical filter and the mirror surface is variable. Therefore, the wavelength characteristic of the light is obtained as an accumulated wavelength characteristic depending on the reflection count.
摘要:
Disclosed herein is an optical amplifier reduced in gain deviation. The optical amplifier includes a nonsilica fiber doped with a rare earth, and a fiber holder in which the nonsilica fiber is inserted and fixed. The fiber holder is optically arranged so that signal light to be amplified propagates in the nonsilica fiber. The nonsilica fiber is pumped so that the nonsilica fiber provides a gain band including the wavelength of the signal light. Opposite ends of the fiber holder are hermetically sealed to thereby easily cut off the nonsilica fiber from the outside air, so that the nonsilica fiber is stabilized physically or chemically. A fluoride glass fiber is suitable for the nonsilica fiber to reduce the gain deviation in a 1.55 &mgr;m band.
摘要:
The invention provides an optical device suitable for use with an optical amplifier, for example, in an optical communication system and advantageous in that different functions of a plurality of optical elements are achieved using an optical element of a simple construction and the optical device can be produced in a reduced size at a reduced cost. The optical device includes a tapered prism constructed such that a first face and a second face thereof opposing to each other do not extend in parallel to each other. A dielectric multi-layer film is formed on the first face of the tapered prism positioned on an optical signal inputting side. A reflection film is formed on the second face for reflecting the optical signal inputted to the tapered prism through the first face at least once toward the first face. A non-reflection film is formed on one of the first face, the second face and the other face or faces of the tapered prism for extracting therethrough the optical signal inputted to and reflected in the tapered prism.
摘要:
An optical repeater having a first optical amplifier for a first optical fiber transmission line and a second optical amplifier for a second optical fiber transmission line. Each of the first and second optical amplifiers has a doped fiber doped with a rare earth element, a pumping light source for outputting pumping light, a supplying optical coupler for supplying the pumping light to the doped fiber, and an extracting optical coupler for extracting the pumping light. Each extracting optical coupler has an exchange port for outputting a part of the pumping light remaining in the corresponding doped fiber after pumping. The optical repeater further has an optical fiber for connecting the exchange ports in the first and second optical amplifiers to exchange the pumping light. With this configuration, even if one of the pumping light sources has failed, the pumping light from the other pumping light source is supplied to both doped fibers, thereby making the optical repeater have redundancy.
摘要:
A polarization independent optical device capable of eliminating the apparent polarization dependence of a dielectric multi-layer film and permitting the design of an optical path at an optional angle of incidence of light beam. The polarization independent optical device comprises a tapered double-refractive crystal disposed so that an optic axis thereof is perpendicular to an incident optical path, and a dielectric multi-layer film disposed on an exit side of light beam with respect to the tapered double-refractive crystal.
摘要:
A polarization beam coupler adapted to produce an output light beam for monitoring is disclosed. The polarization beam coupler includes a polarization beam coupling cube for coupling two incident light beams having polarization planes perpendicular to each other and projecting the coupled light beams on the same optic axis, a beam splitting cube having a beam splitting film formed from a dielectric multi-layer or single-layer film for extracting a monitor beam, and a quarter-wave plate interposed between the polarization beam coupling cube and the beam splitting cube such that incident light beams to the beam splitting cube may be circularly polarized light. Due to the construction, the output level of a monitor light beam can be prevented from depending upon the polarization planes of the incident light.