Showing papers on "Waveplate published in 1991"

Full color three-dimensional flat panel display

Abstract: A full color liquid crystal flat panel display having a step waveplate (22) provides one-quarter and three-quarter wave phase retardation to alternating rows (24, 26) which provide left and right views. The resulting right and left views are circular polarized in opposite directions which to a viewer wearing circularly polarized glasses (23) provides the left and right views to the appropriate eye such that the viewer is able to see full color three-dimensional images.

Polarization illumination device and projector having the same

Abstract: A polarization illumination device and projector having the polarization illumination device are provided. An example of the polarization illumination device comprises an illuminator (1,2) and a polarizer (5). The polarizer comprises a polarization splitting surface (54) and a reflecting surface (53), which form an inverted V shape. The splitting surface (54) splits part of the light into a transmitted component (Lp) and a reflected component (Ls) and directs the former in a first direction and the latter is reflected back to the illuminator by the reflecting surface. the reflecting surface reflects a remaining part of the light and directs it toward the splitting surface. The splitting surface reflects one component back to the illuminator and transmits the other component toward a second direction different from the first direction. The light components reflected back to the illuminator change their plane of polarization by traversing the quarter waveplate twice before being incident on the polarizer again.

Birefringent structures formed by photo-exposure of polymer films and method for fabrication thereof

Abstract: A birefringent structure useful as a waveplate, grating, a hologram, a beam separator, a digital data storage medium or the like is formed by photo-exposure causing photo-reaction between photons and polymeric structures. In a specific embodiment, birefringence is induced by applying optical energy to a polymer film such as a polysilane with sufficient intensity to excite nonlinear absorption in the polymer film such that a pattern of the exposing optical energy is recorded in the polymer film. The optical energy is of a distinct polarization state such that the nonlinear optical ef BACKGROUND OF THE INVENTION This invention was made under contract with or supported by the United States Air Force Office of Scientific Research under Contract No. AFOSR-88-0354. The Government has certain rights in this invention.

Scanning microscope with means for detecting a first and second polarized light beams along first and second optical receiving paths

Abstract: A scanning microscope comprises a sample supporting member for supporting a sample, and a light source for producing a light beam including a light component, which has been polarized linearly in a first direction, and a light component, which has been polarized linearly in a second direction that intersects perpendicularly to the first direction. A first polarizer transmits only the light component, which has been polarized linearly in the first direction. A second polarizer transmits only the light component, which has been polarized linearly in the second direction. A light projecting device forms a small spot of the light beam composed of the light components, which have respectively passed through the first and second polarizers. The sample is scanned with the light spot. A beam trap having a light blocking part, which has a shape corresponding to the shape of the first polarizer, blocks only the direct light component, which has been polarized linearly in the first direction and has passed through the sample. A polarization beam splitter separates the two light components from each otehr which are included in part of the light beam having passed through the sample and then through the beam trap. First and second light receiving devices respectively forms point images of the two separated light components.

Light wave polarization determination using a hybrid system

Abstract: Apparatus and method for determining dynamically the polarization vector direction, or polarization vector components and associated temporal phase angle, of a light beam. The apparatus includes a compact polarization beam splitter that receives a beam of light, separates the beam into two perpendicular polarization components and directs these components to a pair of optical detectors and associated circuits that form the sum and difference signals of the electrical signals produced by the optical detectors. This produces a projection of the polarization vector on a given direction. If the light is generally elliptically polarized, use of two such polarization beam splitters and four optical detectors allows reconstruction of the polarization ellipse for the light beam. Alternatively, use of one such polarization beam splitter, two optical detectors and a rotating wave plate in a multiplexed configuration allows reconstruction of the polarization ellipse. The polarization detector is very compact and may be housed in a container that is no more than a few cm. in diameter.

Contamination detection system

Abstract: A system for detecting minute amounts of water contaminant in semi-conductor microelectronic integrated circuits (MIC) includes two lasers 11,12 producing electromagnetic radiation at two discrete wavelengths. Each laser beam being sent through a chopper 13 and 14 respectively and combined via mirror 16 and beam splitter 17 to form a single two part beam along optical axis 22. The beam passes through a reflective beam splitter 26, a quarter wave plate 28 and lens 29 to be directed to a MIC 31 that is mounted onto drive mechanisms 31 and 32. Diffuse reflections from the bottom of the MIC or specular reflections from metallization layers pass back through MIC 31, lens 29, quarter wave plate 28, beam splitter 27 and through lens 48 to detector 47 which compares the intensity of the radiation at the two wavelengths with the intensities of the wavelengths as detected by detector 21 through a lock-in amplifier 49.

Polarization independent waveguide type optical device

Abstract: PURPOSE:To provide the polarization independent waveguide type optical device which eliminates the polarization dependency on incident signal light. CONSTITUTION:One piece or >=2 pieces of polarization rotating devices 11 for converting a horizontally polarized wave (TE) to a vertically polarized wave (TM) or the vertically polarized wave to the horizontally polarized wave are installed in the mid-way of the waveguide in such a manner that the optical path length to the input of the horizontally polarized wave and the optical path length of the input light of the vertically polarized wave are equal to each other.

Primary radiator in common use with circularly polarized wave and linearly polarized wave

Abstract: PURPOSE: To make the size of the primary radiator small by providing an output means for an electromagnetic wave introduced into a circular waveguide to a side face of a circular waveguide facing a phase circuit at a termination face side so as to reduce the length of the circular waveguide. CONSTITUTION: A 1st phase circuit (metal ingots 3, 4), a rotary type 2nd phase circuit (dielectric plate 7), and a square waveguide 5 are bonded to a side face of a circular waveguide 2 facing the 2nd phase circuit in this order on the circular waveguide 2 from the side of an opening 1 toward a termination face 8. In the case of receiving a circularly polarized wave, the wave is converted into a linearly polarized wave by the 1st phase circuit, the dielectric plate 7 is directed in a direction in which the phase between two linearly polarized wave components is unchanged and a signal is outputted from a square waveguide 5. In the case of receiving a linearly polarized wave, a phase difference caused in the 1st phase circuit with respect to between the two polarized wave components is made in phase by turning the dielectric plate 7 and one linearly polarized wave signal is outputted from the square waveguide 5. Then the dielectric plate 7 is turned so as to set the phase difference to be nearly 180° and the other linearly polarized wave signal is outputted from the square waveguide 5 to reduce the length of the waveguide 2. COPYRIGHT: (C)1993,JPO&Japio

Compensation for temperature dependence of Faraday effect in diamagnetic materials: application to optical fibre sensors

Abstract: The temperature dependence of the Faraday effect in a diamagnetic material can be compensated for by varying the polarisation state of the light entering the material as a function of temperature. The authors demonstrate that this can be done automatically by exploiting the temperature dependence of a linear retarder (waveplate).

Fringe pattern analysis of a birefringent modified spectrum to determine environmental temperature

Abstract: A sensor for use in an optical temperature detector system having a birefringent element made of a single crystal metal oxide plate. A broad band light spectrum is transmitted through a first linear polarizing element to create a linearly polarized wave. The linearly polarized wave on passing through the single crystal metal oxide plate decomposes into first and second orthogonally polarized waves. Propagation of the linearly polarized wave through the birefringent single crystal metal oxide plate introduces a temperature dependent phase shift between the two waves. Thereafter, a second linear polarizer combines the first and second orthogonally polarized waves to create a modulated light spectrum having a fringe pattern, the fringe pattern being a function of the current temperature experienced by said birefringent element. A fiber optic cable connected to the second linear polarizing element carries the modulated light spectrum to an opto-electronic interface where the fringe pattern is extracted and a computer compatible signal is generated for a CPU to accurately indicate current environmental temperature conditions up to 1000° C. experienced by the single crystal plate crystal in the birefringent element.

Intensity noise enhancement in the half-wave plate/polarizer attenuator

Abstract: The conventional optical attenuator for linearly polarized light is usually constructed with a half-wave retardation plate and a polarizer. With one axis of the polarizer aligned so as to transmit the incident beam fully, the addition of the half-wave plate causes the output power to follow a cos(2) 2theta dependence, where theta is the angle between the optic axis of the wave plate and the incident polarization. When the incident light has an additional orthogonal polarization component, the output power dependence becomes more complex and depends on the correlation between the two polarization fields ?E(x)E(y)?. More significantly, if amplitude noise in the polarization fields is correlated, the attenuator will couple the noise processes, which results in relative power fluctuations that increase as the optical power is reduced. The noise produced by this coupling may even exceed the noise of either polarization state alone. Measurements of the statistical behavior of the relative intensity noise of a cw modelocked Nd:YAG laser as a function of the wave-plate angle showed more than a tenfold increase when the output power was reduced to near minimum. In addition, the noise was found to be asymmetrical about the minimum power point, theta = 45 degrees . It is shown that the simple addition of a polarizer ahead of the wave plate strips off the unwanted polarization field and virtually eliminates this added noise effect.

Magneto-optic reproducing device using right and left circularly polarized light

Abstract: A reproducing optical device for a magneto-optical recording medium related to the present invention having light sources that emit linearly polarized lights towards a magneto-optical recording medium, polarization directions of the linearly polarized lights being mutually orthogonal. A quarter wavelength plate disposed between the recording medium and the light sources converts each of the linearly polarized lights into right and left circularly polarized lights respectively. Corresponding to recorded information, the recording medium has magnetized sections that are magnetized in a perpendicularly upward and downward direction with respect to a medium surface. Moreover, the recording medium displays the property of circular dichroism. When the right circularly polarized light and the left circularly polarized light are reflected off the recording medium, a first and a second photodetector generate a first and a second reproduced signal respectively, based on variation in reflected light intensity of each of the circularly polarized lights. This variation corresponds to the upward and the downward magnetization directions of the magnetized sections and is due to the circular dichroism effect. There is a phase difference of half a cycle between the first and the second reproduced signal and the signals vary inversely with respect to each other. Consequently, disk noise is cancelled by differentially amplifying the first and the second reproduced signal, and an SN ratio of a reproduced signal thereby can be improved.

Circularly polarized light generator

Abstract: PURPOSE:To stably obtain the light beam of circularly polarized light by providing a quarter wave plate which is disposed with 45 deg. deviation in the main axis bearing with respect to the polarization direction of the light beams of P polarized light component and S polarized light component and converts the light beam multiplexed by a polarized light multiplexing element to the circularly polarized light. CONSTITUTION:The positions of reflecting mirrors 18, 19 are so set that the optical path length of the light beam 15 of the S polarized light component is longer by the length corresponding to the coherence length of monochromatic light 13 than the optical path length of the light beam 14 of the P polarized light component. The light beam 20 which is made incident on the quarter wave plate 12 after the multiplexing is, therefore, preserved in the straight polarization state without becoming elliptically polarized light. The quarter wave plate 12 is disposed by deviating the main axis bearing thereof by 45 deg. with polarization direction of the light beam 14 of the P polarized light component and the light beam 15 of the S polarized light component so that the incident light beam 20 is converted to the light beam 21 of the circularly polarized light. The light beam of the complete circularly polarized light of always the specified output is easily obtd. in this way.

Interferometric technique for measurement of nonreciprocal optical effects in a sample

Abstract: A method and apparatus for measuring nonreciprocal optical effects contemplates directing two circularly polarized optical beams having a known phase relation to each other at a sample, and detecting the difference in phase between the two beams after they have encountered the sample. In a transmission measurement the two circularly polarized beams have the same handedness, but pass through the sample in opposite directions. In a reflection measurement, the two circularly polarized beams have opposite handedness, but encounter the sample in the same direction. In a particular embodiment of the invention a linearly polarized beam is introduced into a Sagnac interferometer and split into two linearly polarized beams which are ultimately recombined.

Measurement of crystal retarders.

Abstract: We describe procedures for measuring retardation, the uniformity of retardation, and optical axis alignment of birefringent crystals.

Non-contaction survey instrument with three dimension surface shape

Abstract: The invention relates to a kind of surface three-dimension noncontact surveying instrument which belongs to optical surveying instrument and is used for surveying surface microcosmic geometric figure and its roughness. The invention surveying instrument mainly composes of light source, polarizer, light selective prism mirror, micro-objective lens, 1/4 wave plate, deviation detector, and photoelectrical surface matrix detector. Comparing with the existing technique, the advantages of the invention are: resolution factor is high, the structure of shifting assemblage is simple, the prevision of shift is higher, two bands of interference ray pass through the same light path, the interference encountered from outside are same, the influence intensity of interferonce light is less, so that, the system is not sensitive against the influence of mechanical vibration and strength and can be used in usual production environment.

Optical modulation device and display apparatus

Abstract: An optical modulation device is constituted by a polarizer; a first film forming a first state and a second state depending on an electric field applied thereto, the first state causing birefringence and the second state not causing birefringence respectively of polarized light from the polarizer, the first film having a thickness set for functioning as a halfwave plate in its first state; and a second film not causing birefringence of light having passed through the second state of the first film but causing birefringence of light having passed through the first state of the first film, the second film having a thickness set for functioning as quarter wave plate or a halfwave plate when the first film is set in its first state. The light from the second film is caused to enter the second film again through a reflection means or a third film selectively forming a first state causing birefringence of light which has caused birefringence and passed through the second film or a second state not causing birefringence of light which has passed through the second film without causing birefringence. The light thus modulated is then caused to enter an analyzer. As a result, an optical modulation giving a large contrast is provided by using a material having a small birefringence effect for the first film or third film.

Detecting method of shape of object

Abstract: PURPOSE:To enable improvement of precision in measurement of a shape by disposing a polarization control means and an analyzer sequentially on the optical axis of a reflected light from the surface of an object and by intercepting selectively a light being different in the number of times of reflection CONSTITUTION:A linearly-polarized parallel beam generated by a laser light source unit 31 is passed through a lambda/2 wave plate 32 and turned into a light having an arbitrary azimuth angle and falls on a galvanomirror 34 which is made to vibrate by the drive of a motor 33, and thereby scanning of the beam is conducted The beam reflected by the mirror 34 is condensed by a scanning lens 35 and applied to an object 36 The mirror 34 and a stage 37 are controlled synchronously and independently by a computer control so that an image of the object 36 be sensed An image sensing system is constructed by arranging an imaging lens 38, a lambda/4 wave plate 39, an analyzer 40 and PSD 41, a position detecting means, sequentially on the optical axis of a reflected light The lambda/4 wave plate 39 is equivalent to a polarization control means which controls the direction of polarization of the reflected light Even when a light reflected in a plurality of times enters the lens 38, only a light reflected one time is detected by the PSD 41, according to this constitution, and thus the precision in measurement of a shape can be improved

Real image type finder optical system

Abstract: PURPOSE:To minimize the decrease of a light quantity and to substantially eliminate the change in characteristics by gravity by providing a mirror consisting of a refracting power varying member in the finder optical system and disposing a quarter wave plate opposite to this mirror. CONSTITUTION:The refracting power varying mirror is constituted by sealing a nematic liquid crystal 4 which is an optical material to exhibit double refractiveness in the Fresnel lens-like space formed by sticking of a transparent substrate 1 and the quarter wave plate 2 via an insulating spacer 3. Transparent conductive layers 5, 6 and liquid crystal oriented films 7, 8 are formed on the inside surface thereof and the reflecting mirror 9 and a base plate 10 are provided on the surface of the quarter wave plate on the side opposite from the liquid crystal layer. Since this refracting power varying mirror acts as a compensator which does to move, the number of parts is reduced. Since the entire part of the natural light is utilized, the decrease in the light quantity is slight and the distortions of the lenses, etc., of the optical system are not visible, unlike the refracting power varying mirror formed by using a polarizing plate. The refracting power varying mirror of the liquid crystal type requires a slight driving electric power and is free from the change in the characteristics by gravity.

Evaluating device for optical disk substrate

Abstract: PURPOSE:To allow the simple and rapid evaluation on a molding site by irradiating an optical disk with circularly polarized light, branching the 1st order diffracted light and transmitted light from the disk to the double refracted light and non-diffracted light branched by a quarter-wave plate and a beam splitter and measuring the light intensities of these light rays. CONSTITUTION:The P polarized laser beam 1 is polarized from the linearly polarized light to the circularly polarized light by the beam splitter 16 and the quarter-wave plate 5. The disk 6 to be inspected is irradiated with this beam. The 1st order diffracted light I3 is made incident on a 1st order diffracted light receiving sensor 15. On the other hand, the irradiating light transmitted through the disk 6 is polarized to the linearly polarized light by the quarter- wave plate 7 and is branched to double refraction component light I1 and non- double refraction component light I2 by a beam splitter 17. These light rays are made incident to a double refraction component light receiving sensor 9 and a non-double refraction component light receiving sensor 18, by which the light intensities of the light rays I1 to I3 by the light for irradiation of the same optical axis are measured and the evaluation of the disk substrate on the molding site is executed by this constitution in this way.

Polarimeter arrangement for measuring polarisation plane rotation - has half wave delay plate with electrical rotation of main optical axis

Abstract: A polarimeter arrangement contains a half wave delay plate (20) in the beam path of a light beam (10, 11). The plate has an electrical arrangement (22) for rotating its main optical axis at a defined rate of rotation. The half wave plate can be physically rotated or can have electro-optically rotatable main optical axes. The electrical rotation arrangement is associated with a device for deriving a phase reference signal (RS). USE/ADVANTAGE - Measuring rotation of polarisation plane of linearly polarised light beam in measurement path (7) using heterodyne method and tehcnically simple rotation technique.

Method and apparatus for measuring progressive linearity of moving body

Abstract: PURPOSE:To measure the progressive linearity of a moving body with a high accuracy by detecting the polarization angle of light emitted from wavelength phase difference means and calculating a displacement in a direction orthogonal to the moving direction of the moving body on the basis of the polarization angle. CONSTITUTION:Coherent light is emitted from a laser oscillator 11. The coherent light is polarized 13 to become linear polarized light and incident on a reflecting cell 14. Then, reflected from a reflecting surface 14b, the linear polarized light progresses in a direction orthogonal to a crystal axis. At this time, since a normal light component P and an abnormal light component S are different in a refractive index, a phase difference is generated and the linear polarized light becomes elliptically polarized light. Reflected from a reflecting surface 14c, the elliptically polarized light is emitted from the cell 14 and incident on a quarter wave plate 15. When the oscillation planes of an analyzer 16 and of the linear polarized light emitted from the quarter wave plate 15 agree with each other, the maximum quantity of passing light can be obtained and, when both the planes become vertical to each other, the quantity of the passing light becomes zero. The passing light is incident on a photomultiplier 17. Thus, a photoelectrically converted output is obtained from the photomultiplier 17 in accordance with the quantity of the passing light to be inputted to an arithmetic unit 18.

Method and apparatus for inspecting molding strain of resin

Abstract: PURPOSE:To enable execution of stable strain detection with high resolution and to simplify an image processing by taking in an image of a strain by a line camera and by combining the camera with a signal processing element extracting a change in luminance in the radial direction. CONSTITUTION:A light of a specific wavelength is selected by a single wavelength filter 13 from a light emitted from a light source 12, and it is diffused uniformly in the visual field of a line camera 20 by a diffusing plate 14 and reaches a polarizing plate 15. By the operations of the plate 15 and a 1/4 wave plate 16, a single wavelength light turning to be a circularly-polarized light is made to fall on the lower side of an optical disk 1 and the light transmitted therethrough is taken in the camera 20 through a 1/4 wave plate 21 and a polarizing plate 22. A video signal showing the luminance of the visual field of the camera is inputted to a processing element 25, subjected to A/D conversion, sent to a processing element 26 and subjected to floating binary coding and filtering and thereby a place wherein the luminance changes sharply is extracted. A signal of extraction is stored in a memory 27 and a point whereat the luminance changes sharply in comparison with the surroundings is determined to be a strain defect.

Fizeau interferometer for polarized light

Abstract: PURPOSE:To make it possible to give a change in phase and a change in amplitude discretely to each of an object light and a reference light by making the directions of polarization of the two lights intersect each other perpendicularly. CONSTITUTION:Light coming out of a light source 1 passes through a beam expander 2 and a polarizing plate 3 and is turned thereby into linear polarized light. This light is divided by a half mirror 4 and enters a 1/4 wave plate 5. Part of the incident light is reflected to be reference light by a translucent reference surface H just before it enters the 1/4 wave plate 5. An optical axis of the plate 5 is disposed at an angle of 45 degrees to the direction of polarization of the incident light. Therefore an object light reflected on an object 6 of measurement is changed in the direction of polarization by 90 degrees by passing twice through the plate 5. These reference light and object light processed together toward a surface 8 of observation, with the directions of polarization which intersect each other perpendicularly. Since the directions of polarization of the object light and the reference light are made to intersect each other perpendicularly in this way, the object light and the reference light can be separated from each other on the basis of the direction of polarization. According to this constitution, the phases and amplitudes of the object light and the reference light can be operated discretely and freely and thus precision in measurement is improved.

Liquid crystals for lasercom applications

Abstract: Nematic liquid crystals (NLCs) have electronically tunable birefringence and can be used as voltage-controlled switches for channel or redundancy beam switching in a lasercom terminal. To assess the performance of such a switch, we have evaluated the operating voltage, transmission efficiency, polarization crosstalk, and long-term operational reliability of an NLC device at four laser diode wavelengths. Preliminary results are encouraging. Transmission is around 95 percent, and polarization rotation purity is comparable to that obtained with a quartz or polymer waveplate, making this solid-state, voltage-controlled waveplate competitive with a conventional implementation that uses a mechanically inserted or rotated half-wave plate.

Ultrasonic sensor using a polarization maintaining fibre

Abstract: An ultrasonic sensor having a polarization maintaining fibre including two orthogonal linear principal axes and a straight sensing portion. A laser source directs a beam through a quarter wave plate to provide a circularly polarized beam to an input end of the fibre. The beam emerging from an output end of the fibre is directed to a linear polarizer and the intensity of the beam is detected by a photodetector. A signal processor thereafter generates suitable driving signals for a display unit indicative of mode coupling induced in the fibre by incident ultrasonic waves.

Light wave interference type apparatus for measuring microscopic thermal displacement

Abstract: PURPOSE:To measure thermal expansion and thermal shrinkage of a sample in a noncontact manner and precisely by using lights which have polarization components intersecting each other perpendicularly and frequencies being different slightly from each other, and by making reflected lights from measuring and standard samples interfere with each other. CONSTITUTION:As S polarized light from a beam splitter 14 is modulated by acoustooptic elements 22 and 24 and synthesized with a P polarized light by a beam splitter 18. A light thus formed and reflected by a beam splitter 26 is passed through an analyzer 28 and detected as a signal SfB by a reference beat light sensor 30. Meanwhile, a transmitted light is split by a polarization splitter 32, and an S polarized light thereof is focused on a measuring sample 42 through a lambda/4 wave plate 34, a long focus lens 40, etc., while a reflected light therefrom returns along the same path and turns to be a P polarized light. On the other side, a reflected reference light from a standard sample 50 turns to be an S polarized light and it proceeds via the splitter 32 and is detected, together with a P polarized light, as a signal SfD by a measuring beat light sensor 54. A change is an optical path due to thermal expansion of the sample is detected as a phase difference between the signals SFB and SfD.

Light beam in collimating condition, device for detecting angle and method for detecting focal position

Abstract: PURPOSE: To detect the small change of the propagating angle of a light beam by providing a focus sensitive optical component and a photodetector which generates the signal corresponding to the angle of the light beam. CONSTITUTION: The laser light emitted from a right source 12 is made incident to a beam splitter 16 through a collimate lens 14, circularly polarized by means of a 1/4 wave plate 20 through a beam split interface 18, and focused on the surface of an optical disk 22 through an objective lens 24. The beam reflected by the disk 22 is made incident to a focus sensitive optical component 26 through the lens 24, plate 20, and interface 18, interacts with the element 26, and made incident to a detector 28. The detector 28 detects the intensity difference between two segments 32 and 34 and a differential amplifier 30 generates a focus error signal indicating the amount of the focus error of the system.

Detached optical pickup device

Abstract: PURPOSE:To provide the optical axes of fixed optical system wholly on the same plane and to make the optical pickup device thin by supporting a deflecting member so as to be rotated around the axis parallel to the optical axis of a light flux to be made incident from a light flux emitting system for executing tracking operation. CONSTITUTION:The light flux to be emitted from a semiconductor laser 31 in a fixed optical system B is passed through a coupling lens 32, polarizing beam splitter 33 and quarter wave plate 34, which constitute the light flux emitting system, and afterwards, the light flux is made incident on a polarizing prism 35. After the light flux is polarized in this prism, the light flux is emitted to a moving optic system A. Namely, the optical axes of the light fluxes from the light flux emitting system of this fixed optical system B to the polarizing prism 35 are wholly arranged in the same line and the polarizing prism 35 is turned at a prescribed angle with the emitting optical axis of the semiconductor laser 31 as a center and the tracking operation is executed. Thus, the optical axes of the fixed optical system can be wholly set in the same line and the device can be made thin.

Fiber fusion type optical multiplexer for optical fiber amplifier

Abstract: PURPOSE:To allow the effective inputting of signal light and stimulating light to a rare earth doped fiber by providing a quarter wave plate which converts the linearly polarized light inputted to 1st and 2nd input ports to circularly polarized light. CONSTITUTION:An optical fiber 56 is held inserted and fixed even to a ferrule 54 to serve as the ferrule of an optical connector 28 (30) and this ferrule 54 and a lens 58 are held inserted and fixed into a sleeve 60. The sleeves 52, 60 are interposed with the quarter wave plate 62 therebeween and are fixed in a case 64. The light guided into the fused and stretched part of the fiber fusion type optical multiplexer is generally the light which is not specified in the circular polarization state or polarization state and, therefore, even if the polari zation state of the incident signal light or stimulating light varies or fluctuates, the characteristic curve expressing the relation between the coupling ratio and the wavelength is prevented from varying or fluctuating. The effective inputting of the signal light and stimulating light to the rare earth doped fiber is possible in this way.