Sumitomo Metal Mining Company, Ltd.

Smm Precision Co., Ltd.

Junji Iida

Akira Terashima

Kazuo Maeda

Masahiro Ito

Shintaro Ishikawa

Toshiki Kishimoto

Takeo Ide

Shuji Suzuki

Akio Watanabe

Hideharu Okami

Shinji Yamauchi

Mikio Uemura

Provided is a polarization independent optical isolator including: wedge-shaped birefringent crystal plates each made of a LiNbOsingle crystal; a Faraday rotatormade of a magnetic garnet single crystal; and sapphire single crystal platesandbonded to light transmitting surfaces of the Faraday rotator, respectively. A light transmitting surface of each of the sapphire single crystal plates is formed in such a manner as to be offset from the c-plane of the sapphire single crystal plate. An incident angle &#x3b8;a of imaginary lighton each of the sapphire single crystal plates, and an offset angles &#x3b8;off of the light transmitting surface from the c-plane of each sapphire single crystal plates are set within predetermined ranges, the imaginary lightbeing represented by a bisector of an angle formed by optical axes of the ordinary ray and the extraordinary ray.

Polarization independent optical isolator

Provided is a polarization independent optical isolator including: wedge-shaped birefringent crystal plates each being made of a YVOsingle crystal; a Faraday rotatormade of a magnetic garnet single crystal; and sapphire single crystal platesandbonded to light transmitting surfaces of the Faraday rotator, respectively. A light transmitting surface of each of the sapphire single crystal plates is formed in such a manner as to be offset from the c-plane of the sapphire single crystal plate. An incident angle &#x3b8;a of imaginary light on each of the sapphire single crystal plates, and an offset angles &#x3b8;off of the light transmitting surface from the c-plane of each sapphire single crystal plates are set within predetermined ranges, the imaginary light being represented by a bisector of an angle formed by optical axes of the ordinary ray and the extraordinary ray.

In an in-line optical isolator, a first polarization separation element, a Faraday rotatormade of a BIG film, and a second polarization separation elementare placed in that order. The isolator further includes a first optical fiber collimatorbeing placed at the forward-beam incident side of the first polarization separation elementand including a collimating lensand a first optical fiber, and a second optical fiber collimatorbeing placed at the forward-beam exit side of the second polarization separation elementand including a collimating lensand a second optical fiberconnected to a fiber amplifier. Also, an edge filter, which transmits light emitted from the first optical fiberand having a wavelength equal to an oscillation wavelength and which reflects light emitted from the first optical fiberand having wavelengths shorter than this wavelength, is placed between the second optical fiber collimatorand the second polarization separation element

In-line optical isolator

A bidirectional optical module having a devicefor emitting transmitting signal light, an optical fiberwhich the transmitting signal light from the device enters, a light-receiving devicewhich light from the optical fiber enters, and a wavelength splitting filter. The transmitting signal light emitted from the device is sent forward through the optical fiber, and the receiving signal light is received through the optical fiber. The bidirectional optical module has an optical device (optical isolator) of a reflection polarizerbonded to an end face of the optical fiber, a Faraday rotatordisposed integrally on the reflection polarizer and an absorption polarizerdisposed on an optical path extending between the device and the filter. The reflection polarizer has a wavelength dependency which functions as a polarizer for the transmitting signal light, but does not function as a polarizer for the receiving signal light.

Bidirectional optical module

A Faraday rotator in which the isolation function based on a temperature rise is not deteriorated even when the Faraday rotator is used for a high output laser of not smaller than 1W output at a wavelength of not larger than 1.1 &#x3bc;m includes sapphire crystals or rutile crystals bonded as radiation substrates to the incident side and outgoing side of a bismuth substituted type rare earth metal iron garnet crystal (RIG) film, the thickness of the RIG film being not smaller than 130 &#x3bc;m and not larger than 200 &#x3bc;m.

Faraday rotator for high output lasers

A non-destructive sugar content measuring apparatus having a plurality of trays on which vegetables and fruits are to be placed, a transport device for successively delivering the trays at appropriate intervals, and first, second and third measuring sections provided in the course of a transport path and at which laser beams having wavelengths &lgr;1, &lgr;2 and &lgr;3 are respectively made incident on each vegetable or fruit and the amount of light of each laser beam emergent from the vegetable or fruit is measured with a detector provided at each measuring section and the absorbance of each laser beam is determined from the amount of incident light made incident on the vegetable or fruit and the amount of detected light which has been measured with the detector, to measure the sugar content of the vegetables and fruits on the basis of each absorbance.

Non-destructive sugar content measuring apparatus

In a calibrator used for a non-destructive transmission optical measuring apparatus for quantitatively determining a specific component contained in a measuring object by making light incident on the measuring object at its light-incident area, detecting the light having entered, and having been transmitted through, the interior of the measuring object, at its light-emergent area set at a position different from the light-incident area, and measuring absorption of the light to quantitatively determine the specific component contained in the measuring object, the calibrator comprises a closed body having a light inlet and a light outlet, the interior of which is provided with a substrate having light absorption characteristics identical or similar to those of the specific component, and in which a light path length from the light inlet to the light outlet is so set as to be equal or substantially equal to an effective light path length of the light transmitted through the interior of the measuring object. This calibrator can make calibration on the non-destructive transmission optical measuring apparatus without destroying measuring objects and in a high precision and a good reproducibility and also in a simple way and short time.

Calibrator for non-destructive transmission optical measuring apparatus

A non-destructive taste characteristics measuring apparatus comprising trays and a measuring section provided in the course of a transport path and at which light is made incident on a vegetable or fruit to measure its taste characteristics, wherein the trays are each provided with at least two tray-side light passages one opening ends of which are so made as to come in contact with the vegetable or fruit and the other ends of which stand open outward at the bottom of the tray, and the measuring section has at least two measurement-side light passages one opening ends of which are positionally adjustable to the opening ends of the tray-side light passages at its part facing the bottom of said tray, and is provided with i) a means for making light incident on the vegetable or fruit through one of the measurement-side light passages and one of the tray-side light passages and ii) a detector which the light emergent from the vegetable or fruit enters through the other tray-side light passage and the other measurement-side light passage. The apparatus enables continuous measurement of taste characteristics such as sugar content and ripeness of vegetables and fruits at a high speed and a high precision without complicating the structure.

Non-destructive taste characteristics measuring apparatus and tray used

A non-destructive sugar content measuring apparatus for determining the sugar content of a vegetable or fruit by measuring absorption of light in sugar when near infrared light is made incident on the vegetable or fruit; comprising at least one light source that emits light rays having three kinds of wavelengths within a wavelength range of from 860 nm to 960 nm, and a detector that detects the absorption of light. The detector is disposed at a position except the position on an extended line of a straight line that connects i) the center of a light-incident area formed on the surface of the vegetable or fruit by the light emitted from the light source and incident on the vegetable or fruit and ii) the center of the vegetable or fruit, and at the same time at a position where the light-incident area formed on the surface of the vegetable or fruit by the incident light and the detection area formed on the surface of the vegetable or fruit by the light emergent from the vegetable or fruit and to be received by the detector do not overlap each other. This apparatus effectively enables non-destructive measurement of sugar content of vegetables and fruits in an accuracy of about plus-minus 1.0.degree.Brix, which is a resolving limit of sugar content that can be perceived by humans.

Growing community of inventors

Tokyo, Japan

Junji Iida