Wavelength measuring device, light receiving unit, and wavelength measuring method

Abstract

A wavelength measuring device includes: light receiving elements that receive light to be measured; a temperature controller that maintains the light receiving elements at different temperatures from one another; and a calculation unit that determines the wavelength of the light to be measured, based on outputs of the light receiving elements.

1 . A wavelength measuring device comprising:
 a plurality of light receiving elements that receive light to be measured;   a temperature controller that maintains the light receiving elements at different temperatures from one another so that sensitivity curves of the plurality of light receiving elements have peaks respectively that are included in a desired wavelength region; and   a calculation unit that obtains the wavelength of the light to be measured, based on a sensitivity ratio of outputs respectively with respect to the light to be measured within the desired wavelength range.   
   
   
       2 . The wavelength measuring device as claimed in  claim 1 , wherein the light receiving elements exhibit different light receiving sensitivity characteristics from one another at the same temperature. 
   
   
       3 . The wavelength measuring device as claimed in  claim 1 , wherein the light receiving elements exhibit substantially the same light receiving sensitivity characteristics as one another at the same temperature. 
   
   
       4 . A light receiving unit comprising:
 a plurality of light receiving elements that receive light to be measured; and   a temperature controller that applies different temperatures to the respective light receiving elements so that sensitivity curves of the plurality of light receiving elements have peaks respectively that are included in a desired wavelength region,   the light receiving elements outputting detection outputs with respect to the light to be measured.   
   
   
       5 . The light receiving unit as claimed in  claim 4 , wherein the light receiving elements exhibit different light receiving sensitivity characteristics from one another at the same temperature. 
   
   
       6 . The light receiving unit as claimed in  claim 4 , wherein the light receiving elements exhibit substantially the same light receiving sensitivity characteristics as one another at the same temperature. 
   
   
       7 . The light receiving unit as claimed in  claim 4 , wherein:
 the light receiving elements are arranged in series in the incident direction of the light to be measured; and   a later-stage one of the light receiving elements receives the light to be measured transmitted through an earlier-stage one of the light receiving elements.   
   
   
       8 . The light receiving unit as claimed in  claim 4 , further comprising a beam splitter that splits the light to be measured into separate beams,
 wherein the light receiving elements receives the respective separate beams.   
   
   
       9 . The light receiving unit as claimed in  claim 4 , further comprising a moving mechanism that movably holds the light receiving elements,
 wherein the moving mechanism moves one of the light receiving elements to the incident position of the light to be measured.   
   
   
       10 . The light receiving unit as claimed in  claim 4 , further comprising a rotation mechanism that rotatably holds the light receiving elements,
 wherein the rotation mechanism rotates the light receiving elements so as to move one of the light receiving elements to the incident position of the light to be measured.   
   
   
       11 . The light receiving unit as claimed in  claim 4 , wherein the temperature controller includes a Peltier device. 
   
   
       12 . A light receiving unit comprising:
 a light receiving element that receives light to be measured; and   a temperature controller that applies different temperatures to the light receiving element, the different temperatures varying with time, so that respective sensitivity curves have peaks at different wavelengths that are included in a desired wavelength region at the different temperatures,   the light receiving element outputting detection outputs with respect to the light to be measured, the detection outputs being obtained with time.   
   
   
       13 . The light receiving unit as claimed in  claim 12 , wherein the temperature controller includes a Peltier device. 
   
   
       14 . A wavelength measuring method comprising the steps of:
 determining the wavelength of light to be measured, based on a sensitivity ratio of outputs respectively with respect to the light from a plurality of light receiving elements that receive the light to be measured; and   applying different temperatures to the respective light receiving elements so that sensitivity curves of the plurality of light receiving elements have peaks respectively that are included in a desired wavelength region.   
   
   
       15 . The wavelength measuring method as claimed in  claim 14 , wherein the wavelength of the light to be measured is obtained based on an output ratio obtained from the light receiving elements.