Wavelength swept source apparatus and operating method thereof

Abstract

Provided are a wavelength swept source apparatus and a method for operating thereof. According to the provided apparatus and method, single mode light is generated, a basic optical comb including a plurality of light rays having identical frequency differences with adjacent light rays is generated by modulating the generated single mode light, and a plurality of optical combs, that includes same number of light rays as the plurality of light rays, has a different frequency band from that of the basic optical comb, and is distributed in a wider frequency band than that in which the basic optical comb is distributed, is generated by modulating the plurality of light rays. The plurality of light rays and light rays included in the plurality of optical combs are sequentially emitted according to frequencies of the plurality of light rays and the light rays included in the plurality of optical combs.

What is claimed is: 
     
         1 . A wavelength swept source apparatus comprising:
 a light source configured to generate single mode light;   an optical comb generation unit configured to generate a basic optical comb comprising a plurality of light rays having identical frequency differences with adjacent light rays by modulating the generated single mode light;   a frequency band extension unit configured to generate a plurality of optical combs by modulating the plurality of light rays, wherein each of the plurality of optical combs comprises same number of light rays as the plurality of light rays, each of the same number of light rays has identical frequency differences with adjacent light rays, each of the plurality of optical combs does not overlap the basic optical comb and has a different frequency band from that of the basic optical comb, and the plurality of optical combs is distributed in a wider frequency band than that in which the basic optical comb is distributed; and   a light emission unit configured to sequentially emit the plurality of light rays and light rays included in the plurality of optical combs according to frequencies of the plurality of light rays and the light rays included in the plurality of optical combs.   
     
     
         2 . The wavelength swept source apparatus of  claim 1 , wherein each of the plurality of light rays is a harmonic wave of the generated single mode light. 
     
     
         3 . The wavelength swept source apparatus of  claim 2 , wherein the optical comb generation unit comprises one of a double electrode Mach-Zehnder modulator, and an intensity modulator and a phase modulator which are connected to each other in series. 
     
     
         4 . The wavelength swept source apparatus of  claim 3 , wherein one of the double electrode Mach-Zehnder modulator, and the intensity modulator and the phase modulator which are connected to each other in series is formed by one of a light waveguide structure and a structure integrated on a same substrate as that of the light source. 
     
     
         5 . The wavelength swept source apparatus of  claim 1 , wherein the frequency band extension unit is formed of a medium having a self-phase modulation characteristic. 
     
     
         6 . The wavelength swept source apparatus of  claim 5 , wherein the frequency band extension unit is formed of one of a high nonlinear fiber and a photonic crystal fiber. 
     
     
         7 . The wavelength swept source apparatus of  claim 1 , wherein the light emission unit sequentially emits the plurality of light rays and the light rays included in the plurality of optical combs according to a group velocity dispersion characteristic of a medium. 
     
     
         8 . The wavelength swept source apparatus of  claim 7 , wherein the light emission unit is formed of one of a dispersive fiber and a dispersion shifted fiber. 
     
     
         9 . The wavelength swept source apparatus of  claim 1 , wherein the light emission unit comprises a dispersion controller configured to adjust an interval between each time at which each of the plurality of light rays and the light rays included in the plurality of optical combs is emitted. 
     
     
         10 . The wavelength swept source apparatus of  claim 1 , further comprising a polarization controller configured to control a polarization characteristic of input light and/or output light of the optical comb generation unit. 
     
     
         11 . The wavelength swept source apparatus of  claim 1 , further comprising an optical amplifier or optical attenuator configured to adjust intensity of output light of the optical comb generation unit. 
     
     
         12 . The wavelength swept source apparatus of  claim 1 , further comprising an isolator connected to an output terminal of the light emission unit to block reflected light. 
     
     
         13 . A method for operating a wavelength swept source apparatus, the method comprising:
 generating single mode light;   generating a basic optical comb comprising a plurality of light rays having identical frequency differences with adjacent light rays by modulating the generated single mode light;   generating a plurality of optical combs by modulating the plurality of light rays, wherein each of the plurality of optical combs comprises same number of light rays as the plurality of light rays, each of the same number of light rays has identical frequency differences with adjacent light rays, each of the plurality of optical combs does not overlap the basic optical comb and has a different frequency band from that of the basic optical comb, and the plurality of optical combs is distributed in a wider frequency band than that in which the basic optical comb is distributed; and   sequentially emitting the plurality of light rays and the light rays included in the plurality of optical combs according to frequencies of the plurality of light rays and the light rays included in the plurality of optical combs.   
     
     
         14 . The method of  claim 13 , wherein each of the plurality of light rays is a harmonic wave of the generated single mode light. 
     
     
         15 . The method of  claim 13 , wherein the generating of the plurality of optical combs comprises generating the plurality of optical combs according to a self-phase modulation characteristic of a medium. 
     
     
         16 . The method of  claim 13 , wherein the emitting comprises sequentially emitting the plurality of light rays and the light rays included in the plurality of optical combs according to a group velocity dispersion characteristic of a medium.