Optical fiber illuminator, method of fabricating the optical fiber illuminator, and optical recording head and optical recording and reading apparatus having the optical fiber illuminator

Abstract

Provided is an optical fiber illuminator used for recording and reading high density optical information according to a near field recording (NFR) scheme, a method of fabricating the optical fiber illuminator, and an optical recording head and recording apparatus having the optical fiber illuminator. The optical fiber illuminator includes: an optical fiber having a core upon which light is incident and a clad that surrounds the core, one end of the optical fiber having a mirror formed in an inclined manner; and a lens formed on an outer surface of the optical fiber for focusing light reflected by the mirror. The optical fiber illuminator has an improved optical arrangement for optical illumination and detection, it is easy to manufacture, its optical input is easy to control, and it can be readily provided in an array form. When an array type optical recording and reading apparatus having an optical recording head and multiple aperture probes adopts the optical fiber illuminator, the resulting simple arrangement and compact size enables size reduction of the overall apparatus, a signal to noise ratio is high, and high density optical information can be recorded and reproduced at an extremely high rate.

1 . An optical fiber illuminator comprising: 
 an optical fiber having a core upon which light is incident and a clad that surrounds the core, one end of the optical fiber having a mirror formed in an sloped surface; and    a lens formed on an outer surface of the optical fiber for focusing light reflected by the mirror.    
   
   
       2 . The optical fiber illuminator according to  claim 1 , wherein the clad at an end portion of the optical fiber is etched to a predetermined depth such that a surface of the lens matches a surface of the optical fiber.  
   
   
       3 . The optical fiber illuminator according to  claim 1 , wherein the sloped surface has an angle of 45 degrees.  
   
   
       4 . The optical fiber illuminator according to  claim 1 , wherein the lens is made of the same material as the clad or a polymer material.  
   
   
       5 . A method of manufacturing an optical fiber illuminator, comprising: 
 a) forming a mirror formed in an sloped surface at one end portion of an optical fiber including a core upon which light is incident and a clad that surrounds the core;    b) forming a photoresist on an outer surface of the end portion of the optical fiber;    c) exposing a predetermined portion of the photoresist to light incident on the core and reflected by the mirror; and    d) forming a lens by removing a non-exposed portion of the photoresist and heating the remaining photoresist.    
   
   
       6 . The method according to  claim 5 , wherein the sloped surface has an angle of 45 degrees and is polished or coated with a metal to form the mirror.  
   
   
       7 . The method according to  claim 5 , further comprising, after step a), etching the clad of the end portion of the optical fiber to a predetermined depth to match the surface of the lens with the surface of the optical fiber.  
   
   
       8 . The method according to  claim 5 , further comprising, after step d), etching the lens made of the photoresist and the exposed portion of the clad to a predetermined depth such that the lens is formed with the same material as the clad while matching the surfaces of the optical fiber and the lens.  
   
   
       9 . An optical recording head having an optical fiber illuminator, the optical recording head comprising: 
 an optical fiber illuminator manufactured according to the method of any one of  claims 5  to  8 ;    a support frame supporting the optical fiber illuminator and having an opening to pass light incident through the lens;    an aperture probe for collecting light incident through the opening of the support frame to generate near field light through the opening; and    a cantilever having one end portion fixed to the support frame through a spacer, for maintaining a constant gap between the aperture probe and an optical recording medium.    
   
   
       10 . The optical recording head according to  claim 9 , wherein an optical waveguide is formed on the support frame.  
   
   
       11 . The optical recording head according to  claim 9 , wherein the opening of the aperture probe is formed to a size of 50 to 100 nm.  
   
   
       12 . The optical recording head according to  claim 9 , wherein the cantilever comprises: 
 a substrate having one side portion fixed to the support frame through the spacer and accommodating the aperture probe at a portion corresponding to the opening of the support frame;    a piezoresist formed on the substrate around the aperture probe and having an electrical conductivity that varies according to a degree of bending of the substrate; and    a piezo actuator for moving the substrate up and down to maintain a constant gap between the aperture probe and the optical recording medium according to variation of the electrical conductivity of the piezoresist.    
   
   
       13 . The optical recording head according to  claim 12 , wherein the piezoresist is formed on the substrate through an ion implantation process.  
   
   
       14 . The optical recording head according to  claim 12 , wherein the piezo actuator comprises: 
 first and second electrodes; and    a ferroelectric material that expands and contracts according to a voltage applied across the first and second electrodes.    
   
   
       15 . An optical recording and reading apparatus having an optical fiber illuminator, the optical recording and reading apparatus comprising: 
 a support frame having a plurality of openings to transmit light;    a plurality of optical fiber illuminators each having a lens mounted corresponding to a respective one of the plurality of openings;    a plurality of aperture probes for collecting light incident through respective openings of the support frame from the plurality of optical fiber illuminators to generate near field light through the openings;    a cantilever for maintaining a constant gap between the aperture probes and an optical storage medium;    a plurality of light detectors for detecting near field light transmitted through the optical storage medium; and    an objective lens located between the plurality of aperture probes and the plurality of light detectors for guiding the near field light to the respective light detectors.    
   
   
       16 . The optical recording and reading apparatus according to  claim 15 , wherein the optical fiber illuminator comprises: 
 an optical fiber having a core upon which light is incident and a clad that surrounds the core, one end of the optical fiber having a mirror formed in an inclined manner; and    a lens formed on an outer surface of the optical fiber for focusing light reflected by the mirror.    
   
   
       17 . The optical recording and reading apparatus according to  claim 15 , wherein the cantilever comprises: 
 a substrate having one side portion fixed to the support frame through a spacer and accommodating the aperture probes at a portion corresponding to the openings of the support frame;    a piezoresist formed on the substrate around the aperture probes and having an electrical conductivity that varies according to a degree of bending of the substrate; and    a piezo actuator for moving the substrate up and down to maintain a constant gap between the aperture probes and the optical recording medium according to variation of the electrical conductivity of the piezoresist.    
   
   
       18 . The optical recording and reading medium according to  claim 17 , wherein the piezo actuator comprises: 
 first and second electrodes; and    a ferroelectric material that expands and contracts according to a voltage applied across the first and second electrodes.    
   
   
       19 . The optical recording and reading medium according to  claim 15 , further comprising adjusting means for adjusting a position of the objective-lens to exactly focus the near field light on the light detector.  
   
   
       20 . An optical recording head having an optical fiber illuminator, the optical recording head comprising: 
 an optical fiber illuminator manufactured according to the method of any one of  claims 5  to  8 ;    a support frame supporting the optical fiber illuminator and having an opening to pass light incident through the lens;    an aperture probe for collecting light incident through the opening of the support frame to generate near field light through the opening;    a substrate attached to the support frame and accommodating the aperture probe at a portion corresponding to the opening of the support frame; and    at least one sliding pad attached to the lower portion of the substrate for maintaining a constant gap between the aperture probe and an optical recording medium.    
   
   
       21 . The optical recording head according to  claim 20 , wherein the opening of the aperture probe is formed to a size of 50 to 100 nm.  
   
   
       22 . The optical recording head according to  claim 20 , further comprising a suspension support frame connected to the substrate to position the optical recording head close to a surface of the optical recording medium.