Technique for stabilizing laser wavelength and phase

Abstract

A technique to stabilize the effective refraction index of a laser generating system's wave guide, as well as a technique to stabilize the phase of the wave guide. In at least one embodiment of the invention, a polymer is used within the wave guide to counteract the effects of temperature on the clad material of the wave guide in order to create an overall effective refraction index that is substantially independent of temperature variations. Furthermore, in at least one embodiment of the invention relative segment lengths of the wave guide are chosen to stabilize the phase of the wave guide.

What is claimed is:  
     
         1 . An apparatus comprising: 
 a wave guide clad comprising a first material whose refraction index varies by a first magnitude according to a temperature variation of the first material and a second material whose refraction index varies by a second magnitude according to the temperature variation of the second material, the second magnitude being inversely related to the first magnitude;    a wave guide core within the wave guide clad.    
     
     
         2 . The apparatus of  claim 1  wherein the first magnitude contributes to an increase in the refraction index of the first material in response to the temperature variation and the second magnitude contributes to a decrease in the refraction index of the second material in response to the temperature variation.  
     
     
         3 . The apparatus of  claim 2  further comprising a source for producing light.  
     
     
         4 . The apparatus of  claim 3  further comprising grating to reflect a portion of the light as the light passes through the wave guide core.  
     
     
         5 . The apparatus of  claim 4  wherein the second material is a polymer that exists within the grating area.  
     
     
         6 . The apparatus of  claim 1  wherein portions of the first material and the second material contribute to an effective refraction index of the wave guide clad.  
     
     
         7 . The apparatus of  claim 6  wherein the refraction index of the wave guide clad depends upon the relative amount of each of the first and second materials within the optical mode of the wave guide clad.  
     
     
         8 . An apparatus comprising: 
 first means for stabilizing a light's wavelength within a wave guide, the first means comprising two materials, each having a refraction index to change in opposite magnitude in relation to the other in response to variations in temperature of the wave guide.    
     
     
         9 . The apparatus of  claim 8  wherein variations of the light's wavelength in response to temperature variations of the wave guide depends upon the amount of one of the two materials in relation to the other within an optical mode of the wave guide.  
     
     
         10 . The apparatus of  claim 9  wherein one of the two materials is a polymer.  
     
     
         11 . The apparatus of  claim 10  wherein the polymer exists on opposite ends of a grating within the wave guide.  
     
     
         12 . The apparatus of  claim 8  further comprising a second means for stabilizing the phase of the light across varying temperatures of the wave guide.  
     
     
         13 . The apparatus of  claim 12  wherein the second means comprises the two materials in proportionate amounts so as to make a round-trip refraction distance of a photon of the light substantially independently of temperature.  
     
     
         14 . The apparatus of  claim 13  wherein one of the two materials is a polymer and one of the two materials is clad material.  
     
     
         15 . The apparatus of  claim 14  wherein the effective refraction index for the wave guide is dependent upon the product of a length of a polymer segment and the refraction index of the polymer.  
     
     
         16 . An apparatus comprising: 
 first means for stabilizing a light's phase within a wave guide, the first means comprising two materials, each having a refraction index to change in opposite magnitude in relation to the other in response to variations in temperature of the wave guide.    
     
     
         17 . The apparatus of  claim 16  wherein one of the two materials is a polymer distributed in segments along the length of a wave guide core within the wave guide.  
     
     
         18 . The apparatus of  claim 17  wherein the light's wavelength depends upon the length of the segments multiplied by an effective refractive index of each segment, the effective refractive index of each segment depending upon an amount of the polymer distributed within an optical mode of the wave guide.  
     
     
         19 . The apparatus of  claim 18  wherein an effective refraction index of the wave guide is substantially constant from a first end of the wave guide through a grating of the wave guide.  
     
     
         20 . The apparatus of  claim 19  wherein the light is produced by a source external to the wave guide.  
     
     
         21 . The apparatus of  claim 19  wherein the light is produced by a source internal to the wave guide.  
     
     
         22 . The apparatus of  claim 20  wherein the source of the light is a semiconductor optical amplifier (SOA) chip.  
     
     
         23 . The apparatus of  claim 22  wherein the wavelength of the light substantially corresponds to the maximum power within the emission spectrum of the SOA.  
     
     
         24 . A system comprising: 
 a light source to emit a spectrum of light wavelengths;    a wave guide to guide light from the light source having a first wavelength, the wave guide comprising a clad material, the wave guide including a polymer to help maintain an effective wave guide refraction index within an optical mode of the wave guide that is independent of temperature changes in the wave guide.    
     
     
         25 . The system of  claim 24  wherein the refraction index of the polymer changes in opposite magnitude of a clad material of the wave guide in response to temperature variations.  
     
     
         26 . The system of  claim 25  wherein the effective refraction index of the polymer depends upon the relative amounts of polymer and other clad material existing within the optical mode of the wave guide.  
     
     
         27 . The system of  claim 26  wherein the phase of the light is substantially independent of temperature variations within the wave guide.  
     
     
         28 . The system of  claim 26  wherein the wavelength of the light is substantially independent of temperature variations within the wave guide.  
     
     
         29 . The system of  claim 26  wherein the wave guide comprises a grating to reflect light wavelengths within the spectrum emitted by the light source.  
     
     
         30 . The system of  claim 29  wherein the light source comprises a semiconductor optical amplifier (SOA) to amplify the reflected light wavelengths.