Thermal dilation fiber optical flow sensor

A thermal dilation type optical flow sensor comprising:

• probe reflecting means disposed in a flowing fluid for reflecting incident coherent light within a light pipe, wherein a phase of a reflected light within said light pipe relative to a phase of said incident light varies according to a temperature of said probe means;
• optical heating means for heating said probe means with a predetermined heat;
• and
• measurement means for measuring said relative phase of said reflected light relative to said phase of said incident light and calculating said flow rate based on said relative phase of said reflected light relative to said incident light and said predetermined heat;
• and
• wherein said probe reflecting means comprises:
• an optical fiber disposed in said flowing fluid;
• a non-absorbing cladding on a portion of said optical fiber with an absorbing fiber jacket for absorbing light disposed therearound wherein said heating means is said absorbing fiber jacket;
• and
• a reflector disposed on a first end of said optical fiber, opposite to a second end connected to said measurement means.

A thermal dilation type optical flow sensor comprising:

• probe reflecting means disposed in a flowing fluid for reflecting incident coherent light within a light pipe, wherein a phase of a reflected light within said light pipe relative to a phase of said incident light varies according to a temperature of said probe means;
• optical heating means for heating said probe means with a predetermined heat;
• and
• measurement means for measuring said relative phase of said reflected light relative to said phase of said incident light and calculating said flow rate based on said relative phase of said reflected light relative to said incident light and said predetermined heat;
• and
• wherein said probe reflecting means comprises:
• an optical plate disposed in said flowing fluid, wherein said optical plate comprises a material for absorbing a portion of said light and said heating means heats the plate by the absorption of light energy in said material;
• and
• a reflector disposed on a first side of said optical plate, opposite to a second side of said optical plate connected to said measurement means.