Method And Apparatus For The Monitoring And Control Of A Process
A catch side optical system for use in diode laser spectroscopy consisting of a catch side optic optically coupled to a catch side multimode optical fiber and means to mechanically manipulate a section of the catch side multimode optical fiber to minimize catch side mode noise. The mechanical manipulation may consist of twisting the catch side multimode optical fiber around its longitudinal axis. The means to mechanically manipulate the section of the catch side multimode optical fiber in the above fashion may consist of a motor associated with the catch side multimode optical fiber such that a section of fiber is held fast relative to a shaft position of the motor and the motor shaft is repetitively swept through +360 degrees and −360 degrees of motion. The frequency of the motor shaft sweep may be at least 10 Hz to enable effective averaging of the transmitted signal and thereby reduce the effect of catch side mode noise.
1 . A catch side optical system for use in diode laser spectroscopy comprising:
a catch optic optically coupled to a proximal end of a catch side multimode optical fiber; and
means to mechanically manipulate a section of the catch side multimode optical fiber to reduce catch side mode noise.
2 . The catch side optical system of claim 1 wherein the catch side multimode optical fiber has a longitudinal axis parallel to the fiber length and the mechanical manipulation comprises twisting the catch side multimode optical fiber around the longitudinal axis.
3 . The catch side optical system of claim 2 wherein the means to mechanically manipulate the section of the catch side multimode optical fiber comprises a motor operatively associated with the catch side multimode optical fiber such that the section of fiber is attached relative to a shaft position of the motor, and the motor shaft is repetitively swept through +360 degrees and −360 degrees of motion.
4 . The catch side optical system of claim 3 wherein the frequency of the motor shaft sweep enables effective averaging of the transmitted signal, and thereby reduce the effect of catch side mode noise.
5 . The catch side optical system of claim 4 wherein the frequency of the sweep shaft is equal to or greater than 10 Hertz.
6 . A method of coupling light in a diode laser spectroscopy system comprising:
receiving light in a catch optic optically coupled to a proximal end of a catch side multimode optical fiber; and
mechanically manipulating a section of the catch side multimode optical fiber to reduce catch side mode noise.
7 . The method of coupling light in a diode laser spectroscopy system of claim 6 wherein the catch side multimode optical fiber has a longitudinal axis parallel to the fiber length and the mechanical manipulation comprises twisting the catch side multimode optical fiber around the longitudinal axis.
8 . The method of coupling light in a diode laser spectroscopy system of claim 7 wherein the means to mechanically manipulate the section of the catch side multimode optical fiber comprises a motor operatively associated with the catch side multimode optical fiber such that the section of fiber is attached relative to a shaft position of the motor, and the motor shaft is repetitively swept through +360 degrees and −360 degrees of motion.
9 . The method of coupling light in a diode laser spectroscopy system of claim 8 wherein the frequency of the motor shaft sweep enables effective averaging of the transmitted signal, and thereby reduce the effect of catch side mode noise.
10 . The method of coupling light in a diode laser spectroscopy system of claim 9 wherein the frequency of the sweep shaft is equal to or greater than 10 Hertz.