3m Innovative Properties Company

Minnesota Mining and Manufacturing Company

Jay W Dawson

Trevor W MacDougall

Leonard A Johnson

Trevor Wayne MacDougall

John A Valenti

Edward Hernandez

A system for lasing includes a diode laser array for emitting light of wavelength .lambda..sub.0, a tunable Bragg grating fiber laser connected to the diode laser array for emitting single mode light of wavelength 2*.lambda..sub.vis, a cladding pumped power amplifier connected to the diode laser array and the tunable Bragg grating fiber laser, and a second harmonic generator, including an optical cavity and crystal, connected to the cladding pumped power amplifier for emitting light of wavelength .lambda..sub.vis. The second harmonic generator is maximized, thereby maximizing emission of the light of wavelength .lambda..sub.vis, by control electronics connected to the tunable Bragg grating fiber laser, the cladding pumped power amplifier, and the second harmonic generator. The control electronics stabilize the amplitude of the light of wavelength 2*.lambda..sub.vis, emitted by the tunable Bragg grating fiber laser and lock the frequency of the light of wavelength 2*.lambda..sub.vis to the optical cavity resonance.

Frequency doubled fiber laser

An annealing mold and fiber retaining device includes a fiber holding plate having fiber channels and an annealing insert. Retainers are provided for attachment to the plate to retain fibers in the channels. After annealing, the annealing insert is replaced by a packaging insert. The fiber holding plate is mounted between a support plate and a cover plate. The mounted plates include a coextensive current conductor port and the plates are mounted in a housing which includes vibration mounts for isolating the plates from vibration within the housing.

Annealing mold and retainer for making a fiber optic current sensor

A fiber optic, Faraday-effect current sensor (optical current transducer) which has improved temperature sensitivity due to compensation for temperature-induced variations of the Verdet constant. Fiber optic sensing coils can exhibit shifts in their bias angle due to a number of reasons, including physical rotation of the fibers, an apparent circular birefringence attributable to the sensing coil shape (Berry's phase), circular birefringence in the sensing fiber, or a DC magnetic field or current. The present invention takes advantage of the change in bias angle by identifying a preferred channel from the two sensing axes of the output fiber, based on the manner in which these axes respond to the change in bias angle. One of the axes will exhibit a change in sensitivity that exacerbates the change in sensitivity due to the Verdet constant, while the other channel will exhibit a change that complements, or compensates for, the change in sensitivity due to the Verdet constant. Once the preferred channel is identified, a polarizing fiber is attached to the output of the sensing coil, aligned to transmit the preferred channel to the optical detector.

Verdet constant temperature-compensated current sensor

A fiber optic subassembly for a Faraday-effect current sensor has an optical sensing fiber supported by a tubular holder in a square or rectangular configuration, with the three of the four corners thereof designed with bends which have a net zero bend-induced birefringence. The bends are formed by providing two loops which have effective angles of about 90.degree., the two loops lying in orthogonal planes, such that the fast axis of birefringence in the first loop is parallel to the slow axis of birefringence in the second loop, and the slow axis of birefringence in the first loop is parallel to the fast axis of birefringence in the second loop. In this manner, retardance accumulated in the first loop is offset by retardance accumulated in the second loop. If the loops are substantially identical, the offsetting of the retardance is effectively complete such that the bend exhibits negligible bend-induced birefringence.

Growing community of inventors

Round Rock, TX, United States of America

Jay W Dawson