A tunable, single frequency, fiber ring at 1053 nm

Conference · Fri Feb 21 04:00:00 EST 1997

OSTI ID:508734

Wilcox, R B

This laser is a tunable source designed for applications where a shorter pulse will be chopped from a long Q-switched pulse by electrooptic modulators, then amplified in Nd:phosphate glass. The laser employs ytterbium-doped silica fiber as the gain medium, pumped by a laser diode at 980nm. Gain in Yb:silica is distributed over an 90nm range, making it suitable for operation at many wavelengths. Our previous experiments with this medium demonstrated oscillation over a 50nm wide band. In addition, pumping at 980nm allows the use of stable pump diodes used in erbium-doped fiber amplifiers (EDFA`s). We designed the laser to take advantage of this wideband gain medium, and yet operate on a single cavity mode. A circulator causes unidirectional operation, and allows use of a fiber grating in reflection. This grating has a 0.2 Angstrom bandwidth, and defines the coarse tuning of the laser. It is piezoelectrically stretch tuned to the desired wavelength band. A single mode of the cavity is selected by a piezoelectrically tuned fiber grating Fabry-Perot etalon with 64MHz bandwidth. The laser is Q-switched by a bulk acousto-optic device at lkhz reprate. The loss is controlled to allow the oscillator to lase close to threshold for 500{micro}s before the Q-switch is turned off completely, creating a pulse. This ``pre-lasing`` stabilizes the single mode, since Q-switch pulse builds up from the prelase level. To prevent mode hopping during long term operation, cavity length is feedback controlled. Another piezoelectric device stretches a fiber in the cavity according to an error signal derived from the output optical signal. Due to the long, high loss cavity, the Q-switched pulse is about 3OOns long. The central part of this pulse will be gated by an electrooptic modulator to produce a 30ns square pulse, used for further amplification and modulation.

• Research Organization: Lawrence Livermore National Lab., CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 508734
• Report Number(s): UCRL-JC--124515; IL--10087; CONF-9610225--34; ON: DE97053204; IN: IL-10087
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
DESIGN
LASER MATERIALS
OPTICAL PUMPING
PERFORMANCE
Q-SWITCHING
SILICON OXIDES
SOLID STATE LASERS
YTTERBIUM ADDITIONS