Periodically poled lithium niobate efficiently doubles modelocked fiber-laser output

March 1, 1997
Using quasi-phase-matched second harmonic generation (SHG) in periodically poled lithium niobate (PPLN), Martin Fejer and researchers at Stanford University (Palo Alto, CA), collaborating with a grou¥at IMRA America (Ann Arbor, MI), have generated 8.1 mW of frequency-doubled 777-nm output from a passively modelocked femtosecond erbium-fiber laser. The system produced 190-fs, 90-pJ pulses, with conversion efficiencies as high as 25%.

Periodically poled lithium niobate efficiently doubles modelocked fiber-laser output

Using quasi-phase-matched second harmonic generation (SHG) in periodically poled lithium niobate (PPLN), Martin Fejer and researchers at Stanford University (Palo Alto, CA), collaborating with a grou¥at IMRA America (Ann Arbor, MI), have generated 8.1 mW of frequency-doubled 777-nm output from a passively modelocked femtosecond erbium-fiber laser. The system produced 190-fs, 90-pJ pulses, with conversion efficiencies as high as 25%.

The gain medium of the erbium-fiber soliton oscillator consisted of a 1-m-long fiber doped with 0.001% erbium; a large core diameter and high output coupling were used to kee¥circulating intensities low enough to minimize spurious nonlinear effects. A diode laser pumped the fiber laser with 150 mW at 980 nm to produce pulses with an average power of 50 mW and repetition rate of 88 MHz. This output was focused into a 1-mm-long, 0.5-mm-thick sample of PPLN, poled with 18.75-µm periods by an electric field; the crystal was maintained at 80°C to minimize photorefractive damage. Fiber laser SHG experiments with a 1-cm-long beta-barium borate crystal have achieved efficiencies of about 5%; the Stanford grou¥says that a similar pum¥source with a 300-µm-long PPLN crystal would exceed 50% conversion efficiency. When combined with erbium-doped fiber amplifiers, frequency-doubled erbium-fiber lasers could provide an alternative to current solid-state ultrafast sources.

Sponsored Recommendations

Advancing Neuroscience Using High-Precision 3D Printing

March 7, 2025
Learn how Cold Spring Harbor Laboratory Used High-Precision 3D Printing to Advance Neuroscience Research using 3D Printed Optical Drives.

From Prototyping to Production: How High-Precision 3D Printing is Reinventing Electronics Manufacturing

March 7, 2025
Learn how micro 3D printing is enabling miniaturization. As products get smaller the challenge to manufacture small parts increases.

Sputtered Thin-film Coatings

Feb. 27, 2025
Optical thin-film coatings can be deposited by a variety of methods. Learn about 2 traditional methods and a deposition process called sputtering.

What are Notch Filters?

Feb. 27, 2025
Notch filters are ideal for applications that require nearly complete rejection of a laser line while passing as much non-laser light as possible.

Voice your opinion!

To join the conversation, and become an exclusive member of Laser Focus World, create an account today!