Tunable Two-color Fiber Laser for THz Radiation Generation

Bao Dong To^1*, Ming-Hsiung Wu¹, Yen-Chieh Huang¹

¹Electrical Engineering, Photonics Technologies, Hsinchu, Taiwan

* Presenter:Bao Dong To, email:baodong@gapp.nthu.edu.tw

We have been developing a tunable two-color laser to perform difference frequency generation in nonlinear optical materials to generate THz radiation.Two approaches are adopted and will be discussed in this paper. The first approach is to seed a tunable external-cavity diode laser (ECDL) and a fiber-Bragg-grating stabilized diode laser at 1086 nm into a Yb:fiber amplifier. The ECDL was fabricated by using broadband diode laser and diffraction grating arranged in the Littman configuration. The wavelength of the ECDL, generating about 50- mW CW power, can be turned between 1066 to 1086 nm, covering bandwidth of about 6 THz. The 2nd approach is to build a laser with an etalon as its output coupler. On resonance, the etalon output coupler has a high loss to the laser and create dark lines in the output spectrum of the laser. The etalon is made of glass with a thickness of 114 microns, which gives a free spectrum range of 0.9 THz. We have observed a laser output with multiple lines and will present it in the conference.

Keywords: tunable two-color laser, ECDL, Yb:fiber amplifier, THz radiation, etalon output coupler