Yang Changsheng

A Single-Frequency Linearly Polarized Fiber Laser Using a Newly Developed Heavily Tm3+-Doped Germanate Glass Fiber at 1.95 μm

A compact linearly polarized, low-noise, narrow-linewidth, single-frequency fiber laser at 1950 nm is demonstrated. This compact fiber laser is based on a 21-mm-long homemade Tm3+-doped germanate glass fiber. Over 100-mW stable continuous-wave single transverse and longitudinal mode lasing at 1950 nm are achieved. The measured relative intensity noise is less than −135 dB/Hz at frequencies over 5 MHz. The signal-to-noise ratio of the laser is larger than 72 dB, and the laser linewidth is less than 6 kHz, while the obtained linear polarization extinction ratio is higher than 22 dB.

A Compact Low Noise Single Frequency Linearly Polarized DBR Fiber Laser at 1550 nm

A compact low noise single frequency linearly polarized distributed Bragg reflector (DBR) fiber laser based on a 1.4-cm-long homemade Er3+/Yb3+ -codoped phosphate single mode glass fiber has been demonstrated. An over 50 mW stable single frequency linearly polarized fiber laser was achieved. The measured slope efficiency is more than 21.6%, and the signal-to-noise ratio (SNR) is higher than 65 dB and the laser linewidth is less than 2.0kHz. The laser RIN is measured to be less than −150 dB/Hz at the frequencies over 2.0MHz, and the obtained linear polarization extinction ratio (LPER) is more than 30 dB.

Simultaneously Suppressing Low-Frequency and Relaxation Oscillation Intensity Noise in a DBR Single-Frequency Phosphate Fiber Laser

Effective multiple optoelectronic feedback circuits for simultaneously suppressing low-frequency and relaxation oscillation intensity noise in a single-frequency phosphate fiber laser are demonstrated. The forward transfer function, which relates the laser output intensity to the pump modulations, is measured and analyzed. A custom two-path feedback system operating at different frequency bands is designed to adjust the pump current directly. The relative intensity noise is decreased by 20 dB from 0.2 to 5kHz and over 10 dB from 5 to 10 kHz. The relaxation oscillation peak is suppressed by 22 dB. In addition, a long term (24 h) laser instability of less than 0.05% is achieved.

Research advance on the key technology of high-power fiber laser materials and components

Compared with other types of lasers, high-power fiber laser has a compact structure, high conversion efficiency, convenient thermal management, and good beam quality, which has a broad application prospect in industry, national defense and other fields. However, the high-gain fiber materials, the optical components, the high-quality laser pumps, and the high-performance laser seed became the key factors restricting the development of 10-kW-level fiber laser. The development status of the high-power fiber laser materials and the optical components are introduced in this paper. The key technologies of the Yb3+-doped double clad fiber, the optical components (e.g., fiber Bragg grating, cladding power stripper, and combiner), laser pumps, and single-frequency laser seed are analyzed and discussed. Moreover, the new development trends of the fiber laser technology about domestic 10-kW-level even more higher output power is prospected.