In this letter, we experimentally demonstrated a 1550-nm high-power single-longitudinal-mode (SLM) distributed feedback (DFB) semiconductor laser based on sampled moiré grating (SMG). By designing sampling structure with micrometer scale, moiré grating (MG) can be equivalently realized along laser cavity. Then, we can reduce coupling coefficient near laser facet so as to increase output power. The cavity length and ridge width of the fabricated laser are 1.0 mm and 3.0 μ m, respectively. The measured threshold current and the slope efficiency are 30.0 mA and 0.36 mW/mA at the heat-sink temperature of 25 oC, respectively. When the injection current is 800.0 mA, the maximum output power is about 183.0 mW. The saturation power is significantly improved compared with conventional DFB laser with uniform sampled grating (USG), which was fabricated on the same wafer. In addition, a four-channel DFB laser array based on SMG was also fabricated on the same wafer, showing good wavelength uniformity.

In this paper, a widely tunable external cavity diode laser (ECDL) with an ultra-high side mode suppression ratio (SMSR) was fabricated. Three configurations were constructed to investigate the relationship between the grating features and the SMSR. When a 1200 grooves/mm grating with a first order diffraction efficiency of 91% is utilized in the external-cavity laser system, a maximum SMSR of 65 dB can be achieved. In addition, the tunable range reaches 209.9 nm. The results show that the laser performance can be improved by proper high grating groove number and first-order diffraction efficiency.

We demonstrate a narrow-linewidth, high side-mode suppression ratio (SMSR) semiconductor laser based on the external optical feedback injection locking technology of a femtosecond-apodized (Fs-apodized) fiber Bragg grating (FBG). A single frequency output is achieved by coupling and integrating a wide-gain quantum dot (QD) gain chip with a Fs-apodized FBG in a 1-μm band. We propose this low-cost and high-integration scheme for the preparation of a series of single-frequency seed sources in this wavelength range by characterizing the performance of 1030 nm and 1080 nm lasers. The lasers have a maximum SMSR of 66.3 dB and maximum output power of 134.6 mW. Additionally, the lasers have minimum Lorentzian linewidths that are measured to be 260.5 kHz; however, a minimum integral linewidth less than 180.4 kHz is observed by testing and analyzing the power spectra of the frequency noise values of the lasers.

We design a unique external cavity configuration and present an ultra-narrow linewidth external cavity diode laser (ECDL) employing a wide interference filter and diffraction grating. The interference filter is for suppressing the noise floor, and diffraction grating is used for the mode selection. The combination of the filter and diffraction grating can effectively use a narrow linewidth without a significant reduction in optical gain. The Lorentz linewidth reaches 13.6 kHz at a wavelength of 1555 nm. The ECDL can be tuned by rotating the diffraction grating, and a wide tunable range of 40 nm is achieved with a maximum output power of 25.6 mW at an injection current of 200 mA. In addition, the ECDL shows an excellent side mode suppression ratio (SMSR) performance with a maximum of 57 dB at 1555 nm. Additionally, the SMSR changes gently throughout the tuning range at the injection current of 200 mA.

Wireless charging systems are critical for safely and efficiently recharging mobile electronic devices. Current wireless charging technologies involving inductive coupling, magnetic resonance coupling, and microwave transmission are bulky, require complicated systems, expose users to harmful radiation, and have very short energy transmission distances. Herein, we report on a long-distance optical power transmission system by optimizing the external cavity structure of semiconductor lasers for laser charging applications. An ultra-long stable oscillating laser cavity with a transmission distance of 10 m is designed. The optimal laser cavity design is determined by simulating the structural parameters for stable operation, and an improved laser cavity that produces an output of 2.589 W at a transmission distance of 150 cm is fabricated. The peak power attenuation when the transmission distance increases from 50 to 150 cm is only approximately 6.4%, which proves that this wireless power transfer scheme based on a vertical external cavity surface-emitting laser can be used to realize ultra-long-distance power transmission. The proposed wireless energy transmission scheme based on a VECSEL laser is the first of its kind to report a 1.5 m transmission distance output power that exceeds 2.5 W. Compared with other wireless energy transmission technologies, this simple, compact, and safe long-distance wireless laser energy transmission system is more suitable for indoor charging applications.

High-power single-longitudinal-mode regrowth-free gain-coupled distributed feedback laser diode based on ridge waveguide with periodic current injection is achieved at 990 nm. Our device is fabricated only by standard i-line lithography with micron-scale precision, obtains an excellent performance at high injection current. A continuous-wave power of over 0.681 W is achieved at 3 A. The maximum continuous-wave power at single-longitudinal-mode operation is up to 0.303 W at 1.4 A. Narrow linewidth emission has been reached with a 3 dB spectrum width less than 1.41 pm. The high side mode suppression ratio is over 35 dB. The lateral far field divergence angle is only 15.05 °, the beam quality factor M2 is 1.245, achieving a laterally near-diffraction-limit emission. It is more beneficial for single mode fiber coupling as pumping sources and other applications which require high beam quality at high power with easy fabrication technique.