An electro-optic modulator (EOM) is a device that controls the power, phase or polarization of an optical signal through an electrical signal. Its core principle is based on the linear electro-optic effect (Pockels effect). This effect manifests itself in that the applied electric field is proportional to the refractive index change of the nonlinear crystal, thereby achieving effective control of the optical signal.
Direct Modulated Laser diode (DML) can be used to modulate optical power. In DML, the laser output power is adjusted by changing the pump current in the laser gain medium. The pump current is controlled by an electrical drive signal. This type of direct detection (DD) system typically uses On-Off Keying (OOK). In other words, the pump current of the DML is changed through binary signals.
Directly generating visible light from compact all-fiber lasers while maintaining high output characteristics has always been a research topic in laser technology. Here, Ji et al. proposed a method to develop dual-wavelength lasers using the excitation mechanism in holmium-doped ZBLAN fluoride glass fibers, and experimentally achieved high output performance of all-fiber lasers, especially operating in the deep red band under 640 nm pumping. Notably, a maximum continuous wave output power of 271 mW was achieved at 750 nm with a slope efficiency of 45.1%, which is the highest direct output power recorded in all-fiber lasers with a core diameter of less than 10 μm in the deep red band.
A laser diode chip is a semiconductor-based laser that consists of a P-N structure and is powered by current. The laser diode package is a complete device that is assembled and packaged together in a sealed package housing to form a semiconductor laser chip that emits coherent light, a monitoring photodiode chip for feedback control of power output, a temperature sensor chip for temperature monitoring, or an optical lens for laser collimation.
The polarization characteristics of light are a description of the vibration direction of the electric field vector of light. There are five polarization states in total: completely unpolarized light, partially polarized light, linearly polarized light, elliptically polarized light, and circularly polarized light
ASE broadband light generated by erbium-doped fiber is amplified spontaneous emission light generated by short-wavelength laser pumping erbium-doped fiber. As shown in the following diagram, the pumped rare earth ions transition between upper and lower energy levels to generate spontaneous emission light, which is amplified in the stimulated emission process. This process is repeated continuously, and even a fairly high output power can be achieved under sufficient pumping conditions. (ASE=Amplified Spontaneous Emission, amplified spontaneous emission light)
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