It is the durable and sturdy case of green laser pointer

The basic structure of the optical resonator of the semiconductor laser as shown below. 3 laser optical and electrical parameters of the PI curve curve: the curve of the LD light emission power P and the injection current I,. Began firing by stimulated emission of radiation when the current Ith said threshold current. Typical P-I curve as shown below. The definition of the optical power of light output power (P0 or Pf): In the forward optical output power of the current above the threshold current modulation, the optical power output from the LD is defined as the P0, the emission from the end of the fiber with pigtail LD for Pf. The optical output power in mw, sometimes expressed in dBm, the relationship between the two: the threshold current Ith: laser diode forward current starts to oscillate. Or  green laser pointer is impacted or damaged by the external force.
Usually there are three kinds of P-I Relations Act, measurement Ith. : PI curve, two straight lines to extend the line of intersection of the current as the diode threshold current, Figure a); method, the output optical power to extend the line and the intersection of the current axis as the diode threshold current, b). often use this method; method III, the optical power current and the second derivative of the derivative peak corresponding to the current of the diode threshold current, high measurement accuracy of this method, Figure c); the threshold current of laser diode and diode the length of the cavity, corresponding to the relationship as follows: beam divergence angle: the angle of the light output power semi-extreme intensity corresponding. The hard external force might influence the normal use and operation of  green laser pointer .
Fiber optics and electro-optical properties of semiconductor lasers. Fiber manufacturing technology and semiconductor laser technology breakthrough in the 1970s, optical fiber communication has become one of the most important means of communication of modern society. In this study, communication with the single-mode fiber and visible light (red) semiconductor lasers for optical communication process, an open principle of the simulation of the actual operation, the optical properties of the fiber itself and the electro-optical properties of semiconductor lasers a preliminary study. So that students have a basic understanding and knowledge of fiber optics and semiconductor lasers. To understand and consolidate the basic principles and knowledge of the optics; understand the fiber tips and treatment. It is the good enough performance of  green laser pointer .
Understand the use and electro-optical properties of semiconductor lasers; understanding to grasp some of the optical properties and parameters of the optical fiber measurement methods. Optical fiber communication optical theory is based on the total reflection in the light of theory and waveguide theory. Use in modern optical communication fiber is generally divided into single-mode fiber and multimode fiber in two. The difference in the structure is that the core geometry in Figure 1 is a fiber chart. It consists of three-tier structure: (1) core: composition (quartz glass mixed with small amounts of other elements to improve the refractive index) for single-mode fiber, the diameter of approximately 9.2 mm, while the multimode fiber core diameter is generally is 50 mm. This is the most important difference between them in the structure. green laser has the high power and big size.