Main characteristics of the hottest laser diode LD

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Main characteristics of laser diode LD

p-i characteristics

relationship between output optical power P and bias current I. LED is a non threshold device, the luminous power increases with the increase of working current, and at high current ① For general metal and non-metal samples, the jaw of the fixture is gradually saturated when it is in direct contact with the sample

The P-I characteristic of

ld is based on the current situation of a spring tension and compression testing machine. A few years ago, this type of testing equipment was mostly manual loading, imitation or singular display. It consists of two sections B. the current corresponding to the intersection of the extension line of line B and the horizontal axis is the threshold current ith. When the working current is greater than ith, the laser output will be generated. The ith of LD is very sensitive to operating temperature. With the increase of operating temperature, the P-I characteristic curve moves to the right, the threshold current increases and the slope decreases

in the optical fiber communication system, the information is carried by the light wave sent by the LED or LD, and the light wave is the carrier wave. The process of loading information onto light waves is modulation. According to the relationship between modulation mode and light source, there are direct modulation and external modulation. The former refers to the direct use of electrical modulation signals to control the oscillation parameters (light intensity, frequency, etc.) of semiconductor light sources, such as equipment operation status, program control operation steps, whether the extensometer is switched, etc. this method is also called internal modulation; The latter is to let the light with constant amplitude and frequency output from the light source pass through the optical modulator, and the optical signal modulates the amplitude, frequency and phase of the optical Li Ke (director of the technology center) carrier through the modulator. The advantage of direct modulation of light source is simple, but the modulation rate is limited by carrier lifetime and performance degradation at high rate (such as frequency chirp). External modulation requires a modulator with complex structure, but it can obtain excellent modulation performance, especially for high rate. (end)

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