Ultrahigh frequency optical frequency comb quantum dot mode-locked laser and preparation method thereof

Abstract

The invention specifically discloses an ultrahigh frequency optical frequency comb quantum dot mode-locked laser and a preparation method thereof. The mode-locked laser comprises a substrate, a negative electrode evaporated on the lower side surface of the substrate, and an N-type contact layer, an N-type cladding layer, an InAs quantum dot active region, a P-type cladding layer, a P-type contact layer and a positive electrode which are sequentially grown on the upper side surface of the substrate from bottom to top. An N-type contact layer, an N-type cladding layer, an InAs quantum dot active region, a P-type cladding layer and a P-type contact layer are sequentially grown on a substrate through a molecular beam epitaxy growth cavity, and the P-type contact layer is divided into a saturable absorber and a gain region with the length ratio of 1: 4-1: 6 through electrical isolation etching, so that the saturable absorber accounts for 14%-20% of the total cavity length of the mode-locked laser. Therefore, a stable sub-picosecond mode locking state under a no-voltage condition can be achieved, the cost and the consumption are effectively reduced, and great convenience is provided for operation. The method has the characteristics of low energy consumption, high efficiency, low cost, convenience in operation and large-scale production.

Description

technical field [0001] The invention relates to the technical field of mode-locked lasers, in particular to an ultra-high frequency optical frequency comb quantum dot mode-locked laser and a preparation method thereof. Background technique [0002] Mode-locked lasers are also called ultrafast lasers because of the characteristics of narrow pulse width, high peak power, high repetition frequency and wide spectrum. With the rapid development of laser technology, mode-locked lasers have been widely used in many cutting-edge technologies. For example: optical clock, nanomaterial processing, laser radar detection, millimeter wave, terahertz generation, etc. The mode-locking methods of mode-locked lasers can be divided into active mode-locking, passive mode-locking and hybrid mode-locking technologies. Among them, passive mode-locking utilizes the nonlinear optical characteristics of saturable absorbers: that is, it achieves bleaching effect on high-intensity input light pulses,...

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Problems solved by technology

[0005] 1. Basically located in the C-band, lacking O-band light sources;

[0006] 2. The mechanism of pulse wave generation is more complicated. In order to obtain a stable UHF optical frequency comb, the optical path coupling between multiple active / passive optical devices needs to be involved in the actual operation, so the requirements for the operator's skills are relatively high. Not easy to promote and use;

[0007] 3. The material gain is not enough to meet the stable lasing of laser devices with extremely short cavity lengths (hundreds of microns), so it cannot meet the passive mode-locking conditions of monolithic devices;

[0008] 4. Even the simplest two-stage passive mode-locking device still needs to achieve stable mode-locking conditions through the combined effect of voltage and current. The voltage source and current source are indispensable, so the traditional two-stage passive mode-locking device is inevitable There are disadvantages such as cumbersome operation, high energy consumption, high cost, etc.

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