Mode-hop-free FM control method for integrated external cavity semiconductor lasers

Abstract

The invention discloses a mode-hopping frequency modulation control method of an integrated external cavity semiconductor laser. The implementation of the method includes at least one integrated external cavity semiconductor laser, a current tuning device and a temperature tuning device, the current controller and the temperature controller are synchronously driven, the current changes the external cavity mode of the laser, and the temperature changes the external cavity mode of the laser. The central wavelength of the reflection spectrum of the cavity mode and the optical feedback element makes the two modes match, thereby realizing frequency modulation without mode hopping. By using the above-mentioned laser, continuous tuning of the laser frequency without mode hopping can be realized, and the tuning range of the laser without mode hopping can be improved.

Description

technical field [0001] The invention relates to a frequency modulation method for an external cavity semiconductor laser, in particular to a mode-hopping frequency modulation control method for an integrated external cavity semiconductor laser. Background technique [0002] In many application fields such as interferometry, spectroscopy, optical communication, precision spectroscopy, atomic cooling and trapping, it is desirable to obtain a broadband tunable laser source without wavelength mode hopping. The laser mainly achieves the purpose of wavelength tuning by adjusting the resonator, and when the resonator is continuously tuned, the lasing mode of the laser sometimes produces a mode-hopping phenomenon, which is equivalent to the longitudinal mode interval of the laser at the output frequency of the laser. Frequency hopping, which in turn destroys the characteristics of continuous frequency tuning of the laser, will have an adverse effect on the accuracy of frequency tuni...

AI Technical Summary

Problems solved by technology

This mechanical non-mode-hopping FM method is based on a specially designed tuning mechanism, which requires high precision in processing and assembly, and is very expensive.

In general, large-scale mode-hop-free tuning of lasers and high mechanical stability are still two difficult goals to meet simultaneously. In the manufacturing process, there are complex optical and mechanical alignments, additional materials for optical devices There are many problems such as cost, large cavity size, low integration and slow tuning speed, so VBG, FP, FBG and other external cavity semiconductor lasers have attracted people's attention due to their compact structure, miniaturization, and high integration. Large-scale continuous tuning is achieved through temperature tuning, but the mode-hop-free tuning range is limited due to the mismatch between the reflection spectrum of the feedback element and the thermal tuning of the longitudinal mode of the cavity. A control method for frequency modulation without mode hopping

[0005] In summary, there are many problems in the non-mode-hopping frequency modulation method proposed in the prior art, which limits the application of tunable external cavity semiconductor lasers in many fields. Stable, compact and highly integrated mode-hopping frequency modulation method

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