Tunable laser using tunable fabry-perot filter

Abstract

The present invention relates to a tunable laser using a tunable fabry-perot filter. The tunable laser using the tunable fabry-perot filter comprises a laser cavity end mirror, a laser gain medium, an intracavity collimating lens, an active optical phase modulator, the tunable fabry-perot filter, an output lens and a laser driving and controlling system which are arranged orderly. The tunable fabry-perot filter comprises two design schemes. The main technical features of the first design scheme are that the tunable fabry-perot filter comprises a first band pass filter, a liquid crystal phase modulator, a second band pass filter and a drive circuit, the liquid crystal phase modulator is arranged in a fabry-perot cavity formed by a first band pass filter and a second band pass filter, and the drive circuit realizes a tuning function of the filter by controlling the effective refractive index of a liquid crystal material in the fabry-perot cavity. The difference of the second design scheme and the first design scheme is that a long wavelength pass step-type filter and a short wavelength pass step-type filter which have different cut-off frequency spectrums substitute for the first and second band pass filters respectively.

Description

technical field [0001] The invention belongs to the field of optoelectronics, in particular to a tunable laser using a tunable Fabry-Perot filter. Background technique [0002] In external-cavity tunable lasers, the commonly used tuning techniques mainly include the following methods: 1. Tuning is performed by driving the rotation of the grating through a precision stepping motor. The existing problems are reflected in: first, to achieve precise tuning of optical frequency, The stepping accuracy and repeatability of the stepping motor are very high, so the manufacturing cost is relatively high; the second is that it is not easy to miniaturize due to the use of the stepping motor; the third is the poor working stability in harsh working environments, especially The ability to resist various mechanical vibrations is relatively poor. Therefore, the tunable laser using this technology is only suitable for use in the laboratory working environment. 2. Using tunable acousto-optic...

AI Technical Summary

Problems solved by technology

[0002] In external-cavity tunable lasers, the commonly used tuning techniques mainly include the following methods: 1. Tuning is performed by driving the rotation of the grating through a precision stepping motor. The existing problems are reflected in: first, to achieve precise tuning of optical frequency, The stepping accuracy and repeatability of the stepping motor are very high, so the manufacturing cost is relatively high; the second is that it is not easy to miniaturize due to the use of the stepping motor; the third is the poor working stability in harsh working environments, especially The ability to resist various mechanical vibrations is relatively poor. Therefore, the tunable laser using this technology is only suitable for use in the laboratory working environment

2. Using tunable acousto-optic filters for tuning has the advantages of fast tuning speed, no mechanical moving parts, and can be miniaturized. The disadvantage is that the filter bandwidth of tunable acousto-optic filters is relatively wide, which makes the tuning accuracy of the laser lower. Therefore, it is difficult to achieve precise tunability for tunable lasers using this technology alone, and it is only suitable for applications that do not require high tuning accuracy and output bandwidth.

3. Use gratings or other optical filter devices in the laser resonator, such as optical etalons, to tune the frequency of transmitted light with temperature drift. The advantages are high tuning accuracy and narrow spectral bandwidth of the output light. The disadvantage is that the speed is relatively high. Slow, especially in the case where a wide tuning spectrum range is required, this shortcoming is particularly obvious, for example: the temperature drift coefficient of the optical filter device is 0.02 nanometers / degree, the required optical spectrum range is 20 nanometers, and the temperature adjustment range is 100 degrees, This is difficult to achieve in practical applications

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