Actively mode-locking optical fibre ring laser insensible to polarization with stable cavity length for wavelength locking device

Abstract

A laser device is composed of actively mode-locking ring optical fibre laser device and cavity length stabilized feedback loop. Said ring laser device is composed of dispersion compensating fibre (DCF), adjustable optical band-pass filter, polarizer, polarization holding fibre, M-Z model LiNbO3 electro-optical modulator, two optical couplers, optical isolator, optical fibre amplifier and electrically controlled optical delay line. It can increase the wavelength stability of laser device to + / - 0.01 nm.

Description

Technical field [0001] The invention relates to an active mode-locked optical fiber ring laser, in particular to an active mode-locked optical fiber ring laser with a wavelength locker stable cavity length polarization insensitive active mode-locked optical fiber ring laser. Background technique [0002] After entering the 21st century, the continuous development of people's communication needs has promoted the continuous improvement of the speed of optical fiber communication systems. One of the key technologies of high-speed optical communication system is ultra-narrow pulse optical signal source technology. There are currently three main methods of this technology: gain-switched high-speed semiconductor lasers, continuous semiconductor lasers + electroabsorption optical modulators, and active mode-locked fiber lasers. Among them, the "active mode-locked fiber ring laser" can output optical pulses with "transformation limit" and has the characteristics of high repetition ...

AI Technical Summary

Problems solved by technology

However, it still has problems such as loud noise, susceptibility to environmental interference, and unstable work.

This instability mainly has the following sources: 1. The long-term stability of the laser cavity length: Since the cavity length (that is, the length of the optical fiber that constitutes the laser) is relatively long, the cavity length is easily affected by the ambient temperature and stress. The fundamental frequency of the corresponding mode-locked laser will change accordingly

2. The polarization noise problem caused by the instability of the polarization state of the fiber: due to the LiNbO 3 The optical modulator is polarization-sensitive. Changes in the optical fiber loop due to environmental temperature and stress will bring about changes in the polarization state of the light, which are reflected on the modulator as random changes in the modulation depth, thereby forming polarization noise of the mode-locked laser.

However, most of the existing solutions use expensive polarization-maintaining devices, and the cavity length stabilization devices are very complicated and costly, making it difficult to popularize

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