Abstract
1 Introduction
Mode-locked fiber lasers generate trains of femtosecond pulses with equal pulse width, intensity and timing interval, making them ideal sources in pump–probe experiments[
Due to the limited lifetime of the gain medium, the mode-locked laser can function as a low-pass filter. The laser response to the pump laser diode (LD) intensity fluctuations has a bandwidth determined by the interplay of gain dynamics and laser dynamics[
In this work, the transfer functions between the relative intensity noise (RIN) of the pump laser diode and the output RIN, between the RIN of the pump LD and timing jitter of femtosecond fiber lasers are systematically studied by inducing white noise modulation[
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2 Experimental setup and results
2.1 Characterization of the transfer function between the RIN of the pump and the laser
A home-made nonlinear polarization evolution (NPE) mode-locked fiber laser is used as the laser under test (LUT), as shown in Figure
For femtosecond fiber lasers, the RIN of laser output is usually lower than that of the pumping LD, which could be easily covered by the noise floor of the detection system[
First, the transfer function of the RIN in a stretched pulse mode-locked fiber laser is measured with different modulation amplitudes. The net dispersion is
Second, the transfer function of the RIN is systematically studied under a variety of net dispersions. In the experiments, for the laser without the band-pass filter, the mode-locking regime varies with the net dispersion. The pump power is adjusted to be 300 mW, 360 mW, 240 mW and 200 mW at
When the narrow band-pass filter is inserted, the mode-locking regime of the LUT is switched to amplifier similariton, and the optical spectrum almost remains the same, even though the intra-cavity dispersion varies from
2.2 Characterization of transfer function between the RIN of the pump and the timing jitter of the laser
In order to characterize the transfer function between the RIN of the pump LD and the timing jitter of the laser output, another femtosecond fiber laser with nearly identical structure is built as the reference (REF). The laser REF works in the stretched pulse regime with its net dispersion fixed at
First, the transfer function of the LUT is measured when the net dispersion is set to
Second, the net dispersion of the LUT is set to
3 Conclusion
In conclusion, the transfer function between the RIN of the pump LD and the output noise of femtosecond fiber lasers is systematically characterized in terms of intra-cavity net dispersion and band-pass filtering conditions. Upon insertion of the spectral filter, the bandwidth of the RIN transfer function is significantly narrowed in normal-dispersion lasers. In fiber lasers with anomalous dispersion, the amplitude of the RIN transfer function is decreased. Furthermore, the RIN transfer function in filtered fiber lasers is almost invariant with the net dispersion map, while its amplitude is always restricted below 0 dB. The transfer function between the RIN of the LD and the timing jitter is also constant on inserting the narrow band-pass filter, despite the net dispersion variation. Although the bandwidth of the transfer function in filtered lasers is broader than in stretched pulse lasers, the amplitude in the low-frequency domain is sufficiently decreased. The study here provides a simple and effective way to suppress the amplitude and phase noise coupled from the fluctuation of pump power without complex active control and intra-cavity dispersion management, thus demonstrating the potential for high-precision real-world applications of femtosecond fiber lasers.
References
[1] M. Domke, S. Rapp, M. Schmidt, H. P. Huber. Opt. Express, 20, 10330(2012).
[2] C. Kerse, H. Kalaycıoğlu, P. Elahi, B. Çetin, D. K. Kesim, Ö. Akçaalan, S. Yavaş, M. D. Aşık, B. Öktem, H. Hoogland, R. Holzwarth, F. Ö. Ilday. Nature, 537, 84(2016).
[3] M. Xin, K. Safak, M. Y. Peng, A. Kalaydzhyan, W.-T. Wang, O. D. Mucke, F. X. Kartner. Light: Sci. Appl., 6, e16187(2017).
[4] J. Lee, Y.-J. Kim, K. Lee, S. Lee, S.-W. Kim. Nat. Photon., 4, 716(2010).
[5] K. Tamura, E. P. Ippen, H. A. Haus, L. E. Nelson. Opt. Lett., 18, 1080(1993).
[6] A. Chong, J. Buckley, W. Renninger, F. Wise. Opt. Express, 14, 10095(2006).
[7] W. H. Renninger, A. Chong, F. W. Wise. Opt. Express, 19, 22496(2011).
[8] H. A. Haus, A. Mecozzi. IEEE J. Quantum Electron., 29, 983(1993).
[9] Y.-J. Song, K. Jung, J. Kim. Opt. Lett., 36, 1761(2011).
[10] P. Qin, S.-J. Wang, M.-L. Hu, Y.-J. Song. IEEE Photon. J., 10, 1500208(2018).
[11] Y. Wang, H.-C. Tian, D. Hou, F. Meng, Y.-X. Ma, H. Xu, F. X. Kärtner, Y.-J. Song, Z.-G. Zhang. Opt. Express, 27, 11273(2019).
[12] S. Namiki, H. A. Haus. IEEE J. Quantum Electron., 33, 649(1997).
[13] J. J. McFerran, W. C. Swann, B. R. Washburn, N. R. Newbury. Opt. Lett., 31, 1997(2006).
[14] K. Wu, P. P. Shum, S. Aditya, C.-M. Ouyang, J. H. Wong, H. Q. Lam, K. E. K. Lee. Opt. Lett., 37, 1901(2012).
[15] R. Paschotta. Appl. Phys. B, 79, 163(2004).
[16] K. Wu, J. H. Wong, P. Shum, S. Fu, C.-M. Ouyang, H.-H. Wang, E. J. R. Kelleher, A. I. Chernov, E. D. Obraztsova, J.-P. Chen. Opt. Express, 18, 16663(2010).
[17] B. R. Washburn, W. C. Swann, N. R. Newbury. Opt. Express, 13, 10622(2005).
[18] R. Paschotta, J. Nilsson, P. R. Barber, J. E. Caplen, A. C. Tropper, D. C. Hanna. Opt. Commun., 136, 375(1997).
[19] J. J. McFerran, W. C. Swann, B. R. Washburn, N. R. Newbury. Appl. Phys. B, 86, 219(2007).
[20] N. R. Newbury, W. C. Swann. J. Opt. Soc. Am. B, 24, 1756(2007).
[21] P. Z. Marmarelis, K.-I. Naka. Science, 175, 1276(1972).
[22] J. Chen, J. W. Sickler, E. P. Ippen, F. X. Kärtner. Opt. Lett., 32, 1566(2007).
[23] A. J. Benedick, J. G. Fujimoto, F. X. Kartner. Nat. Photon., 6, 97(2012).
[24] P. Qin, Y.-J. Song, H. Kim, J. Shin, D. Kwon, M.-L. Hu, C.-Y. Wang, J. Kim. Opt. Express, 22, 28276(2014).
[25] Y.-J. Song, C. Kim, K. Jung, H. Kim, J. Kim. Opt. Express, 19, 14518(2011).
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