Self-starting harmonic frequency comb generation in a quantum cascade laser

Optical frequency combs1,2 establish a rigid phase-coherent link between microwave and optical domains and are emerging as high-precision tools in an increasing number of applications3. Frequency combs with large intermodal spacing are employed in the field of microwave photonics for radiofrequency arbitrary waveform synthesis4,5 and for the generation of terahertz tones of high spectral purity in future wireless communication networks6,7. Here, we demonstrate self-starting harmonic frequency comb generation with a terahertz repetition rate in a quantum cascade laser. The large intermodal spacing caused by the suppression of tens of adjacent cavity modes originates from a parametric contribution to the gain due to temporal modulations of population inversion in the laser8,9. Using multiheterodyne self-detection, the mode spacing of the harmonic comb is shown to be uniform to within 5 × 10−12 parts of the central frequency. This new harmonic comb state extends the range of applications of quantum cascade laser frequency combs10–13.Self-starting harmonic frequency comb generation with a THz repetition rate in a quantum cascade laser is demonstrated. The mode spacing uniformity is verified to within 5 × 10−12 parts of the central frequency. The findings extend the range of applications of quantum cascade laser frequency combs.

[1]  Mattias Beck,et al.  On-chip, self-detected terahertz dual-comb source , 2016 .

[2]  J. Faist,et al.  Measurement of semiconductor laser gain and dispersion curves utilizing Fourier transforms of the emission spectra , 1999, IEEE Photonics Technology Letters.

[3]  T. Hänsch,et al.  Optical frequency metrology , 2002, Nature.

[4]  Scott A. Diddams,et al.  The evolving optical frequency comb , 2010 .

[5]  K. Vahala,et al.  Phase-coherent microwave-to-optical link with a self-referenced microcomb , 2016, Nature Photonics.

[6]  C. Caneau,et al.  Room Temperature CW Operation of Short Wavelength Quantum Cascade Lasers Made of Strain Balanced Ga $_{\bm x}$In$_{\bm {1-x}}$ As/Al$_{\bm y}$ In$_{\bm {1-y}}$As Material on InP Substrates , 2011, IEEE Journal of Selected Topics in Quantum Electronics.

[7]  Govind P. Agrawal,et al.  Population pulsations and nondegenerate four-wave mixing in semiconductor lasers and amplifiers , 1988 .

[8]  Carlo Sirtori,et al.  High power frequency comb based on mid-infrared quantum cascade laser at λ ∼ 9 μm , 2015 .

[9]  Jérôme Faist,et al.  Dual-comb spectroscopy based on quantum cascade laser frequency combs , 2015, CLEO 2015.

[10]  D. Moltchanov,et al.  Terahertz band communications: Applications, research challenges, and standardization activities , 2016, 2016 8th International Congress on Ultra Modern Telecommunications and Control Systems and Workshops (ICUMT).

[11]  T. Kippenberg,et al.  Optical frequency comb generation from a monolithic microresonator , 2007, Nature.

[12]  Mattias Beck,et al.  Rf-modulation of mid-infrared distributed feedback quantum cascade lasers. , 2016, Optics express.

[13]  W. Lamb.  Theory of an optical maser , 1964 .

[14]  Scott A. Diddams,et al.  The evolving optical frequency comb [Invited] , 2010 .

[15]  R. Holzwarth,et al.  Mid-infrared optical frequency combs at 2.5 μm based on crystalline microresonators , 2013, Nature Communications.

[16]  Cyril C. Renaud,et al.  Advances in terahertz communications accelerated by photonics , 2016, Nature Photonics.

[17]  A. Weiner,et al.  Spectral line‐by‐line shaping for optical and microwave arbitrary waveform generations , 2008 .

[18]  Mattias Beck,et al.  Dispersion engineering of Quantum Cascade Lasers frequency combs , 2015, 1509.08856.

[19]  Ian F. Akyildiz,et al.  Terahertz band: Next frontier for wireless communications , 2014, Phys. Commun..

[20]  T. Hänsch.  Nobel Lecture: Passion for precision* , 2006 .

[21]  T. Kippenberg,et al.  Microresonator based optical frequency combs , 2012, 2012 Conference on Lasers and Electro-Optics (CLEO).

[22]  J. Faist,et al.  Mid-infrared frequency comb based on a quantum cascade laser , 2012, Nature.

[23]  Shin Arahira,et al.  Mode-locking at very high repetition rates more than terahertz in passively mode-locked distributed-Bragg-reflector laser diodes , 1996 .

[24]  Jian Wang,et al.  Reconfigurable radio-frequency arbitrary waveforms synthesized in a silicon photonic chip , 2015, Nature communications.

[25]  Qing Hu,et al.  Terahertz laser frequency combs , 2014 .

[26]  Yamac Dikmelik,et al.  Coherent frequency combs produced by self frequency modulation in quantum cascade lasers , 2014 .

[27]  C. Zah,et al.  Single-mode instability in standing-wave lasers: The quantum cascade laser as a self-pumped parametric oscillator , 2016, 1711.00187.

[28]  Mattias Beck,et al.  Quantum Cascade Laser Frequency Combs , 2015, 1510.09075.