Abstract
Quantum-dash modelocked laser diodes (QD-MLLD) are capable of producing short optical pulses at extremely high repetition rates. As such they are ideally suited to many telecommunications applications [1]. In this paper we present a linear self-referenced measurement of the spectral amplitude and phase of a free-running quantum-dash modelocked laser diode. The technique is suitable for measuring optical signals with repetition rates up to 100 GHz. In contrast to many other linear techniques it requires no external electronic clock synchronized to the signal under test. Using this method we show that compensating for the intra-cavity dispersion of the diode results in 500 fs pulses at a repetition rate of 39.8 GHz. The measurement technique is based on the stepped-heterodyne method presented in Ref. [2]. The signal under test is mixed with a CW narrowband optical local oscillator (LO) and the combined signal detected by a high-speed photodiode, mixed with an electronic LO, and then recorded on a real-time oscilloscope. When the optical LO is placed between two adjacent signal modes the resultant beat signals can be analysed to determine not only the power of each of the signal modes, but also the phase difference between them [2]. Stepping the optical LO across all signal modes allows for a complete measurement of the spectral amplitude and phase of the signal.
© 2011 Optical Society of America
PDF ArticleMore Like This
Ramón Maldonado-Basilio, Sylwester Latkowski, and Pascal Landais
JThA021 National Fiber Optic Engineers Conference (NFOEC) 2011
Ramón Maldonado-Basilio, Sylwester Latkowski, and Pascal Landais
CB3_6 The European Conference on Lasers and Electro-Optics (CLEO/Europe) 2011
Mohsin Haji, Anthony E. Kelly, Lianping Hou, A. Catrina Bryce, John M. Arnold, and Charles N. Ironside
CB12_5 The European Conference on Lasers and Electro-Optics (CLEO/Europe) 2011