Phase synchronization scheme for a practical phase sensitive amplifier of ASK-NRZ signals

IEEE J. Quantum Electron.

Ellis

et al. 2012

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Abstract-In this paper, we describe generation and application of wide, narrow linewidth optical frequency combs using dualmode injection-locking of InP quantum-dash mode-locked lasers. In the first part, the dependence of the RF locking-range on the device's absorber voltage is experimentally investigated. Under optimized absorber voltage, a continuous, wide RF locking-range of ≈400 MHz is achievable for lasers with 21 GHz repetition rate. The total RF locking-range of ≈440 MHz is possible considering of locking-range for positive and negative absorber voltages. This wide tuning >2% of the repetition rate, a record for a monolithic mode-locked laser, is reported from a two-section device without any additional passive section or extended-cavity for repetition rate tuning. It is shown that the effective RF locking-range in dual-mode injection corresponds to the optical locking-range and repetition rate tuning under CW injection which is wider when the free-running mode-locking operation is "less stable". The widest comb consists of 35 narrow lines within 10 dB of the peak, spanning ≈ 0.7 THz, generating 3.7 ps pulses. In the second part, we show the first demonstration of multi pump phase-synchronization of two 10 Gb/s DPSK channels in a phasesensitive amplifier using dual-mode injection-locking technique. The phase-sensitive amplifier based on "black box" scheme shows more than 7 dB phase-sensitive gain and error free performance for both input channels with 1 dB penalty.Index Terms-Mode-locked lasers, optical-injection-locking, optical frequency combs, quantum-dash lasers, and phasesensitive amplifiers.

Section: A Experimental Arrangement and Resultsmentioning

confidence: 99%

Optical Frequency Comb Generation Using Dual-Mode Injection-Locking of Quantum-Dash Mode-Locked Lasers: Properties and Applications

Sooudi

IEEE J. Quantum Electron.

Ellis

et al. 2012

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“…In order to suppress the residual phase modulation present in the extracted carriers, the injection ratio (ratio of injected power to the free running slave's power) should be kept as low as possible [9] (about -30 dB in this experiment). The phase sensitive amplifier was stabilized against thermal fiber expansion using a conventional phase-locked loop [5] and was observed at maximum and minimum gain for both channels, as shown in Fig.…”

Section: Experimental Arrangement and Resultsmentioning

confidence: 99%

Phase Synchronization of a Two-Channel Phase-Sensitive Amplifier based on Optical Injection-Locking of InP Quantum-Dash Mode-Locked Lasers

Sooudi

Optical Fiber Communication Conference

Frascella

et al. 2012

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“…The locking range of the optical injection locking mechanism can be in the order of GHz, much larger than the ~MHz linewidth of typical distributed feedback (DFB) lasers, which enables low phase error performance and robust operation at high symbol rates. This is a noticeable implementation advantage of OIL against alternative synchronization schemes such as optical phase lock loops (OPLLs), which has made them particular attractive for a number of recent demonstrations in phase sensitive amplification [9] and coherent detection [10]. Indeed, traditional OPLL circuits made from commercial off-the-shelf (COTS) fiber pigtailed components have large feedback delays limiting the obtainable loop bandwidth and setting restrictions on the summed laser linewidth of the transmitter (master) and the local oscillator (slave).…”

Section: Injection Locked Laser Based Carrier Enhancementmentioning

confidence: 99%

Stabilization of self-coherent OFDM with injection locked laser

Adhikari

2012 14th International Conference on Transparent Optical Networks (ICTON)

Ellis

et al. 2012

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With the rebirth of coherent detection, various algorithms have come forth to alleviate phase noise, one of the main impairments for coherent receivers. These algorithms provide stable compensation, however they limit the DSP. With this key issue in mind, Fabry Perot filter based self coherent optical OFDM was analyzed which does not require phase noise compensation reducing the complexity in DSP at low OSNR. However, the performance of such a receiver is limited due to ASE noise at the carrier wavelength, especially since an optical amplifier is typically employed with the filter to ensure sufficient carrier power.Subsequently, the use of an injection-locked laser (ILL) to retrieve the frequency and phase information from the extracted carrier without the use of an amplifier was recently proposed. In ILL based system, an optical carrier is sent along with the OFDM signal in the transmitter. At the receiver, the carrier is extracted from the OFDM signal using a Fabry-Perot tunable filter and an ILL is used to significantly amplify the carrier and reduce intensity and phase noise. In contrast to CO-OFDM, such a system supports low-cost broad linewidth lasers and benefits with lower complexity in the DSP as no carrier frequency estimation and correction along with phase noise compensation is required.