Wavelength tunable comb source

The present application provides an optical comb source (1) in which the comb is produced by seeding a gain switched Fabry-Perot laser (2) with light (10) from a single mode laser (4), whilst at the same time driving the Fabry-Perot laser (2) with a DC bias and RF signal

Wavelength tunable comb source

\u3cp\u3eThe present application provides an optical comb source in which the comb is produced by seeding a gain switched Fabry-Pérot laser with light from a single mode laser, whilst at the same time driving the Fabry-Pérot laser with a DC bias and RF signal.\u3c/p\u3

Sub-picosecond pulse generation by 40-GHz passively mode-locked quantum-dash 1-mm-long Fabry-Pérot laser diode

Optical pulses at a repetition rate of 39.8 GHz have been observed in a dc-biased passively mode-locked quantum-dash Fabry-Pérot laser diode. The pulses generated by this diode are studied in the temporal and spectral domains using a second harmonic generation frequency-resolved optical gating system. By using a tunable band-pass filter, it is observed that the pulse width decreases as the number of lasing modes selected by the filter increases. Furthermore, by controlling the phase difference of the modes using a 450m-long single mode fibre, a passive compression of the pulses is obtained. A minimum pulse width of 720 fs has been measured with this type of mode-locked Fabry-Pérot laser

Linewidth analysis of 40-GHz passively mode-locked multi-mode semiconductor lasers

An experimental analysis on the quality of 40-GHz radio-frequency signals generated by various passively mode-locked semiconductor lasers is addressed. The analysis is performed considering the frequency linewidth of 40-GHz optically generated signals and the number of longitudinal modes selected by the cavity of each laser under study. Four of these devices are multi-quantum wells InAlGaAs Fabry-Pérot lasers. They have been engineered to exhibit a specific number of longitudinal modes: 4, 5, 10, and 22 modes, respectively. Another device under test is a bulk distributed Bragg reflector laser exhibiting 3 lasing modes. The last device under study is a quantum-dash Fabry-Pérot laser characterized by 40 lasing modes. From our experimental results it appears that, regardless the nature of the device cavity and active media, the strength of the passively mode-locked mechanism might be enhanced with the number of longitudinal modes oscillating into the laser cavity, allowing a reduction in the frequency linewidth

Wavelength tunability of all-optical clock-recovery based on quantum-dash mode-locked laser diode under injection of a 40-Gb/s NRZ data stream

Wavelength tunability of an all-optical clock recovery operation based on a quantum-dash mode-locked Fabry-Pérot laser diode is experimentally investigated. Synchronization of the device to the injection of 40-Gb/s nonreturn-to-zero (NRZ) incoming data is assessed by analyzing both the carrier-to-noise ratio and the linewidth of the 40-GHz beat-tones measured at the mode-locked laser output. Under optical injection, beat-tone linewidths below 10 Hz are measured. Recovered clock pulses featuring a width of 1.6 ps are obtained irrespective of the wavelength detuning between the laser spectra and the optical carrier of the incoming data stream

Tuning of a widely tunable monolithically integrated InP laser for optical coherence tomography

\u3cp\u3eStep-wise tuning of a monolithically integrated widely tunable continuous wave semiconductor ring laser is investigated, for application in Fourier domain optical coherence tomography (OCT). The device operates around 1530 nm and was realized on an InP generic photonic integration technology platform. The laser is tuned using voltage-controlled electrooptic phase modulators with <100 μW thermal dissipation, which reduces time dependent thermal effects in the filter. Here we present a calibration method with progressively finer wavelength control steps and discuss the limits of wavelength accuracy and repeatability with respect to OCT requirements. It is shown that thermal effects due to light absorption in the phase modulators have a negligible effect on the tuning of the laser for six out of seven phase modulators. To bring the thermal dissipation of the seventh phase modulator in line with the others a design change is proposed. Wavelength switching dynamics are investigated with a numerical model of the laser. A simulation based on this model shows that it takes around 50 ns from the wavelength switching instant to establish a single mode operation with side mode suppression ratio of 30 dB.\u3c/p\u3

A monolithically integrated tunable single longitudinal mode extended cavity ring laser using Intracavity Mach-Zehnder interferometers

A ring geometry laser with a wavelength tunable intracavity filter is demonstrated. The device is realized as a photonic integrated circuit and fabricated within COBRA InP active-passive multi project wafer run. The device under test features a three stage asymmetric Mach-Zehnder interferometer filtering scheme allowing for a single mode operation with the side mode suppression and contrast ratios of 43 dB and 60 dB respectively when the laser is DC biased at 2.5 times of the threshold current

Open standard test framework for photonic integrated circuits

\u3cp\u3eTest, assembly and packaging processes substantially contribute to the overall production cost of photonic integrated circuits. Implementation of test processes across the full production chain is critical in order to deliver statistically significant data sets. These will allow for optimization of the fabrication process widows, early known-good-die selection, improved models in design tools and lead to improved yield, reduced cost and scalability which will open a path to volume production. Progress on developments of open access test infrastructure at our laboratories and open standard test framework will be presented.\u3c/p\u3

Open standards for automation of testing of photonic integrated circuits

\u3cp\u3eFoundry services for photonic integration enable access to such technologies and facilitate fab-less businesses models. The technologies are sufficiently mature for proof-of-concept demonstrators, advanced prototypes, and two-medium small-volume production. Further improvement of the technology processes behind those services requires extensive research and development efforts in order to advance the foundry offerings and assure scalability, process control, and the yield required for volume production. A high-level automation of test and assembly processes in the PIC manufacturing chain is essential to improve statistical process control and scalability of all processes. These allow for early known-good-die identification, optimization of fabrication process window, improved yield, and volume production. In this paper we propose a standardized approach to chip layout that supports automated test and assembly processes already at the design phase. Moreover, we describe a modular test software framework based on open standards. Within this test framework, standard file formats for chip, equipment, and measurement description, and the open file formats for storage and exchange of data are described. This test framework is a part of the openEPDA initiative and enables test automation, user-defined testing, data analysis, exchangeability, and traceability across the full manufacturing chain from design to product.\u3c/p\u3