Three-section DBR Laser Research Articles

Analysis of self-pulsating three-section DBR lasers

The characteristics of a three-section distributed Bragg reflector laser showing self-pulsation have been analyzed using a large signal time-domain traveling-wave simulator. The device dynamic properties have been investigated in all their complexity and analyzed as functions of the linewidth enhancement factor and of the injected current in the active and in the phase control sections. The simulation results have clearly shown the fundamental role of four wave mixing on the laser characteristics (output power, spectrum, etc.) and have been quantitatively correlated with the few available theoretical and experimental results. The considered self-pulsation operation frequencies around 40 GHz are of interest for practical applications.

Three-section sampled-grating DBR lasers: modelling and measurements

The authors consider tunable semiconductor lasers with a tuning range of 29.4 nm suitable for a range of applications including wavelength-division multiplexing and wavelength routing. The structure considered has three-sections for gain, phase adjustment and grating feedback, respectively, and has a new and novel mode of operation. The grating is sampled periodically to give multiple peaks in the reflectivity spectrum; although this causes mode hops to occur, it allows a wider tuning range than a continuous grating. Time-domain modelling has been employed to analyse large signal dynamic behaviour of the lasers, and good agreement with observed behaviour is obtained. The complex structure of the devices makes this model slow, and static tuning characteristics identical to those from the time-domain model have been obtained more rapidly using transfer matrix calculations. Devices have shown 14.7 nm of tuning with complete coverage and 29.4 nm of tuning with partial coverage with at least 30 dB side-mode suppression ratio (SMSR).

Frequency stabilization of tunable DBR laser using multiwavelength light injection locking technique

This paper proposes a frequency stabilization scheme for tunable three-section DBR laser diodes (3S-DBR LD) that use multiwavelength light injection locking. The oscillating wavelength of the SS-DBR LD is discretely switched between cavity modes when the injection current into DBR section is changed, and locked to one wavelength of the multiwavelength light injected from the DBR section facet under the injection locking condition. The light injection properties of the capture range and the relationships of relaxation oscillation versus input power and detuning are investigated experimentally. Injection locking on the multistate wavelength of a tunable DBR LD is performed using a two wavelength multiplexed light. As a result, we demonstrate 1 GHz capture range and more than 26 dB rejection ratio for the multiplexed injected light.

Dynamic wavelength tuning characteristics of the 1.5-μm three-section DBR lasers: analysis and experiment

We present a detailed theoretical analysis of the static and dynamic tuning characteristics of 1.55-/spl mu/m region three-section tunable DBR lasers under discrete tuning and under continuous tuning. We have analyzed the oscillating wavelength, the Bragg wavelength, and output power characteristics using the rate equation that considers the thermal effect, simultaneously analyzed the heat transfer equation, considering the heat transfer among passive waveguides, the LD chip, the submount, and the heat sink. We experimentally confirm the static and dynamic wavelength tuning characteristics using a highly accurate heterodyne measurement system. Static and dynamic characteristics simulated using the three-section DBR laser model and the thermal model agree with the experimental results presented in this paper.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Modelling and performance analysis of an opticalfrequency feedbackloop for tunable DBR laser diodes with fast current switching

A simple linear equivalent circuit of an optical frequency feedback loop is introduced to reduce the thermal drift associated with current switching in three-section DBR laser diodes. Numerical analysis of the proposed circuit reveals design tradeoffs existing among several performance categories of the loop. An optimum design for the loop is then presented.

Switching and optical modulation of three-section DBR lasers

In this paper an improved dynamical model of a three-section distributed Bragg reflector (TSDBR) laser that includes gain saturation effects and mode competition is used to carefully analyze the tuning static characteristics, the switching dynamics, and the optically-controlled frequency conversion of the device. As a result, reasonable estimates of the switching times and insights into the device behavior are obtained, together with curves showing the IM/FM frequency and modulation conversion. >

Increased modulation bandwidth up to 20 GHz of a detuned-loaded DBR laser

A small signal amplitude modulation bandwidth of 20 GHz has been obtained with a three-section tunable DBR laser fabricated with semi-insulating current blocking layers grown by hydride VPE. The modulation bandwidth and laser linewidth are strongly dependent on the position of the lasing mode relative to the Bragg reflection peak. >

Frequency modulation characteristics of three-section DBR lasers

A theoretical analysis of the dynamic behaviour of a three-section DBR laser is presented. The FM response, due to the refractive index modulation resulting from injection current modulation, is studied by means of a small signal analysis. Modulation can be considered in one or more sections. A condition leading to the IM suppression, and to the elimination of relaxation oscillation of the FM response, is derived. The model is based on the transfer matrix method by means of which the whole structure can be reduced to a Fabry—Perot laser with an effective complex reflectivity depending on current modulation in the passive sections. Results for a typical example of such a structure are presented and discussed.

Fast wavelength switching and simultaneous FSK modulation using tunable DBR laser

This letter describes the operation of a tunable three-section DBR laser for multiwavelength switching with up to 48 resolvable wavelengths. Fast switching among wavelengths that are spaced over a 2.2 nm continuous tuning range and simultaneous FSK data modulation of each channel are demonstrated. A novel wide-deviation FSK modulation scheme to reduce temperature induced wavelength drifts is also described.

Spectral characteristics of a three-section wavelength-tunable DBR laser

A study of wavelength tuning characteristics when both phase control and DBR currents are varied is discussed. The change of threshold current, output power, and linewidth under wavelength tuning is also investigated. These characteristics are in good agreement with the theoretical analysis. Additional large-linewidth broadening under wavelength tuning which cannot be explained was observed. >