Marian Majewski | The University of Queensland, Australia (original) (raw)

Papers by Marian Majewski

Proceedings of LEOS '93

ABSTRACT Summary form only given. Vertical-Cavity Surface-Emitting Laser (VCSEL) diodes are seen ... more ABSTRACT Summary form only given. Vertical-Cavity Surface-Emitting Laser (VCSEL) diodes are seen as effective light sources for future optical-fiber communication and optical signal processing applications. Essential to these applications, however, is the device's ability to yield a low-distortion and adequately broad band intensity modulation response. Unfortunately, very little has been published so far regarding these characteristics of VCSELs, and in particular their dependence on the higher-order transverse modes that are typically present in the device cavity. Our recent experimental investigations conducted on a number of different circular index guided VCSELs have indicated that the presence of higher-order cavity modes, even for devices exhibiting reasonably good side-mode suppression ratios can modify the shape of the modulation response and often leads to harmonic distortion even at relatively low modulation signal levels. We attribute these effects to the cavity mode interaction that is associated with the optical gain nonlinearity. This mode interaction results in signal (or noise) beating effects. This is also referred to as the spectral down- or up-conversion process or mixing. In order to investigate the influence of these beat effects on the intrinsic modulation response, “parasitic-free” relative intensity noise (RIN) characteristics for different medium-power VCSELs (6-9 μm diameter range) have been measured

The 15th Annual Meeting of the IEEE Lasers and Electro-Optics Society

Widely tunable semiconductor lasers support a wide range of application areas, including waveleng... more Widely tunable semiconductor lasers support a wide range of application areas, including wavelength-division multiplexing (WDM) systems, spectroscopy, gas analysis, optical reflectometly and radar systems. The Sampled Grating Distributed B r a g Reflector (SGDBR) laser is one of the best candidates. It has the merits of wide tuning range, high mode suppression, low cost, high output power, direct modulation, high speed switching, high reliability and simplicity for integration with other components. Up to now, a quasi-continuous tuning range of 72nm using a SGDBR laser has been achieved [I]. A fiber-coupled optical power above lOmW across 40nm for a SGDBR laser integrated with a semiconductor optical amplifier (SOA) was also published [2]. Noise and distortion performances are important characteristics of a tunable laser in the WDM system with multiple channels, particularly when analog information is transmitted or the laser is used in signal processing. In this paper, we investigate both the intensity noise and intermodulation distortion properties of SGDBR lasers across the whole tuning range. Furthermore, the resonance frequency and the damping factor of the devices are extracted from the noise spectrum analysis. The SGDBR laser in this experiment is similar to that described in [3] and was fabricated by Agility Communications Inc. The device has a CW threshold current of 36mA and fiber-coupled output power of 6mW at a bias current of 12OmA. A quasi-continuous tuning range from 1530 to 1580nm is achieved, with side mode suppression ratio (SMSR) maintained above 45dB by appropriately biasing the gain, phase, front and back DBR sections. The laser is assembled in a 14-pin butterfly package with an internal 60dB optical isolator.

1996 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings

ABSTRACT The transverse mode properties of vertical-cavity surface-emitting lasers (VCSELs) are i... more ABSTRACT The transverse mode properties of vertical-cavity surface-emitting lasers (VCSELs) are investigated by spectrally resolved beam profiling. Near field and far field intensity distributions were measured for a top emitting index guided VCSEL. The Gerchberg-Saxton algorithm was employed to retrieve the phase across the laser aperture

IEEE MTT-S International Microwave Symposium Digest

... Page 4. -40 I I I I I FUNDAMENTAL (I GHz) --- IMD (0.7 GHr , 1.3 GHz) --- 2 nd-HARMONIC ( 2 G... more ... Page 4. -40 I I I I I FUNDAMENTAL (I GHz) --- IMD (0.7 GHr , 1.3 GHz) --- 2 nd-HARMONIC ( 2 GHz) .- / DFB-1.3pm T.19.6 % E -50-I,,=20 mA rn U I-no - ... RS = 5Q,Cs = 15.pF, RB = 2Q, L p = 2nH, Cp = 0.25pF. The dynamic characteristics for the 1.3pm DFB LD are shown in Fig 4. ...

2006 International Conference on Microwaves, Radar & Wireless Communications, 2006

The small signal modulation characteristics of a vertical-cavity, surface-emitting laser (VCSEL) ... more The small signal modulation characteristics of a vertical-cavity, surface-emitting laser (VCSEL) are determined using three different measurements: relative intensity noise, frequency response, and high resolution optical spectra. The resonant and damping frequencies were measured, and related rate equation parameters were extracted; excellent agreement was found both between experiment and theory, and amongst the different measurement techniques. The results and procedures are compared, and the findings are presented below.

In a microlens-based free-space optical interconnect, it is usually assumed that the arrangement ... more In a microlens-based free-space optical interconnect, it is usually assumed that the arrangement of transmitters, microlenses and receivers in their respective arrays is "square". This paper shows that it is possible to improve the optical signal-to-noise ratio by up to 50% by slightly altering the array geometry.

A simple, multi-mode, rate equation based thermal model has been developed for vertical-cavity, s... more A simple, multi-mode, rate equation based thermal model has been developed for vertical-cavity, surface-emitting lasers. The misalignment between cavity supported modes and the material gain peak is considered to be the primary cause of the higher order transverse modes and power rolloff observed in these devices. Experiments are performed on a Mode 8085-2008 VCSEL to determine its modal composition over a range of currents and temperatures. The rate equation model was fitted to these modally resolved light current curves with good success

Conference on Optical Fiber Communication/International Conference on Integrated Optics and Optical Fiber Communication, 1993

One of the most important device parameters of distributed- feedback (DFB) semiconductor lasers i... more One of the most important device parameters of distributed- feedback (DFB) semiconductor lasers is the coupling coefficient k, which describes the strength of the coupling due to the internal diffraction grating between two counterpropagating waves. The coupling coefficient of actual devices has been determined by observing the stop-band width in below-threshold emission spectra.1 However, this is not an easy task unless reflectivity of both the cleaved facets is sufficiently reduced (typically less than 1%). If facet reflection exists, the intrinsic emission spectrum of the DFB cavity is distorted by the Fabry- Perot (FP) cavity, which makes precise determination of the stop-band width difficult. The stop-band width becomes dependent on the positions of the facets relative to the spatial phase of the grating.

2000 22nd International Conference on Microelectronics. Proceedings (Cat. No.00TH8400), 1999

Calculation of the optical constants of InP and GaP is presented. The employed model is a modific... more Calculation of the optical constants of InP and GaP is presented. The employed model is a modification of Adachi's model of the optical constants of semiconductors, which employs adjustable broadening instead of the conventional Lorentzian one. In this work we do not take into account excitonic effects at E1 and E1+Δ1 critical points. In such a manner, fewer adjustable model

In this work, we present genetic algorithm based approach for the design of asymmetric Bragg mirr... more In this work, we present genetic algorithm based approach for the design of asymmetric Bragg mirrors for the microcavity organic light emitting diodes (OLEDs) applications. The phase shift of the Bragg mirror is calculated using the matrix formulation for light propagation through a thin film multilayer. The objective function to be minimized is the wavelength shift in Ag/Alq3/TPD/ITO/Bragg mirror/glass device,

Optics Communications, 1999

ABSTRACT The feasibility of lensless free-space optical interconnects (FSOI's) using Vert... more ABSTRACT The feasibility of lensless free-space optical interconnects (FSOI's) using Vertical-Cavity-Surface-Emitting Lasers (VCSEL's) is investigated. The signal-to-noise ratio (SNR) and interconnect capacity of FSOI's in the presence of higher order modes are analyzed. The dependence of the SNR on feature parameters of VCSEL and photodetector arrays and the dependence of the capacity on channel spacing are simulated. The results have shown that lensless FSOI's can be achieved in chip level applications and the presence of higher order modes will deteriorate their performance. Moreover, the maximum distance of interconnection and the effect of lateral misalignment are also investigated.

Gaussian diffraction model is employed to analyze the optimal design of free-space optical interc... more Gaussian diffraction model is employed to analyze the optimal design of free-space optical interconnects (FSOI’s) based on the arrays of multi-tranverse mode vertical cavity surface emitting lasers (VCSEL’s), microlenses, and photodetectors. The optical channel crosstalk and the signal-to-noise ratio (SNR) are analyzed in relation to the multi-transverse mode VCSEL’s. We have found that the positioning of VCSEL’s relative to the transmitter lens has a significant impact on the SNI3 and the interconnect distance. In addition, the presence of higher order modes deteriorates the performance of interconnects. Free-space optical interconnects (FSOI’s) are seen as well suited for the chip-level and board-level interconnects. A major concern of high speed and high density FSOI’s is the optical channel crosstalk arising from the laser beam diffraction and the misalignment between VCSEL’s, microlenses, and photodetectors. The issue of optical crosstalk in interconnects has previously been in...

Journal of Applied Physics, 1999

Extension of Adachi's model with a Gaussianlike broadening function instead of a Lorentzian one i... more Extension of Adachi's model with a Gaussianlike broadening function instead of a Lorentzian one is used t o model the optical dielectric function of the alloy AI,Gal-,As. Gaussian-like broadening is accomplished by replacing the damping constant in the Lorentzian line shape with a frequency dependent expression. In such a manner, the comparative simplicity of analytic formulae of the model is preserved, while the accuracy becomes comparable to more intricate models, and/or models with a significantly greater number of parameters. The employed model describes accurately the optical dielectric function in the spectral range from 1.5 t o 6.0 e V in the entire alloy composition range. Relative rms error obtained for the refractive index is below 2.2% for all compositions.

IEEE Journal of Quantum Electronics, 1993

The temperature dependence and power output of vertical-cavity surface-emitting lasers (VCSEL's) ... more The temperature dependence and power output of vertical-cavity surface-emitting lasers (VCSEL's) are of great importance when considering these devices for real applications. We have deliberately offset the peak wavelength of the quantum well from the wavelength of the device cavity mode so that they are aligned at elevated temperatures. The result of this design change is to produce an 8 pm diameter VCSEL capable of operation to 145"C, as well as CW operation of broad area (70 pm diameter) heat-sunk devices to record power levels. Fiber coupling experiments were also carried out, and a record 33 mW CW power was coupled to a multimode fiber.

Electronics Letters, 2002

ABSTRACT The dynamic range of sampled-grating distributed Bragg reflector lasers is investigated.... more ABSTRACT The dynamic range of sampled-grating distributed Bragg reflector lasers is investigated. The system noise is limited by the photodiode shot noise, which is below -160 dBm/Hz at normal bias current. The spur-free dynamic range is between 100-112 dB·Hz2/3. Both the noise and linearity are uniform over the whole tuning range of 50 nm, and are relatively insensitive to mode detuning

Journal of Lightwave Technology, 2007

This paper critically compares, for the first time, common microwave and optical procedures used ... more This paper critically compares, for the first time, common microwave and optical procedures used for the highspeed characterization of vertical-cavity surface-emitting lasers (VCSELs). The intrinsic small-signal modulation characteristics of a VCSEL are measured, and the related rate equation parameters are extracted. Observed trends show excellent agreement with theory. The modulation characteristics of the VCSEL are determined by examining three different responses: relative intensity noise, S21 response, and high-resolution optical spectra. The various experimental techniques yielded consistent results. The relative strengths and weaknesses of each measurement are investigated.

Modern Physics Letters A, 1993

The differential realization of the recently proposed deformed Poincaré algebra is considered. Th... more The differential realization of the recently proposed deformed Poincaré algebra is considered. The notion of covariant wave functions is introduced and their explicit form in the "minimal" (in Weinberg's sense) case is given. The deformed Dirac equation is constructed.

Summer Topical Meeting Digest on Broadband Analog and Digital Optoelectronics, Optical Multiple Access Networks, Integrated Optoelectronics, Smart Pixels

ABSTRACT