Applications of optical feedback in laser diodes

AIP Conference Proceedings, 1999

Laser diode technology continues to advance at a very rapid rate due to commercial applications such as telecommunications and data storage. The advantages of laser diodes include, wide diversity of wavelengths, high efficiency, small size and weight and high reliability. Semiconductor and fiber optical-amplifiers permit efficient, high power master oscillator power amplifier (MOPA) transmitter systems. Laser diode systems which incorporate monolithic or discrete (fiber optic) gratings permit single frequency operation. We describe experimental and theoretical results of laser diode based instruments currently under development at NASA Goddard Space Flight Center including miniature lidars for measuring clouds and aerosols, water vapor and wind for Earth and planetary (Mars Lander) use.

Journal of Lightwave Technology, 2002

An experimental study has been performed of the relative intensity noise (RIN) of a semiconductor laser in optical feedback regimes I to V. At low bias current, a low RIN is observed with low feedback ratio, the RIN increased in the coherence collapse regime (regime IV) and decreased in regime V. The RIN in regime V is lower than that of the solitary laser. For higher bias current, a higher feedback ratio is needed for the semiconductor laser to transit from regime IV to V. The measurements are found to be in good qualitative and quantitative agreement with theoretical predictions Index Terms-Laser diodes, noise, optical feedback.

Physical Review E, 2007

Filtered optical feedback (FOF) can be used to stabilize a semiconductor laser but also to generate chaotic laser emission that may find applications in chaos communication schemes. We study theoretically the dynamics the FOF laser and identify the feedback phase as an important parameter that organizes the huge degree of multi-stability in this system. A systematic experimental study of the phase effect on the dynamics is presented that is supported by theoretical findings.

Novel In-Plane Semiconductor Lasers XVIII

Unwanted optical feedback is a common problem in many optical setups of laser systems. To quantify the effect, the influence of a controlled external feedback on the emission properties of a low power distributed feedback ridge waveguide and a high power distributed Bragg reflector tapered diode laser are analyzed. The measured influence of the phase dependent feedback over several orders of magnitude in feedback power attenuation on emission wavelength is discussed and compared to theory.

IEEE Transactions on Instrumentation and Measurement, 1993

We present precision optical spectral lineshape measurements on semiconductor lasers using Michelson and Fabry-Perot interferometers. Measurements ranging from 30 MHz up to 100 GHz give the spectral behavior above and below threshold even for very small emitted optical powers. Variations of the linewidth above and below threshold as a function of injected current have been measured and used to evaluate the linewidth enhancement factor and behavior at threshold. The lineshape can differ from the modified Schawlow-Townes almost Lorentzian form for semiconductor lasers above threshold when submitted to operating system conditions such as modulation and optical feedback. Under modulation, line frequency and signal form are modified because of chirping effects. We propose a simple method for chirp evaluation at low frequencies based on lineshape evaluation. Optical feedback effects are also studied as a function of the feedback coefficient C showing various regimes differing for singlemode and multimode laser diodes.

SpringerBriefs in Physics, 2012

IEEE Access, 2021

The back-reflection of emitted laser beam (optical feedback, also know as selfmixing) from various external interfaces are sufficient to cause instability, and prohibiting its use in various fields such as communication, spectroscopy, imaging to name a few. So it is desirable to study the laser dynamics and the conditions causing it to be stable in spite of strong optical feedback. With the aid of mathematical formulation, simulation and backed by experimental evidences, it is demonstrated that the frequency deviation of the laser emission due to current (intensity) modulation alters the dynamic state and boundary conditions of the system such that even under large optical feedback strength, the laser may attain stability and retain single modal state. The frequency deviation resulting from former is shown to modify the phase of the system in opposite direction to that induced by the later, showing that there exists an optimal modulation current which compensates the effect of optical feedback and may be used to retain the laser in single modal stationary state. The method thus provides a methodology to avoid optical feedback-induced instability in semiconductor lasers by using the proper amplitude of current (intensity) modulation.

1981

This report is a .study of the dynamic properties of semiconductor laser diodes. The measurement of some important lc;ser diode parameters necessary for dyn?mic behaviour prediction is described. The relc;xation oscillation behaviour for laser diodes pumped with nanosecond time scale current pulses is predicted using both an approximate an~lytic solution c;nd computer simulations. This predicted behaviour is compared with experimental results. DynC~mic experiments with c;n externc;l cavity for extra optical feedb2ck and a regenerativE loop for optoelectronic feedback are also described and discussed. Details of the experimental setups and techniques used are given. iii and B.L.C. for their support. Special thanks to John Goodwin for numerous discussions and immeasurable help throughout this work.

Optical Engineering, 2001

We propose a new technique to measure the angle of a remote flat surface with respect to the propagation direction of a laser beam, based on injection detection in a laser diode. The surface under test acts as the remote mirror of an external cavity laser, and causes the laser diode to operate in the coherent collapse regime. The power emitted by the laser depends on the alignment of the remote surface, and an ac technique enables us to measure angle with a sensitivity of 0.1 arcsec (i.e., 5ϫ10 Ϫ7 rad). The attained performances are comparable to those of existing autocollimators, with the advantage of simplicity and compactness that makes the new technique interesting for the development of a measuring instrument.

IEEE Journal of Quantum Electronics, 2000

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IEEE Transactions on Instrumentation and Measurement, 1999

The frequency of a diode laser has been stabilized to the hyperfine spectrum of molecular iodine at 633 nm. A frequency stability and a (day-to-day) reproducibility of 4 2 10 012 and 5 2 10 011 , respectively, were obtained. In particular, we have investigated the effect of optical feedback on the locking point frequency of the stabilized diode laser. Optical feedback can cause amplitude variations and harmonic distortion of the frequency modulation of the diode laser and, subsequently, cause a significant shift of the locking point of the laser. The optical feedback is shown to have undesired effects even at very small (7 2 10 010 ) levels.

Applied Physics B, 2010

This paper describes the effects of optical feedback on the sensitivity of VCSEL tunable-diode laser spectroscopy (TDLS). Three VCSELs, emitting at different wavelengths in the near-infrared, were used. A TDLS system, subjected to optical feedback, exhibited a common signal-to-noise ratio profile for all three lasers. A catastrophic degradation of TDLS sensitivity occurred when feedback exceeded a level which we associate with coherence collapse. The TDLS system had a CH 4 minimum detection limit of 7.5 ppmm without optical feedback. Optical feedback of less than ten percent reduced this sensitivity by two orders of magnitude. This reduction of system sensitivity was accompanied by a second-harmonic absorption signal baseline shift which degraded the system accuracy. 1 Introduction Absorption spectroscopy with tunable laser diodes is a useful technology for remote gas sensing [1, 2]. Field-usable diode laser sensors have been developed for applications ranging from gas monitoring of industrial processes [3] D. Vujanic () • J. Tulip

2015

Abstract—The nonlinear dynamic behavior of a direct fre-quency-modulated diode laser with strong optical feedback is examined and compared to a laser diode subject to electro-op-tically modulated, strong optical feedback. Direct modulation is achieved by sinusoidal modulation of the diode laser injection current. Electro-optic modulation is achieved by applying a sinusoidal voltage to an intracavity phase modulating element. The output state (characterized by the output power versus time, the intensity noise spectrum and the optical frequency spectrum) for both types of modulation is dependent on the ratio of the modulation frequency to the external cavity resonant frequency, and the modulation power. A number of distinct states are observed: conventional amplitude modulation (with FM spectra); multimode, low-noise amplitude modulation; mul-timode, high-noise amplitude modulation; periodic limit-cycle operation; quasi-periodicity; chaos; low-frequency fluctuations; and mode-locking....

Applied Optics, 2004

Compared with conventional optical heterodyne detection, laser optical feedback imaging ͑LOFI͒ allows for a several orders of magnitude higher intensity modulation contrast. The maximum contrast amplification is typically 10 3 for a diode laser in the gigahertz range and 10 6 for a microchip laser in the megahertz range. To take advantage of the wavelength tunability of a laser diode and of the lower resonant detection frequency of a microchip laser, we used LOFI modulation induced by the frequencyshifted optical feedback in a laser diode as a modulated pumping power for a microchip laser for resonant dynamic amplification. In this way, we were able to transfer the optical feedback sensitivity of the laser diode to the megahertz range. Application to telemetry is also reported.