Self-seeded Laser Research Articles

A self-induced white light seeding laser in a femtosecond laser filament

We report on the generation of remote self-seeding laser amplification by using only one 800 nm Ti:sapphire femtosecond laser pulse. The laser pulse (∼40 fs) is first used to generate a filament either in pure nitrogen or in ambient air in which population inversion between the and states of is realized. Self-induced white light inside the filament covering the transition is then serving as the seed to be amplified. The self-induced narrow-band laser at 428 nm has a pulse duration of ∼2.6 ps with perfect linear polarization properties. This finding opens new possibilities for remote detection in the atmosphere.

An upstream multi-wavelength shared PON based on tunable self-seeding Fabry-Pérot laser diode for upstream capacity upgrade and wavelength multiplexing

We proposed an Upstream Multi-Wavelength Shared (UMWS) PON architecture based on a tunable self-seeding Fabry-Perot laser diode (FP-LD) at ONU. The performances of the wavelength and power stability, side-mode suppression ratio (SMSR), tuning range for the proposed tunable self-seeding laser module at ONU are experimentally investigated. The BER is measured with direct modulation on FP-LD of 1.25 Gbps upstream data. The extensive simulations not only evaluate the enhanced performance from the upstream wavelength-sharing, but also for the first time investigate the impact of channel Switch Latency (SL) on the network performance.

Tunable self-seeding Fabry–Pérot laser diode for upstream multiwavelength shared ethernet passive optical network

We present a novel upstream multiwavelength shared ethernet passive optical network architecture, based on a proposed self-seeding Fabry-Perot laser diode (FP-LD) at the optical network unit. The performances of the wavelength and power stability, side-mode suppression ratio, and tuning range for the proposed tunable self-seeding laser module are experimentally investigated. The bit-error-rate measurement is performed with direct modulation on FP-LD of 1.25 Gbps upstream data. The performance benefits from the upstream wavelengths sharing are showed via simulations.

Simultaneous Measurements of Dispersion Parameter and Fiber Length Using the Self-Seeding Laser Oscillation of a Fabry–PÉrot Laser Diode

A simultaneous measurement technique of the dispersion parameter and the length of an optical fiber has been demonstrated by using the self-seeding laser oscillation of a Fabry-Perot laser diode. We measured the dispersion parameter and the length of an optical fiber from the modulation frequency changes required to induce single-mode laser oscillations through an optical closed-loop path. The dispersion and fiber length measurements were within 1.5% and 0.2%, respectively, of the values measured by commercial instruments.

Dispersion measurement technique based on the self-seeding laser oscillation of a Fabry–Perot laser diode

A simple dispersion measurement technique has been proposed and demonstrated by using the self-seeding laser oscillation of a Fabry–Perot laser diode through an optical closed-loop path. When the multi-mode optical pulses emitted from the laser are re-injected into the laser after traversing a fiber-under-test, a single mode laser oscillation occurs through the closed-loop path due to the group velocity difference between the pulses of different wavelengths. We measured the dispersion parameter of the fiber-under-test from the modulation frequency changes required to induce single-mode laser oscillations through the optical closed-loop path. The maximum measurement error was less than 1.5% for the optical fibers as compared with a commercial instrument.

Fiber Length Measurement Technique Employing Self-Seeding Laser Oscillation of Fabry–Perot Laser Diode

A simple fiber length measurement technique has been proposed and demonstrated that uses the self-seeding laser oscillation of a Fabry–Perot laser. We measured the length of an optical fiber from the modulation frequency changes required to induce single-mode laser oscillations through an optical closed-loop including the fiber and the laser diode. The maximum error of the proposed technique was less than 0.24% for various fiber lengths from 0.1 to 75 km.

Fabry-Perot 레이저의 자기궤환 레이저 발진을 이용한 색분산 측정법

Fabry-Perot 레이저의 자기궤환 레이저 발진을 이용한 색분산 측정법

Subharmonic Pulse-Gating in Self-Seeded Laser Diodes for Time- and Wavelength-Interleaved Picosecond Pulse Generation

A new approach of generating high-repetition-rate picosecond pulses at sequentially switching wavelengths has been proposed and experimentally demonstrated. The approach is based on subharmonic pulse-gating and self-seeding of a single Fabry-Perot laser diode. Output of up to ten wavelengths at a repetition rate of 10 GHz has been achieved. The output exhibits a relatively uniform power across the selected wavelengths. The nonlasing modes are being suppressed by more than 20 dB. The maximum timing jitter of an individual wavelength and the ten-wavelength output are measured to be 222 and 181 fs, respectively.

Dispersion-tuned, wavelength-switched short pulses generated from optically controlled self-seeded laser diode

Optical pulses at alternating wavelengths have been generated from a self-seeded laser diode. Individual wavelength control is realised by dispersion tuning in each of the frequency-halved feedback paths. A 3 GHz output is obtained with a tuning range of 10 nm.

Fast wavelength tuning of a self-seeded Fabry-Perot laser diode with a Fabry-Perot semiconductor filter

In this letter, we describe a new and simple method for achieving fast wide-range wavelength tuning in a self-seeded Fabry-Perot laser diode (FPLD). The method relies on the provision of optical feedback to a self-seeded laser diode from a Fabry-Perot semiconductor filter (FPSF). Wavelength selection is realized by electrically tuning the comb-like spectral response of the FPSE Using an ordinary FPLD biased below its threshold as an FPSF, we have demonstrated stepwise wavelength tuning over a range of 9.0 nm with a sidemode suppression ratio higher than 15 dB throughout the range, and a pulse buildup time as short as a few microseconds.

Switching dynamics between single-mode and dual-mode pulse emissions from a self-seeded laser diode

Spectrally selected, self-seeded pulses are generated from a Fabry–Perot laser diode in an external cavity containing a two-chromatic fiber grating. Electrical switching between single-mode and dual-mode operations is demonstrated by controlling the amplitude of the ac signal applied to the laser diode. The principle is based on carrier induced frequency chirp that determines the spectral overlap of the Fabry–Perot modes with the grating reflection band during the pulse buildup time. We also investigate the switching dynamics and show that the steady states can be reached after about five to six round-trip cycles. The buildup of single-mode emissions is slightly faster than that of the dual mode.

Electrically wavelength-tunable picosecond pulses generated from a self-seeded laser diode using a compensated dispersion-tuning approach

We developed a compensated dispersion-tuning approach to generate electrically wavelength-tunable short pulses from a self-seeded Fabry-Perot laser diode. Single-mode pulses with a sidemode-suppression ratio over 30 dB are obtained across most of the 18.5-nm tuning range in the fiber configuration. The use of both dispersion-compensating fiber and standard single-mode fiber with equal and opposite group velocity dispersion allows electrical tuning to be performed at a constant repetition rate.

Electrooptical sampling using 1.55-μm self-seeded semiconductor laser with soliton pulse compression

We report on a compact, reliable and easy to use electrooptic sampling system based on a self-seeded semiconductor laser having a temporal resolution of <1 ps and a shot noise limited sensitivity of 1 mV. With an operating wavelength of 1.55 /spl mu/m and 0.5-ps time jitter of the optical source, it is particularly suited for ultrahigh-speed devices and integrated circuits. For demonstration, results for an ultrafast metal-semiconductor-metal photodetector are presented.

Competing mode suppression ratio of electrically wavelength tunable self-seeded lasers

The competing mode suppression ratio of electrically wavelength tunable self-seeded semiconductor laser systems is investigated experimentally and theoretically for varying length differences between the feedback cavities, It is shown that for length differences more than 10 mm, the selected mode is dominating by more than 15 dB the unwanted mode. The buildup of stable single-mode emission takes less than five to ten round-trips for these length differences. Thus, switching frequencies of up to 100 MHz between the modes can be achieved.

Wavelength-tunable picosecond pulses generated fromstable self-seeded gain-switched laser diode with linearly chirped fibre Bragg grating

A simple robust self-seeded laser diode scheme for generating electrical wavelength-tunable picosecond pulses at a fixed repetition rate is presented. Wavelength tuning of transform-limited pulses with a pulsewidth of ~ 10 ps and a sidemode suppression ratio of 15 dB overall, and 28 dB at best, was obtained among six cavity modes corresponding to a tuning range of 7.6 nm. Very stable operation was observed at each wavelength because there was a relatively large locking range for each wavelength.

An extended external cavity for the generation of tunable multi-wavelength pulses from a self-seeded laser diode

We have developed a technique to generate tunable multi-wavelength picosecond pulses using a self-seeded gain-switched laser diode. The external cavity allows simultaneous feedback of up to four wavelengths into the laser diode for mode selection. A tunable spectral spacing of about 20 nm among the wavelength channels can be obtained. The optimized output side-mode suppression is higher than 20 dB. Different channels in the output are separated temporally and can be individually accessed for modulation.

Dual-wavelength operation of a self-seeded dye laser oscillator

We demonstrate simultaneous dual-wavelength operation of a self-seeded dye laser. The laser cavity consists of one dye cell, two pairs of grating and tuning mirrors, and two reflecting mirrors. This configuration can be decomposed with two grazing-incidence cavities and a standing-wave cavity. The self-seeded dual-wavelength output beams are collinear and independently tunable. We were able to vary the output powers at the two wavelengths smoothly by changing the cavity length of a master oscillator.