1.25-Gb/s Operation at 50-GHz Channel Spacing Based on Intensity Noise Suppression of Wavelength-Locked Fabry–PÉrot Laser Diode

We demonstrate 1.25-Gb/s operation at 50-GHz channel spacing and 10-km single-mode fiber, which is based on a wavelength-locked Fabry-Perot laser diode (F-P LD) and an intensity noise suppression by a gain saturation of F-P LD in front of the receiver. The wavelength-locked F-P LD employs the spectrum-sliced incoherent light with narrow bandwidth of 35 GHz. The intensity noise of wavelength-locked F-P LD is suppressed about 6 dB by the F-P LD in the front of the receiver. As a result, the bit-error-rate curves exhibit the error-free performances over the detuning conditions to cover a whole mode spacing period of F-P LD.     

Enhanced Modulation Bandwidth of a Fabry–PÉrot Semiconductor Laser Subject to Light Injection From Another Fabry–PÉrot Laser

Variations in optical spectrum and modulation bandwidth of a modulated Fabry-Perot (FP) semiconductor laser subject to the external light injection from another FP Laser is investigated in this paper. Optimal wavelength matching conditions for two FP lasers are discussed. A series of experiments show that two FP lasers should have a central wavelength overlapping and a mode spacing difference of several gigahertz. Under these conditions both the magnitude and phase frequency responses can be improved significantly.     

A Simple and Color-Free WDM-Passive Optical Network Using Spectrum-Sliced Fabry–PÉrot Laser Diodes

We propose and demonstrate a simple and color-free wavelength-division-multiplexing passive optical network (WDM-PON) using spectrum-sliced Fabry-Perot laser diodes (F-P LDs). Due to its low front facet reflectivity (~0.1%), the F-P LD shows a broadband lasing spectrum and reduced mode partition noise. By utilizing multiple peaks that are separated by the free-spectral range of the cyclic arrayed waveguide gratings, the 16-channel WDM-PON is successfully demonstrated at 155 Mb/s.     

Measurement of Facet Reflectivity Through Reflection Gain in Fabry–PÉrot Laser Diode

We propose a simple and useful method to measure the facet reflectivity in a Fabry-Perot laser diode (LD). The new measurement method does not require information on LD parameters such as threshold current or optical spectrum. The measurement is based on a simple formula that describes the relationship of facet reflectivity and reflection gain with launching the probe beam of a narrow spectral width.     

Tunable Dual-Wavelength Fiber Laser Using Optical-Injection Fabry–PÉrot Laser

In this investigation, we propose and experimentally demonstrate a dual-wavelength fiber laser based on a self-injected Fabry–PÉrot laser diode and an erbium-doped fiber. The dual-wavelength tuning range is 39.49 nm, from 1526.27 to 1565.76 nm, and the mode spacing of the dual-wavelength can be tuned from 1.32 to 39.49 nm. In addition, the output power difference of the dual-wavelength can be controlled and smaller than 1 dB.      

40-Gb/s Polarization-Insensitive All-Optical Clock Recovery Using a Quantum-Dot Fabry–PÉrot Laser Assisted by an SOA and Bandpass Filtering

We experimentally demonstrate polarization- insensitive all-optical clock recovery using a passively mode-locked quantum-dot Fabry–PÉrot (QD-FP) semiconductor laser at 40 Gb/s. Polarization insensitivity is achieved by using a wavelength conversion stage based on cross-phase modulation in a semiconductor optical amplifier and optical bandpass filtering. A clock signal with a root-mean-square timing jitter of 300 fs is recovered for an input data signal with a scrambled state-of- polarization (SOP). This is comparable to that from the QD-FP laser alone for an input signal with a fixed SOP. Moreover, an improvement in the tolerance to a degradation in the optical signal-to-noise ratio of the input signal is achieved by the use of the wavelength conversion stage.      

High-Power Single-Longitudinal-Mode Fiber Laser With a Ring Fabry–PÉrot Resonator and a Saturable Absorber

We demonstrated a high-power single-longitudinal-mode (SLM) all-fiber laser. In the cavity, a fiber Bragg grating is used to select the appropriate wavelength at 1565 nm, and a fiber ring is incorporated to act as a Fabry-Perot resonator, which greatly reduces the longitudinal-mode density. Meanwhile, an unpumped erbium-doped fiber serves as a saturable absorber to ensure the SLM operation. Finally, a high-power SLM fiber laser producing as high as 867-mW output power has been experimentally demonstrated.     

Detailed Comparison of Injection-Seeded and Self-Seeded Performance of a 1060-nm Gain-Switched Fabry–PÉrot Laser Diode

We investigate and compare the performance of a gain-switched picosecond Fabry-Perot laser diode operated at 1.06 mum under both injection- and self-seeded conditions. Our experiments show that comparable performance can be obtained for both modes of operation, with the self-seeding arrangement offering overall benefits in terms of reduced system complexity and cost, providing the associated quantization of available pulse repetition rate can be tolerated.     

Multiple Dual-Wavelengths Erbium-Doped Fiber Ring Laser Using a Polarization-Maintaining Fabry–PÉrot Filter

A multiple dual-wavelengths erbium-doped fiber laser is demonstrated. It is designed by using a narrowband polarization-maintaining Fabry–PÉrot filter in a ring cavity. More than 30 power equalized dual-wavelengths are achieved in a 10-nm range. The switchability from multiple dual-wavelengths to normal multiple wavelengths laser is also demonstrated experimentally.      

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.     

A WDM-PON Employing Fabry–PÉrot Laser Diodes Without a Seed Light Injection

We propose and demonstrate a wavelength-division-multiplexed passive optical network by employing double-contact Fabry-Perot laser diodes (F-P LDs) without a seed light injection. To avoid the high mode partition noise at low frequency, we use a binary phase-shift keying as a modulation format at a low relative intensity noise window. An error-free transmission is achieved by compensating a lasing envelope shift due to temperature variation with the double-contact F-P LD.     

Temperature-Dependent Saturation Characteristics of Injection Seeded Fabry–PÉrot Laser Diodes/Reflective Optical Amplifiers

In this paper, the temperature dependence of the gain and saturation power of injection seeded Fabry–Perot laser diodes/reflective semiconductor optical amplifiers are analyzed theoretically and experimentally. For a constant gain, the saturation power increases with the ambient temperature. This dependency explains the observed variation in relative intensity noise versus injection power, as a function of temperature.      

Cavity Length Independent Continuous Repetition Rate Tuning of a Self-Seeded Gain-Switched Fabry–PÉrot Laser

We propose a novel method that allows continuous repetition rate tuning of a self-seeded gain-switched Fabry-Perot laser without the need for change in cavity length. This is achieved by employing a linearly chirped fiber Bragg grating with a large dispersion parameter. The dispersed pulses overlap to produce a continuous-wave-like feedback into the gain-switched laser cavity. By using the proposed experimental setup, we demonstrate pulses portraying sidemode suppression ratios of at least 30 dB and widths of about 30 ps over the entire repetition rate tuning range of 2.5-10 GHz.     

Array Antenna With Increased Element Separation Based on a Fabry–PÉrot Resonant Cavity With AMC Walls

A new method is presented for increasing the separation between the radiating elements of a 1-D array antenna by incorporating it into a Fabry-Perot type resonant cavity with artificial magnetic conductor (AMC) walls. The AMC walls create a more uniform distribution of field within the cavity and, moreover, eliminate diffracted fields. The concept is demonstrated via 3-D full-wave simulations as well as experimental measurements for a prototype antenna. Comparison between an antenna with AMC walls and an identical reference antenna, without walls, shows a reduction in the sidelobe level. An array element separation of 2lambda is achieved whilst maintaining good radiation performance. The performance of the proposed structure is also compared to that of an antenna incorporating PEC walls. Finally, the effect of the sidewall and central AMC walls are considered separately in order to isolate their corresponding effect on the antenna performance.     

Temperature-Insensitive Micro Fabry–PÉrot Strain Sensor Fabricated by Chemically Etching Er-Doped Fiber

Micro extrinsic Fabry–PÉrot interferometric (MEFPI) sensors are fabricated by chemically etching Er-doped fibers with mixed hydrochloric (HCl) and hydrofluoric (HF) acid and fusion splicing. Compared with MEFPI sensors fabricated by etched single-mode fibers, the sensor performance is greatly improved by the chemical reaction between HCl acid and doped ${hbox {Er}}_{2}hbox{O}_{3}$ . A maximum visibility of $sim$ 24 dB is obtained, comparable to that of MEFPI sensors fabricated by excimer lasers. Our MEFPI sensor has high mechanical strength as the etching rate difference between fiber core and cladding is enlarged. Preliminary results indicate that this kind of sensor is insensitive to temperature while highly sensitive to strain, with sensitivities of $sim$0.65 $hbox{pm}/^{circ}hbox{C}$ and $sim$3.15 $hbox{pm}/muvarepsilon$ , respectively.      

A Low-Noise Broadband Light Source for a WDM-PON Based on Mutually Injected Fabry–PÉrot Laser Diodes With RF Modulation

We demonstrated improved performance of a low-noise broadband light source (BLS) based on mutually injected Fabry–PÉrot laser diodes for a large capacity and high bit-rate wavelength-division-multiplexed passive optical network (WDM-PON). The 3-dB linewidth and relative intensity noise of each mode of the low-noise BLS are improved by radio-frequency modulation, where the frequency was detuned from the fundamental noise peak of the low-noise BLS. Then, a 622-Mb/s WDM-PON was demonstrated. Furthermore, a 1-Gb/s WDM-PON can be realized with Manchester coding at a channel spacing of 100 GHz. Thus, the proposed low-noise BLS can be employed to realize a highly scalable WDM-PON.      

Multi-Data-Rate System Performance of a 40-GHz All-Optical Clock Recovery Based on a Quantum-Dot Fabry–PÉrot Laser

Bit-error-rate assessment of a multi-rate all-optical clock recovery (OCR) based on a narrow linewidth mode-locked quantum-dot (QD) Fabry-Perot laser is presented in this letter. OCR has been achieved without external feedback. We use a QD Fabry-Perot semiconductor laser designed for 40-GHz clock extraction. We then present OCR performance with 40-, 80-, and 160-Gb/s input data signal and demonstrate that clock recovery has been obtained thanks to subharmonic locking process. Results are presented through penalty measurement using an original characterization based on recovered clock remodulation with electrical data from the transmitter. This technique allows us to evaluate the quality of the recovered clock.     

Effects of In-Band Crosstalk in Wavelength-Locked Fabry–PÉrot Laser-Diode-Based WDM PONs

We investigated the impact of in-band crosstalk on the system's performance in wavelength-locked Fabry-Perot laser-diode (FP-LD)-based wavelength-division-multiplexed passive optical networks (WDM PONs). As expected, wavelength-locked FP-LD, which was injected by using an incoherent broadband light source, was more tolerant to in-band crosstalk than distributed-feedback (DFB) laser diode. A 1-dB power penalty in the wavelength-locked FP-LD-based PON system was observed when the crosstalk-to-signal ratio was ~-9 dB. We also compared the measured power penalties with the calculated power penalties. It has been shown that the in-band crosstalk-induced power penalty in wavelength-locked FP-LD-based WDM PON could be estimated properly by taking into account both effects of power addition and signal-crosstalk beat noise.     

Locking and Noise Properties of Multisection Semiconductor Lasers With Optical Injection. Application to Fabry–PÉrot and DFB Cavities

An analytical theory is presented for the study of injection locking in multisection semiconductor lasers. The Helmoltz equation for the electric field is solved using the Green's function method and the injected fields are included via the boundary conditions. Two cases are distinguished, injection through the front facet of the laser and injection through the rear facet. In both cases, an equation of evolution for the envelope of the electric field is established, taking into account the longitudinal distribution of the carrier and photon densities and the nonlinear gain. The expressions of the intensity, phase and carrier density noise spectra are derived using a matrix formulation. Comparison to classical equations used for Fabry-Perot lasers is discussed. The locking properties of a distributed feedback laser with an antireflection coated front facet are studied in detail. Results demonstrate the strong sensitivity of the locking properties on the phase grating and rear facet reflectivity.     

Single-Longitudinal-Mode Erbium-Doped Fiber Ring Laser Based on High Finesse Fiber Bragg Grating Fabry–PÉrot Etalon

We present a simple and stable single-longitudinal-mode (SLM) erbium-doped fiber laser. It consists of an apodized fiber Bragg grating (FBG) and a high finesse FBG-based Fabry-Perot (FP) etalon in the ring cavity. The apodized FBG acts as a wavelength discriminative component selecting a few oscillation modes while the FP etalon serves as narrow bandwidth bandpass filter to further discriminate and select SLM efficiently. Stable SLM laser output at 1.55 m with linewidth about 2.5 kHz is acquired. Furthermore, continuous wavelength tuning over 8 nm is achieved by simultaneously applying strain to the FBG and the FP etalon.