High fibre coupled output power 37 nm tunable laser module using matrix DFB laser

The thermally-controlled laser module, integrating 12 distributed feedback (DFB) lasers in the form of a 2/spl times/6 matrix to realise both high output power and wide wavelength tunability, has been fabricated. The module has shown excellent characteristics, such as high fibre coupled power over 30 mW and tunability over 37 nm.     

High-precision high-yield laser source using DFB array

We present high-yield efficient distributed-feedback lasers with excellent wavelength control. An array of 12 lasers with highly reflecting/antireflecting facets is fabricated on a single chip with precisely controlled variations in the grating period or phase relative to the facets. The stripe that best meets requirements is selected for bonding. From 200 unscreened chips, 93% contained lasers that achieved the specified power of 25 mW at 175 mA, 55/spl deg/C, and 41% achieved a /spl plusmn/0.1-nm wavelength tolerance at 25 mW, 55/spl deg/C. This low-cost high-precision device requires little thermal tuning for wavelength-division-multiplexed applications and reduces the power consumption of the transmitter.     

A tunable dual-wavelength fiber Bragg grating laser using an external-injected DFB laser

A tunable dual-wavelength fiber Bragg grating (FBG) laser based on a distributed feedback (DFB) laser injection is proposed and experimentally demonstrated. The wavelength spacing can be tuned by adjusting the operation temperature of the DFB laser. When the DFB works at 25 ℃, a dual-wavelength simultaneous oscillation at 1 549.67 nm and 1 553.44 nm with wavelength spacing of 3.77 nm is achieved. Our experimental results demonstrate the new concept of dual-wavelength lasing with a DFB laser injection and the technical feasibility.     

345-mW 1836-nm single-frequency DFB fiber laser MOPA

We demonstrate an in-band-pumped continuous-wave single-frequency distributed-feedback (DFB) fiber laser emitting at a wavelength of 1836 nm with an output power of /spl sim/5 mW. The laser is subsequently amplified to 345 mW using a master-oscillator power amplifier configuration. To the best of the authors' knowledge, this is the first report of a Tm-co-doped single-frequency DFB fiber laser that is in-band pumped at 1565 nm. The laser is confirmed to operate in a single mode, using a scanning Fabry-Pe/spl acute/rot interferometer.     

Thermal interaction in a distributed-feedback laser diode (DFB LD) array module

The thermal interaction in a four-element distributed-feedback laser diode (LD) array module is investigated. When the injection current of each element was 200 mA, the interactive temperature rise of an element at one end was 6.6 degrees C. At the same time, temperature rise of the mounting structure (submount, header, and heatsink) was 4.9 degrees C, or about 75% of the interactive temperature rise of the element. According to two-dimensional thermal analysis, the temperature rise of the mounting structure accounts for 98% of the interactive temperature rise of the element. These experimental and analytical results show that the temperature rise in the mounting structure is the main cause of the interactive temperature rise of this module. Stabilization of the submount temperature instead of the heatsink temperature reduced the interactive temperature rise due to the three neighboring elements to 1/3 of that achieved by conventional heatsink temperature stabilization. The thermal analysis also showed that a thicker submount further reduces the thermal interaction in an LD array module.<>     

Photonic MEMS tunable laser sources

This article covers laser configurations, design and experiments of photonic microelectromechanical systems (MEMS) tunable laser sources. Three different types of MEMS tunable lasers such as MEMS coupled-cavity lasers, injection-locked laser systems and dual-wavelength tunable lasers are demonstrated as examples of natural synergy of MEMS with photonics. The expansion and penetration of the MEMS technology to silicon optoelectronic creates on-chip optical systems at an unprecedented scale of integration. While producing better integration with robustness and compactness, MEMS improves the functionalities and specifications of laser chips. Additionally, MEMS tunable lasers are featured with small size, high tuning speed, wide tuning range and CMOS compatible integration, which broaden their applications to many fields.     

Design and analysis of widely tunable sampled grating DFB laser diode integrated with sampled grating distributed Bragg reflector

A new widely tunable laser diode structure that requires only two tuning currents is proposed. The laser diode consists of a sampled grating distributed feedback (SGDFB) laser diode monolithically integrated with a sampled grating distributed Bragg reflector (SGDBR). The phase control sections are properly inserted between the grating bursts of the SGDBR and SGDFB sections for the discrete and continuous tuning. To confirm the feasibility of the new structure, the split-step time domain model is used. The simulation result for a particular design shows that the tuning range as wide as 27 nm is possible with side-mode suppression ratio exceeding 35 dB. Furthermore, the output power is larger than that from SGDBR laser diodes with similar parameters.     

同步泵浦宽可调谐范围染料激光器

报道一台微微秒宽可调谐范围染料激光器,只用一种染料溶液,调谐范围可达450埃。     

Multiwavelength grating reflectors for widely tunable laser

We propose a new reflector approach in order to get the reflectivity comb needed in widely tunable lasers. This reflector is realized by holographic exposure of superimposed multiple Bragg gratings. It provides efficient reflectivity with short guide sections (150 /spl mu/m) leading to improved static laser characteristics. This reflector has been successfully included in 20-nm tuning DBR lasers.     

Thermally controlled wavelength locker integrated in widely tunable SGDBR-LD module

A sampled-grating distributed Bragg reflector laser module having an integrated multiwavelength locker has been developed and evaluated. The uniquely designed wavelength locker made of thermally controlled etalon has provided uniform wavelength monitoring and very stable wavelength locking in the 188-ITU grid channels (37 nm) with 25-GHz spacing. Over the case temperature from -5/spl deg/C to 65/spl deg/C, the laser wavelength was locked within /spl plusmn/0.5 GHz, and the total power consumption of the module was less than 4 W.     

Four channel integrated DFB laser array with tunable wavelengthspacing and 40-Gb/s signal transmission capacity

A four-channel distributed-feedback (DFB) laser array integrated with four heating filaments has been fabricated for high-density wavelength-division-multiplexing systems. The DFB lasers have a threshold current of 4 mA at room temperature. By changing the power in the heater, the wavelength of each laser can be continuously tuned by as much as 5 nm. Therefore, a tunable wavelength spacing anywhere from 1 nm to 2 nm can be achieved. Each laser can operate at 10 Gb/s. However, the bias current has to be increased to avoid the degradation of the eye pattern as the wavelength is thermally tuned over 2 nm. An electric crosstalk of 0.6 dB is measured when two adjacent lasers are modulated at 10 Gb/s simultaneously     

High-speed direct Modulation of widely tunable MG-Y laser

The dynamic performance of the modulated-grating Y-branch laser is presented. In order to reach over 40-nm tuning range, the devices utilize an additive Vernier effect and relative tuning of two reflecting gratings. The device shows high (>13 dBm ex-facet) and uniform (<1.2-dB variation) steady state output power over the tuning range, and sidemode suppression ratio >40 dB. The laser behavior under small- and large-signal operation conditions is investigated. The laser exhibits a resonance frequency of 7.4-8.8 GHz at 80-mA bias. A 10-Gb/s eye diagram measurement showed high extinction ratio and signal-to-noise ratio.     

12 nm tunable WDM source using an integrated laser array

A 12 nm tunable source with up to 15 mW fibre coupled power has been fabricated by integrating four DFB lasers and a booster amplifier to provide a single output. High-yield and low-cost techniques are used, such as quarter-wave-shifted phase-masks for wavelength definition and an integration technique with only two regrowths     

40-GHz dual-mode-locked widely tunable sampled-grating DBR laser

Generation of 40-GHz alternate-phase pulses is demonstrated using a dual-mode-locked sampled-grating distributed Bragg reflector laser. More than 10-dB extinction and >20-dB sidemode suppression ratio is measured over the >40-nm tuning range of the laser. Based on captured phase noise spectra, the timing jitter is estimated in the 0.35-0.41-ps range. The demonstrated dual-mode laser would form an attractive basis for an integrated 40-Gb/s return-to-zero transmitter.     

Frequency separation locking and synchronization for FDM opticalsources using widely frequency tunable laser diodes

A laser diode (LD) frequency separation locking method (called the reference pulse method) is proposed. This method has advantageous features for frequency division multiplexing (FDM) networks from the viewpoint of frequency separation stability with a strict frequency separation standard, modulation format independence, controllability over a large number of LDs, and frequency synchronization capability. Frequency locking experiments, using four and ten controlled LDs, confirmed that the control system using the method can stabilize frequency spacing for more than 100 LDs. The frequency fluctuation is suppressed to less than 10 MHz. Frequency synchronization, utilizing the reference pulse method, is proposed and demonstrated experimentally for two controlled LD groups, each consisting of three LDs. Frequency discrepancy between two LD groups was only 2.7% of the frequency separation. Required frequency-swept light power and controlled LD power at the detector input for frequency synchronization indicate that more than 50000 LD groups within a 10 km area, each having 100 LDs, can be synchronized simultaneously     

Multiwavelength DFB laser array with integrated spot sizeconverters

We describe the design, fabrication, and performance of a five-element quarterwave-shifted distributed feedback laser array with monolithically integrated spot size converters intended for use as a multiple-wavelength source in dense wavelength-division telecommunications systems. Facet power in excess of 10 mW with less than 150 mA bias and longitudinal side mode suppression greater than 40 dB were routinely achieved. Narrow far-field full-width at half-maximum angles of 6.9°×16.3° provided 3.5-dB coupling loss into single-mode fiber with 1.0-dB misalignment tolerances of ±2.0 μm. With ±10°C thermal tuning, 22 1555-nm channels spaced by 50 GHz were accessed with this device. Thorough field evaluation indicates that such a device is consistent with manufacturing requirements     

Multi-λ ridge waveguide gain-coupled DFB laser array

Multi-wavelength gain-coupled quantum well DFB laser array has been fabricated on an InP substrate by simply varying the ridge waveguide width of the element lasers. Owing to the gain-coupling effect, seven singlemode lasing wavelengths around 1.55 μm with ~2 nm spacing were obtained simultaneously. The lasers had low threshold currents and small beam divergence     

Chirped ladder-type interferometric filter for widely tunable laser diode

A dominant passband response has been achieved by chirping a ladder-type interferometric filter. This response is indispensable for obtaining a single lasing wavelength in a widely tunable laser diode employing a ladder-type filter. Chirping the device is not accompanied by any excess loss nor does it require any additional fabrication processes.