A new buried heterostructure (BH) is proposed for high-speed optical sources, based on selective regrowth of semi-insulating (SI-) InAlAs around an active mesa stripe. The performances of a first BH laser structure realised using SI-InAlAs were compared to that of standard InP:p/InP:n BH lasers, showing a reduction of the structure capacitance with no degradation of the threshold current nor of the external efficiency.

Side-illuminated photodiodes designed for surface hybrid integration on a silicon optical bench are described. InGaAs PIN photodiode chips fabricated on a 2inch-wafer with an integrated dry etched waveguide input facet with an antireflection coating deposition on the wafer, exhibit very low dark currents of typically 20 pA at -10 V bias voltage and 25/spl deg/C. Fiber coupled responsivity as high as 0.95 A/W at 1.3 /spl mu/m wavelength, and vertical coupling tolerance at -1 dB as wide as /spl plusmn/2 /spl mu/m are demonstrated. Reliability testing under high temperature and bias-stress conditions shows very stable operation.

A new buried heterostructure (BH) is proposed for high-speed optical sources, based on selective regrowth of semi-insulating (SI-) InAlAs around an active mesa stripe. The performances of a first BH laser structure realised using SI-InAlAs were compared to that of standard InP:p/InP:n BH lasers. A reduction of the structure under both forward and reverse bias is obtained, with no degradation of the optical properties of the source

We present here the design, fabrication, and static as well as dynamic characteristics of a ten-wavelength, 200-GHz channel spacing emitter for wavelength-division multiplexing applications. The source is based on the monolithic integration on InP of a ten distributed Bragg reflector laser array with a square-shaped transmission response PHASAR. The specific design of the PHASAR is detailed. The continuous-wave operation-one channel at a time-demonstrates a high monomode stability with a rejection better than 32 dB for all channels and all injected currents; the 200-GHz channel spacing can be reached with an accuracy better than 25 GHz. High-speed characteristics demonstrate a 6.5-GHz direct modulation bandwidth at -3 dB for a 70-mA current in the 900-/spl mu/m-long active section. The chirp measured for a 2.5-Gb/s modulation with a 10-dB extinction ratio is less than 1.5 /spl Aring/ for every wavelength.

A 10 lambda selectable source, with 1.6 +/-0.2nm channel spacing and SMSR better than 30dB, is demonstrated by the monolithic integration of a DBR laser array with a PHASAR. The design of a wide-squared spectral response for the PHASAR, as well as the lasers tunability, guaranty wavelength matching between the PHASAR transmission comb and the laser array comb.

We report on a meander-type InP filter exhibiting a 130 nm pass-band at 1.5 mum and 30 dB suppression ratio of the signal at 1.3 mum. The same filter is usable in both optical terminals of a FTTH access network.

A 10-wavelength 200-GHz channel spacing emitter was realized by monolithically integrating on InP a 10 distributed-Bragg-reflector laser array and a PHASAR used as a 10/spl rarr/1 combiner. The design of a wide-squared spectral bandwidth for the PHASAR as well as the lasers tunability ensure wavelength matching between the PHASAR transmission comb and the laser array comb. The channel spacing accuracy of the source is better than 25 GHz and the rejection is higher than 32 dB for all bias.

To investigate physical mechanisms involved in longterm wavelength drift of tunable distributed Bragg reflector (DBR) laser, the evolution of the tuning characteristics as well as the Bragg section intensity modulation response of several DBR lasers have been simultaneously assessed by current injection in the Bragg section only. Current versus voltage I(V) characteristics under aging have also been recorded to compare the role of leakage current and nonradiative recombination defect evolution, The wavelength drift as well as the carrier lifetime, of the tuning section vary following an exponential law A + B exp(-t(A)/tau) versus aging time t(A). The time constant tau is aging temperature and Bragg current dependant. The carrier lifetime decreases with time indicating a wavelength drift mainly due to nonradiative recombination defect increase. Modeling of the I-B(V) and lambda B(I-B) characteristics is presented, that fits nicely the experimental data. The exponential form of the wavelength drift is used to propose novel and adequate burning conditions of DBR lasers.

The authors report, for the first time to their knowledge, a full-duplex sensitivity of -27 dBm at 155 Mbit/s (RX)-54 Mbit/s (TX) which meets system requirements with an in-line transceiver assembly using a commercially available transimpedance amplifier.

The authors report, for the first time to their knowledge, a full-duplex sensitivity of –27 dBm at 155 Mbit/s (RX) - 54Mbit/s (TX) which meets system requirements with an in-line transceiver assembly using a commercially available transimpedance amplifier.

A new tunable laser structure using a single electroabsorption (EA) tuning super structure grating (SSG) section for fast wavelength switching operation is reported. Instead of index change by carrier density or by thermal variation, the tuning mechanism of this absorption change (AC) distributed Bragg reflector (DBR) InGaAsP strained QW laser is based on a localized absorption variation induced in a Franz-Keldysh EA SSG section used as Bragg reflector. According to a simulation which takes into account the absorption and refractive index variations of the SSG section versus voltage and wavelength, an optimized device theoretically allows a wide tuning range of up to 11 nm with nine regularly spaced wavelength channels. Over this whole tuning range, the variation of the AC-DBR laser threshold gain is lower than 2 cm/sup -1/. Compared to a standard DBR laser exhibiting an 8-cm/sup -1/ threshold gain variation for the same wavelength shift, this AC-DBR laser would present extremely low threshold current and emitted power variations under tuning. Owing to its tuning mechanism, the switching time of the AC-DBR laser is independent of the wavelength shift, and only limited by the parasitic capacitance of the SSG ridge section. A test structure, easier to realize, with only a theoretical tuning range of 3 nm over four regularly spaced channels has been fabricated. These devices exhibiting a tuning range of 2.5 nm with three modes, present threshold current and output power variations under tuning of less than 8 mA and 1.2 dB, respectively. A switching time between two successive wavelength channels shorter than 250 ps has been observed, in agreement with typical capacitances of 0.8 pF/100 /spl mu/m measured on the SSG section.

Single-mode operation with output power up to 100 mW is reported for the first time for InGaAsP-InP DBR lasers. These devices exhibiting a record 17-nm tuning range, have been realized using a three-step MOVPE process. The output power variations under tuning are limited to about 1.5 dB, and the tuning range remains quasiconstant with the output power. Using a two-wavelength DBR laser array with Bragg wavelengths spaced by 15 nm, 61 channels regularly spaced by 0.5 nm are accessible by controlling only two currents. Moreover systematic investigations of accelerated aging of these components have been realized for the first time. For all the tests performed on both active and tuning sections, no spectral degradations are observed, and the tunability remains unchanged. To define the lifetime of a tunable laser, e.g., a DBR laser, we propose a new failure criterion based on both active operating current and wavelength degradations. Using this criterion, the lifetime at 60 degrees C is estimated to be more than 7.10(4) h, and is not limited by the wavelength degradation, but effectively by the operating current degradation.

Singlemode operation with an output power of up to 100mW is reported for the first time for InGaAsP/InP DBR lasers. These devices exhibiting a record 17nm tuning range, have been realised using a three-step MOVPE process. The output power variations under tuning are limited to similar to 1.5dB, and the tuning range remains quasi-constant with output power.

In-line transceiver chip emitting at 1.3 mu m and receiving at 1.55 mu m is described regarding the crosstalk occurring between the 1.3-mu m laser and the 1.55-mu m integrated photodiode. Contribution of optical and electrical crosstalk to the overall crosstalk is measured and discussed. Techniques to overcome the crosstalk are proposed and demonstrated by showing the feasibility of system compatible diplex sensitivities.

We report a new fabrication technique for multigrating components using a single grating holographic exposure associated with localized selective etching steps. 4-wavelength DBR laser arrays with a 5-nm Bragg wavelength spacing have been demonstrated, showing uniformly very good characteristics.

Simultaneous emission and reception have been demonstrated with an in-line-type transceiver emitting al 1.3 mu m and receiving at 1.55 mu m. A receiver sensitivity of -14.6 dBm is reported at 68 Mbit/s by modulating the 1.3 mu m laser simultaneously at 50 Mbit/s. The power penalty caused by the modulation was 7.4 dB.

A simple technique, using a single-grating holographic exposure associated with localized selective etching steps, has been developed for multiwavelength device fabrication, four-wavelength DBR laser arrays with a 5 nm Bragg wavelength spacing have been fabricated for wavelength division multiplexing (WDM) applications with this method, These devices exhibit uniformly low-threshold currents (10-15 mA), high-output powers (15 mW) and wide tunabilities (12 nm), leading to an overall accessible wavelength domain of 28 nm for the array.