Temperature- and polarization-insensitive responsivity of a1.3-μm optical transceiver diode with an integrated spot-sizeconverter

We have demonstrated an optical transceiver diode integrated with a spot-size converter. We clarify that the design of a detection layer is essential for the temperature- and polarization-insensitive characteristics of the responsivity. Because the detection layer was introduced, 0.65 dB of responsivity deviation was obtained in the wide temperature range of -10°C-85°C with a high laser performance. A spot-size converter enables the coupling loss to be 1.8 dB for a flat-end optical fiber. The frequency response was also obtained up to 1 GHz in both laser and detector modes     

Multi-active region laser diode with a narrow beam divergence angle

In order to get a high coupling efficiency into opticalfiber ,semiconductor lasers with narrowbeamdivergenceare desired.Endeavors have been made to reduce thetransverse far field angle,including the periodic indexseparate confinement heterostructure laser…     

1.3-μm AlGaInAs-InP buried-heterostructure lasers with modeprofile converter

AlGaInAs buried-heterostructure (BH) lasers with a mode profile converter (MPC) have been successfully fabricated for the first time. The thickness of the multiple-quantum-well (MQW) waveguide was vertically tapered by selective area growth (SAG). The threshold current I_th was 14.6 mA with a 600-μm-long cavity and a high-reflective-coated rear facet. The full-width at half-maximum of the far-field pattern in the perpendicular and horizontal directions were 9.2° and 12.6°, respectively. The optical coupling loss between lasers with MPC and a single-mode fiber was 3.0 dB when the distance between the laser and fiber was 20 μm     

Improved high-temperature characteristics in a thickness-tapered1.3-μm beam-expander integrated ridge-waveguide laser

High-temperature performance of a beam-expander (BEX) integrated laser was dramatically improved by reducing the current leakage in both longitudinal and lateral directions. Proton implantation into the BEX region and a reverse-mesa structure were combined to improve the high-temperature characteristics. A threshold current of 23.1 mA at 85°C and a very high-characteristic temperature T₀ (25°C-85°C) of 74 K were achieved. Stable operation for over 3000 h under a 10-mW output power at 70°C were confirmed     

A 6-b 1.3-Gsample/s A/D converter in 0.35-μm CMOS

A 6-b Nyquist A/D converter (ADC) that converts at 1.3 GHz is reported. Using array averaging and a wideband track-and-hold, a 6-b flash ADC achieves better than 5.5 effective bits for input frequencies up to 630 MHz at 1 Gsample/s, and five effective bits for 650-MHz input at 1.3 Gsample/s. Peak INL and DNL are less than 0.35 LSB and 0.2 LSB, respectively. This ADC consumes about 500 mW from 3.3 V at 1Gsample/s. The chip occupies 0.8-mm² active area, fabricated in 0.35-μm CMOS     

Dynamic characteristics of a 1.3 μm laser diode integrated witha spot-size converter coupled to a silica planar lightwave circuit

Dynamic characteristics are clarified for a laser diode integrated with a spot-size converter coupled to a silica planar lightwave circuit. The laser was developed with a butt-jointed selectively grown spot-size converter. A maximum coupling efficiency of -0.74 dB was achieved. Bit error rate performances are estimated to clarify the allowable reflection when optical feedback from the fibre output end occurs     

Aging analysis of nMOS of a 1.3-μm partially depleted SIMOX SOItechnology comparison with a 1.3-μm bulk technology

Hot carrier degradation of nMOS of a 1.3-μm partially depleted rad-hard SOI CMOS technology is analyzed in detail. The relative importances of the maximum electric field, the localization of the trapped charges, and the LDD structure are pointed out through two-dimensional simulations and systematic comparisons with a 1.3-μm CMOS bulk technology. It is shown that the higher degradation rate of the SOI technology logically results from the contradictory constraints between rad-hardness (low-temperature process) and hot carrier resistance requirements. An annealing scheme comparable to the bulk one would lead to similar degradations     

High output-power and narrow spectral-linewidth operation of a1.3-μm gain-coupled DFB laser with InAsP buried absorptive grating

High output-power and narrow spectral-linewidth operation of 1.3-μm gain-coupled distributed feedback lasers with grating are reported. The fabricated output power of 230 mW and a linewidth of 100 kHz by reducing optical confinement in multiple quantum wells to improve the single-mode stability at high output-power operation     

A highly integrated wideband millimeter-wave MMIC converter using0.25-μm P-HEMT technology

A highly integrated wideband converter that was designed to upconvert the entire 6- to 18-GHz input RF frequency band to a 22-GHz intermediate frequency using a 28- to 40-GHz local oscillator (LO) is described. The circuit was designed using 0.25-μm pseudomorphic HEMT technology. The converter incorporates a three-stage RF amplifier, a three-stage LO amplifier, and an active balanced mixer, all integrated on a chip 96 mil×96 mil in size. The upconverter monolithic microwave integrated circuit (MMIC) has an average of 10-dB conversion gain across the full 6-18-GHz input band     

1.3-μm GaInAsP/InP transverse-mode stabilized buried-crescentlasers by a new fabrication technique using a reactive ion beam etching

Transverse-mode-stabilized, 1.3-μm, GaInAsP/InP, buried-crescent (BC) lasers fabricated using a reactive ion beam etching (RIBE) technique are presented. Yields of single-transverse-mode operation as high as 95% are achieved with low threshold currents of 11-25 mA. Transverse-mode stability under both high-power and long-term operation (50°C, 20 mW, 1000 h) is demonstrated. A coupling efficiency into a single-mode fiber of 63% and a coupled power of 40 mW at 160 mA are achieved. Stable continuous-wave operation is also confirmed under a constant power of 5 mW (50 and 70°C) and 20 mW (50°C) in an aging test     

A V-band planar narrow bandpass filter using a new type integrated waveguide transition

A surface mountable planar narrow bandpass filter is proposed and demonstrated at V-band. The filter is constructed using an integrated waveguide in an alumina substrate employing a novel microstrip line to waveguide transition. The insertion loss per one transition is less than 0.1 dB over 43 to 73 GHz. A fabricated three-pole Chebyshev filter exhibits an insertion loss of 3 dB with a 3.3% bandwidth at a center frequency of 62 GHz and the return loss is better than 15 dB in the passband.     

A new device-a power semiconductor diode with an integrated thermalsensor

A power semiconductor diode with an integrated thermal sensor is introduced. Means for producing such a device are presented, and the resulting device is analyzed. The theoretical model agrees with the experimental results within 10%. The practical conditions in which the sensor can be used are discussed     

A superluminescent diode at 1.3 μm with very low spectralmodulation

An edge-emitting superluminescent diode has been fabricated from an MOCVD-grown InGaAsP/InP double heterostructure, for light emission at 1.3 μm. Using a ridge-waveguide geometry with an integrated absorber, the goals of high power coupled into a single-mode fiber and very low spectral modulation are fulfilled. Interferometric measurements of the residual modulation determine the location of internal optical reflections in the device. The results are interpreted and compared to the predictions of a transmission-line model     

Strained-layer InGaAsP diode lasers with tapered gain region foroperation at λ=1.3 μm

A report is given of the first high-power InP-based tapered lasers. Continuous output powers of 0.5 W with nearly 80% of the power in the central lobe have been obtained. This is the highest reported brightness of a 1.3 μm source     

1.3-μm Pr-doped In-Ga-based fluoride fiber amplifiers pumped bygrating-fiber-pigtailed 0.98-μm-band laser diodes with a detunedwavelength of 1 μm

At most efficient pump wavelength, a praseodymium-doped In-Ga-based fluoride fiber is directly pumped by four 0.98-μm-band laser diodes. These lasing wavelengths are detuned from 0.98 to 1 μm by external selective optical feedback from fiber grating reflectors. Maximum signal output power of +13.5 dBm is obtained at 1.296 μm. Four-wavelength multiplexed signals at 1.296-1.311 μm are amplified with a deviation of gain less than 1.9 dB. By using the amplifier as a power booster, data of 2.5 Gb/s is successfully transmitted more than 100 km     

3-D semivectorical beam propagation analysis of a spotsize-converter-integrated laser diode in the 1.3-/spl mu/m-wavelength region

Spotsize converters (SSCs), consisting of a lateral taper, thin-film core, and ridge, have been accurately designed to develop spotsize-converted laser diodes (SS-LDs) in the 1.3-/spl mu/m-wavelength region based on the 3-D semivectorial finite-difference beam propagation method (FD-BPM) with nonequidistant discretization. The effects of the structural parameters on the sum of spot-conversion loss and coupling loss between the laser diode eigenmode and single-mode fiber (SMF) eigenmode are clarified. It is shown that a small loss of around 1.5 dB can be realized by introducing nonlinear tapers to these types of SSC's. The calculated results agree well with the measured results.     

A 14-bit 10-μs subranging A/D converter with S/H

A microprocessor-compatible, 14-bit, 10-μs subranging analog-to-digital converter with a sample/hold amplifier (SHA) is described. The chip architecture is based on a five-cycle subranging flash technique using both analog and digital error correction. The conversion speed is enhanced by an analog correction method, whereby redundant bit currents allow digital/analog converter updates without changing bits determined in previous cycles. The residue signal path uses simple circuitry and is highly differential. Prototype performance has been demonstrated     

A new soft-switched PFC boost rectifier with integrated flyback converter for stand-by power

This paper presents a magnetic integration approach that reduces the number of magnetic components in a power supply by integrating magnetic components in two conversion stages. Specifically, in the proposed approach, a single transformer is used to implement the continuous-conduction-mode boost power-factor-corrected (PFC) converter and the dc/dc flyback converter. The integrated boost and flyback converters offer soft switching of all semiconductor switches including a controlled di/dt turn-off rate of the boost rectifier. The performance of the proposed approach was evaluated on a 150-kHz, 450-W, universal-line range boost PFC converter with 12-V/2.2-A integrated stand-by flyback converter.     

A 1.3/1.55-μm wavelength-division multiplexing optical moduleusing a planar lightwave circuit for full duplex operation

We developed a hybrid integrated optical module for 1.3/1.55-μm wavelength-division multiplexing (WDM) full-duplex operation. The optical circuit was designed to suppress the optical and electrical crosstalk using a wavelength division multiplexing filter, and an optical crosstalk of -43 dB and an electrical crosstalk of -105 dB were achieved with a separation between the transmitter laser diode and the receiver photodiode of more than 9 mm. We used the optical circuit design to fabricate an optical module with a bare chip preamplifier in a package. This module exhibited a full duplex operation of 156 Mbit/s with a minimum sensitivity of -35.2 dBm at a bit error rate of 10^-10     

Compact and highly efficient fiber amplifier modules pumped by a0.98-μm laser diode

Highly efficient and small-size erbium-doped fibers with a gain coefficient of 4.9 dB/mW and a strained quantum-well-type InGaAs laser diode with a lasing wavelength of 0.98 μm as a pumped light source. As a result, the module 4×6×1.5 cm, realized a maximum net gain of 33 dB with an electricity consumption of only 175 mW, which corresponds to a drive current of 80 mA. The module consists of four individual components: a pumping laser diode submodule, a wavelength-division-multiplexing-type fiber coupler, a polarization-insensitive optical isolator, and an erbium-doped single-mode fiber coil