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Compact and stable electroabsorption optical modulator modules
K. Yoshino;T. Takeshita;I. Kotaka;S. Kondo;Y. Noguchi;R. Iga;K. Wakita
Very compact electroabsorption optical modulator modules that demonstrate high coupling efficiency and high stability have been developed. The modules show very good potential such as an insertion loss as low as 5 dB, or ultrahigh speed modulation of up to 46 GHz. The module fabrication techniques are also applicable to other optical devices that require fiber connections at both facets.Show More
High-frequency and low-jitter optical pulse generation using semiconductor mode-locked lasers
This paper describes optical short pulse generation at over 100 GHz using semiconductor mode-locked lasers integrated with electroabsorption modulators. Active mode locking at 102 GHz is performed by a half-frequency modulation technique. The phase noise of a generated pulse train is evaluated by means of an opto-electrical down conversion technique using a unitraveling-carrier photodiode. A low-t...Show More
High-repetition frequency pulse generation at >100 GHz using mode-locked lasers integrated with electroabsorption modulators
K. Sato;I. Kotaka;A. Hirano;M. Asobe;Y. Miyamoto;N. Shimizu;K. Hagimoto
Summary form only given. We demonstrated high frequency pulse generation by using a modelocked semiconductor laser integrated with electroabsorption (EA) modulators. Pulses of 2.4 ps at 102 GHz repetition frequencies were obtained. We measured low timing jitter of 0.36 ps by means of a mixing technique.Show More
Frequency range extension of actively mode-locked lasers integrated with electroabsorption modulators using chirped gratings
We have fabricated actively mode-locked lasers integrated with electroabsorption modulators and chirped gratings. A chirped grating with a large chirp rate of 1.45 /spl Aring///spl mu/m can be realized by using multiphase-shifted patterns. Short pulses of 4-6 ps were generated over a wide frequency range from 18.9-19.8 GHz. We observed jumps in the wavelength during detuning. These jumps arise fro...Show More
Very low insertion loss (<5 dB) and high-speed InGaAs-InAlAs MQW modulators buried in semi-insulating InP
K. Wahita;K. Yoshino;S. Matsumoto;I. Kotaka;N. Yoshimoto;S. Kondo;Y. Noguchi
Proceedings of Optical Fiber Communication Conference (
Year: 1997 | Conference Paper |
Cited by: Papers (2)
We have succeeded in reducing the insertion loss by using thin strain-compensated InGaAs-InAlAs multiple quantum wells (MQWs) and semi-insulating InP burying layers. The resultant modulator modules are also noteworthy for their polarization insensitivity and low chirp. In this paper we explain the use of thin and narrow MQW layers to obtain both low insertion loss and high speed operation. We beli...Show More
Actively mode-locked strained-InGaAsP multiquantum-well lasers integrated with electroabsorption modulators and distributed Bragg reflectors
This paper describes picosecond pulse generation at 20 Gb/s by monolithic mode-locked lasers integrated with electroabsorption modulators and distributed Bragg reflectors. The electroabsorption modulator using strained-InGaAsP multiquantum wells acts as a pulse shortening gate when a sinusoidal voltage is driven at a large reverse bias voltage. To obtain transform-limited picosecond pulses, the re...Show More
Monolithic integration of MQW modulators on an optical multiplexer on InP for 100 Gb/s transmission
F. Zamkotsian;K. Sato;H. Okamoto;K. Kishi;I. Kotaka;M. Yamamoto;Y. Kondo;H. Yasaka;Y. Yoshikuni;K. Oe
We report on an InP-based optical multiplexer integrated with high-speed multiquantum-well (MQW) electroabsorption modulators for 100 Gb/s transmission. The optical multiplexer is based on a multimode interference (MMI) splitter, a waveguide array, and a taper-type combiner designed using the beam propagation method (BPM). The modulators are integrated on the top of the optical multiplexer. The in...Show More
Blue-chirp electroabsorption modulators with very thick quantum wells
Electroabsorption modulators operating at a wavelength of 1.55 μm with very thick quantum wells of 19.6 mm were fabricated using InGaAlAs-InAlAs multiple quantum wells. Blue-chirp (/spl alpha/<0) operation for low applied bias was demonstrated with low insertion loss.Show More
40-Gbit/s operation of InGaAs/InAlAs MQW electroabsorption modulator module with very low driving-voltage
K. Yoshino;K. Wakita;I. Kotaka;S. Kondo;Y. Noguchi;S. Kuwano;N. Takachio;T. Otsuji;Y. Imai;T. Enoki
Proceedings of European Conference on Optical Communication
Year: 1996 | Conference Paper |
Cited by: Papers (5)
4O-Gbit/s NRZ operation is demonstrated with the electroabsorption modulator modules using strain-compensated InGaAs/lnAlAs MQW structures. Clear eye patterns are observed with very low driving-voltages as small as 0.9 V/sub pp/.Show More
Optical pulse generation at 50-GHz repetition frequency by half-frequency modulation of mode-locked lasers integrated with electroabsorption modulators
International Topical Meeting on Microwave Photonics. MWP '96 Technical Digest. Satellite Workshop (Cat. No.96TH8153)
Year: 1996 | Conference Paper |
This paper describes optical pulse generation at a 50-GHz repetition frequency achieved by modulation at half (25 GHz) the cavity resonance frequency using a monolithic mode-locked InGaAsP laser integrated with an electroabsorption modulator.Show More
Polarization-independent electroabsorption modulators using strain-compensated InGaAs-InAlAs MQW structures
IEEE Photonics Technology Letters
Cited by: Papers (29)
The improved modulation properties of strain compensated InGaAs-InAlAs multiple quantum well (MQW) electroabsorption modulators and their modules have been demonstrated. Introduction of a 0.5% tensile strain in wells and a 0.5% compression in barriers provides highly efficient operation such as a low driving voltage (V/sub 20/ dB=1.6 V) and a large modulation bandwidth (f/sub 3/ dB>20 GHz). This i...Show More
Polarization-independent electroabsorption modulator using strain-compensated InGaAs/lnAIAs MQW stru
Technical Digest. CLEO/Pacific Rim'95. The Pacific Rim Conference on Lasers and Electro-Optics
Year: 1995 | Conference Paper |
Cited by: Papers (4)
First Page of the Article
Show MoreLaser diodes integrated with spot-size converters fabricated on 2-inch indium phosphide substrates
M. Wada;M. Kohtoku;K. Kawano;S. Kondo;Y. Tohmori;Y. Kondo;K. Kishi;Y. Sakai;I. Kotaka;Y. Noguchi;Y. Itaya
Technical Digest. CLEO/Pacific Rim'95. The Pacific Rim Conference on Lasers and Electro-Optics
Year: 1995 | Conference Paper |
First Page of the Article
Show MoreChirping characteristic of electroabsorption-type optical-intensity modulator
IEEE Photonics Technology Letters
Cited by: Papers (12)
A method of precisely estimating the /spl alpha/ factor for electroabsorption-type optical-intensity modulators is described. This method takes into account the nonlinearity of extinction-ratio characteristics. It yields smaller /spl alpha/ factor values than the conventional method under linear extinction-ratio characteristics for large-signal modulation. InGaAs/InAlAs MQW modulators are conseque...Show More
A low-drive-voltage, high-speed monolithic multiple-quantum-well modulator/DFB laser light source
IEEE Photonics Technology Letters
Cited by: Papers (24)
A high-speed InGaAs/InAlAs multiple-quantum-well (MQW) intensity modulator and an InGaAsP/InGaAs MQW distributed feedback laser were monolithically integrated by using a hybrid growth technique combining molecular beam epitaxy and metalorganic vapor phase epitaxy. An operating drive voltage of only 2.0 V, a 20-dB on/off ratio, and a 3-dB bandwidth greater than 15 GHz were obtained. This device ope...Show More
Transform-limited 7-ps optical pulse generation using a sinusoidally driven InGaAsP/InGaAsP strained multiple-quantum-well DFB laser/modulator monolithically integrated light source
A 20-GHz optical pulse train is generated using a sinusoidally driven InGaAsP/InGaAsP strained multiple-quantum-well (MQW) DFB laser/intensity modulator monolithically integrated light source operating at low voltages (from -4- to -5-V DC bias with a 3.2- and 4.0-V peak-to-peak RF signal). An approximately-transform-limited 7-ps-wide optical pulse, with a spectral width of 47 GHz, is obtained.<>Show More
High-speed and low-drive-voltage monolithic multiple quantum-well modulator/DFB laser light source
IEEE Photonics Technology Letters
Cited by: Papers (27)
Monolithic integration of an InGaAsP/InGaAs multiple quantum well (MQW) distributed-feedback (DFB) laser with a high-speed InGaAs/InAlAs MQW intensity modulator is demonstrated. A 3-dB bandwidth. in excess of 16 GHz and low-drive-voltage operation (4.0 V) for a 20-dB on-off ratio are obtained. Good coupling efficiency between an MQW DFB laser and an MQW modulator is accomplished using hybrid cryst...Show More
High-speed InGaAlAs/InAlAs multiple quantum well electrooptic phase modulators with bandwidth in excess of 20 GHz
High-speed phase modulation (in the frequency bandwidth of 20 GHz, the highest yet reported for multiple quantum well (MQW) phase modulators) for waveguided InGaAlAs/InAlAs MQW optical modulators is reported. The modulator successfully operates at a long wavelength of 1-55 mu m with a low required voltage for phase shift (V pi =3.8 V), small intensity modulation depth below 1.5 dB, and without any...Show More
Design of InGaAs-InAlAs multiple-quantum-well (MQW) optical modulators
Design of InGaAs-InAlAs multiple-quantum-well (MQW) optical modulators is described by employing the step segment method (SSM), the three-dimensional beam propagation method (3-D BPM), and the lumped element circuit model. Optical waveguides are treated as materials with complex refractive index. Field distributions, power confinement factors ( Gamma factors), propagation losses, etc. are calculat...Show More
Chirping characteristic and frequency response of MQW optical intensity modulator
O. Mitomi;S. Nojima;I. Kotaka;K. Wakita;K. Kawano;M. Naganuma
The spectral linewidth enhancement factor and frequency responses of electro-absorption-type optical-intensity modulators, especially InGaAs/InAlAs MQW modulators, are described. A method of exactly estimating the value of the alpha factor is presented under the nonlinearity of extinction-ratio characteristics. For measuring the frequency response of modulators, the sideband strength of the modula...Show More
Observation of low-chirp modulation in InGaAs-InAlAs multiple-quantum-well optical modulators under 30 GHz
IEEE Photonics Technology Letters
Cited by: Papers (31)
Modulated light spectra were measured in long-wavelength InGaAs-InAlAs multiple-quantum-well intensity modulators under 30-GHz large-signal modulations. The linewidth broadening factor alpha is determined from the relation between the intensity modulation index and the sideband strength relative to the carrier. The minimum alpha value is estimated to be 0.70 at 1.54 mu m, which is almost the same ...Show More
High-speed InGaAlAs/InAlAs multiple quantum well optical modulators
K. Wakita;I. Kotaka;O. Mitomi;H. Asai;Y. Kawamura;M. Naganuma
High-speed modulation over 22 GHz for waveguided InGaAlAs/InAlAs multiple quantum well (MQW) optical modulators is described. A large on/off ratio of over 25 dB is demonstrated with a low-drive voltage (6 V) operating in the 1.55- mu m wavelength region. The design and characteristics of MQW p-i-n modulators are discussed. The causes of large-insertion loss and the required drive voltage bandwidth...Show More
InGaAs/InAlAs SCH-MQW lasers with superlattice optical confinement layers grown by MBE
InGaAs/InAlAs separate-confinement-heterostructure multiple-quantum-well (SCH-MQW) lasers with superlattice optical confinement layers grown by molecular beam epitaxy are discussed. Room-temperature operation with a low threshold current density of 1.7 kA/cm/sup 2/ at 1.537 mu m wavelength is obtained for these lasers.<>Show More
Dynamic frequency response for InGaAs/InAlAs multiple quantum well optical modulators
The frequency response of InGaAs/InAlAs multiple-quantum-well (MQW) optical modulators and their dependence on incident light power are described. No decrease in small-signal modulation bandwidth was observed up to ten times the initial value of 1 mW. The mechanism of the frequency-response difference between InGaAs/InAlAs MQW modulators and InGaAs/InP modulators is discussed.<>Show More
High-speed electrooptic phase modulators using InGaAs/InAlAs multiple quantum well waveguides
High-speed phase modulation of waveguided InGaAs/InAlAs multiple-quantum-well optical modulators operating at 1.55 mu m is described. The modulator requires a low voltage for pi -phase-shift (V/sub pi /=2.5 V) as well as a small intensity modulation depth of 1 dB. The measured electrical 3-dB bandwidth is 10 GHz, giving a bandwidth-to-voltage ratio of 4 GHz/V.<>Show More
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