• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.214-219
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• 1997

We propose a new scheme of high-resolution heterodyne interferometer that employs the two-axial mode He-Ne laser with an inter-mode beat frequency of 600-1000 MHz. An electronic RF-heterodyne circuit lowers the beat frequency down to 5 MHz, so that the phase change of the interferometer output is precisely measured with a displacement resolution of 0.1 nanometer without significant loss of dynamic bandwidth. A thermal control scheme is adopted to stabilize the cavity length with aims to suppress frequency drifts caused by the phenomena of frequency pulling and polarization anisotropy of the two-axial mode laser to a stability level of 2 parts in $10^9$. The two-axial mode HeNe laser yields a high output power of 2.0 mW, whlch allows us to perform multiple measurements of up to 10 machine axes simultaneously.

• Journal of information and communication convergence engineering
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• 제5권3호
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• pp.281-284
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• 2007

We have analyzed the short pulse generation using heterodyne techniques. The numerical model for semiconductor lasers under the heterodyne technique is based on the Lang's equation and has been extended in order to take into account the simultaneous injection of the multiple sidebands of the current-modulated laser. The unselected sidebands will affect the optical and RF-spectral characteristics even when the semiconductor laser is locked to the target sidebands.

• 한국정밀공학회지
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• 제19권4호
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• pp.195-201
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• 2002

We propose a new scheme of high-resolution heterodyne interferometer that employs the two-axial mode He-Ne laser with an inter-mode beat frequency of 600~1000 MHz. An electronic RF-heterodyne circuit lowers the beat frequency down to 5 MHz, so that the phase change of the interferometer output is precisely measured with a displacement resolution of 0.1 nanometer without significant loss of dynamic bandwidth. A thermal control scheme is adopted to stabilize the cavity length with ainus to suppress frequency drifts caused by the phenomena of frequency pulling and polarization anisotropy of the two-axial made laser to a stability level of 2 parts in $10^9$. The two-axial mode HeNe laser yields a high output power of 2.0 mW, which allows us to perform multiple measurements of up to 10 machine axes simultaneously.

• 한국광학회지
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• 제14권2호
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• pp.161-165
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• 2003

Master laser(ML)의 직접 변조로 생성된 여러 개의 side-bands 중 두 개의 target band게 두 개의 Slave laser(SL)가 각각 lock이 되도록 하는 side-band injection-locking 방법을 이용하여 광학적 60㎓의 밀리미터파 신호를 구현하였다 ML에 lock이 된 두 SL의 output들은 photo detection시 서로 beating하여 안정적이고 매우 깨끗한 60㎓ 신호를 생성하였다.