本論文以光致螢光光譜探討光子晶體耦合L3共振腔的耦合現象。利用空間距離調變觀察到共振波長分裂量與共振腔耦合強度成正比，兩者隨著共振腔距離增加而減少；利用孔柱移動調變觀察到空氣孔柱的移動使共振腔大小的差異增大，耦合強度減弱；利用基板加熱調變觀察到隨著溫度升高，耦合共振波長紅移，但基板折射率的改變對共振腔耦合強度影響不大；利用雷射局部加熱調變觀察到兩共振腔相對折射率的改變使波長分裂量增大，共振腔耦合強度減弱，且當雷射功率大於11mW時看到了光譜譜線出現動態分岔現象，推測可能是光子晶體薄膜產生熱震盪所致。 In this thesis, we investigate the coupling behavior of photonic crystal coupled L3 cavities through micro-photoluminescence (μ-PL) spectroscopy. By spatial separation tuning, we found that the mode splitting is proportional to the cavity coupling strength, and both of them decrease with the increasing distance between the two cavities. By air-holes-shift tuning, the movement of air holes results in size detune of the two cavities and decreases the coupling strength. By substrate heating tuning, the rising temperature causes the resonant wavelength red shift, but the change of refractive index of substrate does not influence the coupling strength significantly. By laser local heating tuning, the refractive index detune of the two cavities increases the mode splitting and decreases the cavity coupling strength. While the laser power exceeds 11mW, we observe spectral bifurcation phenomenon which results from the thermal vibration on photonic crystal membrane.